Clinical
Review for NDA 21-686
NDA: 21-686
Sponsor: AstraZeneca
Drug name: Exanta (ximelagatran) Tablets
Indications:
1)
Prevention
of venous thromboembolism (VTE; defined as deep
vein thrombosis [DVT], pulmonary embolism [PE], or both), in patients
undergoing knee replacement surgery;
2)
Long-term
secondary prevention of VTE after standard treatment for an episode of acute
VTE;
3)
Prevention
of stroke and other thromboembolic complications
associated with atrial fibrillation (AF). (see Medical Officer’s review from the Division of Cardio-Renal Drug
Products for details)
Date submitted:
Date received:
Review completed:
Reviewer: Ruyi
He, M.D.
NOTE: This is a preliminary/draft review that is not
intended to provide any recommendations on the approvability of NDA
21,686. Any opinions expressed in the
review do not necessarily reflect those of the Division/Office.
Table
of Contents............................................................................................ 2
Executive Summary......................................................................................... 5
I. Summary of Clinical Findings................................................................................ 5
A........ Brief
Overview of Clinical Program................................................................ 5
B......... Efficacy......................................................................................................... 6
C........ Safety............................................................................................................ 7
D........ Dosing......................................................................................................... 11
E......... Special
Populations...................................................................................... 11
Clinical Review.............................................................................................. 14
I. Introduction and Background.............................................................................. 14
A........ Drug
Established and Proposed Trade Name, Drug Class, Sponsor’s Proposed
Indication(s), Dose, Regimens, Age Groups................................................................................ 14
B......... State
of Armamentarium for Indication(s)..................................................... 14
C........ Important
Milestones in Product Development.............................................. 15
D........ Other
Relevant Information.......................................................................... 15
E......... Important
Issues with Pharmacologically Related Agents............................... 15
II. Clinically Relevant Findings From
Chemistry, Animal Pharmacology and Toxicology, Microbiology, Biopharmaceutics,
Statistics and/or Other Consultant Reviews 15
III. Human Pharmacokinetics and
Pharmacodynamics............................................ 16
A........ Pharmacokinetics......................................................................................... 16
B......... Pharmacodynamics...................................................................................... 17
IV. Description of Clinical Data and Sources........................................................... 18
A........ Overall
Data................................................................................................ 18
B......... Tables
Listing the Clinical Trials.................................................................... 19
C........ Postmarketing
Experience............................................................................ 19
D........ Literature
Review........................................................................................ 20
V. Clinical Review Methods..................................................................................... 20
A........ How
the Review was Conducted................................................................. 20
B......... Overview
of Materials Consulted in Review................................................. 21
C........ Overview
of Methods Used to Evaluate Data Quality and Integrity............... 21
D........ Were
Trials Conducted in Accordance with Accepted Ethical Standards...... 22
E......... Evaluation
of Financial Disclosure................................................................. 22
VI. Integrated Review of Efficacy............................................................................. 22
A........ Brief
Statement of Conclusions..................................................................... 22
B......... General
Approach to Review of the Efficacy of the Drug.............................. 23
C........ Detailed
Review of Trials by Indication......................................................... 24
D........ Efficacy
Conclusions.................................................................................... 24
VII. Integrated Review of Safety................................................................................ 27
A........ Brief
Statement of Conclusions..................................................................... 27
B......... Description
of Patient Exposure................................................................... 31
C........ Methods
and Specific Findings of Safety Review.......................................... 33
D........ Adequacy
of Safety Testing......................................................................... 84
E......... Summary
of Critical Safety Findings and Limitations of Data......................... 84
VIII. Dosing, Regimen, and Administration Issues..................................................... 85
IX. Use in Special Populations................................................................................... 85
A........ Evaluation
of Sponsor’s Gender and Age Effects Analyses and Adequacy of Investigation 85
B......... Evaluation
of Evidence for Race, or Ethnicity Effects on Safety or Efficacy.... 86
C........ Evaluation
of Pediatric Program................................................................... 86
D........ Comments
on Data Available or Needed in Other Populations...................... 87
Appendix A: List of abbreviations…………………………………………………….89
Appendix B: Individual More
Detailed Study review………………………...……...91
A.
STUDY
SH-TPO-0010 (EXULT A)……………………………………....91
B.
STUDY SH-TPO-0012
(EXULT B)………………………………….…..115
C.
Study SH-TPV-0003 (THRIVE
III)……………………………………142
Clinical
Review for NDA 21-686
EXANTA ® (ximelagatran)
is an oral anticoagulant and a prodrug of melagatran, a potent, reversible,
competitive and direct inhibitor of thrombin. Ximelagatran prevents a key step
in the coagulation cascade, the conversion of fibrinogen to fibrin.
Ximelagatran is in
development for several indications, of which the following 3 are being
submitted in this
application: prevention of VTE (defined as deep vein thrombosis [DVT],
pulmonary embolism [PE], or both), in patients undergoing knee replacement surgery;
long-term secondary prevention of VTE after standard treatment for an episode
of acute VTE; and prevention of stroke and other thromboembolic complications
associated with atrial fibrillation (AF). All 3 indications are for the adult
population only.
The studies were
designed to demonstrate that fixed doses of ximelagatran, without coagulation
monitoring or dosage
adjustment, offers superiority to placebo (VTE Secondary Prevention),
superiority to warfarin
(Knee Replacement Surgery), and non-inferiority to warfarin (Atrial
Fibrillation).
The development program
includes 82 clinical studies with ximelagatran and/or melagatran
(60 Phase I studies and
22 Phase II and III studies), in which 30,698 subjects were randomized. A total
of 17,593 randomized subjects received the oral prodrug ximelagatran, or the
active drug melagatran. In the long-term treatment populations, 6931 patients
received ximelagatran, 5024 of whom received treatment for at least 6 months
and 3509 for at least a year in
patients with atrial fibrillation (up to 2.5 years in the pivotal SPORTIF
studies and up to 4 years in the ongoing SPORTIF IV study).
Each Phase 3 study was
conducted as a multi-center, randomized, parallel-group, comparator-controlled
design. All studies were double-blind except for SH-TPA-0003 (SPORTIF III for
the indication of prevention of stroke in patients with AF; which was an
open-label in design). All studies used a central laboratory for all
protocol-specified laboratory measurements.
For the
indication of prevention of VTE in patients undergoing elective knee
replacement surgery, the sponsor conducted
three Phase 3 studies in comparison with warfarin in patients undergoing
primary, elective total knee replacement (TKR) surgery (SH-TPO-0006, EXULT A
and EXULT B). A total of 5284 patients were randomized in these three studies
(1927 to ximelagatran 36 mg bid, 2247 to warfarin, and 1110 to ximelagatran 24
mg bid).
To support the indication of prolonged
prophylaxis of VTE after a six-month anticoagulation treatment for VTE, the
sponsor provided only one 18-month study, SH-TPV-0003 (THRIVE III). A total of
1233 patients were randomized, with 914 completing the 15-month duration (475
on ximelagatran 24 mg bid and 439 on placebo) and only 193 completing the
entire 18-month study (107 on ximelagatran 24 mg bid and 86 on placebo).
For the indication of prevention of stroke and
systemic embolic events in patients with nonvalvular atrial fibrillation,
Division of Cardio-Renal drug products (HFD-110) is conducting the review for
both efficacy and safety.
Indication 1: prevention of VTE in patients undergoing
elective total knee replacement (TKR) surgery
Oral
ximelagatran 36 mg bid were superior to warfarin in reducing total VTE and/or
all- cause mortality at end of 7-12 days therapy among patients undergoing TKR
surgery in two Phase 3 studies.
In
the pooled EXULT A and EXULT B analyses, the incidence of total VTE and/or
all-cause
mortality among patients
undergoing TKR was 21.7% for patients in the ximelagatran 36 mg
group and 30.2% for
patients in the warfarin group (p<0.001). However, the benefit was mainly
due to a reduction in asymptomatic distal DVT diagnosed by venography which is
not clinically meaningful. There were no clinically or statistically significant
differences between ximelagatran and warfarin groups in reducing the frequency
of proximal
There are several major problems with using warfarin as an
active comparator in these two studies. Warfarin is not approved for this short
term indication. The comparison is unfair, because warfarin will take about 3-5
days to reach therapeutic level, while Exanta reaches therapeutic levels within
hours. Mean days of exposure were 8.1 days for ximelagatran and 6.7 days for
warfarin in these two studies. The results show that 33.1% - 35.2% of patients
receiving warfarin had an INR less than 1.8 at postoperative day 3, and 24.0 –
26.9% % of patients receiving warfarin had an INR less than 1.8 at end of treatment
(day 7 – 12). Because this study is
designed to show superiority of ximelagatran, efficacy results for ximelagatran
in these studies may still be acceptable, since warfarin may be considered to
be placebo.
In EXULT A ximelagatran
24 mg bid was not superior to warfarin in reducing total VTE and/or all-cause
mortality (27.6% warfarin vs 24.9% ximelagatran 24 mg) at end of 7-12 days
therapy.
Indication 2: long-term secondary prevention of
VTE after standard treatment for an
episode of acute VTE
Ximelagatran
significantly reduced the recurrence rate of symptomatic, objectively confirmed
VTE (the primary variable of the study) as compared to placebo over 18 months
of treatment (cumulative risk of 2.8% versus 12.6%; hazard ratio 0.16;
p<0.0001). The number of patients with a VTE event was 12 in the
ximelagatran group and 71 in the placebo group. The number of patients with a
PE event was lower in the ximelagatran group compared to the placebo group (2
and 23) respectively. The results
for the secondary variable, all-cause mortality, showed no significant
difference between the treatment groups (1.1% vs 1.4% for patients on
ximelagatran and placebo, respectively) during the 18 months.
C.1. Safety of ximelagatran in patients
undergoing a surgical procedure (use < 35 days)
A total of 1913 patients were exposed to
ximelagatran 36 mg bid, 1097 patients were exposed to ximelagatran 24 mg bid,
and 2226 patients were exposed to warfarin with a mean duration of exposure of 8
days for the ximelagatran groups.
Overall, more than 55%
of patients in each treatment group experienced at least 1 adverse event (AE).
Post-operative complications were mostly related to bleeding and were reported
at a higher frequency in the ximelagatran groups (17% at 36 mg, 23% at 24 mg)
than in the warfarin groups (15% and 20%, respectively).
There were 18 deaths (12
patients exposed to ximelagatran and 6 patients exposed to warfarin). Of the 12
fatal SAEs reported among the 3010 patients who received ximelagatran (0.4%), 2
were fatal bleeding events (both on ximelagatran 36 mg). Six were fatal events in which ‘PE could not
be excluded’. The last 4 fatal SAEs in patients who received ximelagatran were
adjudicated as ‘death not associated with VTE or bleeding’. The investigators reported the causes of
death in 1 patient on treatment as sudden death, and in the other 3 patients
after treatment as intestinal perforation, acute MI, and pneumonia. Of the 6
deaths reported among the 2226 patients who received warfarin (0.3%), 2 were
fatal events in which ‘PE could not be excluded’. The causes of death in 2
patients on treatment were arrhythmia and MI and in the other 2 after treatment
were colon carcinoma and AMI.
There were more adverse
events leading to discontinuation of study drug (DAEs) in the ximelagatran
36-mg group (2.6%) than in the warfarin group (2.0%) and in the ximelagatran
24-mg group compared to warfarin group (3.1% versus 2.1%, respectively) with
postoperative complication, the most common adverse event leading to study drug
discontinuation.
With respect to
on-treatment adjudicated events, major bleeding occurred in 0.9% of patients
treated with ximelagatran 36 mg, compared to 0.5% of patients treated with
warfarin. There were 2 fatal bleeding events (both on ximelagatran 36 mg). Major/minor bleeding occurred in 5.1% of
patients treated with ximelagatran 36 mg and 4.1% of patients treated with
warfarin.
Incidences of ALAT
elevation reported as AEs were higher in the 36-mg ximelagatran group (2.1%)
than other groups (1.3-1.5% warfarin; 1.4% ximelagatran 24-mg). There were no
hepatobiliary fatal SAEs, non-fatal SAEs or DAEs in either ximelagatran group.
During the follow-up period (4-6 weeks), 8 patients in the ximelagatran group,
and 1 in the warfarin group had their first ALAT elevation >3x ULN. However,
patients were only followed up for 4-6 weeks post operation. Drug effects on
liver toxicity beyond 4-6 weeks are unknown. It should be noted that in studies
with long-term exposure to ximelagatran elevation of hepatic enzymes was
typically seen between 2nd and 6th month after starting
ximelagatran.
In both studies Exult A
and Exult B, the proportion of patients with coronary artery disease adverse
events (MI or ischemia/angina) was significantly higher in the ximelagatran
groups than in the warfarin groups. In patients undergoing TKR surgery (Exult A
and Exult B), proportion of patients with coronary artery disease adverse
events was statistically significantly higher in the ximelagatran group
(20/2677, 0.75%) than in the warfarin group (5/1907, 0.26%) (p=0.02800). The
proportion of patients with MI was also higher in the ximelagatran group
(16/2677, 0.60%) than in the warfarin group (4/1907, 0.21%) in the TKR
population (p=0.04951). There were no appreciable differences between the
treatment groups for underlying diseases including hypertension,
hypercholesterolemia, diabetes mellitus, coronary atherosclerosis, as well as
age, gender and weight. Considering ximelagatran as an anticoagulant with
potential to treat MI, these results are worrisome.
Overall, these studies
raised some safe concerns for use of oral ximelagatran 36 mg bid for 7 to 12
days after surgery (beginning the morning after surgery) in the prevention of
VTE in patients undergoing elective knee replacement surgery. There is a
potential risk of higher coronary artery disease adverse events including acute
myocardial infarction. Potential long-term use that will cause liver toxicity
is high. Also, major bleeding events were
higher in patients treated with ximelagatran than in patients treated with
warfarin. The long-term follow up (6 months) data may also be considered
to adequately assess liver toxicity for short-term use of ximelagatran.
C.2. Safety of ximelagatran in patients
with long-term exposure (> 35 days)
A total of
6931 patients received doses from 20 to 60 mg of ximelagatran, for a median of
370 days. A total of 5024 patients were exposed to ximelagatran for at least 6
months and 3509 for at least 12 months. A total of 6216 patients were exposed
for a median of 455 days to warfarin (n=4967) and placebo (n=1249).
C.2.1. Death
There were 224 deaths during active treatment, 112 in the
ximelagatran treatment groups and 112 in the comparator groups. A further 331
patients died after stopping study drug (166 in the ximelagatran group and 165
in the comparator group). There was no differences between the treatment
groups. The most common fatal SAE was myocardial infarction.
C.2.2. Non-fatal SAE
A total of 26.3% of patients in the ximelagatran group and
27.1% of patients in the comparator group experienced a non-fatal SAE during
treatment. A further 5.5% of patients in
the ximelagatran group and 4.3% of patients in the comparator group experienced
a non-fatal SAE after stopping study drug. The most common non-fatal SAEs were
cardiovascular events. The most common non-fatal SAEs considered to be causally
related to ximelagatran were increases in hepatic transaminases.
C.2.3.
Discontinuation
The proportion of patients who discontinued study drug was
higher in the ximelagatran group (1189/6931, 17.2%) than in the comparator
group (801/6216, 12.9%). This was mostly
due to the discontinuation of study drug due to elevated hepatic transaminases.
Data from discontinuation of ximelagatran secondary to AEs indicate that
“coronary artery disorders (CAD)” were more common in the ximelagatran group
than in the comparator group (0.6% vs. 0.3%, respectively) whereas
thromboembolic events were less common DAEs in the ximelagatran group (0.4% vs.1.3%, respectively), because
of a placebo control. Other common causes of discontinuations included bleeding
events, with no difference between ximelagatran and the comparators, except for
haematuria and rectal haemorrhage/ melaena, which caused slightly more
discontinuations in the ximelagatran group than in the comparator groups.
C.2.4. Bleeding
Events
In patients with atrial fibrillation (AF), ximelagatran 36
mg was associated with fewer major bleeding events than warfarin (AF pool; 2.4%
and 3.4% for the ximelagatran and warfarin group, respectively, p=0.0288). However, there were no significant
differences for major bleeding events between the groups in each of the 2
pivotal studies (SH-TPA-0003 and STP-0005). In patients with acute VTE, ximelagatran
36 mg was associated with numerically fewer major bleeding events than
enoxaparin/warfarin. In patients undergoing extended secondary prophylaxis for
VTE, ximelagatran 24 mg was associated with a similar incidence of major
bleeding events to placebo. A total of 38 patients experienced bleeding-related
SAEs with a fatal outcome, 19 cases in each treatment group (ximelagatran or
comparator).
C.2.5. Hepatobiliary Toxicity
In patients receiving long-term administration of
ximelagatran (>35 days) an increase in ALAT >3xULN occurred in 6-13%
(average 7.6%, 531/6948) compared to 0-2% (average 1.1%, 68/6230) of patients
receiving comparator treatments. Including local laboratory data, 620 patients
showed an ALAT elevation >3xULN during the studies, 546 patients in the
ximelagatran group (cumulative incidence 7.8%) and 74 patients in the
comparator group (cumulative incidence 1.1%).
Among the 531 patients in the
ximelagatran group who presented with an ALAT >3xULN, 206 (39%) completed
the study on study drug. The remaining
325 patients (61%) discontinued study drug prematurely.
The time pattern of ALAT elevations was consistent across
patients. The increase typically
occurred between 1 and 6 months after the initiation of ximelagatran. Before and after this time frame the
incidence of ALAT increase was similar to that in the comparator groups. Of the 531 ximelagatran-treated patients who had
an ALAT elevation >3xULN recorded by the central laboratory, 502 (95%) had
their ALAT return to <2xULN (235 with study drug continued). Most cases show
a
Eighteen patients who
discontinued study drug with elevations of ALAT subsequently resumed treatment
after ALAT had returned to the normal range. Of these 18 patients, 2 again
experienced elevations of ALAT after drug was resumed.
An evaluation of potential
risk factors for increase in ALAT indicated an increased risk in the
post acute coronary
syndrome (ACS) (p=0.0009), VTE-treatment (VTE-T) populations (p=0.0003), in
female patients (p=0.0002), in patients with low BMI (<27 kg/m2)
(p<0.0001), and in patients receiving concomitant treatment with statins
(p=0.019). Asian patients were found to have a decreased risk (p=0.0038).
Although a single factor identified above may not be strong enough to eliminate
the subgroup population, consideration may be given to contraindicating
ximelagatran in patients who have 2 or more risk factors, such as, female
patients with low body weight or who are taking a statin.
ALAT >3xULN was
associated with bilirubin >2xULN (within one month following the rise in
ALAT) in 0.53% (37/6948)
of all patients who were exposed to ximelagatran >35 days as compared to
0.08% (5/6230) of patients exposed to comparators. Concomitant elevations of
ALAT >3xULN and bilirubin >2xULN were observed during the first month of
ximelagatran therapy in 6 of 37 patients. Nine ximelagatran-treated patients
(24.3%, 9/37) died with concomitant ALAT >3xULN and bilirubin >2xULN.
Among these, 3 died from heart failure; 3 died from carcinomas with hepatic
metastases; 2 (ID# 7259, and 7859) died from GI bleeding with coagulopathy (1
with biopsy documented hepatic necrosis) and 1 (ID# 5442) died from hepatitis
B. Liver failure/toxicity by ximelagatran might have caused or at least
contributed to these deaths. Only one autopsy was done in these 9 deaths and it
showed a small, friable and diffusely mottled liver suggestive of severe
diffuse hepatic necrosis.
C.2.6. Adverse Events of Coronary Artery Disease
In all study populations
except the post acute coronary syndrome, the proportion of patients with
coronary artery disease adverse events was higher in the ximelagatran groups
than in the comparator groups (7.0% and 6.7% for the AF pool, 1.3% and 0.1% for
the VTE-treatment (VTE-T) pool and 2.6% and 2.0% for the VTE-prevention (VTE-P)
pool, for the ximelagatran and comparator groups, respectively). This trend was consistent across the pools
for myocardial infarction.
The proportion of
patients with coronary artery disease adverse events was statistically
significantly higher in the ximelagatran group (32/1848, 1.7%) than in the
warfarin/placebo group (12/1859, 0.7%) in the VTE (VTE-T + VTE-P) population
(p=0.00411). The proportion of patients with MI was also significantly higher
in the ximelagatran group (13/1848, 0.7%) than in the warfarin/placebo group
(3/1859, 0.16%) in the VTE population (p=0.01183). There were no appreciable
differences between the treatment groups for underline diseases including
hypertension, diabetes mellitus, hypercholesterolemia, coronary
atherosclerosis, as well as age, gender and weight. Considering ximelagatran as
an anticoagulant with potential to treat MI, these results are worrisome.
For the indication of prevention of VTE in patients
undergoing elective knee replacement surgery, the proposed dose is oral ximelagatran 36 mg bid for up to 12 days. For
the indication of prolonged prophylaxis VTE after a six-month anticoagulation
treatment for VTE, the proposed dose is oral ximelagatran 24 mg bid.
In term of
hepatobiliary toxicity, there was not a marked dose response over the dose
range 24 mg to 60 mg ximelagatran, but there was a noticeably lower incidence
of elevation of liver transaminases at the 24 mg dose compared to the higher
doses.
For short-term use (<
35 days)
For the indication of prevention of VTE in patients
undergoing elective knee replacement surgery, the majority of the patients were female (61.5%); most were Caucasian
(95.1%); and most were greater than 64 years of age (65.6%). The mean age was
approximately 67 years, but ranged from 26 years to 91 years. Almost half the patients had a body mass
index >30 kg/m2, which is typical for TKR surgery patients but
higher than the general population.
The incidence of VTE
and/or all-cause mortality was significantly higher in female and older
patients. Results for these subgroups are summarized in the following Table:
Table 1: Incidence of total VTE and/or all-cause
mortality for selected subgroups (efficacy ITT population) – Pooled 36 mg bid

The subgroup factors that had no
significant impact on the incidence of total VTE and/or all-cause mortality
were: race, body mass index, estimated CrCL, general anaesthesia (yes/no), time
to first dose, and time to ambulation.
For
long-term use (> 35 days)
For
the indication of prolonged prophylaxis of VTE after a six-month
anticoagulation treatment for an episode of acute VTE, the majority of the
patients were male (54%), Caucasian (93%), and less than 60 years of age (52%).
The mean age was approximately 57 years, but ranged from 18 years to 90 years. Subgroup factors that had no significant
impact on the VTE events were: sex, age, race, body mass index, estimated CrCL,
initial proximal/or distal DVT (yes/no), previous VTE events (yes/no).
An evaluation of
potential risk factors for increase in ALAT indicated an increased risk in the
Post ACS (p=0.0009), and
VTE-T (p=0.0003) populations and also in female patients (p=0.0002), patients
with low BMI (<27 kg/m2) (p<0.0001) and patients receiving
concomitant treatment with statins (p=0.019); Asian patients were found to have
a decreased risk (p=0.0038). Although single factor identified above may not be
strong enough to eliminate the subgroup population, consideration may be given
to contraindicating ximelagatran in patients who have 2 or more factors, such
as, female patients with low body weight or who are taking a statin.
All three indications
are for the adult population only. AstraZeneca requests a waiver for
pediatric studies for the indications claimed in this application. It is
unlikely that a substantial number of pediatric patients will be treated with
EXANTA for the claimed indications. The estimated number of pediatric patients
diagnosed with atrial fibrillation in the US in 2002 is less than 1,500
children. The estimated total number of pediatric patients treated for VTE (of
which prevention of recurrent events, the indication claimed in this
application, is a subset of patients) in the US in 2002 is less than 3,000
children. The estimated cumulative number of pediatric patients diagnosed with
conditions for which EXANTA will be indicated is less than 5,000 children.
Thus, the number of pediatric patients likely to be treated with EXANTA for the
claimed indications is well below the number defined as a substantial number in
the Pediatric Final Rule. Therefore, I recommend that the sponsor’s requests
for waiver of the requirements to conduct pediatric studies be granted for the
indications claimed in this application.
Subjects with renal impairment
Melagatran, the active
metabolite of ximelagatran, is eliminated primarily via renal excretion. Renal function decreases with age and the
target patient population for ximelagatran is of older age (median age about 65
years). As expected, subjects with severe renal impairment had higher plasma concentrations
of melagatran. The mean (SD) half-lives of melagatran were 6.8 (2.0) h and 9.3
(3.5) h after subcutaneous injection melagatran and oral ximelagatran dosing,
respectively, in the subjects with renal impairment. These half-lives were about 3-fold higher
than for control subjects with normal renal function. Therefore, usage of
ximelagatran in patients with severe (CrCL < 30mL/min) renal impairment is
not recommended. A dosing reduction should be considered for the patients who
have moderate renal impairment (CrCL < 80mL/min).
Subjects with hepatic impairment
The absorption of
ximelagatran and the metabolic biotransformation to its active form,
melagatran, are not influenced for subjects with mild and moderate hepatic
impairment. However, patients who have abnormal liver function or history of
liver diseases have been excluded from the studies. Due to high risk of liver
toxicity, the use of ximelagatran in patients with hepatic disease and/or ALT
> 2 times the upper limit of normal at the start of therapy is
contraindicated.
EXANTA ® (ximelagatran)
is an oral anticoagulant and a prodrug of melagatran, a potent, reversible,
competitive and direct inhibitor of thrombin.
Ximelagatran is in
development for several indications, of which the following 3 are being
submitted in this
application: prevention of VTE (defined as deep vein thrombosis [DVT],
pulmonary embolism [PE], or both) in patients undergoing knee replacement
surgery; long-term secondary prevention of VTE after standard treatment for an
episode of acute VTE; and prevention of stroke and other thromboembolic
complications associated with atrial fibrillation (AF). All 3 indications are
for the adult population only.
For
the indication of prevention of VTE in patients undergoing knee replacement
surgery, the proposed dosing is EXANTA 36 mg twice-daily for a treatment period
of 7 to 12 days.
Provided hemostasis has
been established, the first dose should be given the morning after surgery, but
no sooner than 12 hours from the time of surgery. For the indication of
long-term secondary prevention of VTE, it is proposed that patients who have
received standard anticoagulant treatment for DVT or PE be treated with EXANTA
24 mg twice-daily. For the
indication in patients with atrial fibrillation, please see Medical Officer’s
review from the Division of Cardio-Renal Drug Products for details. No dosage
adjustment is necessary with EXANTA in patients with a creatinine clearance
(CrCL) >30 mL/min. Usage of
EXANTA in patients with severe renal impairment (CrCL <30 mL/min) is not
recommended. The use of EXANTA in patients with hepatic disease and/or ALT
>2 times the upper limit of normal at the start of therapy is
contraindicated.
Warfarin is approved for:
·
the prophylaxis and/or treatment of venous
thrombosis and its extension, and PE;
·
the prophylaxis and/or treatment of the
thromboembolic complications associated with atrial fibrillation and/or cardiac
valve replacement;
·
reducing the risk of death, recurrent MI, and
thromboembolic events such as stroke or systemic embolization after MI.
The “Dosage and Administration” section of warfarin labeling
refers to “longer term therapy” for indications such as VTE, in patients with
A-Fib or mechanical and bioprosthetic heart valves. It also states that the
duration of therapy in each patient should be individualized and anticoagulant
therapy should be continued until the danger of thrombosis and embolism has
passed. Thus, the indications and dosing recommendations for warfarin are
sufficiently broad to encompass extended prophylaxis of DVT.
Lovenox (enoxaparin sodium), a low molecular weight heparin,
is approved for the indication of the prophylaxis of DVT in patients undergoing
knee replacement surgery. Arixtra (fondaparinux sodium) injection, a synthetic
inhibitor of activated Factor X (Xa), is approved for the indication of the
prophylaxis of DVT in patients undergoing hip or knee replacement surgery.
A Marketing
Authorization Application (MAA) was submitted to the European Union (EU) in
June 2002 and approved
by France in December 2003 for the prevention of VTE in patients undergoing hip
or knee replacement surgery. National Marketing Authorizations for additional
14 countries in EU are issued in June 2004. UK and Ireland have been withdrawn
from the Mutual Recognition Procedure. However, approved dose in EU is 24 mg
twice a day, instead of 36 mg twice a day proposed in this submission.
EXANTA
® (ximelagatran) is the first oral direct inhibitor of thrombin. Iprivask
(desirudin for injection) is an iv inhibitor of thrombin that was approved for
the indication of the prevention of VTE in patients undergoing hip (not knee)
replacement surgery.
The prodrug ximelagatran
is a poor inhibitor of thrombin, while the active metabolite, melagatran, is a
potent, rapid and reversible direct thrombin inhibitor. Melagatran prolongs
coagulation times in all species studied and inhibits the thrombin-induced
aggregation of human, dog and rat platelets. In plasma coagulation assays such as Activated
Partial Thromboplastin Time (APTT) and Prothrombin Time (PT) there is a
variation in the response to fixed melagatran plasma concentrations between
available various test kits for each assay. Thrombin Time (TT) and Ecarin
Clotting Time (ECT) are assays that have been used in order to characterize
synthetic or recombinant direct thrombin inhibitors, such as melagatran and
hirudin.
In the Safety
Pharmacology study investigating intestinal motility in rats, the highest dose,
200 mmol/kg (95 mg/kg), of ximelagatran, inhibited intestinal motility. Oral,
but not subcutaneous, administration of melagatran inhibited gastrointestinal
motility at doses above 10 mmol/kg (4.3 mg/kg). Based on the equal exposure to
melagatran after sc and oral administration it was concluded that the effect is
elicited from the mucosal side of the gastrointestinal tract. High doses of
melagatran given iv to dogs induced vasodilatation and increased vascular
permeability, which was explained by histamine release. No liver toxicity or
cardiac toxicity were reported from pre-clinical toxicology studies.
According to the sponsor’s report, ximelagatran has
following PK/PD profiles.
After oral
administration to healthy subjects, the absorption of ximelagatran and the
bioconversion to melagatran is rapid. The bioavailability of melagatran after
oral dosing with ximelagatran to healthy subjects is about 20%, with low inter-
and intra-individual variability. Melagatran is mainly excreted unchanged in
urine with a renal clearance that corresponds to the glomerular filtration
rate. The half-life of melagatran is about 3 hours after oral dosing with
ximelagatran to young healthy subjects.
The pharmacokinetics of
melagatran, following oral administration of ximelagatran and parenteral
administration of melagatran to healthy subjects, are dose proportional, i.e.,
the exposure of melagatran increases linearly in proportion to the given dose
(15 to 60 mg). No time-dependent changes in the pharmacokinetics of melagatran
are observed during repeated oral dosing with ximelagatran to healthy subjects.
The interindividual variability in melagatran exposure is low (coefficient of
variation (CV) ~20%) and the intraindividual variability is even lower (CV
~10%).
The pharmacokinetics of
melagatran, following oral administration of ximelagatran and parenteral
administration of melagatran, are consistent across the different patient
populations studied, and in agreement with pharmacokinetic properties observed
in healthy subjects. After oral administration of ximelagatran, the half-life
of melagatran is about 4 to 5 hours in the patient populations studied, which
is longer than in young healthy subjects. This appears to a large extent to be
due to the age-related lower renal function in patients.
The interindividual
variability of melagatran exposure is higher for patients (CV ~50%) than for
healthy volunteers, which to a large extent appears to be due to the
interindividual variability in renal function. No time-dependent changes in the
pharmacokinetics of melagatran are observed for patients receiving long-term
oral treatment with ximelagatran. The intraindividual variability of melagatran
exposure is low (CV ~25%), suggesting that the pharmacokinetics of melagatran
are predictable and reproducible.
Race has no influence on
the absorption and metabolism of ximelagatran. Compared to patients with normal
renal function (CrCL >80 mL/min), the melagatran exposure was about 1.5 and
2.5 times higher for patients with mild renal impairment (CrCL 50 to 80 mL/min)
and moderate renal impairment (CrCL 30 to <50 mL/min), respectively.
After oral
administration of ximelagatran to patients with severe renal impairment (CrCL
10 to 30 mL/min), the melagatran exposure was 5 times higher than for control
subjects with normal renal function. Compared with the average for the studied
patient populations, melagatran exposure is increased about 3-fold and the half-life
is increased about 2-fold in patients with severe renal impairment. For
patients with end-stage renal disease requiring dialysis, the clearance of
melagatran is low and comparable to the non-renal clearance in healthy
subjects. Melagatran clearance is increased during dialysis, suggesting that
dialysis is effective in accelerating the elimination of melagatran. Mild to
moderate liver impairment has no influence on the absorption or metabolism of
ximelagatran. Gender, age, body weight and obesity have no influence on the
absorption and metabolism of ximelagatran. The influence of these intrinsic
factors on the elimination of melagatran appears to a large extent to be
related to differences in renal function.
The extent of absorption
and conversion of ximelagatran is not affected by food. Oral
administration of
ximelagatran with food causes a 1-hour delay of the tmax of melagatran but the
AUC and Cmax of melagatran are unaffected. The pharmacokinetics of ximelagatran
is not influenced by concomitant intake of alcohol. In vivo drug interaction studies with drugs that are substrates of
CYP3A4 (nifedipine, atorvastatin, amiodarone, diazepam), CYP2C9 (diclofenac)
and CYP2C19 (diazepam) showed no interaction and confirmed that ximelagatran
has a low potential for drug interactions mediated by cytochrome P450
metabolism. Upon co-administration of ximelagatran and erythromycin to healthy
subjects, the bioavailability of melagatran increased by approximately 80%.
Erythromycin is known to interact with many drugs, as it is metabolized by and
inhibits CYP3A4. However, this isoenzyme is not judged to be the site of the
interaction as in vitro studies with
ximelagatran and melagatran have shown that they are not substrates of CYP3A4.
Concomitant chronic treatments had no significant influence on the
pharmacokinetics of melagatran for any of drugs or drug classes evaluated in
the studied patient populations.
Statistically
significant concentration-response relationships were detected between melagatran
plasma concentrations and inhibition of thrombin generation, platelet
activation and thrombus formation. Oral
administration of ximelagatran results in a predictable and rapid onset of
action as indicated by statistically significant inhibition of thrombin
generation, platelet activation and thrombus formation measured at 2 hours
post-dosing.
Melagatran induces a
relatively small prolongation of the Capillary bleeding time (CBT) (up to 35%)
following doses of 24 to 72 mg oral ximelagatran. These prolongations were additive with
therapeutic doses of ASA
and diclofenac (up to 43% prolongation in combination) but synergistic with a
therapeutic dose of clopidogrel (98% prolongation in combination).
Oral ximelagatran
prolongs to varying degrees and with varying sensitivity conventional
coagulation-time assays such as the activated partial thromboplastin time
(APTT), activated clotting time (ACT), thrombin time (TT) and prothrombin
time/international normalized ratio (PT/INR).
The coagulation time assay prolongations occur in a concentration-dependent and
non-linear (APTT, ACT, PT/INR) or linear (TT) manner. The APTT, ACT, and PT/INR
assays are rather
insensitive and show variable responses to melagatran concentrations
whereas the TT is very
sensitive to melagatran plasma concentrations. The ecarin clotting time (ECT),
an experimental assay that is not widely available, was prolonged by melagatran
in a concentration-dependent and linear manner. Oral dosing with ximelagatran
results in a predictable and rapid onset of anticoagulation. The APTT is
prolonged within 20 minutes of dosing with oral ximelagatran and peak
prolongations are observed 2 hours postdosing. Melagatran-induced prolongation
of the APTT is largely independent of the intrinsic (age, renal impairment,
mild to moderate hepatic impairment, obesity, ethnicity, and disease) and
extrinsic (food, alcohol, ASA, diclofenac, clopidogrel, amiodarone,
atorvastatin, erythromycin, digoxin) factors studied.
The offset of action of
24 or 36 mg ximelagatran is rapid, with low but pharmacologically active
concentrations of melagatran remaining for approximately 12 to 24 hours
following the last dose.
There are no currently
available haemostatic agents that have been demonstrated to have clinical value
in reversing the anticoagulant effects of ximelagatran.
The development program
for ximelagatran has been designed to offer an oral alternative
anticoagulant to
warfarin for major indications. Ximelagatran has been evaluated in various
patient populations in
large controlled, worldwide, clinical studies.
The development program
includes 82 clinical studies with ximelagatran and/or melagatran
(60 Phase 1 studies and
22 Phase 2 and 3 studies), in which 30698 subjects were randomized. A total of
17593 randomized subjects received the oral prodrug ximelagatran, or the active
drug melagatran. In the long-term treatment populations, 6931 patients received
ximelagatran, 5024 of whom received treatment for at least 6 months and 3509
for at least a year (up to 2.5 years
in the pivotal SPORTIF studies and up to 4 years in the ongoing SPORTIF IV
study).
The design of the
clinical studies has varied between indications but some important features
are common to most of
them, as described below:
Overall design: Each
Phase 3 study was conducted as a multi-center, randomized, parallel-group,
comparator-controlled design. All studies were double-blind except for
SH-TPA-0003
(SPORTIF III; which was
open-label in design). All studies used a central laboratory for all
protocol-specified
laboratory measurements.
Control groups and
randomization: Each Phase 3 study included a control group and treatment
allocation randomized by a central randomization service (interactive voice
response system [IVRS]) to reduce bias.
Independent adjudication
of clinical endpoint events: In each pivotal study, the endpoint events
(efficacy, all-cause mortality, and bleeding events) were identified and
assessed by the investigator but the primary efficacy evaluation was based on
endpoint events confirmed by an independent expert adjudication committee who
were blinded to the treatment taken by the patient.
Independent committees:
In addition to the independent committee adjudicating the endpoint
events, each study
incorporated an Independent Drug Safety Monitoring Board (DSMB;
responsible for
reviewing safety during the conduct of the study), and an Independent Executive
Committee (EC; responsible for oversight of the conduct and reporting of the
study).

The reviewer
has searched the literatures related to ximelagatran up to July 2004 and
incorporated them into the review.
The efficacy evaluation of the indication for prevention of VTE in patients undergoing knee
replacement surgery is based on 2 clinical trials conducted by the sponsor
(EXULT A and EXULT B). The sponsor conducted 3 multi-center, double-blind,
parallel-group, Phase 3 studies in patients undergoing primary, elective TKR
surgery (SH-TPO-0006, EXULT A and EXULT B). A total of 5284 patients were
randomized in these 3 studies (1927 to ximelagatran 36 mg bid, 2247 to
warfarin, and 1110 to ximelagatran 24 mg bid). All 3 studies evaluated
ximelagatran administered postoperatively (beginning the morning after surgery)
for 7 to 12 days compared to warfarin titrated to an INR of 2.5 (INR range 1.8
to 3.0) that was initiated the evening of the day of surgery.
Ximelagatran 36 mg bid
was used in both studies EXULT A and EXULT
B and ximelagatran 24 mg bid only was used in study SH-TPO-0006. The sponsor
proposed 36 mg bid for this indication. Therefore, in this review, I mainly
examine studies EXULT A and EXULT B
for the efficacy evaluation of indication for prevention of VTE in patients undergoing knee replacement surgery.
For the indication of
prolonged prophylaxis of VTE after a six-month anticoagulation treatment, the
sponsor provided only one study, SH-TPV-0003 (THRIVE III). This was a
multi-center, double-blind, parallel-group, placebo control study. Ximelagatran
24 mg bid or placebo were given as prolonged prophylaxis after a 6-month
anticoagulation treatment for VTE. A total of 1233 patients were randomized,
with 903 completing the study on the study drug (468 on ximelagatran 24 mg bid
and 435 on placebo).
The medical officers from the Division of Cardio-Renal Drug Products
will conduct the review for the indication of prophylaxis of stroke in patients
with atrial fibrillation.
The safety evaluation
included assessment of the data from all clinical studies which were divided
into short term use (<35 days) and long-term use (> 35 days).
There is no post-marketing safety data available.
Data from 10 Phase 2 and
Phase 3 studies are presented in 4 pools based on the indication that was
investigated. These indications were AF, VTE treatment (VTE-T), VTE secondary
prevention (VTE-P) and post ACS. A fifth pool, the long-term exposure (LTE)
pool, combines data from all of these indications.
The long-term (>35
days) safety of ximelagatran has been studied in a large population of 6931
patients comprising 3838 patients with atrial fibrillation (AF), 1236 patients
for treatment (VTE-T), 612 patients for secondary prevention (VTE-P) of VTE and
1245 patients with recent acute coronary syndrome (post ACS). These 6931
patients received doses from 20 to 60 mg, for a median of 370 days,
representing an overall exposure of 6768 patient-years. A total of 5024
patients were exposed to ximelagatran for at least 6 months (>180 days) and
3509 for at least 12 months (>360 days). All the studies were controlled,
thus enabling comparison with a cohort of 6216 patients exposed for a median of
455 days mainly to the reference anticoagulant warfarin (n=4967), but also to
placebo in a smaller number of patients (n=1249).
In this
review, I have examined material in following sections: Cover letter, Labeling,
Summaries, and clinical study reports, including data listings and case report
forms (CRF).
The Division of Scientific Investigations
has been consulted to conduct inspection for the following sites:
The sponsor
has submitted informed consent with each clinical trial protocol. According to
the sponsor, the protocol and all amendments for this study were reviewed by an
Independent Ethics Committee (IEC), and monitoring and audit procedures
performed prior to, during, and upon completion of this study have verified
that this study was conducted in accordance with the ethical principles.
The sponsor
submitted a FDA Form 3454 certifying that no investigator of any of the covered
clinical studies had any financial interests to disclose.
Indication 1: prevention of VTE in patients undergoing
elective knee replacement surgery
Oral
ximelagatran 36 mg bid was superior to warfarin in reducing total VTE and/or
all- cause mortality among patients undergoing TKR surgery in 2 large Phase III
studies.
In the pooled EXULT A
and EXULT B analyses, the incidence of total VTE and/or all-cause
mortality among patients
undergoing TKR was 21.7% for patients in the ximelagatran 36 mg
group
and 30.2% for patients in the warfarin group, for an absolute risk reduction
(ARR) of 8.6% (p<0.001). The ARR of 8.6% provided an number needed to treat
(NNT, 1/ARR) of 12 (95% CI: 9 to 18).
The benefit was mainly
due to a reduction in asymptomatic distal DVT diagnosed by venography which is
not clinically meaningful. There were no clinically or statistically
significant differences between ximelagatran and warfarin in reducing the
frequency of proximal DVT, PE, and/or all-cause mortality in this population.
There are several major problems for comparison with
warfarin as an active comparator in these two studies. Warfarin is not approved
for the indication of prevention of DVT in patients undergoing elective knee
replacement surgery. The comparison is unfair, because warfarin will take about
3-5 days to reach therapeutic level, while Exanta reaches therapeutic levels
within hours. The results show that 33.1% - 35.2% of patients receiving
warfarin had an INR less than 1.8 at postoperative day 3, and 24 – 26.9% % of
patients receiving warfarin had an INR less than 1.8 at end of treatment (day 7
– 12). Because the study is designed to
show superiority of ximelagatran, efficacy results for ximelagatran in these
studies are still acceptable, considering warfarin group as placebo.
Indication 2: Prolonged prophylaxis VTE after a
six-month anticoagulation treatment for a acute episode of VTE
Ximelagatran
significantly reduced the recurrence rate of symptomatic, objectively confirmed
VTE (the primary variable of the study) as compared to placebo over 18 months
of treatment (cumulative risk of 2.8% versus 12.6%; hazard ratio 0.16;
p<0.0001). The number of patients with a VTE event was 12 in the
ximelagatran group and 71 in the placebo group. The number of patients with a
PE event was lower in the ximelagatran group compared to the placebo group (2
and 23 in ximelagatran and placebo group respectively).
The results for the
secondary variable, all-cause mortality, showed no significant difference
between the treatment groups (1.1% vs 1.4% for patients on ximelagatran and
placebo, respectively) during the 18 months.
The efficacy evaluation of indication for prevention of VTE in patients undergoing knee
replacement
surgery is based on 2 clinical trials conducted by the sponsor (EXULT A and
EXULT B).
For the indication of
prolonged prophylaxis VTE after a six-month anticoagulation treatment, the
sponsor provided only one study, SH-TPV-0003 (THRIVE III). This was a
multi-center, double-blind, parallel-group, placebo control study and this
study was reviewed in detail.
The medical officers from the Division of Cardio-renal Drug
Products will conduct the review for the indication of prophylaxis of stroke in
patients with atrial fibrillation. Therefore, for the efficacy evaluation
regarding the indication of prophylaxis of stroke in patients with atrial
fibrillation, please see Dr. Desai’s Meidcal Officer Review on this submission.
Indication 1: prevention of VTE in patients undergoing
elective knee replacement surgery
The
sponsor conducted 3 multi-center, double-blind, parallel-group, Phase 3 studies
in patients undergoing primary, elective TKR surgery (EXULT A, EXULT B and
SH-TPO-0006). A total of 5284 patients were randomized in these 3 studies (1927
to ximelagatran 36 mg bid, 2247 to well-controlled warfarin, and 1110 to
ximelagatran 24 mg bid). All 3 studies evaluated ximelagatran administered
postoperatively (beginning the morning after surgery) for 7 to 12 days compared
to warfarin titrated to an INR of 2.5 (INR range 1.8 to 3.0) that was initiated
the evening of the day of surgery.
Ximelagatran 36 mg bid was used in both
studies EXULT A and EXULT B and
ximelagatran 24 mg bid was used in study SH-TPO-0006. The sponsor proposed 36
mg bid for this indication. Therefore, in this review, I mainly examine studies
EXULT A and EXULT B. Please see
Appendix B for detailed review of the trials.
Indication
2: Prolonged prophylaxis VTE after a six-month anticoagulation treatment for
an acute episode of VTE
The sponsor provided only one study, SH-TPV-0003
(THRIVE III) to support this indication. This was a multicentre, double-blind,
parallel-group, placebo control study. Ximelagatran 24 mg bid or placebo were
given as prolonged prophylaxis after a 6-month anticoagulation treatment for
VTE. A total of 1233 patients were randomized, with 903 completing the study on
the study drug (468 on ximelagatran 24 mg bid and 435 on placebo). Please see
Appendix B for detailed review of the trial.
Indication 3: prevention of strokes and systemic
embolic event in patients with nonvalvular atrial fibrillation
Division of Cardio-Renal Drug Products (HFD-110)
was consulted to review this indication. Please see medical officer’s review
from HFD-110 for details.
Indication 1: prevention of VTE in patients undergoing
elective knee replacement surgery
Oral ximelagatran 36 mg bid was superior to
warfarin in reducing total VTE and/or all- cause mortality among patients
undergoing TKR surgery in 2 large Phase 3 studies. Table 3 summarizes primary
endpoints- incidence of total VTE
and/or all-cause mortality (efficacy ITT population) from both studies EXULT A
and EXULT B, and Pooled 36 mg bid.
Table 3: Incidence of total VTE and/or all-cause
mortality (efficacy ITT population) – EXULT A, EXULT B, and Pooled 36 mg bid

In EXULT A, the
incidence of total VTE and/or all-cause mortality among patients undergoing TKR
was 20.3% for patients in the ximelagatran 36 mg group and 27.6% for patients
in the warfarin group, for an absolute risk reduction (ARR) of 7.3% (p=0.003).
The ARR of 7.3% provided a relative risk reduction (RRR) of 26.5% and a number
needed to treat (NNT=1/ARR) of 14 (95% CI: 8 to 40).
EXULT B replicated the
superior efficacy of ximelagatran 36 mg bid versus warfarin group demonstrated
in EXULT A. In EXULT B, the incidence of total VTE and/or all-cause mortality
among patients undergoing TKR was 22.5% for patients in the ximelagatran 36-mg
group and 31.9% for patients in the warfarin group, for an ARR of 9.3%.
(p<0.001). The ARR of 9.3% provided an RRR of 29.5% and an NNT (1/ARR) of 11
(95% CI: 8 to 19).
In the pooled EXULT A
and EXULT B analyses, the incidence of total VTE and/or all-cause
mortality among patients
undergoing TKR was 21.7% for patients in the ximelagatran 36 mg
group
and 30.2% for patients in the warfarin group, for an ARR of 8.6% (p<0.001).
The ARR
of 8.6% provided an RRR
of 28.1% and an NNT (1/ARR) of 12 (95% CI: 9 to 18).
However, the benefit was
mainly due to a reduction in asymptomatic distal DVT diagnosed by venography
which is not clinically meaningful (Table 4). There were no clinically or
statistically significant differences between ximelagatran and warfarin in
reducing the frequency of proximal DVT, PE, and/or all-cause mortality in this
population.
Table 4: Objectively confirmed symptomatic and
asymptomatic VTE over the entire study (efficacy ITT population) – EXULT A and
B 36 mg bid

In EXULT A, the
incidence of proximal DVT, PE, and/or all-cause mortality among patients
undergoing TKR was 2.7% for patients randomized to ximelagatran 36 mg and 4.1%
for patients randomized to warfarin (1.4% reduction; p=0.171). In EXULT B, the
incidence of proximal DVT, PE, and/or all-cause mortality among patients
undergoing TKR was 3.9% for patients randomized to ximelagatran 36 mg and 4.1%
for patients randomized to warfarin (0.3% reduction; p=0.802).
Approximately 95% of
patients in each treatment group had unilateral surgery performed and,
therefore, the reductions in total VTE and/or all-cause mortality for the
combined surgeries approximated the reduction for patients with unilateral
surgery.
In both studies, a
higher frequency of total VTE and/or all-cause mortality was observed across
both treatment groups for female patients (relative to males), older patients
(relative to younger patients), patients enrolled at sites in Canada (relative
to those in the United States and the rest of the world).
In EXULT A ximelagatran
24 mg bid was not superior to warfarin
in reducing the rate of total VTE and/or all-cause mortality (27.6%
warfarin vs 24.9% ximelagatran 24 mg).
There are several major problems for comparison of
ximelagatran with warfarin in these two studies. Warfarin is not approved for
this short-term indication. The comparison is unfair, because warfarin will
take about 3-5 days to reach therapeutic level, while Exanta reaches
therapeutic levels within hours. The results show that 33.1% - 35.2% of
patients receiving warfarin had an INR less than 1.8 by postoperative day 3,
and 24 – 26.9% % of patients receiving warfarin had an INR less than 1.8 by end
of treatment (day 7 – 12).
Indication 2: Prolonged VTE prophylaxis after a
six-month anticoagulation treatment for an acute episode of VTE
Ximelagatran
significantly reduced the recurrence rate of symptomatic, objectively confirmed
VTE as compared to placebo over 18 months of treatment (cumulative risk of 2.8%
versus 12.6%; hazard ratio 0.16; p<0.0001). The number of patients with a
VTE event was 12 in the ximelagatran group and 71 in the placebo group. The
number of patients with a PE event was lower in the ximelagatran group compared
to the placebo group (2 and 23 in ximelagatran and placebo group respectively
(Table 5).
Table 5: The number of patients with VTE events
in ximelagatran and placebo groups

The results for the
secondary variable, all-cause mortality, showed no significant difference
between the treatment groups (1.1% vs 1.4% for patients on ximelagatran and
placebo, respectively) during the 18 months.
A1. Safety of Ximelagatran in Patients Undergoing
a Surgical Procedure (use <35 days)
A total of 1913 patients
undergoing keen surgery were exposed to ximelagatran 36 mg bid, 1097 patients
were exposed to ximelagatran 24 mg bid, and 2226 patients were exposed to
warfarin with a mean duration of exposure of 8 days for the ximelagatran
groups.
Overall, more than 55%
of patients in each treatment group experienced at least 1 adverse event (AE).
The frequency of AEs was similar between the treatment groups. Post-operative
complications were mostly related to bleeding and were reported at a higher frequency
in the ximelagatran groups (17% at 36 mg, 23% at 24 mg) than in the warfarin
groups (15% and 20%, respectively).
There were 18 deaths (12
patients exposed to ximelagatran and 6 patients exposed to warfarin). Of the 12
fatal SAEs reported among the 3010 patients who received ximelagatran (0.4%), 2
were fatal bleeding events (both on ximelagatran 36 mg). Six were fatal events in which ‘PE could not
be excluded’. The last 4 fatal SAEs in patients who received ximelagatran were
adjudicated as ‘death not associated with VTE or bleeding’. The investigators reported the causes of
death in 1 patient on treatment as sudden death, and in the other 3 patients
after treatment as intestinal perforation, acute MI, and pneumonia. Of the 6
deaths reported among the 2226 patients who received warfarin (0.3%), 2 were
fatal events in which ‘PE could not be excluded’. The causes of death in 2
patients on treatment were arrhythmia and MI and in the other 2 after treatment
were colon carcinoma and AMI. None of the on-treatment major bleeding events in
the ximelagatran 24 mg group
or warfarin group was fatal.
Adverse events leading
to discontinuation of study drug (DAEs) were higher in the ximelagatran 36 mg
group (2.6%) than in the warfarin group (2.0%) as well as in the ximelagatran
24 mg group compared to warfarin (3.1% versus 2.1%, respectively) with
postoperative complication the most common reason for a DAE.
With respect to
on-treatment adjudicated events, major bleeding occurred in 0.9% of patients
treated with ximelagatran 36 mg, compared with 0.5% of patients treated with
warfarin. Major/minor bleeding occurred in 5.1% of patients treated with
ximelagatran 36 mg and 4.1% of patients treated with warfarin. Similar results
were observed for ximelagatran 24 mg bid compared with warfarin.
Incidences of ALAT
elevation reported as AEs were higher in the 36 mg ximelagatran group (2.1%)
than other groups (1.3-1.5% warfarin; 1.4% ximelagatran 24 mg). There were no
hepatobiliary fatal SAEs, non-fatal SAEs or DAEs in either ximelagatran group.
During the follow-up period (4-6 weeks), 8 patients in the ximelagatran group,
and 1 in the warfarin group had their first ALAT elevation >3x ULN. However,
patients were followed up only for 4-6 weeks post operation. Drug effects on
liver toxicity beyond 4-6 weeks are unknown. It should be noted that elevation
of hepatic enzymes was typically seen between 2nd and 6th
month after starting ximelagatran.
In both Exult A and
Exult B, the proportion of patients with coronary artery disease adverse events
(MI or ischemia/angina) was higher in the ximelagatran groups than in the
warfarin groups. The proportion of patients with coronary artery disease
adverse events was statistically significantly higher in the ximelagatran group
(20/2677, 0.75%) than in the warfarin group (5/1907, 0.26%) in the TKR
population (Exult A and Exult B) (p=0.02800). The proportion of patients with
MI was also higher in the ximelagatran group (16/2677, 0.60%) than in the
warfarin group (4/1907, 0.21%) in the TKR population (p=0.04951). There were no
appreciable differences between the treatment groups for underlying diseases
which include hypertension, hypercholesterolemia, diabetes mellitus, coronary
atherosclerosis, as well as age, gender and weight. Considering ximelagatran as
an anticoagulant with potential to treat MI, these results are worrisome.
A2. Clinical Safety of Ximelagatran in
Patients with long-term exposure (> 35 days)
A total of
6931 patients received doses from 20 to 60 mg of ximelagatran for > 35 days,
with a median of 370 days. A total of 5024 patients were exposed to
ximelagatran for at least 6 months and 3509 for at least 12 months. A total of
6216 patients were exposed for a median of 455 days to warfarin (n=4967) and
placebo (n=1249).
A2.1 Death
There were 224 fatal cases during active treatment, 112 in
the ximelagatran treatment groups and 112 in the comparator groups. A further
331 patients died after stopping study drug (166 in the ximelagatran group and
165 in the comparator group). There was no difference between the treatment
groups. The most common fatal SAE was myocardial infarction.
A2.2 Non-fatal SAE
A total of 26.3% of patients in the ximelagatran group and
27.1% of patients in the comparator group experienced a non-fatal SAE during
treatment. A further 5.5% of patients in
the ximelagatran group and 4.3% of patients in the comparator group experienced
a non-fatal SAE after stopping study drug. The most common non-fatal SAEs were
cardiovascular events. The most common non-fatal SAEs considered to be causally
related to ximelagatran were increases in hepatic enzymes.
A2.3 Discontinuation
The proportion of patients who discontinued study drug was
higher in the ximelagatran group (1189/6931, 17.2%) than in the comparator
group (801/6216, 12.9%). This was mostly
due to the discontinuation of study drug due to elevated liver function tests.
Data from discontinuation of ximelagatran secondary to AEs indicates that
coronary artery disorders were more common in the ximelagatran group (0.6% vs.
0.3%) whereas thromboembolic events were more common DAEs in the comparators
group (1.3% vs. 0.4%), because of placebo control. Other common causes of
discontinuations included bleeding events, with no difference between
ximelagatran and the comparators, except for haematuria and rectal haemorrhage/
melaena, which caused slightly more discontinuations in the ximelagatran group
than in the comparators group.
A2.4 Bleeding Events
In patients with AF, ximelagatran 36 mg was associated with
fewer major bleeding events than warfarin (AF pool; 2.4% and 3.4% for the
ximelagatran and warfarin group, respectively, p=0.0288). However, there were no significant
differences for major bleeding events between the groups in each of 2 pivotal
studies (SH-TPA-0003 and STP-0005). In patients with acute VTE, ximelagatran 36
mg was associated with numerically fewer major bleeding events than
enoxaparin/warfarin. In patients undergoing extended secondary prophylaxis for
VTE, ximelagatran 24 mg was associated with a similar incidence of major
bleeding events to placebo. A total of 38 patients experienced bleeding-related
SAEs with a fatal outcome, 19 cases in each treatment group (ximelagatran or
comparator).
A2.5 Hepatobiliary toxicity
In patients receiving long-term administration of
ximelagatran (>35 days) an increase in ALAT >3xULN occurred in 6-13%
(average 7.6%, 531/6948) compared to 0-2% (average 1.1%, 68/6230) of patients
receiving comparator treatments. Including local laboratory data, 620 patients
showed an ALAT elevation >3xULN during the studies, 546 patients in the
ximelagatran group (cumulative incidence 7.8%) and 74 patients in the
comparator group (cumulative incidence 1.1%).
Among the 531 patients in the
ximelagatran group who presented with an ALAT >3xULN, 206 (39%) completed
the study on study drug. The remaining
325 patients (61%) discontinued study drug prematurely.
The time pattern of ALAT elevations was consistent across
patients. The increase typically
occurred between 1 and 6 months after the initiation of ximelagatran. Before and after this time frame the
incidence of ALAT increase was similar to comparators. Of the 531 ximelagatran-treated patients who had an ALAT elevation
>3xULN recorded by the central laboratory, 502 (95%) had their ALAT return
to <2xULN with treatment continued in 235 patients (46.8%). Most cases show
a peak of ALAT within the first 2 to 3 months post-randomization and a decline
back towards baseline within about 6 months post-randomization.
Eighteen patients who
discontinued study drug with elevations of ALAT subsequently resumed treatment
after ALAT had returned to the normal range. Of these 18 patients, 2 again
experienced elevations of ALAT after drug was resumed.
An evaluation of
potential risk factors for increase in ALAT indicated an increased risk in the
Post ACS (p=0.0009), and
VTE-T (p=0.0003) populations and also in female patients (p=0.0002) patients
with low BMI (<27 kg/m2) (p<0.0001) and patients receiving concomitant
treatment with statins (p=0.019); Asian patients were found to have a decreased
risk (p=0.0038). Although single factor identified above may not be strong
enough to eliminate the subgroup population, presence of 2 or more risk
factors, such as, female patients with low body weight or who are taking a
statin, should be considered a contraindication for ximelagatran.
ALAT >3xULN was
associated with bilirubin >2xULN (within one month following the rise in
ALAT) in 0.53% (37/6948)
of all patients who were exposed to ximelagatran >35 days as compared to
0.08% (5/6230) of patients exposed to comparators. Nine ximelagatran-treated
patients (24.3%, 9/37) died with concomitant ALAT >3xULN and bilirubin
>2xULN. Among these, 3 died from heart failure; 3 died from carcinomas with
hepatic metastases; 2 (ID# 7259, and 7859) died from GI bleeding with
coagulopathy (1 with biopsy documented hepatic necrosis) and 1 (ID# 5442) died
from hepatitis B. Liver failure/toxicity by ximelagatran might have caused or
at least contributed to these deaths. Only one autopsy was done in these 9
deaths and it showed a small, friable and diffusely mottled liver suggestive of
severe diffuse hepatic necrosis.
A2.6 Adverse Events of Coronary Artery Disease
In all study populations
except the post acute coronary syndromes, the proportion of patients with
coronary artery disease adverse events was higher in the ximelagatran groups
than in the comparator groups (7.0% and 6.7% for the AF pool, 1.3% and 0.1% for
the VTE-T pool and 2.6% and 2.0% for the VTE-P pool, for the ximelagatran and
comparator groups, respectively). This
trend was consistent across the pools for myocardial infarction.
The proportion of
patients with coronary artery disease adverse events was statistically
significantly higher in the ximelagatran group (32/1848, 1.7%) than in the
warfarin/placebo group (12/1859, 0.7%) in VTE (VTE-T + VTE-P) population
(p=0.00411). Proportion of patients with MI was also significantly higher in
the ximelagatran group (13/1848, 0.7%) than in the warfarin/placebo group
(3/1859, 0.16%) in VTE population (p=0.01183). There were no appreciable
differences between the treatment groups for underlying diseases. Considering
ximelagatran as an anticoagulant with potential to treat MI, these results are
worrisome.
An overview of days of
exposure to treatment for the surgical population who received study
drug for < 35 days is provided in
Table 6.

Table 6: Overview of exposure:
Warfarin-comparison Pool
In the 36-mg (EXULT)
Pool, 1913 and 1897 patients were exposed to active ximelagatran 36 mg and
warfarin, respectively. In the 24 mg Pool, 1097 patients received active
ximelagatran 24 mg and 1081 patients received warfarin. In total, the
Warfarin-comparison Pool comprised 1913 patients exposed to ximelagatran 36 mg,
1097 patients exposed to ximelagatran 24 mg, and 2226 patients exposed to
warfarin. Mean days of exposure were 8.1 days for ximelagatran 24 mg or 36 mg,
6.7 days for warfarin, which does not include the first dose of warfarin given
the evening of surgery. More patients (73%) in each of the ximelagatran 24-mg
or 36-mg groups remained on treatment from 7 to 9 days, compared to the
warfarin group (43%). This finding probably reflects warfarin treatment being
withheld due to INRs within normal range.
For non-Surgical
Populations who received study drug for > 35 days, data from 10 Phase II and Phase III studies, in
which patients received ximelagatran for up to 4 years, are presented in 4
pools based on the indication that was investigated. These indications were AF,
VTE treatment (VTE-T), VTE secondary prevention (VTE-P) and post ACS. A fifth
pool, the long-term exposure (LTE) pool, combines data from all of these
indications.
The long-term (>35
days) safety of ximelagatran has been studied in a large population of 6931
patients comprising 3838 patients with atrial fibrillation (AF),1236 patients
for treatment (VTE-T) and 612 patients for secondary prevention (VTE-P) of
venous thromboembolism (VTE) and 1245 patients with recent acute coronary syndrome
(post ACS). These 6931 patients received doses from 20 to 60 mg, for a median
of 370 days, representing an overall exposure of
6768 patient-years. A
total of 5024 patients were exposed to ximelagatran for at least 6 months
(>180 days) and 3509 for at least 12 months (>360 days). All the studies
were controlled, thus enabling comparison of a cohort of 6216 patients exposed
to ximelagatran for a median of 455 days mainly to the reference anticoagulant
warfarin (n=4967), but also to placebo in a smaller number of patients
(n=1249).
Demographic and other characteristics: the long-term exposure (LTE) pool
The treatment groups were
well-balanced regarding demographic characteristics. Nearly all (>93%) of
the patients were Caucasian and the majority (64%) were males. The majority of
the females (89%) were over 45 years of age (an arbitrary cut-off to
distinguish females of childbearing potential). Most patients (64.1%) were 65
years or over although there was a wide range of ages in the program (18 to 97
years). Demographic characteristics of all treated patients in the LTE pool are
shown in Table 7.

Table 7: Demographic description: LTE
pool
1:
The surgical population who received study drug for < 35 days
The treatment groups
were well-balanced regarding demographic characteristics. Nearly all (>94%)
of the patients were Caucasian and there were more females (62%) than males
(38%).
Approximately two-thirds
of patients were 65 years or older (66%) although there was a
wide range of ages in
the program (24 to 91 years of age). There were 18% to 20% of patients above
100 kgs and about 50% with a BMI >30 kg/m2 . A total of 16
patients had severe renal impairment (CrCL <30 mL/min) (in violation of
entry criteria). Approximately 35% of the patients had some renal impairment
(CrCL <80 mL/min).
1.1 Most common AEs –Warfarin-comparison Pool
Overall, more than 55%
of patients in each treatment group experienced at least 1 AE. The frequency of
AEs was similar in the ximelagatran 24-mg and the warfarin groups (66% and 61%,
respectively). The frequency of AEs was similar in the ximelagatran 36-mg and
the warfarin groups (58% and 56%, respectively).
The incidence of SAEs
was higher in the ximelagatran treatment groups than in the concurrent warfarin
group (3.8 vs. 3.2% for 36 mg of ximelagatran vs. warfarin and 3.2% vs. 2.7%
for 24 mg of ximelagatran vs. warfarin).
The incidence of
discontinuations was higher in the ximelagatran treatment groups than in the
concurrent warfarin group (2.6% vs. 2.0% for 36 mg of ximelagatran vs. warfarin
and 3.1% vs. 2.1% for 24 mg of ximelagatran vs. warfarin respectively).
1.2 Deaths
There were 18 fatal
cases in the Warfarin-comparison Pool (12 patients exposed to ximelagatran and
6 patients exposed to warfarin) with 4 and 3 fatalities occurring during the
treatment period,
respectively.
Of the 12 fatal SAEs
reported among the 3010 patients who received ximelagatran (0.4%), 2 were fatal
bleeding events (both on ximelagatran 36 mg).
Six were fatal events in which ‘PE could not be excluded’. The last 4
fatal SAEs in patients who received ximelagatran were adjudicated as ‘death not
associated with VTE or bleeding’. The
investigators reported the causes of death in 1 patient on treatment as sudden
death, and in the other 3 patients after treatment as intestinal perforation,
acute myocardial infarction, and pneumonia.
Of the 6 fatal SAEs
reported among the 2226 patients who received warfarin (0.3%), 2 were fatal
events in which ‘PE could not be excluded’. The last 4 fatal SAEs in
warfarin-treated patients were adjudicated as ‘death not associated with VTE or
bleeding’. The investigators reported
the causes of death in 2 patients on treatment as arrhythmia and MI and in the
other 2 after treatment as colon carcinoma and acute myocardial infarction.
Two fatal cases of GI
hemorrhage occurred during treatment in the ximelagatran 36-mg group. The
number and percentage of patients who died during or after treatment in the
Warfarin-comparison Pool is presented in Table 8.
Table 8: Number (%) of patients with fatal SAEs
during or after treatment, presented by preferred term: The Warfarin-
comparison Pool (exposed safety population)

1.3 Serious Adverse Events other than deaths –
Warfarin-comparison Pool
Within both 36-mg
(EXULT) and 24-mg pools, the frequency of non-fatal SAEs was higher in either
ximelagatran treatment group (3.7% and 3.5%) than in their respective warfarin
groups (3.1 and 2.6%) during treatment.
Including both during
study treatment and after study treatment periods, the most frequently
occurring non-fatal SAEs were postoperative complications and myocardial
infarction, which occurred more frequently in the ximelagatran groups, and
atrial fibrillation, which occurred more frequently in the warfarin group.
The number of patients
with the most commonly reported non-fatal SAEs during and after
treatment is presented
in Table 9.
Table 9 Number (%) of patients with the most
commonly reported non- fatal SAEs during and after treatment: The Warfarin-
comparison Pool (exposed safety population)

Please see the section
of 1.7: coronary artery disease adverse events for more details about the
adverse events related to myocardial infarction and coronary artery diseases.
1.4 Discontinuations due to AEs -
Warfarin-comparison Pool
Discontinuations due to
AEs (DAE) were slightly higher in the ximelagatran 36-mg group (2.6%) than
warfarin (2.0%) as well as in the ximelagatran 24-mg group comparison to
warfarin (3.1% versus 2.1%, respectively); this was driven by an excess of
bleeding-related AEs. Regardless of treatment group, the most common reason for
a DAE was postoperative complication, with a similar incidence between
treatment groups.
1.5 Bleeding events in the Warfarin-comparison Pool
Major bleeding events
were uncommon overall and higher in ximelagatran groups than warfarin groups
during the treatment period (0.9% ximelagatran 36 mg, 0.5% warfarin; 0.9%
ximelagatran 24 mg, 0.6% warfarin). In the 36-mg Pool, the difference in the
frequencies of major bleeding events between ximelagatran and warfarin was 0.4%
(95% CI, –0.1% to1.0%). Similar results were noted for the 24-mg Pool
(ximelagatran-warfarin, 0.3%; 95% CI, -0.5% to 1.0%). The proportions of
patients with on-treatment major bleeding events in the Warfarin-comparison
Pool, for both the 36-mg and 24-mg Pools, are summarized in Table 10.
Table 10 Number (%) of patients with on-
treatment adjudicated major bleeding events: Warfarin- comparison Pool (exposed
safety population)

Adjudication
criteria for major bleeding were medical or surgical intervention for the
reported
bleeding event and/or
bleeding index >2. The distribution of all major bleeding events by
adjudication criteria was similar to the distribution of on-treatment events.
In the 36-mg Pool, the
most common locations of on-treatment major bleeding events in the ximelagatran
group were wound hematoma, gastrointestinal bleeding, and wound bleeding.
Events in these locations occurred with comparable frequency in the warfarin
group. In the 24-mg Pool, wound hematoma and gastrointestinal bleeding were
more frequent in the ximelagatran group than in the warfarin group, while wound
bleeding occurred only in the warfarin group. There were no major nasal or
urinary bleeding events in any treatment group.
The frequencies of
patients with on-treatment major/minor bleeding events were higher in
ximelagatran groups than warfarin groups (5.1% ximelagatran 36 mg, 4.1%
warfarin; 5.7%
ximelagatran 24 mg, 4.7%
warfarin).
Two fatal on-treatment
major bleeding events occurred in the ximelagatran 36-mg group; both
events were coded as GI
hemorrhage. None of the on-treatment major bleeding events in the ximelagatran 24-mg group was fatal. There were no fatal on-treatment
bleeding events in the warfarin-groups.
Two critical-site
on-treatment bleeding events occurred during ximelagatran treatment (0.9%).
One patient
(SH-TPO-0012-029-10779) treated with ximelagatran 36 mg developed postoperative
confusion just after surgery. A CT scan revealed a subdural hematoma. The other
patient (SH-TPO-0010-016-2131), who was treated with ximelagatran 24 mg, was
found by CT scan to have a left frontal brain hemorrhage after 6 days of
postoperative confusion; a biopsy
revealed a malignant
glioma; the reported AE was coded as cerebral hemorrhage. No
bleeding at other
critical sites (intraspinal, intraocular, retroperitoneal, or pericardial) was
reported in the
ximelagatran groups. None of the major bleeding events reported in warfarin-treated
patients occurred at a critical site (intracranial, intraspinal, intraocular,
retroperitoneal,
or pericardial).
In the ximelagatran
groups, on-treatment major bleeding events included GI bleeding in
9 patients (5 in the
36-mg group, 4 in the 24-mg group), with 2 events in the 36-mg group
reported as fatal
bleeding SAEs as noted above. Additional on-treatment major bleeding events
included 12 wound hematomas (7 in the 36-mg group, 5 in the 24-mg group) and 5
wound-bleeding events (all in the 36-mg group). Medical or surgical
intervention for the bleeding event was required in 14 ximelagatran-treated
patients (11 in the 36-mg group, 3 in the 24-mg group). These interventions
included evacuation/aspiration of clot or hematoma, incision and drainage,
wound irrigation and debridement, closure of wound, re-operation, endoscopy,
laparotomy and gastrostomy for ulcers and evacuation of subdural hematoma.
In the warfarin-treated
groups, on-treatment major bleeding events included GI bleeding in
3 patients and
haemarthroses in 2 patients. Additional on-treatment major bleeding events
included 5 wound
hematomas and 2 wound-bleeding events. Medical or surgical intervention for the
bleeding event was required in 6 warfarin-treated patients. The interventions included
evacuation/aspiration of blood or hematoma, surgical drainage, debridement of
wound haematoma, re-operation and removal of blood from knee, and transfusion.
1.5.1 Incidence of reported bleeding events
Fewer than 8% of
patients in each treatment group had a reported bleeding event during study
treatment. Two patients in the ximelagatran 36-mg group had fatal nonsurgical
bleeding events of GI hemorrhage.
In the 36-mg Pool, the
frequency of patients with a reported bleeding event was higher in the
ximelagatran group than in the warfarin group (7% and 5%, respectively).
Overall, the proportions of patients who had at least 1 reported bleeding event
were higher in the ximelagatran treatment groups (6.7% and 7.2% respectively)
than in the warfarin groups (5.0 and 5.6% respectively), as were the
proportions of patients who had an event that led to discontinuation of study
treatment (1.1% in ximelagatran group vs. 0.5% in warfarin groups). There was
no appreciable difference among groups with respect to SAEs of bleeding.
The overall frequencies
of on-treatment reported bleeding events for the 36-mg and 24-mg Pools are
shown in Table 11.
Table 11: Number (%) of patients who had an
on-treatment reported bleeding event in any category: Warfarin-comparison Pool
(exposed safety population)

The overall incidence of
adjudicated bleeding with ximelagatran was low and considered to be clinically
acceptable.
1.5.2 Conclusions on bleeding
A numerically higher
frequency of bleeding events was observed for ximelagatran in the oral
only, post-operative
program for TKR when compared with warfarin. The overall incidence of bleeding
with ximelagatran was low and considered to be clinically acceptable.
With respect to
on-treatment adjudicated events, major bleeding occurred in 0.9% of patients
treated with ximelagatran 36 mg, compared with 0.5% of patients treated with
warfarin. Major/minor bleeding occurred in 5.1% of patients treated with
ximelagatran 36 mg and 4.1% of patients treated with warfarin. Similar results
were observed for ximelagatran 24 mg bid compared with warfarin.
Fewer than 8% of
patients in any of the ximelagatran or warfarin groups had a reported bleeding
event during study treatment, and most events were non-serious. There was no
apparent relationship between ximelagatran dose and bleeding risk, as indicated
by similar proportions of patients with bleeding events (major and major/minor)
in the ximelagatran 36-mg and 24-mg groups in Study SH-TPO-0010.
Subgroup analyses of
major/minor bleeding events in the 36-mg and 24-mg comparison groups did not
reveal a subgroup with a clinically important difference in bleeding risk from
the entire population (ie, one which might require dose adjustment). In
general, treatment differences were consistent across subgroups.
1.6 Analysis of ALAT elevations in the Surgical
population
Since ALAT is a more
specific marker of liver cell damage than ASAT, and because there was no
pattern for an increase in alkaline phosphatase (ALP) or bilirubin in
isolation, ALAT forms the basis of the analysis. A threshold of >3x ULN ALAT
was used to indicate a signal of potential clinical relevance.
1.6.1 Studies EXULT A (SH-TPO-0010) and EXULT B
(SH-TPO-0012)
Changes from baseline in
clinical chemistry parameters, including elevations in ALAT,
reflected surgical
intervention and postoperative recovery and were generally comparable in
the ximelagatran and
warfarin treatment groups. These changes generally occurred during the
immediate postoperative course of treatment and at the time of the end of
treatment with a return to near baseline levels at follow-up.
In EXULT A, there were
no differences between the ximelagatran groups and the warfarin
group for patients who
had ALAT elevation >3x ULN at the end of treatment (6/723, 36-mg;
4/706, 24-mg; 12/704
warfarin). During the follow-up period, 4 patients in the ximelagatran
36-mg group, 1 patient
in the ximelagatran 24-mg group, and 0 in the warfarin group had their
first ALAT elevation
>3x ULN. Three of the 4 patients in the ximelagatran 36-mg group had their
first ALAT elevation >30 days after receiving their last ximelagatran dose
while the fourth patient had their first ALAT elevation 28 days after receiving
their last ximelagatran dose.
In EXULT B, there were
no differences between the ximelagatran and warfarin groups for
patients who had ALAT
elevations >3x ULN at end of treatment (7/1095, ximelagatran 36-mg
group; 6/1087 warfarin
group). During the follow-up period, 4 additional patients had their
first ALAT elevation
>3x ULN: 3 in the ximelagatran 36-mg group and 1 in the warfarin
group. For all 3
ximelagatran 36 mg patients, the elevations were resolved within 30 days of elevation, including one patient
(SH-TPO-0012-510-14309) who began a LMWH on postoperative day 11 as treatment
for DVT.
Drug effects on liver
toxicity beyond 4-6 weeks are unknown. It should be noted that elevation of
hepatic enzymes was typically seen between 2nd and 6th
month after starting ximelagatran (long-term exposure data).
1.6.2 Hepatobiliary AEs in the Surgical
population Warfarin-comparison Pool
Overall frequency of AEs
in the liver and biliary system disorder was slightly higher in
the ximelagatran 36-mg
(EXULT) group compared to warfarin (6.7% vs 5.4%) and in the
ximelagatran 24-mg
group, 5.5% ximelagatran 24-mg versus 5.1% warfarin. This was due to a higher
rate of reported GGT increased (ximelagatran: 5.6% in the 36-mg group, 4.4% in
the 24-mg group, versus 4.2% in both warfarin groups).
Incidences of ALAT
(SGOT) increased reported as AEs were similar across the groups (36-mg
ximelagatran comparison: 2.1% ximelagatran 36-mg, 1.3% warfarin; 24-mg
comparison group: 1.4% ximelagatran 24-mg, 1.5% warfarin). There were no
hepatobiliary fatal SAEs, non-fatal SAEs or DAEs in either ximelagatran group.
1.6.3 Conclusions of hepatobiliary effects in the
Surgical population
There were no
differences in the on-treatment incidences of ALAT elevation between
ximelagatran and warfarin. However, during the follow-up period (4-6 weeks), 7
patients in the ximelagatran group, and 1 in the warfarin group had their first
ALAT elevation >3x ULN. Drug effects on liver toxicity beyond 4-6 weeks are
unknown. It should be noted that elevation of hepatic enzymes was typically
seen between 2nd and 6th month after starting
ximelagatran (long-term exposure data).
1.7 Coronary artery disease adverse events
Serious adverse events
on coronary artery disease including MI are summarized in table 12.
Table 12: Summary of CAD adverse events following short-term use
of ximelagatram#
|
|
Exult A |
|
Exult B## |
|
Exult A and B |
|
|||
|
Event: N (%) |
Exanta N=1526 |
Warfarin N=759 |
Exanta N=1151 |
Warfarin N=1148 |
Exanta N=2677 |
Warfarin N=1907 |
|||
|
MI |
11 (0.72) |
1 (0.13) |
5 (0.43) |
3 (0.26) |
16* (0.60) |
4* (0.21) |
|||
|
Other
CAD (Angina/ischemia) |
3 (0.2) |
0 |
1 (0.17) |
1 (0.09) |
4 (0.15) |
1 (0.05) |
|||
|
Total |
14 (0.92) |
1 (0.13) |
6 (0.7) |
4 (0.35) |
20** (0.75) |
5** (0.26) |
|||
*p=0.04951; **
p=0.02800
#Excluded 4 patients who did not
take study medications, 3 in ximelagatran group (ID: #3206, #7086 and #10944)
and 1 in warfarin group (ID: #9089) whose death was also adjudicated by the
central adjudication committee as PE.
##one case of sudden death
(#15016) in the warfarin group was included as MI and two cases of sudden
deaths in the Exanta group (ID: #14366 and 12122) were excluded from the
analysis.
Summarized
from Module 5, vol. 1 Table 54 and vol. 2 Table 11.3.5.1; vol. 3 Table 55 and
vol. 4 Table 11.3.5.1
In both Exult A and
Exult B, the proportion of patients with coronary artery disease adverse events
(MI and angina) was higher in the ximelagatran groups than in the warfarin
groups. After combining Exult A and Exult B, proportion of patients with
coronary artery disease adverse events was statistically significantly higher
in the ximelagatran group (20/2677, 0.75%) than in the warfarin group (5/1907,
0.26%) in the TKR population (p=0.02800). Proportion of patients with MI was
also higher in the ximelagatran group (16/2677, 0.60%) than in the warfarin
group (4/1907, 0.21%) in the TKR population (p=0.04951). There were no
appreciable differences between the treatment groups for underlying diseases
including hypertension, diabetes mellitus, hypercholesterolemia, coronary
atherosclerosis, as well as age, gender and weight (Table 13).
Table 13: Concomitant medical conditions in
studies EXULT A and B
___________________________________________________________
Ximelagatran Warfarin
N=2225 N=1575
n
(%) n (%)
___________________________________________________________
Hypertension
1325 (59.6) 963 (61.1)
hypercholesterolemia 339
(15.2) 243 (15.4)
Diabetes mellitus 290
(13.0) 199 (12.6)
Coronary atherosclerosis 155
(6.9) 99 (6.3)
____________________________________________________________
N=2677 N=1907
Gender Male 1015 (37.9) 715 (37.5)
Age, years Mean (SD) 67.7 (9.5) 67.5 (9.5)
Weight (kg) Mean (SD) 84.3
(18.1) 84.5 (17.7)
____________________________________________________________
All of events occurred
during the first 2 weeks, except 2 cases of MI in the ximelagatran group that
occurred at day 28 and day 39, and 1 case in the warfarin group reported at day
21. In the ximelagatran group, 14 cases occurred during the treatment period; 3
cases occurred 1-4 days after last dose of ximelagatran; 2 cases, beyond 1 week
after last dose. The relationship between last dose and events in 1 other case
is unclear. The diagnoses of MI in 1 patient in the warfarin group is unclear
(PE can not be ruled out). One case was reported at day 21. Four other cases
were reported during the treatment period.
Considering ximelagatran as an anticoagulant with potential to treat MI,
these results are worrisome.
2: The non-surgical
population who received study drug for > 35 days
2.1 Common
adverse events: long-term exposure (LTE) pool
The overall frequencies of AEs, fatal SAEs, non-fatal
SAEs and DAEs during active treatment
are presented for the LTE pool in Table 14.
Table 14:
Number (%) of patients who had an adverse event: LTE pool

The overall proportion of patients reporting adverse events
was high (85%) due to the severity of the underlying diseases in these
populations but there was no difference between the treatment groups. The
frequency of SAEs (fatal and non-fatal) was similar between the treatment
groups. The proportion of patients who discontinued study drug was higher in
the ximelagatran group (17.2%) than in the comparator group (12.9%). This was
mostly due to discontinuation of study drug due to elevation of hepatic
function tests. The
most commonly reported AEs in the LTE pool are presented in Table 15. Adverse
events reported with a frequency of at least 4.0% in any column are presented.
The events are sorted by the ximelagatran column.
Table 15: Number (%)
of patients with the most commonly reported AEs: LTE pool

2.2 Deaths
The overall mortality in the ITT population was 3.9% in the
ximelagatran group and 4.4% in
the comparator group. AEs that most frequently led to death
were myocardial infarction,
sudden death, cardiac arrest and cardiac failure, events
expected for the 2 populations at risk
of cardiovascular events, AF and post ACS.
2.2.1
Deaths: LTE pool
Death was included in the definition of the endpoints in the
studies in the LTE pool and all
cause mortality is analyzed using the ITT population.
Overall mortality was similar between ximelagatran and comparators.
Table 16: Risk of
death in the LTE pool, estimated relative risk with 95% CI (ITT population)

Because the comparator
was placebo in the VTE-P and Post ACS pools, a higher mortality
might have been expected
for the comparator group. Therefore, the overall mortality has also
been compared between
ximelagatran and the active comparator (warfarin). Overall mortality was
similar between ximelagatran (6.5%) and warfarin (7.1%).
2.2.2
Fatal SAEs in the safety population
There were 224 fatal cases during active treatment, 112 in
the ximelagatran treatment groups and 112 in the comparator groups. A further
331 patients died after stopping study drug (166 in the ximelagatran group and
165 in the comparator group).
The most common fatal SAE was myocardial infarction (MI).
During active treatment, the proportion of patients who died due to acute MI
was the same for the 2 treatment groups (0.2%). However, after stopping
treatment fatal acute MIs occurred more frequently in the ximelagatran group
(0.4%) than the comparator group (0.2%).
In the post ACS pool, there was an increased proportion of
fatal myocardial infarctions in the post-treatment period (1.1% vs 0.5%). There
were 29 fatal cases during active treatment, 15 (1.2%) in the ximelagatran
treatment groups and 14 (2.2%) in the placebo group. A further 35 patients died
after stopping study drug, 27 (2.2%) in the ximelagatran groups and 8 (1.3%) in
the placebo group. All deaths during treatment were reported in terms
associated with cardiovascular
disease, with the exception of one suicide in the placebo
group.
2.2.3
Fatal SAEs considered causally related by the investigator: LTE pool
There were no differences between treatments concerning the
number of fatal SAEs considered by the investigators to be causally related to
study drug (Table 17).
Table 17: Number (%)
of patients with fatal serious adverse event considered causally related by the
investigator: LTE pool
|
During the treatment
After treatment
ximelagatran
Comparators ximelagatran Comparators
n=6931 n=6216
n=6819 n=6104
n (%) n
(%)
n (%) n
(%) |
|
Total 14 (0.2) 10 (0.2) 5 (0.1)
8 (0.1) GI haemorrhage 1
1 Haematemesis 1
1 Hepatitis infectious
1 Myocardial infarction 1 Cardiac arrest 1 2 Cardio-respiratory arrest 1 Fibrillation ventricular 1 Cerebral haemorrhage 2 2 1 2 Cerebrovascular disorder 1 1 2 Haemorrhage intracranial 1 1 Subarachnoid haemorrhage 1 Aspiration pneumonia 1 Bronchitis aggravated
1 Hypoxia
1 Resp distress syndrome adult
1 Respiratory disorder 1 Retroperitoneal haemorrhage
1 Myeloid metaplasia
2 Pulmonary carcinoma 1 Sudden death 3 1 Sepsis 1 |
2.2.4
Comparison of deaths between pools
There was a similar mortality rate in patients taking
ximelagatran and those taking comparators in all pools. The most frequent AEs leading to death were
driven by the 2 populations at risk of cardiovascular events, AF and post ACS:
myocardial infarction, sudden death, cardiac arrest, cardiac failure. There were no obvious differences in the
rates of such fatal cardiac events between groups, except for an excess of
myocardial infarctions in patients who had discontinued ximelagatran and this
was seen in the post ACS pool. Most of
these AMIs started during treatment.
2.3 Serious adverse events other than death
There was a higher frequency of SAEs in the hepatobiliary in
the ximelagatran groups relative to comparator treatment in all pools.
A higher frequency of SAEs related to coronary artery
disease was seen in the ximelagatran groups in all pools with the exception of
the Post ACS pool.
Subjects in the safety population who experienced non-fatal
SAEs during or after active study treatment are included in the following
tables.
Table 18 Number (%) of patients with the most
commonly reported non-fatal serious adverse events: LTE pool

A total of 26.3% of patients in the ximelagatran group and
27.1% of patients in the comparator group experienced a non-fatal SAE during
treatment. A further 5.5% of patients in
the ximelagatran group and 4.3% of patients in the comparator group experienced
a non-fatal SAE after stopping study drug.
The most common non-fatal SAEs were cardiovascular events
which reflect the diseases under study. The most common non-fatal SAEs
considered to be causally related to ximelagatran were increases in hepatic
enzymes.
The profile of the non-fatal SAEs was consistent with the
pattern of all AEs in the pool. There was a higher reporting frequency of SAEs
in the hepatobiliary organ system in the ximelagatran groups compared to
warfarin or placebo in all pools.
A higher frequency of SAEs related to coronary artery
disease was seen in the ximelagatran groups in all pools with the exception of
the Post ACS pool.
2.4 Discontinuation
of Study Drug due to an Adverse Event (DAE)
The most common AEs causing discontinuation of study drug
for the LTE pool are presented in Table 19.
Table 19: Number (%) of patients with the most commonly
reported DAEs: LTE pool

The proportion of patients who discontinued study drug was
higher in the ximelagatran group (17.2%) than in the comparator group (12.9%). This was mostly due to the discontinuation of
study drug due to increased liver function tests (LFTs).
Apart from increases in hepatic enzymes, the most frequent
reasons for discontinuations were related to coronary artery disorder in the
ximelagatran group (0.6% vs. 0.3%). Thromboembolic events were more common DAEs
in the comparators group (1.3% vs. 0.4%), because of placebo control in
secondary prevention study.
Other common causes of discontinuations included bleeding
events, with no difference between ximelagatran and the comparators, except for
hematuria and rectal haemorrhage/melaena, which caused slightly more
discontinuations in the ximelagatran group than in the comparators group.
2.5 Bleeding Events
2.5.1 Major bleeding events
The risk of a major bleeding event is summarized by
treatment group in Table 20.
Table 20: Risk of a
major bleeding event per patient year

In patients with AF, ximelagatran 36 mg was associated with
statistically significantly fewer major bleeding events than warfarin (AF pool;
2.4% and 3.4% for the ximelagatran and warfarin group, respectively,
p=0.0288). However, there were no
significant differences for major bleeding events between the groups in each of
2 pivotal studies (SH-TPA-0003 and STP-0005). In patients with acute VTE,
ximelagatran 36 mg (1.1%, 14/1240) was associated with numerically fewer major
bleeding events than enoxaparin/warfarin (2.1%, 26/1249).
In patients undergoing extended secondary prophylaxis for
VTE, ximelagatran 24 mg was associated with a similar incidence of major
bleeding events to placebo (1% and 0.8%, respectively).
2.5.2 Major/minor bleeding events
The risk of a major/minor bleeding event is summarized by
treatment group in Table 21.
Table 21: Risk
of a major/minor bleeding event per patient year

In patients with AF, ximelagatran 36 mg was associated with statistically
significantly fewer major/minor bleeding events than warfarin (AF pool; 32.0% and 39.1% for the
ximelagatran and warfarin groups, respectively, p<0.0001). In patients with acute VTE, ximelagatran 36
mg was associated with numerically fewer major/minor bleeding events than
enoxaparin/warfarin (5.5% vs. 7.0%).
In patients undergoing extended secondary prophylaxis for
VTE, ximelagatran 24 mg was associated with a numerically more major/minor
bleeding events than placebo (21.9% and 18.2% for the ximelagatran and the
placebo group, respectively).
In the dose-finding study in post ACS patients, the risk of
a major/minor bleeding event with ximelagatran plus ASA increased with
increasing dose. Patients who received
ximelagatran plus ASA had statistically significantly more major/minor bleeding
events than patients who received placebo plus ASA (pooled doses; 19.8% and 11.3% for the ximelagatran plus
ASA, and the placebo plus ASA, respectively, p<0.0001).
2.5.3
Fatal bleeding events
The incidence of fatal bleeding events (adjudicated fatal
events, and bleeding-related serious
adverse events leading to death) is summarized by treatment
group in Table 22.
Table 22: Summary of
fatal bleeding events, by study

OT: on treatment
In addition to the 13 patients with bleeding-related serious
adverse events leading to death whilst on treatment in Table 20 (safety
population), a further 16 patients had bleeding-related serious adverse events
leading to death after stopping treatment.
Of these 16 patients, 7 had received ximelagatran and 9 had received
warfarin. Thus in total, 29 patients
experienced bleeding-related SAEs with a fatal outcome.
Almost all fatal bleeding events were intracranial (17
cases) or gastrointestinal (10 cases), except 1 case of pericardial and 1 case
of retroperitoneal bleeding.
Of the 29 patients who experienced bleeding-related SAEs
with a fatal outcome, 13 were not included in the “on treatment” analysis of
bleeding outcomes. Ten events were
intracerebral haemorrhages that were adjudicated as strokes by the adjudication
committee.
Patient SH-TPV-0002-701-4723 was not included in the
OT-analysis as a fatal bleed. This
patient had a “Bleeding per rectum” that started 30 days after last study drug
intake and therefore the adjudication committee classified this as "Death
not associated with VTE or bleeding".
Conversely, 7 patients in the ximelagatran group and 2 patients
in the warfarin group who had a fatal major bleed according to the adjudication
committee are not included in the 29 patients who experienced bleeding-related
SAEs with a fatal outcome. Eight
patients were not captured by the search on bleeding terms because the term
used by the investigator to describe the AE leading to death did not match the
preferred terms used to identify patients with bleeding events. The remaining
patient (SH-TPA-0003-316-2826) in the ximelagatran group died after discontinuing
study drug and is therefore not shown in the AE tables.
In summary, a total of 38 patients experienced
bleeding-related SAEs with a fatal outcome, 19 cases in each treatment group
(ximelagatran or comparator).
2.5.4 Overview of
reported bleeding-related adverse events across indication pools
An overview of the incidence of bleeding adverse events is
summarized by treatment for the individual pools in Table 23.
Table 23:
Number (%) of patients who had bleeding-related adverse events

In patients with AF, the incidence of reported bleeding
adverse events with ximelagatran 36 mg (32.6%) was less than that observed with
warfarin (40.1%). The incidence of
serious adverse events and discontinuations due to a bleeding adverse event was
low and similar in both treatment groups.
In patients with acute VTE, the incidence of reported bleeding adverse
events with ximelagatran 36 mg (18.3%) was less than that observed with
enoxaparin/warfarin (25.4%). The
incidence of serious adverse events and discontinuations due to a bleeding
adverse event was low and similar in both treatment groups.
In patients undergoing extended secondary prophylaxis for VTE, the
incidence of reported bleeding adverse events with ximelagatran 24 mg was
numerically greater than that observed with placebo. The incidence of serious adverse events and
discontinuations due to a bleeding adverse event was low and similar in both
treatment groups.
The incidence of
reported bleeding adverse events in patients receiving ximelagatran and ASA
(20.1%) was higher than that observed with placebo and ASA (11.4%). The incidence of serious adverse events and
discontinuations due to a bleeding adverse event with ximelagatran plus ASA was
low (2.7% and 4.5% for serious adverse events and discontinuations due to
adverse events, respectively), but higher than that observed with placebo and
ASA (1.1% and 0.9% for serious adverse events and discontinuations due to
adverse events, respectively).
In AF patients, the most
commonly reported bleeding related AEs for ximelagatran-treated patients were
purpura (which was the preferred term used to code unspecified hematomas,
bruises and petechiae) (11.1%), epistaxis (7.2%), haematuria (5.4%) and rectal
haemorrhage (2.9%).
In patients with an
acute VTE, the most commonly reported bleeding related AEs for
ximelagatran-treated patients were purpura (4.6%), epistaxis (3.2%), haematuria
(2.8%) and gingival bleeding (2.0%).
In patients undergoing
extended secondary prophylaxis for VTE the most commonly reported bleeding
related AEs for ximelagatran-treated patients were haematuria (6.0%), purpura
(4.7%), melaena (3.6%), and rectal haemorrhage (1.6%).
The most commonly
reported bleeding AEs in patients receiving ximelagatran and ASA were epistaxis
(4.9%), haematuria (4.9%), melaena (3.7%) and purpura (3.6%).
2.5.5 Relationship between exposure to melagatran and bleeding events
The association between
AUC and the cumulative risk of a major/minor bleeding event is summarized for
ximelagatran-treated patients in the AF pool in Table 24.
Table 24:
Association between AUC and cumulative risk of having a bleeding event
(major or minor) after one year in the study

The risk of having a
major/minor bleeding event with ximelagatran 36 mg increases with increasing
AUC values (hazard ratio 1.17, 95% CI: 1.12, 1.21)
There was no
statistically significant relationship between the risk of having a major/minor
bleeding event with ximelagatran 24 mg and increasing AUC values (hazard ratio
1.08, 95% 0.90, 1.29).
2.5.6 Subgroup analyses of bleeding events:
Within-treatment group
comparisons suggested that, for both ximelagatran and warfarin, patients >75
years old, and those with prior stroke/TIA, were at an increased risk of
major/minor bleeding. In the
ximelagatran group only, CrCL <80 mL/min, previous CAD and diabetes mellitus
were also suggested to be associated with an increased risk of major/minor
bleeding events. In the warfarin group,
the same conclusion was suggested for patients with paroxysmal AF and those who
had previously taken aspirin.
For the majority of
subgroups investigated, patients were statistically significantly less likely
to have a major/minor bleed with ximelagatran 36 mg than warfarin. Two significant treatment by risk factor
interactions were detected, for CrCL <80 mL/min (p<0.001) and diabetes
mellitus (p=0.002). In terms of the key
demographic characteristics, the following subgroups were statistically
significantly less likely to have a major bleed with ximelagatran 36 mg than
warfarin patients with a CrCL >80 mL/min, patients less than 75 years
old, patients with a BMI >25, males and females, patients with a
weight >50 kg and Caucasians.
There were no subgroups
that were statistically significantly less likely to have a major/minor bleed
with warfarin compared to ximelagatran.
2.6 Hepatobiliary effects
It should be noted that
the following patients have been excluded from the studies:
·
Patients
with known clinically significant liver disease (as judged by the investigator)
or persistent ASAT and/or ALAT > 3 x ULN (defined by central laboratory)
·
Patients
with continuous treatment with NSAID or Known drug addiction and/or alcohol
abuse
In
studies with ximelagatran (bid, fixed dose), from June 2000, liver enzymes were
monitored
at least monthly for the
first 6 months and if ALAT increased to >3xULN, were monitored
weekly; if ALAT reached
>7xULN study drug was stopped. From 2 November 2001, this
algorithm was changed.
The threshold for beginning weekly monitoring was reduced from
3xULN to 2xULN and the
threshold for discontinuation of study drug was revised from
7xULN to 5xULN (or
persistent increase >3xULN for up to 4-8 weeks). In the program,
40% of the
ximelagatran-treated patients who had an ALAT >3xULN were monitored using
the more stringent
algorithm.
2.6.1 Patients contributing to ALAT measurement
The number of randomized
patients contributing to ALAT testing is shown in Table 25.
Table 25: Number of patients randomized, and
contributing ALAT measurements over time in the long-term studies (ITT
population) - Central laboratory data only

Of the 6948 patients
randomized to ximelagatran, 6840 contributed at least one ALAT measurement and
5528 had an ALAT measurement at the 6-month visit.
2.6.2
Elevations in liver function tests (LFTs)
The distribution of patients with elevated ALAT, ASAT, ALP
and total bilirubin, according to
various multiples of ULN is shown for the LTE pool in Table
26 (Central laboratory data
only).
Table 26: Cumulative
incidence of patients with elevated ALAT, bilirubin, ASAT, G-GT and ALP (ITT
population): LTE pool - Central laboratory data only

The pooled data shows a similar pattern to that seen in the
individual studies. ALAT showed a significant increase in ximelagatran-treated
patients compared to those treated with comparators at all thresholds. ASAT
increased in conjunction with ALAT. There was no similar increase for
ximelagatran relative to comparators in total bilirubin and ALP.
ALAT is the main marker of a hepatic effect in the
ximelagatran group compared to the comparator. There is a strong correlation
with ASAT, but ALAT is generally higher and is known to be more specific to the
liver. The elevation in the other tests is not as different between groups, and
there is no correlation between ALAT and ALP or bilirubin. These features point
to a predominantly hepatocellular type of hepatic injury, as opposed to a
cholestatic type.
As ALAT is a more specific marker of liver cell damage than
ASAT, and there was no pattern
for an increase in ALP or bilirubin in isolation, ALAT was
used for monitoring and management decisions and forms the basis of the
analysis. A threshold of >3xULN ALAT is generally considered to represent a
clinically significant elevation. Lower cut-off levels are considered to be
less informative due to the commonness of slight elevations in untreated
populations. Therefore, ALAT values of >3xULN have been used to indicate a
signal of potential clinical relevance.
2.6.3 ALAT
elevation according to various thresholds
The distribution of patients with elevated ALAT
according to various multiples of the upper limit of the normal range is shown
by study for patients treated with ximelagatran in Table 27 and for patients
treated with comparator in Table 26.
These tables present central laboratory data only.
Table 27 Cumulative incidence of
ximelagatran-treated patients with elevated ALAT by study (ITT population) -
Central laboratory data only

Table 28 Cumulative incidence of
comparator-treated patients with elevated ALAT by study (ITT population) -
Central laboratory data only

There was a higher incidence of ALAT elevation in
ximelagatran –treated patients regardless of the threshold (xULN) and the
effect was consistent across all studies.
Overall, approximately twice as many
ximelagatran-treated patients experienced an ALAT elevation >ULN (30.0% vs
15.2%). There were approximately 4 times
as many ximelagatran-treated patients who experienced an increase in ALAT
>2xULN (12.1% vs 2.9%) and this difference increased to 7-fold at
>3xULN. The additional data obtained
from local laboratories did not affect the patterns seen in the Central
laboratory data.
2.6.4 Patients
with ALAT>3xULN measured at the Central laboratory
The number of patients with an increase in ALAT
>3xULN is presented for both ximelagatran and the comparators in Table
29.
Table 29 Elevations of ALAT >3xULN (ITT
population) - Central laboratory data only

In patients receiving long-term administration of
ximelagatran (>35 days) an increase in ALAT >3xULN occurred in 6-13%
(average 7.6%, 531/6948) compared to 0-2% (average 1.1%, 68/6230) of patients
receiving comparator treatments.
The overall incidence of ALAT > 3xULN in
SH-TPA-0002/4 after 2 years of treatment was 6.4% (12/187) in the ximelagatran
group and 0% (0/67) in the warfarin group.
The incidence was comparable in the other 2 studies in AF patients,
SH-TPA-0003 (6.3%) and SH-TPA-0005 (6.0%); the incidence in the warfarin group
was 0.8% in both of these studies. The
incidence in both the ximelagatran group and the warfarin group was higher in
VTE-T patients (9.6% and 2.0%,
respectively). The higher incidence in
the warfarin group may have been due to the enoxaparin given as part of the
treatment regimen in the comparator group.
In the post ACS study, SH-TPC-0001, the incidence was notably higher in
the ximelagatran 36, 48 and 60 mg dose
groups (12 to 13%) but the incidence in the 24 mg group was similar to that
seen in AF patients (6.5%).
There were a further 11 patients who had an ALAT
elevation >3xULN recorded after study closure and are therefore excluded
from the ITT analyses of these data.
These 11 patients comprised 9 patients in study SH-TPV-0002/5 (6 in the
ximelagatran group and 3 in the enoxaparin/warfarin group) and 2 patients in
study SH-TPC-0001 (1 in the ximelagatran 36 mg group and 1 in the placebo
group). Finally, Patient 012-205 in
study SH-TPA-0004 had an ALAT elevation >3xULN after 2.5 years of treatment
with ximelagatran. This patient is not
included in the analysis because only data up to 30 June 2001 (the date of the
interim CSR ) from this ongoing study have been integrated in the safety
database.
2.6.5 Time
course of ALAT elevations
As shown in the previous section, 599 patients showed
an ALAT elevation >3xULN during the studies, 531 patients in the
ximelagatran group (cumulative incidence 7.6%) and 68 patients in the
comparator group (cumulative incidence 1.1%).
Note that this is the central laboratory data only. Including local laboratory data, 620 patients
showed an ALAT elevation >3xULN during the studies, 546 patients in the
ximelagatran group (cumulative incidence 7.8%) and 74 patients in the comparator
group (cumulative incidence 1.1%).
The time pattern of ALAT elevations was
consistent. The increase typically
occurred between 1 and 6 months after the initiation of ximelagatran. Before and after this time frame the
incidence of ALAT increase was similar to comparators. The divergence occurred largely up to 6
months and thereafter the additional increment was 1.0% for ximelagatran and
0.4% for comparators. Figure 1 shows the number of patients presenting for the
first time with an increase in ALAT >3xULN during each month of treatment.
Figure 1: Number
of new patients with ALAT >3xULN by month since randomization (ITT
population): LTE pool – Central laboratory data only

The figure shows the
number of patients presenting with ALAT >3xULN for the first time and it
should be noted that there were 6948 patients in the ximelagatran group and
6230 in the comparator group. In the
first month of treatment there was no difference in the incidence of ALAT
>3xULN between ximelagatran (23 cases) and comparator-treated patients (25
cases). The difference became
significant at 2 months. Of the 531
ximelagatran-treated patients who had ALAT >3xULN, 495 (93.0%) were detected
during the first 6 months and 519 (97.7%) were detected within the first 12
months. Beyond 12 months, few new patients
presented with ALAT >3xULN.
Regardless of the
magnitude of the ALAT increase examined, the time pattern was consistent. In
the ximelagatran group, the majority of patients who experienced an elevation
in ALAT presented between 2 and 4 months. Beyond 12 months the incidence of
increased ALAT was similar to the comparators.
2.6.6 Recovery of elevated ALAT values towards normal
Among
the 531 patients in the ximelagatran group who presented with an ALAT
>3xULN, 206 (39%) completed the study on study drug. The remaining 325 patients (61%) discontinued
study drug prematurely. The
analysis of the reduction of elevated ALAT toward normal is presented in Table
30.
Table 30
Number of ximelagatran-treated patients with ALAT>3xULN, measured at
the Central laboratory by magnitude of last recorded ALAT measurement (ITT
population): LTE pool

This table includes
ximelagatran-treated patients who had an ALAT >3xULN recorded at the Central
laboratory during the studies categorized by their maximal ALAT elevation
(>3, >5 or >10xULN). For each
category, the number of patients who had a last recorded ALAT value of <1,
<2, <3 or >3xULN, is shown. The
table is further subdivided into those patients who continued on study drug and
those who stopped study drug. For
example, from the second column of the table it can be seen that 84 patients
who had a maximal ALAT elevation of >3xULN but <5xULN, had returned to an
ALAT <1xULN at their last recorded measurement, while continuing to
take study drug. From the penultimate
column in the table it can be seen that 8 patients who had a maximal ALAT
elevation of >10xULN, still had ALAT >3xULN at their last recorded
measurement, having stopped taking study drug.
Of the 531
ximelagatran-treated patients who had an ALAT elevation >3xULN recorded by
the central laboratory, 502 (95%) had their ALAT return to <2xULN by the
last measurement taken before the cut-off for this file. So far, it is not possible to identify who
the patients are that will not return to baseline. The mean number of days
taken for ALAT to return to <2xULN was similar whether the patients
continued to take ximelagatran or not (Table 31).
Table 31
Mean number of days between first ALAT elevation >3xULN (measured at
the Central laboratory) to normalization for ximelagatran-treated patients (ITT
population): LTE pool

Most cases show a peak
of ALAT within the first 2 to 3 months post-randomization and a decline back
towards baseline within about 6 months post-randomization.
The pattern of return to
baseline or ULN was similar whether the patient discontinued study drug or not,
and only sustained above ULN in a few cases.
A total of 35 patients,
30 in the ximelagatran group and 5 in the comparator group, still had ALAT
>2xULN at the last measurement (including local laboratory measurements). Of
the 30 ximelagatran-treated patients, 11 died while their ALAT was still
elevated; 3 patients had an alternative explanation for the raised LFTs
(alcohol); 2 patients were lost to follow-up and one patient had a final ALAT
measurement that according to the investigator had “decreased to a medically
insignificant level”. The remaining 13
patients continued under surveillance at the time of the cut-off for this
file.
2.6.7 Re-challenge to ximelagatran after
temporary discontinuation of study drug with ALAT elevations
Eighteen patients who
discontinued study drug with elevations of ALAT subsequently resumed treatment
after ALAT had returned to the normal range. Of these 18 patients, 2 (Patient SH-TPA-0003-017-2619
and Patient SH-TPA-0005-370-5718) again experienced elevations of ALAT after
drug was resumed.
2.6.8 Elevated ALAT by dose
Table 32 shows the
cumulative incidence of ximelagatran-treated patients with elevated ALAT by
dose in study SH-TPC-0001.
Table 32
Cumulative incidence of ximelagatran-treated patients with elevated ALAT
by dose in study SH-TPC-0001 (ITT population)

There was not a marked
dose response over the dose range 24 mg to 60 mg but there was a noticeably lower
incidence of all multiples of ULN at the 24 mg dose compared to the higher
doses.
2.6.9 Combination of ALAT and bilirubin elevation
The combination of
transaminase and bilirubin elevation has been considered to predict the
occurrence of severe injury in some patients.
The number of patients in each of the studies that contribute to the LTE
pool who had an increase in total bilirubin >2xULN within one month
following an increase in ALAT >3xULN are shown in Table 33.
Table 33
Concomitant elevations of ALAT >3xULN and bilirubin >2xULN (ITT
population) - Central laboratory data only

ALAT >3xULN was
associated with bilirubin >2xULN (within one month following the rise in
ALAT) in 0.4% (26/6948) of all patients who were exposed to ximelagatran >35
days as compared to 0.1% (4/6230) of patients exposed to comparators.
Additional ALAT and
bilirubin data were obtained from tests performed at local laboratories. These
included 11 new cases (10 ximelagatran, 1 comparator) who had an increase in bilirubin
>2xULN within one month following an increased ALAT >3xULN. One additional patient (#7859) described in
the section of Deaths in ximelagatran-treated patients with ALAT >3xULN (see
below) had bilirubin elevation >
5.6x ULN. This patient was not included in the sponsor’s analysis for
combination elevation. Therefore, at
the cut-off date for this file there were 37 such cases in the ximelagatran
group and 5 in the comparator group (0.53% vs 0.08%). The ximelagatran-treated patients who had an
increase in total bilirubin >2xULN within one month following an increase in
ALAT >3xULN are summarized in Tables below.
Table 34
List of ximelagatran-treated patients with concomitant elevations of
ALAT >3xULN and bilirubin >2xULN – Central laboratory data only


Table 35
List of ximelagatran-treated patients with concomitant ALAT >3xULN
and bilirubin >2xULN – local laboratory data only

Table 36
List of ximelagatran-treated patients with concomitant ALAT >3xULN
and bilirubin >2xULN – local laboratory data only

Concomitant elevations
of ALAT >3xULN and bilirubin
>2xULN were observed during the first month of ximelagatran therapy in 6 of
37 patients.
Two comparator-treated
patients with concomitant ALAT >3xULN and bilirubin >2xULN died and both
died from pancreatic cancer.
Nine
ximelagatran-treated patients who died are presented here more in detail
(including patient # 7859 who was missed by the sponsor for concomitant ALAT
and bilirubin elevation analysis).
·
Patient
7259, an 80 year old male, began ximelagatran 36 mg bid treatment on 11 June
2001. He experienced elevated liver transaminases with biopsy-demonstrated
hepatic necrosis and a fatal bleed due to a duodenal ulcer. The patient had a
medical history of hyperlipidemia treated in the past with simvastatin until
March 1999, AF since 1996, hydronephrosis probably related to an ectopic ureter
insertion, urinary retention, fibromyalgia treated with prednisone in the past,
coronary artery disease treated with bypass grafting in 1999, and right colon
cancer diagnosed in 1999. Concomitant medications included Lopressor
(metoprolol), digoxin, and Flomax (tamsulosin). On 30 May 2001, the patient's
baseline liver function tests were normal with ALAT 16 U/L, ASAT 22 U/L, ALP 67
U/L and total bilirubin 0.9 mg/dL . On 6 August 2001, at the Month 2 Visit, his
LFTs were mildly elevated, but less than the 3x ULN threshold that required
discontinuation of study medication . At the next scheduled visit (4 September
2001) the transaminases were found to be further elevated (ALAT 970 U/L, ASAT
698 U/L, ALP 142 U/L), leading to weekly LFT monitoring and study drug
discontinuation on 7 September 2001. Transaminases continued to increase. On 19
September 2001, ALAT and ASAT were 1502 U/L and 1355 U/L, respectively; ALP was
154 U/L; total bilirubin was 2.4 mg/dL (nearly twice the ULN) and direct
bilirubin was 0.6 mg/dL. Serologies for hepatitis A, B, and C, cytomegalovirus,
Epstein-Barr, and herpes simplex viruses did not show a recent viral infection.
Carcino-embryonic antigen and antinuclear antibodies were negative. Abdominal
ultrasound showed normal liver, normal gallbladder, normal biliary tree and 2
simple cysts in the right kidney. An abdominal and pelvic CT scan performed on
21 September 2001 showed no significant new findings compared to a prior
examination (3 August 2000). Liver transaminases peaked on 27 September 2001
and then decreased on 4 October 2001. ALP peaked at 198 U/L on 3 October 2001
and decreased to 170 U/L on 4 October 2001. Total bilirubin was 10.7 mg/dL on 3
October 2001 and then decreased to 7.9 mg/dL on 4 October 2001. Prothrombin
time (13.6 sec) and INR (1.2), which were close to normal on hospital admission
(20 September 2001) started to increase on 1 October 2001, reaching16.3 sec and
1.7 respectively. Conversely, albumin decreased to 2.9 g/dL on 2 October 2001.
This laboratory profile suggested impairment of his synthetic liver function. A
liver biopsy performed on (27 September 2001) demonstrated "severe active
hepatitis with hepatocyte necrosis, areas of collapse and marked bile ductular
proliferation consistent with acute submassive necrosis." The hepatologist
considered the most likely explanation was medication-induced hepatitis. INR
remained elevated (1.8 on 8 October 2001) and serum albumin low (2.5 g/dL on 8
October 2001). platelet count was 65,000/mm3 (29 October 2001).
Profound fatigue continued with no evidence of encephalopathy. However, he had
developed ascites, significant lower extremity edema and oliguria. On the
morning of 3 November 2001, the patient's wife found him unresponsive at home.
Resuscitation failed and the patient was pronounced dead. The cause of death
was upper GI bleed due to duodenal ulcer. An autopsy confirmed the presence of
atherosclerotic disease, ischemic heart disease with triple CABG and atrial
septal defect repair; adenocarcinoma of the colon resected with no evidence of
recurrence or metastatic disease, and left hydronephrosis with no evidence of
mechanical obstruction. The significant findings were: A large duodenal ulcer
(2.5 cm) with erosion into pancreas and peripancreatic soft tissue and
hemorrhagic contents through most of the small intestine with intact bowel. A
small, friable and diffusely mottled liver suggestive of severe diffuse hepatic
necrosis. Microscopically, there was extensive liver necrosis with hepatocyte
dropout and bile duct proliferation, similar to that seen in the previous
biopsy. A significant amount of hepatic parenchyma remained. Tissue
architecture showed early resolution of the inflammation compared to the
previous biopsy. There was serous ascites in the abdomen. The spleen was not
enlarged. Moderate reduction of megakaryocytes in bone marrow. The cause of
death was an acute gastrointestinal bleed from a duodenal ulcer, with a
coagulopathic state from hepatic injury contributing to death. Both decreased
clotting factors and platelet reduction cause the coagulopathy, the latter
related to a decreased number of megakaryocytes in the bone marrow. The autopsy
report speculated that prednisone therapy may have caused the duodenal ulcer
and decreased synthesis of thrombopoietin by the liver could have played a role
in the thrombocytopenia. The investigator assessed the event of liver failure
as being related and the event of fatal bleed due to duodenal ulcer as not
related to the study medication.
·
Patient 5442
was a 73 year old male Caucasian. Relevant medical history included diabetes
mellitus, systemic lupus erythematosus, hypertension, heart disease, gastric
ulcer, COPD and cardiac arrhythmia. The reason for entering the study was DVT.
The patient received 36 mg Ximelagatran b.i.d. Transaminases were slightly
increased (ASAT 60 U/l; ALAT 60 U/l; AP 210 U/l), nine days after start of
study medication, but this was thought to be due to the known lupus
erythematosus which was otherwise not active (titer of antinuclear antibodies
> 1:80, i.e. normal). Eighteen days after commencing study medication, the
patient experienced hepatitis type B and was hospitalized. Hepatitis serology
had been done six days before admission because of rising transaminases and
showed HBs antigen, HBc antibody and HBe antigen 2 positive, while HBs
antibodies, hepatitis C virus antibodies, HBe antibodies, HAV-Ak-IgM and
HBc-Ak-IgM were all negative. From this constellation with absence of
antibodies an acute hepatitis B was diagnosed. With regard to the normal
incubation time, infection had probably occurred before inclusion into the
study, but a plausible source of infection could not be detected. Transaminases
continued to rise. Four days after hospitalization, ASAT was 354 U/l, ALAT 367
U/l, AP 292 U/l and G-GT 54 U/l. LDH had increased to 360 U/l and bilirubin was
1.8 mg/dl. Two days later study medication was withdrawn. The patient's general
condition was good, without signs of hepatic encephalopathy or failure. Two
days after withdrawal of study medication, ASAT was 593 U/l, ALAT 518 U/l and
bilirubin 4 mg/dl. The next day the patient was transferred to an infection
treatment unit. The patient began to develop icterus and bilirubin tests taken
ten days, 15 days and 19 days after onset, showed a rapid increase to 8 mg/dl,
17.2 mg/dl and 26.8 mg/dl, respectively. Transaminases meanwhile decreased
slightly. Eleven days after onset of the event, the patient complained of
nausea and pain in his right flank. Five days later, a gastroscopy performed
showed multiple gastric ulcers covered with fibrin, but no signs of acute
bleeding. Quick value, which had been around 40% before, dropped to 29 % with
an international normalized ratio of 2.3. ASAT value was 287 U/l and ALAT was
189 U/l approximately three weeks after onset. Therapy consisted of low
molecular heparin, oral iron substitution, pantoprazole, metoclopramide,
lactulose, prednisolone, amino acid infusions and amoxicilline + clavulanic
acid. The patient's general condition deteriorated. Abdominal computerized
tomography performed 18 days after onset, showed beginning formation of
ascites. On that day the patient complained of vertigo and nausea and felt very
tired. The next day repeated enuresis was reported. Agitation, signs of hepatic
encephalopathy and tarry stools appeared three weeks after onset. During the
next two days the patient deteriorated dramatically. All therapy was stopped
because of poor prognosis. The patient became comatose and died from hepatic
failure two days later. Autopsy was not performed. All attending doctors agreed
that the cause of death was fulminant hepatitis B, but it seemed debatable
whether this was an acute condition or an exacerbation of a chronic disease
that had already been present in 2001, but had been masked by the
immunosuppressive therapy for lupus erythematosus. Azathioprine induced
hepatotoxicity is another aggravating factor under discussion. The investigator
considered there was a reasonable possibility that the event may have been
caused by study medication.
·
Patient 3963
was a 45 year old Caucasian. Relevant medical history included constant atrial
fibrillation, left heart failure, congestive cardiomyopathy, chronic
bronchitis, paroxysmal ventricular tachycardia and an automatic implantable
cardioverter/defibrillator. Pre-study stroke prophylaxis consisted of warfarin.
As study treatment the patient was allocated to receive ximelagatran 36 mg
b.i.d. Approximately 28 weeks after commencing study medication the patient was
hospitalized with dyspepsia, nausea, vomiting, increased weight and girth. In
addition the pacemaker had been activated three times for the last few days
because of ventricular tachycardia. The condition was consistent with
deterioration of congestive heart failure with increased right heart failure,
peripheral edema and possible liver enlargement. Blood samples including liver
enzymes were taken. An ultrasound of the liver showed severe intra-abdominal
obesity and fatty liver. The slightly increased liver enzymes were assessed due
to hypoperfusion and liver stasis. The patient's treatment with diuretics and
antiarrhythmics was adjusted after which the condition stabilized. The day
before the planned discharge, the condition aggravated acutely with cardiogenic
shock. The patient was transferred to another hospital where in spite of
maximum inotropic support, the patient died. The patient died approximately
nine days after the onset of the event. Cause of death was cardiac failure and
shock. An autopsy has not been performed. The investigator considered there was
no reasonable possibility that the events may have been caused by study
medication. Additional safety surveillance resulted in the following
information: Approximately 6 months from start of study drug (day 190),
elevated LFTs were noted by the central laboratory: ALT 4.81 x ULN, AST 4.33 x
ULN, ALP 1.98 x ULN and Bil 2.77 x ULN. Repeat sampling on day 203 showed ALT
1.31 x ULN, AST 1.17 x ULN, ALP 1.36 x ULN, and Bil 1.77 x ULN. At this time
point the patient was re-hospitalized with deterioration of congestive heart
failure, as described above.
·
Patient 0430
was a 90 year old Caucasian. Relevant medical history included hypertension,
myocardial infarction, diabetes, lumbar pain, insomnia and bronchopneumopathy.
The reason for entering the study was an acute coronary syndrome with a peak
Troponin I value of 0.44 (ULN=0.04). The patient received ximelagatran 24 mg
b.i.d. and ASA 160 mg o.d. After four weeks on study drug the patient developed
right cardiac failure which was considered non-serious. After 17 days the event
was considered medically important and the patient was hospitalized. He
presented with bilateral lower leg edema and jugular turgescence. The patient
was hospitalized for worsening of right cardiac failure after 16 weeks on study
drug. He presented with edema. Study drug was withdrawn (total study drug
treatment was 18 weeks) and the patient died from right cardiac failure 3 days
after stop of study drug. No autopsy was performed. The investigator considered
that there was no reasonable possibility that the events may have been caused
by study medication or by other medication. Additional safety surveillance
resulted in the following information: Four and a half months from start of
study drug (day 132) elevated LFTs were noted by the central laboratory: ALT
4.42 x ULN, AST 6.35 x ULN, ALP 4.30 x ULN, and Bil 2.23 x ULN. ALT had been
slightly increased at start of study drug (1.33 x ULN), but was normal from day
8 until day 132. ALP was elevated throughout the study with a peak at the last
sampling on day 132. Bil was slightly elevated from day 84. The patient
experienced a minor conjunctival bleeding 11 days prior to the ALT elevation
and muscular pain 4 days prior to the ALT elevation. As described above, the
patient also had hematuria followed by worsening of right cardiac failure with
fatal outcome at the time of the ALT elevation.
·
Patient 2893
was a 66 year old Caucasian. Medical history included paroxysmal atrial
fibrillation, angina pectoris, myocardial infarction, chronic obstructive
airways disease, cholelithiasis and hypercholesterolaemia. Pre-study stroke
prophylaxis consisted of warfarin. As study treatment the patient was allocated
to receive ximelagatran 36 mg b.i.d. Approximately 40 weeks after commencing
study medication, the patient experienced abdominal pain and nausea. The
patient was hospitalized and hepatic colic was diagnosed. After one week in
hospital he also experienced severe heart failure. This event lasted only one
day. The patient remained in hospital. One week after the episode with severe
heart failure the patient had symptoms of ventricular tachycardia. He was
treated with DC shock and xylocaine. He was discharged from hospital after five
weeks, and was recovered from all events at that time. Study drug continued
unchanged. Approximately one year and seven weeks after start of study drug the
patient suffered from eruption of erysipeloid. He was hospitalized one week
later and treated with ciprofloxacin. During the hospitalization stay,
approximately one month after he was admitted the patient suffered from
abdominal pain due to cholelithiasis. The clinical condition deteriorated and
he died the next day. Cause of death was cardiac arrest. The investigator
suggested that the abdominal pain surcharged the heart and thereby caused the
cardiac insufficiency. There was no action taken regarding study drug prior to
the death. The investigator considered there was no reasonable possibility that
the events may have been caused by study medication. Additional safety
surveillance resulted in the following information: Local ALT peak was 18.4 x
ULN at day 287, but ALT never exceeded 3 x ULN in central labs.
·
Patient 1793
was a 69 year old Caucasian. Relevant medical history included constant atrial
fibrillation and unspecified essential hypertension. Pre-study stroke
prophylaxis consisted of warfarin. As study treatment the patient was allocated
to receive ximelagatran 36 mg b.i.d. Approximately 34 weeks after commencing
study medication, the patient experienced dyspepsia, icterus and weight loss.
The patient was hospitalized. Study medication was withdrawn due to the event
icterus. Metastases in liver were discovered. During the hospital stay
approximately 12 days later malignant neoplasm was discovered in the stomach.
Computed tomography, sonogram and laparotomy were performed. The patient was
given symptomatic treatment. Nine days after the operation the patient suddenly
died. An autopsy was performed which confirmed the cause of death as pulmonary
embolism. The investigator considered there was no reasonable possibility that
the events may have been caused by study medication. Additional safety
surveillance revealed the following information: Approximately eight months
from start of study drug (day 237) elevated LFTs were noted by the central
laboratory: ALT 3.56 x ULN, AST 2.51 x ULN, ALP 3.54 x ULN, and Bil 5.00 x ULN.
No further central labs were obtained for reasons described above.
·
Patient 2065
was a 51 year old Caucasian. Relevant medical history included sleep apnoea.
The reason for entering the study was an acute coronary syndrome with a peak
CKMB value of 331 (ULN=3). The patient received ximelagatran 60 mg b.i.d. and
ASA 160 mg o.d. After three weeks and five days on study drug treatment the
patient had icterus. A liver ultrasound was performed showing a 4 times 4 cm
large tumor in the pancreatic gland. Bilirubin was 141 (normal range 4-21), ALP
was 10.2 (normal range 0.8-4.6) and ALAT was 11.2 (normal range < 0.80).
Study drug was withdrawn. The patient was discharged after two weeks and six
days. Six weeks after stop of study drug the patient had visual field loss. A
CT-scan of the brain was done. Treatment with heparin fraction was given.
According to available information the event was still present when the patient
died. Two weeks and six days later the patient was again hospitalized due to
worsening symptoms of his pancreatic tumor with liver metastasis. Ultrasound
showed ascites, which was evacuated. No chemotherapy was given during this
hospitalization. He was discharged after one week and four days. The patient
died at home three days later because of his cancer. The investigator
considered that there was no reasonable possibility that the events had been
caused by the study medication. Additional safety surveillance resulted in the
following information: Expressed as multiples of ULN, ALT peak value was 11.81
x ULN at day 34, which was 8 days after study drug had been stopped. At day 40
ALT was 4.79 x ULN, AST 2.02 x ULN, ALP 2.35 x ULN, and Bil 12.45 x ULN. No
further central labs were obtained before death.
·
Patient 4035
was a 76 year old Caucasian. Relevant medical history included previous VTE
event, hypertension, parkinsonism, pyeloglomerulonephritis and coronary
disease. The reason for entering the study was DVT. The patient received
ximelagatran 36 mg b.i.d. Fifteen weeks after start of study drug the patient
was hospitalized due to melaena, decreased haemoglobin and anaemia. HB was 8.6.
Bleeding from the digestive tract was suspected. Study drug was permanently
stopped. Blood transfusion (two units of blood) was given. Gastroscopy was
normal. The patient recovered from the bleeding and was discharged from
hospital one week after start of event. Hb was now 12.0 (normal for this
patient). Two weeks after discharge from hospital colonoscopy and
ultrasonography were done that revealed adenocarcinoma of colon. Four weeks
after stop of study drug the patient was hospitalized for operation of colon
adenocarcinoma and liver metastases in the right liver lobe. Resection of
sigmoideum and right liver lobe were done. After six days X-ray of abdomen
showed fluid levels. An abscess of the anastomosis was diagnosed and he was
re-operated. Four days later a multiorgan failure developed diagnosed with
abdominal ultrasound and x-ray. The patient was treated with antibiotics,
fluid, enoxaparin, blood, plasma and digoxin. He died the same day and the
probable cause of death was the multiorgan failure. The investigator considered
there was a reasonable possibility that the event bleeding from digestive tract
may have been caused by study medication, but that there was no reasonable
possibility that the events adenocarcinoma, liver metastases, abscess of
anastomosis and multiorganic failure may have been caused by study medication.
·
Patient 7859
(not included in the sponsor’s concomitant ALAT and bilirubin elevation
analysis) was a 77 year old Caucasian and initiated on ximelagatran 36 mg bid
treatment on 13 August 2001. Past medical history included a cholecystectomy,
duodenal ulcer, sick sinus syndrome, pacemaker insertion, hypertension, carotid
stenosis, abdominal aortic aneurysm repair (13 April 2001), and coronary artery
disease. On 15 October 2001 (day 63), safety laboratory results demonstrated
elevated liver transaminases: ALAT 216 U/L, ASAT 154 U/L; ALP was 156 U/L and
total bilirubin 1.3 (baseline 1.1) mg/dL. He took his last dose of study
medication in the evening on day 80. The next day (on 2 November 2001), the
patient awoke with stomach pain and light-headedness. Bowel movements produced
bloody stools. He was admitted to hospital that same morning. At admission, he
had pallor, blood pressure 76/45 mm Hg, and heart rate 103/min. Laboratory
tests showed hemoglobin of 7 g/dL, hematocrit 20%, prothrombin time 37 sec, INR
3.4, aPTT 69 sec, albumin 2 g/dL, ASAT 629 U/L, ALAT 569 U/L, ALP 173 U/L and
plasma melagatran was 0.25 mM (therapeutic range). During hospitalization, he
received vitamin K, packed red blood cells (19 units), fresh frozen plasma (15
units), cryoprecipitate (30 units) and fluids. On 03 Nov laboratory tests
showed hemoglobin of 9.6 g/L, hematocrit of 27.3%, prothrombin time 14.5 secs,
aPTT 53 secs and INR 1.1. Liver enzymes also decreased: ALAT 134 U/L, ASAT 236
U/L and ALP 49U/L, but bilirubin was 6.2 (5.6x ULN). The patient underwent a
gastroscopy that revealed a Bilroth II anastomosis. There was bleeding in the
pre-anastomotic area and epinephrine was injected to attempt to decrease the
bleeding. The same day (3 November 2001) he presented with signs of respiratory
failure. Echocardiogram showed 55% left ventricular function and no major
cardiac abnormalities. However, heart rate was 130 to 140/min. Vasopressors
were necessary to sustain blood pressure and diltiazem was given to decrease
the heart rate. Synchronized cardioversion failed 4 times to establish sinus
rhythm. Shock persisted despite resuscitation with fluids, 2 units of packed RBC,
10 units of fresh frozen plasma and 1 unit of platelets. Profound coagulopathy
occurred. A consulting surgeon deemed operation futile. Support was
subsequently withdrawn and the patient died on 3 November 2001. No autopsy was
conducted but the cause of death was considered to be hemorrhage. The
investigator assessed the event as possibly related to the study medications
and concluded that the liver problems contributed to the bleeding.
2.6.10 Deaths in
ximelagatran-treated patients with ALAT >3xULN
The number of deaths in
ximelagatran-treated patients having maximum ALAT >3xULN is 19 (3.6%,
19/531) and in patients having maximum ALAT <3xULN is 251 (251/6417,
3.9%) for central laboratory ITT population.
There was no apparent difference in the incidence of death between
ximelagatran-treated patients who experienced an increase in ALAT >3xULN
(3.6%) and those who did not (3.9%).
In addition to the 19
patients (19/531, 3.6%) who had ALAT >3xULN measured at the Central
laboratory subsequently died, an additional patient died after study closure
and is therefore not counted in the ITT analysis and a further 3 patients who
had ALAT >3xULN measured at a local laboratory subsequently died. Therefore, a total of 23 patients who had
ALAT >3xULN subsequently died. The one individual who had an hepatic SAE
leading to death was Patient SH-TPV-0002-265-5442 (see details above). ALAT was elevated 12 days after starting
study medication and he died 6 days thereafter from an acute hepatitis B
rapidly evolving to fulminant hepatitis.
This pattern of ALAT elevation was not consistent with the previously
observed pattern of elevations in patients exposed to ximelagatran. Although ximelagatran was not the cause of
the infectious hepatitis, the investigator could not rule out the possibility
that it aggravated the outcome. Two
other patients who died due to GI hemorrhage with severe coagulopathy had
elevated hepatic enzymes prior to death; both cases (patient 7259 and 7859)
were described above. Clearly, coagulopathy was due to ximelagatran and it
aggravated and contributed to these 2 patients’ deaths.
Patients who had ALAT >3xULN measured at the Central laboratory and
subsequently died are presented in Table 37.
Table 37: List of ximelagatran-treated patients
who had ALAT >3xULN measured at the Central laboratory and subsequently died

An additional patient
died after study closure and is therefore not counted in the ITT analysis.
Patient SH-TPC-0001-062-0286, an 82 year old female, died from AMI 2 weeks
after stopping study drug (ximelagatran 36 mg bid) due to a previous AMI.
A further 3 patients who
had ALAT >3xULN measured at a local laboratory subsequently died. These were as follows:
Patient
SH-TPA-0005-0050-8357, a 74-year-old female, died from sepsis while taking
ximelagatran 36 mg bid, and the temporary ALAT elevation was found during a
previous hospitalization for pneumonia.
Patient
SH-TPA-0003-217-2893, a 67-year-old male, died while taking ximelagatran 36 mg
bid due to acute cholecystitis and cardiac arrest. The reported SAE term was abdominal colic.
Patient
SH-TPV-0002-504-4035, a 76-year-old male, died due to multiorgan failure. The patient had been hospitalized for
operation of colon adenocarcinoma and liver metastases in the right liver lobe,
4 weeks after stop of study drug (ximelagatran 36 mg bid).
Seven of 19 cases
(#1793, 3963, 7259, 7859, 5442, 0430 and 2065) have been discussed above in
detail. Patient 2826 died from rupture of aorta and patient 6603 died 16 months
after discontinuing study drug.
2.6.11 Potential prognostic factors related to
ALAT >3xULN.
The multivariate
analysis of potential prognostic factors for the risk of ALAT>3xULN was
performed using a
logistic regression model with a stepwise selection algorithm. The following
factors were tested for inclusion; sex (female vs male), age, (>=75 vs
<75 years), weight (>=75 vs <75 kg), BMI (>=27 vs <27 kg/m2),
CrCL (>=80 vs <80 mL/min), ethnic origin (Asian vs rest, i.e. all
others), concomitant aspirin use (yes vs no), concomitant statin use (yes vs
no), and patient population (VTE-T vs rest, VTE-P vs rest and Post ACS vs rest,
AF was used as "baseline"). Stepwise analyses are presented in Table
38 (for patients in the ximelagatran group only).
Table 38: ALAT >3xULN, analysis of potential
prognostic factor, stepwise model
selection algorithm, (ximelagatran group only) (ITT population): LTE pool

From these analyses 6
risk factors were statistically significant for the ximelagatran group:
Post ACS population
(p=0.0009), VTE-T population (p=0.0003), use of statins (p=0.019),
BMI <27 kg/m2
(p<0.0001), non-Asian race (p=0.0038) and female sex (p=0.0002, 9.4% vs.
6.7%).
2.6.12 Relationship between exposure to
melagatran and ALAT elevation.
Exposure to melagatran
has been evaluated in patients in the non-surgical long-term studies. Individual melagatran AUCs were estimated by
population PK modeling. The distribution
of melagatran AUC in patients with an event is largely within the melagatran
AUC range in patients without an event.
These data suggest that for the patient population and doses studied
exposure is not predictive of ALAT >3xULN in individual patients.
The calculated
cumulative risk (hazard ratio) of an increase in ALAT for each unit increment
of AUC, in each pool, is shown in Table 39.
Except for the VTE-P and post ACS pools, there is a statistically
significant relationship between exposure and the risk of an ALAT elevation
above 3xULN in each pool.
Table 39 Relationship of melagatran AUC to
occurrence of ALAT elevation >3xULN

2.6.13 Summary of hepatobiliary toxicity
In patients receiving
long-term administration of ximelagatran (>35 days) an increase in
ALAT >3xULN occurred
in 6-13% (total: 531/6948, 7.6%) compared to 0-2% (total: 68/6230, 1.1%) of
patients receiving comparator treatments. ASAT increased in conjunction with
ALAT. The time pattern of ALAT elevations was consistent and typically occurred
between 1 and 6 months after the initiation of ximelagatran. Prior to and after
this time frame the incidence of ALAT increase was similar to comparators.
These data are based on ALAT sampling in 6840 patients.
Among the 531 patients
in the ximelagatran group who presented with an ALAT >3xULN, 206 (39%)
completed the study on study drug. The
remaining 325 patients (61%) discontinued study drug prematurely. The hepatic
transaminases returned to <2xULN in the majority of patients (95%), whether
the patient continued treatment with ximelagatran or not.
An evaluation of
potential risk factors for increase in ALAT indicated an increased risk in the
Post ACS (p=0.0009), and
VTE-T (p=0.0003) populations and also in female patients (p=0.0002) patients
with low BMI (<27 kg/m2) (p<0.0001) and patients receiving concomitant
treatment with statins (p=0.019); Asian patients were found to have a decreased
risk (p=0.0038). Although any single factor identified above may not be strong
enough to justify to excluding the subgroup population, the patients who have 2
or more risk factors should not be given ximelagatran, such as, female patients
with low body weight or who are taking statin.
ALAT >3xULN was
associated with bilirubin >2xULN (within one month following the rise in
ALAT) in 0.53% (37/6948)
of all patients who were exposed to ximelagatran >35 days as compared to 0.08%
(5/6230) of patients exposed to comparators (including 10 ximelagatran and 1
comparator by local laboratory measurement). A total of 14 ximelagatran-treated
patients (14/37, 35.1%) have no alternative explanation for concomitant ALAT
and bilirubin elevation. Concomitant elevations of ALAT >3xULN and bilirubin
>2xULN were observed during the first month of ximelagatran therapy in 6 of
37 patients. Nine of the ximelagatran-treated patients who had ALAT >3xULN
and bilirubin >2xULN (24.3%, 9/37) died with these elevations. Among them, 3
died from heart failure; 3 died from carcinomas with hepatic matastases; 2 (ID#
7259, and 7859) died from GI bleeding with coagulopathy and 1 (ID# 5442) died
from hepatitis B. One patient developed biopsy documented hepatic necrosis with
coagulopathy with a fatal outcome from a duodenal ulcer (#7259). Liver
failure/toxicity by ximelagatran might have caused or at least contributed to
these deaths.
In conclusion, safety
data on hepatobiliary toxicity does not support the safe use of ximelagatran
for long-term (>35 days) treatment of patients with AF or DVT for either 36
mg bid or 24 mg bid dosing.
2.7 Analysis of adverse events of pancreatic
effects
Pancreatic hyperplasia has been observed in pre clinical
studies in rats. A “pancreas sub-study” was performed as part of study
SH-TPA-0005 to determine if there was a safety concern for ximelagatran
regarding pancreatic hyperplasia. CCK
plasma concentrations were measured after approximately 3 months of receiving
study drug in a subset of patients. The
objective of this assessment was to determine whether ximelagatran was
associated with elevations in plasma CCK after a standard meal because this is
the mechanism by which rats undergo pancreatic trophic stimulation, possibly
leading to pancreatic adenomas and occasionally, pancreatic carcinoma. In addition, special abdominal CT scans were
performed, which were designed to measure pancreas volume, obtained prior to
drug exposure and then again after 12 months’ exposure to study drug. The objective of this assessment was to
determine whether long-term administration of ximelagatran was associated with
increased pancreas volume because a trophic effect on pancreas would yield
increased volume of pancreatic tissue.
2.7.1 CCK in
plasma – laboratory findings
A total of 130 patients (62 ximelagatran, 68 warfarin) were
enrolled in the CCK subset, of whom 119 (56 ximelagatran, 63 warfarin) provided
CCK plasma data at 3 months. Mean (SD)
CCK plasma concentration was 14.97±18.32 picomolar for the ximelagatran-treated
patients and 11.39±16.51 picomolar for the warfarin-treated patients. Median CCK plasma concentration was 6.63
(range 2.00 to 62.50) picomolar for the ximelagatran-treated patients and 4.50
(range 2.00 to 62.50) picomolar for the warfarin-treated patients. There was no statistically significant
difference in the plasma concentrations between the 2 groups, p=0.225 (Mann-Whitney test). The data were not normally distributed and no
transformations were applied and hence the Mann-Whitney test was used.
2.7.2
Pancreas volume – laboratory findings
Complete sets of pancreatic CT scans were available for a
subset of 34 patients in the ximelagatran group and 28 patients from the
warfarin group. The mean ±SD change from
baseline in pancreatic volume was -10.85±13.63 for the ximelagatran group
and -10.49±13.85 for the warfarin group
and was statistically significant for both treatment groups (p=0.0001 and
0.0004, respectively). However, the
between group comparison was not statistically significant, p=0.92 (Student’s
t-test). Pancreatic volume change over
one year did not correlate with CCK plasma concentration at 3 months. Treatment, CCK, and treatment-CCK interaction
did not affect pancreatic volume.
2.7.3
Analysis of AEs affecting the pancreas:
long-term exposure (LTE) pool
During the program, 13 patients (2 ximelagatran, 11
comparator) were diagnosed with a pancreatic cancer. Fifteen patients developed pancreatitis during active treatment in the
program (6 ximelagatran, 9 comparator). A further 2 patients had an AE of
pancreatitis in the follow-up period, one after treatment with ximelagatran
(SH-TPA-0003-096-2960) and one after treatment with warfarin
(SH-TPA-0005-2690-7288).
Taking into account both
the AE profile and the sub study data, there is no safety concern for
ximelagatran regarding pancreatic events.
2.8 Analysis of adverse events of coronary artery
disease
Patients with coronary
artery disease (CAD) adverse events are summarized in Table 40.
Table 40: Summary of patients with adverse events
of coronary artery diseases (safety population)
|
CAD AE |
Ximelagatran (AF, n=
3836) (VTE-T,
n=1236) (VTE-P,
n=612) n % |
Warfarin (AF, n=
3719) (VTE-T,
n=1248) (VTE-P,
n=611 placebo) n % |
p-value |
|
AF:
Total CAD MI |
268
7.0 62 1.6 |
248
6.7 52 1.4 |
P=0.584 |
|
VTE-T
Total CAD MI |
16
1.3 3 0.2 |
1
0.1
0 0 |
P=0.00024 |
|
VTE-P
Total CAD MI |
16
2.6 10 1.6 |
12
2.0 3 0.5 |
P=0.447 P=0.05131 |
|
VTE
Total CAD MI |
32 1.7 13 0.7 |
13 0.7 3 0.16 |
P=0.00411 P=0.01183 |
VTE=VTE-T + VTE-P
In all study populations
except the post ACS, the proportion of patients with coronary artery disease
adverse events was higher in the ximelagatran groups than in the comparator
groups (7.0% and 6.7% for the AF pool, 1.3% and 0.1% for the VTE-T pool and
2.6% and 2.0% for the VTE-P pool, for the ximelagatran and comparator groups,
respectively). This trend was consistent
across the pools for myocardial infarction; however, the difference in event
rates (%/patient year) was small (0.9% and 0.6% for the AF pool, 0.6% and 0% for the VTE-T pool and 1.1% and
0.2% for the VTE-P pool, for the ximelagatran and comparator groups,
respectively). Proportion of patients with coronary artery
disease adverse events was statistically significantly higher in the
ximelagatran group (32/1848, 1.7%) than in the warfarin/placebo group (12/1859,
0.7%) in VTE (VTE-T + VTE-P) population (p=0.00411). Proportion of patients
with MI was also significantly higher in the ximelagatran group (13/1848, 0.7%)
than in the warfarin/placebo group (3/1859, 0.16%) in VTE population
(p=0.01183). There were no appreciable differences between the treatment groups
for underlying diseases including hypertension, hypercholesterolemia, diabetes
mellitus, coronary atherosclerosis, as well as age, gender and weight.
Considering ximelagatran as an anticoagulant with potential to treat MI, these
results are worrisome.
2.9
Clinical Laboratory Evaluations
The analyses of clinical
laboratory data in the individual studies in this application have not
identified any adverse findings with the exception of increases in LFTs.
Microscopic hematuria
was more common in the ximelagatran group than in the placebo group in the post
ACS pool; however, in the warfarin comparison pools there was no difference.
A reduction in
triglycerides, cholesterol and LDL was seen in the ximelagatran group in the AF
pool.
2.10
ECG analysis in patient studies
There have been no
signals of any relevant effect on QT intervals in patients exposed to
ximelagatran (24 mg bid) in studies investigating prophylactic treatment after
hip and knee replacement operations.
ECG measurements were
performed in 2 studies carried out on the prophylactic effect of ximelagatran
on postoperative thrombo-embolism in patients undergoing total hip or total
knee replacement. In these studies (SH-TPO-0005 and SH-TPO-0006, n=2491) ECG
was recorded at baseline and at the time of venography (6-12 days
postoperatively).
The most common ECG
abnormality on the day of venography was atrial arrhythmia and the incidence of
this abnormality was comparable in the ximelagatran and enoxaparin groups. No
clinically meaningful differences between treatment groups were observed in
changes from baseline in any of the ECG parameters during this study.
At the time of
venography, heart rate and the QTc interval calculated using Bazett’s formula
were increased relative to baseline, while the PR and QT intervals were
reduced. There was little change in the
QTc interval when calculated using Fridericia’s formula and the study specific
formula. The mean changes in these ECG
parameters were small and comparable in both treatment groups.
The proportion of
subjects with a large increase in QTc (>60 ms) from baseline to last
day on study drug was numerically lower among subjects receiving ximelagatran
(3.1% - 4.0%).
In SH-TPV-0003 ECG
recordings were done at the randomization visit (Visit 2, before first intake
of study drug) and the visits at 2 weeks (Visit 3) and 9 and 18 months (Visit 6
and 9) after randomization. ECGs from
approximately 250 patients were sent for central reading and evaluation by one
cardiologist. The following ECG
variables were measured: RR interval, PQ interval, QRS duration and QT
interval. T-wave abnormalities and
U-waves were to be noted.
There were minor changes in the distribution of
T-U fusion and U-wave abnormalities from baseline to last visit on treatment,
but to a similar extent in the ximelagatran and placebo groups. There was no effect of ximelagatran on QTc
time.
2.11 Safety in Special Groups and Situations
2.11.1 Gender,
long-term exposure (LTE) pool
In the ximelagatran
treatment group, increased hepatic enzymes were more commonly reported for
women than for men.
In both treatment
groups, coronary artery disorders were more commonly reported for men than for
women (female 8.4% vs male 11.4% in the ximelagatran group and female 7.7% vs
male 9.8% in the comparator group). In general, bleeding events were more
frequently reported for women than men.
For example purpura was reported for 10.7% of females vs 6.6% of males
in the ximelagatran group and 16.3% of females vs 9.5% of males in the
comparator group.
2.11.2
Age, long-term exposure (LTE) pool
To evaluate the
frequency of AEs in older vs younger patients, patients were grouped into 3 age
categories: below 65 years, 65 to 74 years and 75 years and above.
Irrespective of
treatment group, the overall frequency of reported AEs was higher amongst the
elderly. Patients aged >75 years reported fewer non-fatal SAEs in the
ximelagatran treatment group compared to the comparator group (30.3% vs 36.3%),
while more patients in the ximelagatran treatment group discontinued study
treatment due to AEs in this age group (20.5% vs 16.1%).
In both treatment
groups, the overall AE reporting rate was higher with increasing age, with the
exception of elevated hepatic enzymes which was reported with a similar
frequency in all age groups.
2.11.3
Race, long-term exposure (LTE) pool
To evaluate the
frequency of AEs in different race groups, the patients were grouped into four
categories: Caucasian, Black, Asian and Other.
In the ximelagatran
treatment group, less than 10% of the population were non-Caucasian races. There was no indication of a different AE
profile in these sub-groups.
2.11.4
Body weight, LTE pool
To evaluate the
frequency of AEs in different body weight groups, patients were grouped into 3
weight categories: less than 50 kg, 50 to 100 kg and above 100 kg.
The AE profile was
similar in all weight categories. Fewer than 2% of patients in each treatment
group weighed less than 50 kg. The AE
profile was not different in this sub-group.
In the ximelagatran
treatment group, elevated hepatic enzymes and bleeding events were less
frequently reported in patients above 100 kg.
2.11.5
Body mass index (BMI), LTE pool
To evaluate the
frequency of AEs in groups with different BMI, patients were grouped into 3 BMI
categories: less than 25, 25 to 30 and above 30.
For patients in the
lowest BMI category, the reporting frequency of non-fatal SAEs was lower in the
ximelagatran treatment group (24.8% vs 28.0%).
There was a higher frequency of reported AEs leading to drug discontinuation
in the ximelagatran treatment group compared to comparators group (19.3% vs
14.9%).
In the BMI category
25-30, there was a higher reporting frequency of drug discontinuations due to
AE in the ximelagatran treatment group compared to comparators treatment group
(18.3% vs 13.2%).
For the ximelagatran
treatment group in the BMI category >30, there was a higher reporting
frequency of AEs leading to drug discontinuations compared to comparators group
(13.8% vs 10.7%).
In the ximelagatran
treatment group, reporting frequency of elevated hepatic enzymes and bleeding
events increased with decreasing BMI.
2.11.6
Influence of renal function, LTE pool
To evaluate if renal
function had any influence on the frequency and pattern of reported AEs, the
patients were grouped into 4 categories: calculated creatinine clearance below
30, between 30 (inclusive) and 50 (non-inclusive), between 50 (inclusive) and
80 (non-inclusive) or above 80 (inclusive).
Apart from elevated
hepatic enzymes, no difference was seen in the overall AE profile between
ximelagatran and comparators for any category of calculated CrCL.
Patients with calculated
creatinine clearance below 30 mL/min were to be excluded from the clinical
studies. Although a few patients
(<1%) in this category were recruited and the pattern of AEs was not
different from that in other CrCL categories. There was a trend towards an
increased frequency of bleeding-related AEs by decreasing calculated creatinine
clearance in both treatment groups.
There was no indication
of an increased frequency of elevated hepatic enzymes reported as AEs in any
calculated CrCL group.
2.11.7
Subjects with renal impairment
Melagatran, the active
metabolite of ximelagatran, is eliminated primarily via renal excretion. Renal function decreases with age and, as the
target patient population is of older age (median age about 65 years), patients
with severe renal impairment (creatinine clearance of less than 30 mL/min) have
been excluded in the patient studies with melagatran/ximelagatran. Study SH-TP1-0026 was conducted to
investigate the pharmacokinetics of oral ximelagatran and subcutaneous
melagatran in subjects with severe renal impairment (CrCL 10 to 30 mL/min,
n=12). Subjects with normal renal
function (CrCL >50 mL/min, n=12) were included as a control group.
As expected, subjects
with severe renal impairment had higher plasma concentrations of melagatran
both after subcutaneous administration of melagatran and oral dosing of
ximelagatran. The renally impaired
subjects had about 4 times higher AUC after subcutaneous melagatran and about 5
times higher AUC after oral ximelagatran, compared to the control
subjects. The mean (SD) half-lives of
melagatran were 6.8 (2.0) h and 9.3 (3.5) h after sc melagatran and oral
ximelagatran dosing, respectively, in the subjects with renal impairment. These half-lives were about 3-fold higher
than for control subjects. The clearance
and the renal clearance of melagatran were lower in the renally impaired
subjects and were linearly correlated to renal function measured with iohexol
clearance (mean (SD) of 12.5 (5.2) mL/min and 86.5 (9.7) mL/min for subjects
with renal impairment and normal controls).
Study SH-TP1-0027
investigated the effect of melagatran given via dialysate, compared to
dalteparin, in 11 uraemic patients (GFR <8 mL/min). The frequency of clot formation in tubings
and in the dialysis filter, the iohexol clearance and the filter pressure were
comparable between treatments. The
half-life of melagatran was longer when melagatran was administered between
dialyses compared to during hemodialysis.
The clearance of melagatran was increased by about 7-fold and comparable
to the iohexol clearance during haemodialysis.
2.11.8
Subjects with hepatic impairment
Study SH-TP1-0013
investigated the influence of hepatic impairment on the absorption, metabolic
biotransformation of ximelagatran to the active form and excretion in subjects
with
mild to moderate hepatic
impairment (as defined by Child Pugh score).
Age, weight and gender-matched subjects with normal hepatic function
were included as a control group. After adjusting for differences in creatinine
clearance between the 2 groups, the AUC estimates were comparable. The results support that the absorption of
ximelagatran and the metabolic biotransformation to its active form melagatran
are not influenced for subjects with mild and moderate hepatic impairment.
However, because of liver toxicity risk, patients who have abnormal liver
function or history of liver diseases have been excluded from the studies.
2.11.9
Drug/drug interaction
Concomitant
administration of an anticoagulant and an antiplatelet agent may result in
increased bleeding risk, therefore co-administration should be undertaken with
caution.
The AUC and Cmax of melagatran
was increased by approximately 82% and 74%, respectively, after
co-administration of a single dose of ximelagatran and multiple doses of
erythromycin (500 mg tid) compared with ximelagatran alone. The mechanism of
this interaction is not known. Therefore, caution should be exercised in
patients who have increased exposure already, such as patients with moderate
renal impairment.
There were no
P450-mediated interactions with ximelagatran, in vitro.
2.11.10 Use in pregnancy and lactation
Three cases, all from
the VTE-T and VTE-P pools, of ximelagatran exposure during pregnancy have been
reported from studies in the present application. In 2 of the ximelagatran
cases the pregnancies were completed and full-term babies were delivered. For one of these (study SH-TPV-0002 Subject
063-5395), it was estimated that the maximal exposure to drug could have been 3
weeks from estimated conception. No
complications were present during the pregnancy and a completely healthy girl
was born. In the other case (study
SH-TPV-0003, Subject 653-1285) the maximal exposure to drug was estimated to be
up to 2 months from estimated conception.
A full-term baby was delivered after an uneventful pregnancy. The boy was found to have a hypospadia that
needed surgical correction. Otherwise
the baby was healthy.
The third pregnancy
reported on ximelagatran, both pregnancies reported on warfarin and 3 of the
pregnancies on placebo were terminated through elective abortion, none due to
medical reasons.
A study, SH-TP1-0029,
was performed with the primary objective to assess the excretion of
ximelagatran and its metabolites into breast milk after administration of
ximelagatran (single 36 mg dose) to breast-feeding women. Ximelagatran and its
2 intermediates were not detectable in breast milk. Only trace amounts of melagatran (mean
0.00091% of given dose ximelagatran 36 mg) were excreted into breast milk. The exposure of melagatran to a breast-fed
child is therefore not believed to be of concern.
2.11.11 Overdose
One case of overdose on
melagatran/ximelagatran has been reported in the present program. For a period of 11 days Patient
SH-TPV-0002-231-4935, received oral ximelagatran 144 mg daily by mistake,
instead of 72 mg daily. No adverse
effect was reported.
Ximelagatran doses above
the recommended regimen may lead to an increased risk of bleeding. Overdose associated with bleeding
complications should lead to temporary treatment discontinuation. There is no
antidote but ximelagatran is mainly renally excreted with a short half
life. Therefore, satisfactory diuresis
should be maintained. Melagatran is
efficiently eliminated by dialysis. Plasma and blood products can be
administered as needed in case of bleeding.
2.11.12 Drug abuse
Based on its
pharmacological properties, ximelagatran is not likely to have a potential for
drug abuse. No findings during the
clinical study program indicate that ximelagatran induces drug abuse.
2.11.13 Withdrawal and rebound
In Study SH-TPA-0003 (AF
population), 11 patients had a stroke after stopping ximelagatran. Of these 11 patients, 2 had primary events
within 30 days of stopping study drug; one was being treated with aspirin and
LMWH (nadroparin), the other was being treated with clopidogrel. The remaining 9 patients had primary events
more than 30 days after stopping drug.
The treatments taken by these 9 patients after stopping study drug were:
Vitamin K antagonists (3 patients), aspirin (2), clopidogrel (2), LMWH (1) and
no treatment (1). There is therefore no
indication of a rebound effect in this study.
A follow-up visit was
performed in study SH-TPV-0002/5 (VTE-T population) at approximately 2 weeks
after completing the randomized treatment period to allow for the observation
of any rapid rebound effect. No patient
in the ximelagatran treatment group experienced VTE events during the 2-week
follow-up period.
For post ACS pool, the
total frequency of AMIs after stopping treatment was similar for ximelagatran
(1.5%) and placebo (1.4%), and the total mortality was similar between the
treatments. However, after stopping treatment fatal AMIs occurred more
frequently in the ximelagatran group (0.4%) than the comparator group (0.2%).
In the post ACS pool, there was an increased proportion of fatal myocardial
infarctions in the post-treatment period (1.1% vs 0.5%).
3 Safety update
The sponsor submitted a 4-months safety update report on
April 23, 2004. This safety update report included safety information between
27 June 2003 and 23 March 2004. Safety information included in this report
consists of new and follow-up data from recent Phase I studies and studies in
patients. No other safety data are available, as ximelagatran has not been
marketed in any country as of 23 March 2004.
A summary of new safety data associated with the SH-TPA-0004
(SPORTIF IV) study is included in this section. SH-TPA-0004 (SPORTIF IV) is an
ongoing, open-label, 5-year (recently amended to 10-year) continuation study of
the dose guiding study SH-TPA-0002 (SPORTIF II) in patients with AF. The 187
patients in the ximelagatran group received 20, 40, or 60 mg (double-blind,
SPORTIF II) for 12 weeks. Those patients (n=125) who continued into the long
term study (SPORTIF IV) transferred to a 36 mg bid dose. The warfarin group (67
patients) in SH-TPA-0002 received open-label warfarin (INR 2-3) and continued
into SH-TPA-0004 without change. The primary objective of SH-TPA-0004 is to
evaluate the safety and tolerability of long-term treatment with fixed oral
dose ximelagatran compared to warfarin.
There were 17 deaths (9.1%) by March 23, 2004 in the
ximelagatran group and 4 deaths (6.0%) in the warfarin group. The breakdown of
these numbers is presented in Table 41.
Table 41 Total Deaths
in Long Term Studies SH-TPA-0002 and SH-TPA-0004

Although proportion of
total deaths was not statistically significantly higher in the ximelagatran
group (17/187, 9.1%) than in the warfarin group (4/67, 6.0%) (p=0.426), there
were numerically more deaths in the
ximelagatran group than in the warfarin group. The reasons for the 5
deaths during this safety update period are listed below.

For detailed evaluation for this study report, please see
Medical Officer’s Review dated July 22, 2004 by Dr. Mehul Desai from the
Division of Cardio-renal Drug products.
Safety testing regarding liver
toxicity in patients taking Exanta < 35 days is not adequate. In both
study EXULT A and EXULT B, the patients were only followed up for 4 weeks after
operation.
Based on the long-term clinical data,
liver enzymes elevations in patients who taken Exanta were found typically
between 2nd month and 6th month after initiation of
Exanta. Liver toxicity was not seen typically during first 4 weeks, even in the
patients who had severe liver failure and died from liver failure. Therefore,
it is inadequate to monitor liver toxicity for only 4-6 weeks. Clinical data
with 6 month follow-up may be needed for adequately assessing liver toxicity
following short term use of Exanta.
Safety testing regarding liver
toxicity in patients taking Exanta < 35 days is not adequate. In both
study EXULT A and EXULT B, the patients were only followed up for 4 weeks after
operation. Clinical data with 6 month follow-up are needed to assess liver
toxicity following short term use of Exanta.
In patients receiving
long-term administration of ximelagatran (>35 days) an increase in
ALAT >3xULN occurred
in 6-13% (total: 531/6948, 7.6%) compared to 0-2% (total: 68/6230, 1.1%) of
patients receiving comparator treatments. ASAT increased in conjunction with
ALAT. The time pattern of ALAT elevations was consistent and typically occurred
between 1 and 6 months after the initiation of ximelagatran.
ALAT >3xULN was
associated with bilirubin >2xULN (within one month following the rise in
ALAT) in 0.53% (37/6948)
of all patients who were exposed to ximelagatran >35 days as compared to
0.08% (5/6230) of patients exposed to comparators (including 10 ximelagatran, 1
comparator by local laboratory measurement). A total of 14 ximelagatran-treated
patients (14/37, 35.1%) have no alternative explanation for concomitant ALAT
and bilirubin elevation. Nine ximelagatran-treated patients with concomitant
ALAT >3xULN and bilirubin >2xULN died (24.3%, 9/37). Among these, 3 died
from heart failure; 3 died from carcinomas with hepatic matastases; 2 (ID#
7259, and 7859) died from GI bleeding and 1 (ID# 5442) died from hepatitis B.
One patient developed biopsy documented hepatic necrosis with coagulopathy with
a fatal outcome from a duodenal ulcer (#7259). Liver failure/toxicity due to
ximelagatran might have caused or at least contributed to these deaths.
The proportion of
patients with coronary artery disease adverse events (MI or ischemia/angina)
was significantly higher in the ximelagatran groups than in the
warfarin/placebo groups for both short-term (7-12 days) and long-term (>35
days) use. In the patients undergoing TKR surgery (Exult A and Exult B),
proportion of patients with coronary artery disease adverse events was
statistically significantly higher in the ximelagatran group (20/2677, 0.75%)
than in the warfarin group (5/1907, 0.26%) (p=0.02800). Proportion of patients
with MI was also higher in the ximelagatran group (16/2677, 0.60%) than in the
warfarin group (4/1907, 0.21%) in TKR population (p=0.07308). There were no
appreciable differences between the treatment groups for underline diseases
including hypertension, hypercholesterolemia, diabetes mellitus, coronary
atherosclerosis, as well as age, gender and weight.
The proportion of
patients with coronary artery disease adverse events was statistically
significantly higher in the ximelagatran group (32/1848, 1.7%) than in the
warfarin/placebo group (12/1859, 0.7%) in the VTE (VTE-T + VTE-P) population
(p=0.00411). The proportion of patients with MI was also significantly higher
in the ximelagatran group (13/1848, 0.7%) than in the warfarin/placebo group
(3/1859, 0.16%) in the VTE population (p=0.01183). In all study populations
except the post ACS, the proportion of patients with coronary artery disease
adverse events was higher in the ximelagatran groups than in the comparator
groups (7.0% and 6.7% for the AF pool, 1.3% and 0.1% for the VTE-T pool and
2.6% and 2.0% for the VTE-P pool, for the ximelagatran and comparator groups,
respectively). This trend was consistent
across the pools for myocardial infarction.
EXANTA should be taken
twice daily, with or without food. Patients should be advised that if they miss
their scheduled dose they should not double the next dose.
Following are dosage
regimens supported by the submitted studies:
Knee Replacement Surgery
The treatment is
initiated with EXANTA at a dose of 36 mg twice-daily for a treatment period of
7 to 12 days. Provided hemostasis has been established, the first dose should
be given the morning after surgery, but no sooner than 12 hours from the time
of surgery.
Long Term Secondary Prevention of Venous
Thromboembolic Events
Patients who have
received standard anticoagulant treatment for DVT or PE are to be treated with
EXANTA 24 mg twice-daily.
Patients with Renal Impairment: No dosage adjustment is necessary with EXANTA in
patients with a creatinine clearance >30 mL/min. Usage of EXANTA in
patients with severe (CrCL <30 mL/min) renal impairment is not recommended.
Patients with Hepatic Impairment: The use of EXANTA in patients with hepatic
disease and/or ALT >2 times the upper limit of normal at the start of
therapy is contraindicated.
In study EXULT A and B for prevention of DVT in patients
undergoing elective knee replacement surgery, the incidence of VTE and/or all-cause mortality was higher in females and
older patients and summarized in table below.
Table 42 Incidence of total VTE and/or all-cause
mortality for selected subgroups (efficacy ITT population; blinded ICAC
assessment) – Pooled 36 mg bid

Female sex, older age,
and a prior history of VTE are known risk factors for VTE. The reasons for the
increased incidence of total VTE and/or all-cause mortality in females versus
males are unclear. The incidence of proximal DVT, PE, and/or all-cause mortality
was also examined as a function of these same pre-specified subgroups. The
results for the subgroup comparisons were in agreement with those for total VTE
and/or all-cause mortality; however, there were too few events to perform a
logistic regression analysis involving proximal DVT, PE, and/or all-cause
mortality.
An evaluation of
potential risk factors for increase in ALAT indicated an increased risk in
female patients (p=0.0002) patients with low BMI (<27 kg/m2) (p<0.0001)
and patients receiving concomitant treatment with statins (p=0.019).
The subgroup factors
that had no significant impact on the incidence of total VTE and/or all cause
mortality in patients undergoing elective knee replacement surgery were: race, body mass index, estimated CrCL,
general anaesthesia (yes/no), time to first dose, and time to ambulation.
An evaluation of
potential risk factors for increase in ALAT indicated an increased risk in the
Post ACS (p=0.0009), and
VTE-T (p=0.0003) populations and also in female patients (p=0.0002) patients
with low BMI (<27 kg/m2) (p<0.0001) and patients receiving concomitant
treatment with statins (p=0.019); Asian patients were found to have a decreased
risk (p=0.0038).
There are no pediatric data in this submission. AstraZeneca
requests that the requirements to conduct pediatric studies as per the
Pediatric Research Equity Act be waived for the indications claimed in this
application.
It is unlikely that a substantial number of pediatric
patients will be treated with EXANTA for the claimed indications. The estimated
number of pediatric patients diagnosed with atrial fibrillation in the US in
2002 is less than 1,500 children (Mattson Jack Group). The estimated total
number of pediatric patients treated for venous thromboembolism (of which
prevention of recurrent events, the indication claimed in this application, is
a subset of patients) in the US in 2002 is less than 3,000 children
(Solucient). The estimated cumulative number of pediatric patients diagnosed
with conditions for which EXANTA will be indicated is less than 5,000 children.
Therefore, the number of pediatric patients likely to be treated with EXANTA
for the claimed indications is well below the number defined as a substantial
number in the Pediatric Final Rule. Therefore, I recommend that request for
waiver of pediatric study for the indications claimed in this application be
granted.
The sponsor has
adequately conducted studies to assess the influence of renal function,
subjects with renal impairment. There are no adequate data to assess the safety
in pregnant women. Ximelagatran is contraindicated for patients with liver
impairment, because of high risk of liver toxicity. Some findings are
summarized below.
Influence of renal function
Apart from raised
hepatic enzymes, no difference was seen in the overall AE profile between
ximelagatran and comparators for any category of calculated CrCL.
Patients with calculated
creatinine clearance below 30 mL/min were to be excluded from the clinical
studies. Nevertheless, a few patients
(<1%) in this category were recruited and the pattern of AEs was not different
from that in other CrCL categories. There was a trend towards an increased
frequency of bleeding-related AEs by decreasing calculated creatinine clearance
in both treatment groups.
Melagatran, the active
metabolite of ximelagatran, is eliminated primarily via renal excretion. Renal function decreases with age and, as the
target patient population is of older age (median age about 65 years), patients
with severe renal impairment (creatinine clearance of less than 30 mL/min) have
been excluded in the patient studies with melagatran/ximelagatran. Study SH-TP1-0026 was conducted to
investigate the pharmacokinetics of oral ximelagatran and subcutaneous
melagatran in subjects with severe renal impairment (CrCL 10 to 30 mL/min,
n=12). Subjects with normal renal
function (CrCL >50 mL/min, n=12) were included as a control group.
As expected, subjects
with severe renal impairment had higher plasma concentrations of melagatran
both after subcutaneous administration of melagatran and oral dosing of ximelagatran. The renally impaired subjects had about 4
times higher AUC after subcutaneous melagatran and about 5 times higher AUC
after oral ximelagatran, compared to the control subjects. The mean (SD) half-lives of melagatran were
6.8 (2.0) h and 9.3 (3.5) h after sc melagatran and oral ximelagatran dosing,
respectively, in the subjects with renal impairment. These half-lives were about 3-fold higher
than for control subjects. The clearance
and the renal clearance of melagatran were lower in the renally impaired
subjects and were linearly correlated to renal function measured with iohexol
clearance (mean (SD) of 12.5 (5.2) mL/min and 86.5 (9.7) mL/min for subjects
with renal impairment and normal controls).
Study SH-TP1-0027
investigated the effect of melagatran given via dialysate, compared to
dalteparin, in 11 uraemic patients (GFR <8 mL/min). The frequency of clot formation in tubings
and in the dialysis filter, the iohexol clearance and the filter pressure were
comparable between treatments. The half-life
of melagatran was longer when melagatran was administered between dialyses
compared to during hemodialysis. The
clearance of melagatran was increased by about 7-fold and comparable to the
iohexol clearance during haemodialysis.
Safety in pregnancy
Three cases, all from
the VTE-T and VTE-P pools, of ximelagatran exposure during pregnancy have been
reported from studies in the present application. In 2 of the ximelagatran
cases the pregnancies were completed and full-term babies were delivered. For one of these (study SH-TPV-0002 Subject
063-5395), it was estimated that the maximal exposure to drug could have been 3
weeks from estimated conception. No
complications were present during the pregnancy and a completely healthy girl
was born. In the other case (study
SH-TPV-0003, Subject 653-1285) the maximal exposure to drug was estimated to be
up to 2 months from estimated conception.
A full-term baby was delivered after an uneventful pregnancy. The boy was found to have a hypospadia that
needed surgical correction. Otherwise
the baby was healthy.
The third pregnancy
reported on ximelagatran, both pregnancies reported on warfarin and 3 of the
pregnancies on placebo were terminated through elective abortion, none due to
medical reasons.
Ximelagatran and its 2
intermediates were not detectable in breast milk. Only trace amounts of melagatran (mean
0.00091% of given dose ximelagatran 36 mg) were excreted into breast milk. The exposure of melagatran to a breast-fed
child is therefore not believed to be of concern.
ABBREVIATIONS AND CONVENTIONS
_______________________________________________________________
Term Abbreviation
_______________________________________________________________
ACS Acute
coronary syndrome
ACT Activated
coagulation time
AE Adverse
event
AF Nonvalvular
atrial fibrillation
ALAT (ALT)
alanine aminotransferase
ALP Alkaline
phosphatase
AMI Acute
myocardial infarction
APTT Activated
partial thromboplastin time
ASA Acetylsalicylic
acid
ASAT (AST)
aspartate aminotransferase
AUC Area
under the curve
bid Twice
daily
BMI Body
mass index
CBT Capillary
bleeding time
CCK Cholecystokinin
CEAC Clinical
event adjudication committee
CFR Code
of Federal Regulations
CI Confidence
interval
Cmax Maximum
plasma concentration
CrCL Estimated
creatinine clearance
CSR Clinical
study report
CT Computerized
tomography
CYP Cytochrome
P450
DAE Discontinuation
of study drug due to an adverse event
DTI Direct
thrombin inhibitor
DVT Deep
vein thrombosis
ECG Electrocardiogram
EU European
Union
EXULT EXanta
Used to Lessen Thrombosis
EXULT A SH-TPO-0010
(290A)
EXULT B SH-TPO-0012 (290B)
GCP Good
Clinical Practice
H 319/68 Melagatran
H 376/95 Ximelagatran
_______________________________________________________________
Term Abbreviation
_______________________________________________________________
ICAC Independent
central adjudication committee
ICH International
Conference on Harmonization
INR International
normalized ratio (prothrombin time)
ITT Intention-to-treat
LMWH Low
molecular weight heparin
LFT Liver
function test
LTE Long-term
exposure pool
MAA Marketing
Authorization Application
NNT Number
needed to treat
NOS Non-specific
NSAID Nonsteroidal
anti-inflammatory drug
OS Orthopedic
surgery
OT On-treatment
PD Pharmacodynamics
PE Pulmonary
embolism
PK Pharmacokinetics
PT Prothrombin
time
SAE Serious
adverse event
sc Subcutaneous
SEE Systemic
embolic event
SPORTIF Stroke
Prevention using an ORal Thrombin Inhibitor in atrial Fibrillation
SPORTIF II SH-TPA-0002
SPORTIF III SH-TPA-0003
SPORTIF IV SH-TPA-0004
SPORTIF V SH-TPA-0005
TIA Transient
ischemic attack
THRIVE THRombin
Inhibitor in Venous thromboEmbolism
THRIVE III SH-TPV-0003
THR Total
hip replacement
TKR Total
knee replacement
tmax Time
to reach maximum plasma concentration
UFH Unfractionated
heparin
ULN Upper
limit of normal
VKA Vitamin
K antagonist
VTE Venous
thromboembolism (includes both distal and proximal deep vein thrombosis, plus
pulmonary embolism)
VTE-T Treatment
of VTE
1 STUDY SH-TPO-0010 (EXULT A)
Exult A was studied
between May 2001 and April 2002. Title of the protocol was “Optimization of
Dose of H 376/95 (Oral Direct Thrombin Inhibitor) Compared to Warfarin
(COUMADIN) for the Prevention of Venous Thromboembolism Following Total Knee
Arthroplasty.
1.1 Objectives:
The primary objective was to determine the more effective dose of oral
ximelagatran using 2 doses (24 and 36 mg) compared with warfarin for the
prevention of total VTE and/or all-cause mortality in TKR patients after
unilateral or bilateral TKR.
Secondary objectives
were to compare ximelagatran with warfarin for the incidence of proximal DVT
and/or PE and/or all-cause mortality, and total VTE and/or all-cause mortality
according to on-site evaluations, and to compare the incidence of bleeding
between treatments.
Efficacy was assessed by
the number of patients with confirmed distal and/or proximal DVT and/or
symptomatic PE and/or all-cause mortality during the treatment period and
safety was assessed by standard means with a focus on bleeding complications.
1.2 Design:
A randomized,
double-blind, double-dummy, parallel-group multicentre study designed to
determine the more effective dose of oral ximelagatran at 24 and 36 mg bid
begun at least 12 hours after surgery versus oral warfarin begun the evening of
surgery and titrated to a target INR of 2.5 (INR range 1.8 to 3.0) in
preventing VTE in patients undergoing TKR. Treatment duration was 7 to 12 days,
with follow-up at 4 to 6 weeks after surgery.

1.3
Selection of study population
Inclusion criteria
For inclusion in the
study, patients had to fulfill all of the following criteria:
1. Be scheduled for
elective primary unilateral or bilateral TKR
2. Be at least 18 years
old
3. Weigh between 88 lbs
(40 kg) and 300 lbs (136 kg)
4. Be a male, or a
female that is using a reliable form of contraception.
5. Provide written
informed consent
Exclusion criteria
Any of the following was regarded as a criterion for exclusion from the
study:
1. Be scheduled for hemiarthroplasty or surface repair or revisionary
surgery
2. Have had a traumatic epidural/spinal puncture for this surgery (> 3
attempts or gross bleeding)
3. Have any condition resulting in immobilization for > 3 days
4. Have treatment with anticoagulant or antiplatelet drugs within 7 days
prior to surgery. Aspirin
up to 500 mg daily and
non-steroidal anti-inflammatory drugs (NSAIDs) were allowed.
5. Have a known disorder associated with an increased risk of bleeding
6. Have had an ischemic stroke or myocardial infarction within the 30
days prior to surgery
7. Have had any major surgical procedure within 30 days prior to surgery
8. Have significant renal impairment (an estimated creatinine clearance
or CrCL <30 mL/min)
9. Have abused drugs and/or alcohol within the last 6 months
10. Have malignancy currently under active cytotoxic treatment, or being
the reason for joint
replacement surgery
11. Have a known clinically significant liver disorder, or aspartate
aminotransferase (ASAT)
and/or alanine
aminotransferase (ALAT) above 2 times the upper limit of normal (ULN)
12. Have thrombocytopenia (platelet count <100 x 109 /L)
13. Have a known allergy to contrast media or iodine
14. Have any condition that would preclude
venography
15. Have been previously randomized into this study or any other study of
melagatran
or ximelagatran
16. Be mentally or legally incapacitated
17. Have any condition that may interfere with full participation in the
study or produce a
significant risk to the
patient
18. Have received any investigational agent (drug or device) for any
therapeutic reason
19. Have planned use of intermittent pneumatic compression or foot pump
device.
20. Have a contraindication to warfarin
1.4 Doses and treatment regimens
Patients were randomized
to 1 of 3 treatment groups:
(1) ximelagatran 24 mg
tablet with a 36 mg placebo tablet given twice a day in the morning and evening
with doses taken at intervals as close to 12 hours as possible and placebo
capsule(s) matching warfarin given in the evening, or
(2) ximelagatran 36 mg
tablet with a 24 mg placebo tablet given twice a day in the morning and evening
with doses taken at intervals as close to 12 hours as possible and placebo
capsule(s) matching warfarin given in the evening, or
(3) warfarin 2.5 mg
capsule(s) given once a day in the evening and titrated to a target INR of 2.5
(range 1.8 to 3.0) and two placebo tablets matching ximelagatran 24 mg and 36 mg
given twice a day in the morning and evening,
Patients were permitted
to take study medication with or without meals. The first dose of warfarin or
placebo was to be administered in the evening of the day of surgery. The first
dose of ximelagatran 24 mg or placebo and ximelagatran 36 mg or placebo was to
be administered the morning after surgery (no sooner than 12 hours
postoperatively). If adequate hemostasis was not achieved at the scheduled
start times or if the patient was unable to take oral medication, study therapy
was to begin as soon as adequate hemostasis had been achieved or oral intake
was possible. All anticoagulant or antiplatelet medications, except for aspirin
‹500 mg/day and short-acting NSAIDs were discontinued at least 7 days prior to surgery.
1.5 Efficacy variable
Primary variable
The primary efficacy
variable in this study was the number of patients with VTE (objectively
confirmed DVT and/or PE) and/or all-cause mortality.
Secondary variables
The
secondary efficacy variables in this study include incidence of proximal VTE
(venographic assessment of the proximal veins + symptomatic, objectively
confirmed proximal DVT and/or symptomatic PE, with objective site evaluations,
during the treatment period) and/or all-cause mortality during the treatment
period (ITT population), and incidence of total venous thromboembolism and/or
all-cause mortality (local
assessment).
1.6 Statistical Analyses of efficacy variables
All efficacy parameters
were evaluated using centrally adjudicated events and presented for the
efficacy ITT population. The primary analysis was also presented for patients
without any major protocol violations (per-protocol population).
To address the primary
objective of this study, the ximelagatran 36 mg treatment group was compared to
the warfarin treatment group. As part of this comparison, the incidence of VTE
was estimated for each treatment group by the type of surgery performed
(unilateral/bilateral) using the observed proportions with 95% confidence
interval (CI). An estimate of the between-treatment group difference was also
provided with 95% CI. Treatment differences were tested using the CMH
chi-square test, stratified by type of surgery. If this comparison was
statistically significant (p<0.05), then the ximelagatran 24 mg treatment
group was to be compared to the warfarin-treatment group, also at a
significance level of 0.05. If the initial comparison of ximelagatran 36 mg and
warfarin was not statistically significant (p>0.05), then no further
statistical testing was performed. For a complete assessment of efficacy
results, the ximelagatran 24 mg and 36 mg treatment groups were also compared.
All secondary objectives were assessed at a significance level of 0.05.
1.7 Protocol deviations
The numbers of patients with
protocol deviations that resulted in data being excluded from analyses are
summarized by treatment group in Table A1.
Table
A1: Number (%) of patients with major protocol deviations (randomized
population)

Number (%) of patients
with major protocol deviations is similar between the treatment groups.
1.8 Disposition
Of 2656 patients
enrolled in 116 centers, 2301 were randomized to receive double-blind treatment
with ximelagatran 24 mg (n=762), ximelagatran 36 mg (n=775), or warfarin
(n=764) at 114 centers located throughout the United States, Canada, Israel,
Mexico, and Brazil.
Sixteen randomized
patients were excluded from the safety analysis population because they did not
receive study drug; 5 patients were excluded from the ximelagatran 24 mg
treatment group, 6 from the ximelagatran 36 mg treatment group, and 5 from the
warfarin treatment group.
Approximately 92% of
patients from each treatment group completed the study. The proportion of early
discontinuations from treatment for any reason were not appreciably different
among treatment groups; 5.4% (41) patients discontinued from treatment with
ximelagatran 24 mg, 6.8% (53) patients from ximelagatran 36 mg, and 5.6% (43)
patients
from warfarin. More
patients discontinued treatment because of adverse events in ximelagatran
groups (23 patients in each group, 3%) than warfarin group (13 patients, 1.7%).
1.9 Demographic and other patient characteristics
The demographic
characteristics of study patients are summarized in Table A2.
Table A2: Summary of demographic characteristics
of study patients


Of the 2285 patients
included in the safety population, slightly more than 60% were female in each
treatment group (from 60.5% to 64.0%), 96% of all patients were Caucasian in
each treatment group. At baseline, approximately 60% of patients were
non-smokers in each treatment group and slightly more than 60% of patients did
not consume alcohol in each treatment group (from 62.0% to 65.5%).
The mean age of patients
in each treatment group was approximately 68 years and
approximately 56% were
70 years of age or younger in each treatment group. Approximately 56% of
patients had a maximum body weight of 85 kg and approximately 52% had a maximum
body mass index of 30 kg/m2. The reasons for total knee replacement
surgery are summarized in Table A3.

Over 95% of patients in
each treatment group had unilateral knee surgery, predominately from a medial
parapatellar approach (more than 88% in each treatment group). A total of 15% of patients (278 patients out
of a total 1851) underwent epidural catheter placement and approximately
one-third of this number (96 patients out of the total 278) had a catheter in
place for more than 12 hours. No epidural bleeding was reported. Prostheses
were cemented in place in approximately 90% of the patients in each treatment
group and tibial osteotomies were seldom performed. Mean tourniquet use
approximated 75 minutes in each treatment group; mean operating times were approximately
95 minutes.
In each treatment group,
the mean time to the first dose of study drug was approximately
20 hours, the mean time
to ambulation was 1.6 days, and the mean hospital stay was approximately 6
days. Approximately 60% of patients in each treatment group were ambulatory
within 1 day, and the majority of patients in each treatment group were fully
weight-bearing when discharged from the hospital. Approximately 40% of patients
in each treatment group had maximum hospital stays of 4 days. More than 60% of
patients in each treatment group used passive embolism stockings following
surgery. More than 95% of patients in each treatment group were discharged
following surgery to their home (from 57.4% to 59.3%) or to a rehabilitation
center (from 36.6% to 38.2%).
1.10 Efficacy Results
1.10.1 Primary variable: Incidence of total
venous thromboembolism and/or all-cause mortality
The frequency of total
VTE and/or all-cause mortality among patients undergoing knee replacement was
24.9% for patients randomized to ximelagatran 24 mg, 20.3% for patients
randomized to ximelagatran 36 mg, and 27.6% for patients randomized to warfarin
(see Table below).
Table A4: Frequency of total VTE and/or
all-cause mortality (efficacy
intention-to-
treat population)

Ximelagatran 36 mg was
superior compared to warfarin (p=0.003) in reducing total VTE and/or all-cause
mortality among patients with TKR according to blinded ICAC assessment. The
reduction in the frequency of total VTE and/or all-cause mortality in patients
randomized to ximelagatran 36 mg was 7.3% relative to patients randomized to
warfarin (p=0.003). The corresponding absolute reduction for patients in the
ximelagatran 24 mg treatment group was 2.7% (p=0.282).
According to blinded ICAC
assessment, the absolute reduction in the frequency of total VTE and/or
all-cause mortality was 7.3% with ximelagatran 36 mg compared to warfarin
(27.6% warfarin vs 20.3% ximelagatran 36 mg), providing a relative risk
reduction of 26.4% and the number needed to treat (1/ARR) was 14 (95% CI 8-39).
In those patients who received oral 24 mg ximelagatran twice daily, the rate of
total VTE and/or all-cause mortality was 24.9%; the relative risk reduction was
9.8% and the absolute risk reduction was 2.7%. However, the difference between
the rate of 24.9% (ximelagatran 24 mg) and the warfarin rate of 27.6% was not
significant.
For
patients with unilateral TKR, the reduction in total VTE and/or all-cause
mortality was 2.2% in the ximelagatran 24 mg treatment group and 7.1% in the
ximelagatran 36 mg treatment group relative to warfarin. Corresponding
reductions in total VTE and/or all-cause mortality for patients with bilateral
TKR were 15.7% and 12.6%, respectively. As approximately 96% of patients in
each treatment group had unilateral surgery, the reductions in total VTE and/or
all-cause mortality for the combined surgeries approximate the reductions for
patients with unilateral surgery.
The reduction in the
frequency of total VTE and/or all-cause mortality among patients randomized to
ximelagatran 36 mg was 4.6% relative to patients randomized to ximelagatran 24
mg, but this difference was not statistically significant (p=0.055).
1.10.2 Secondary variables
Incidence of proximal deep vein thrombosis,
pulmonary embolism, and/or all-cause mortality (blinded ICAC assessment)
The frequency of
proximal DVT, PE, and/or all-cause mortality among patients undergoing total
knee replacement was 2.5% for patients randomized to ximelagatran 24 mg, 2.7%
for patients randomized to ximelagatran 36 mg, and 4.1% for patients randomized
to warfarin (Table A5).
Table A5 Frequency of proximal DVT, PE, and/or
all-cause mortality (efficacy intention-
to-treat population; blinded ICAC assessment)

Reductions in the
frequency of proximal DVT, PE, and/or all-cause mortality was
1.4% for patients
randomized to ximelagatran 36 mg relative to patients randomized to
warfarin (p=0.171) and
1.7% for patients randomized to ximelagatran 24 mg (p=0.104). There was no
statistically significant difference between the treatment groups for the
frequency of composite endpoint of proximal DVT, PE, and/or all-cause mortality
that is a clinically meaningful endpoint.
Incidence of total venous thromboembolism and/or
all-cause mortality (local
assessment)
The frequency of total
VTE and/or all-cause mortality assessed locally at study centers was
approximately 10% higher than assessed centrally by the ICAC. The locally
assessed
frequency of total VTE
and/or all-cause mortality among patients undergoing knee
replacement was 33.4%
for patients randomized to ximelagatran 24 mg, 29.6% for patients randomized to
ximelagatran 36 mg, and 37.7% for patients randomized to warfarin (Table A6).
Table A6 Frequency of total VTE and/or all-cause
mortality according to local assessments
(safety population with evaluable local assessments)

Corresponding
frequencies according to central assessment were 24.9%, 20.3% and 27.6%.
Ximelagatran 36 mg was superior to warfarin in reducing total VTE and/or
all-cause mortality among patients with TKR according to local assessments. The
absolute reduction in the frequency of total VTE and/or all-cause mortality in
patients randomized to ximelagatran 36 mg was 8.2% relative to patients randomized
to warfarin (p=0.002) according to local assessments versus 7.3% according to
central assessments. Corresponding reductions for patients in the ximelagatran
24 mg treatment group were 4.3% (p=0.108) according to local assessments versus
2.7% according to central assessments.
The reduction in the
locally assessed frequency of total VTE and/or all-cause mortality among
patients randomized to ximelagatran 36 mg was 3.9% relative to patients
randomized to ximelagatran 24 mg, according to local assessments, but this
difference was not statistically significant (p=0.138).
Although the rates of
total VTE and/or all-cause mortality assessed by local study centers tended to
be greater than those assessed centrally, analyses based on the local
assessments were consistent with central assessments.
Symptomatic and asymptomatic thromboembolic
events
There were 34
symptomatic thromboembolic events over the entire study period, 10 (1.6%) in
the ximelagatran 24 mg treatment group, 13 (2.1%) in the ximelagatran 36 mg
treatment group, and 11 (1.8%) in the warfarin treatment group (Table A7).
study
(efficacy intention-to-treat population)

There were no
appreciable differences among treatment groups in the incidences of syptomatic
DVT, PE, or death. The main difference between the treatment groups is the
incidence of asyptomatic distal DVT which is not clinically meaningful.
1.10.3 Subgroup analyses
The frequency of total
VTE and/or all-cause mortality was examined by subgroup factors
relating to prespecified
demographic and other patient characteristics. The results of the subgroup
analysis were consistent with the overall pattern of results seen for all
patients, with the incidence of total VTE and/or all-cause mortality
consistently lower in the ximelagatran 36 mg group and comparable to or
slightly lower in the ximelagatran 24 mg group, in comparison to the warfarin
group, for a majority of subgroups examined.
Table A8 Frequency of total VTE and/or all-cause
mortality by selected subgroup (efficacy
intention-to-treat population; blinded ICAC assessment)

Results of the logistic
regression analysis showed that the majority of subgroups factors analyzed had
no significant impact on the incidence of total VTE and/or all-cause mortality.
However, female patients, older patients and patients enrolled at sites in
Canada were associated with higher rates of VTE (p = 0.043, 0.009 and <
0.001, respectively). The interaction of each subgroup factor with treatment
was also analyzed and indicated no statistically significant interactions
between treatment and any examined subgroup (p > 0.1).
1.10.4 INR in the warfarin treatment arm
At the time of venography,
only 58.3% of patients in the warfarin treatment group had INR values within
the therapeutic range of 1.8 to 3.0 (Table A9).
Table A9 Proportion of
patients in the warfarin treatment group with INR within the
therapeutic range (efficacy
intention-to-treat population)

There was no appreciable
difference in mean INR between patients with confirmed VTE and with no
confirmed VTE at the postoperative Day 3 and End of Treatment Period study
visits, although the patients with confirmed events had a mean INR slightly
less than patients without confirmed events (2.30 and 2.36, respectively for
patients at postoperative Day 3; 2.31 and 2.43, respectively for patient at the
End of Treatment Period study visit).
There were no
appreciable differences between the distribution of INR values in patients with
and without confirmed VTE.
There
are several major problems in this study using warfarin as a comparator:
·
Warfarin is not suitable for
short-term therapy for prevention of VTE in patients with TKR surgery. Warfarin
is not approved for this indication.
·
The comparison is unfair,
because warfarin will take about 3-5 days to reach therapeutic level, while
Exanta reaches therapeutic levels within hours.
·
The results show that 35.2% of
patients receiving warfarin had an INR less than 1.8 by postoperative day 3 and
24% by end of treatment (day 7 – 12).
Therefore,
it is unacceptable to claim that ximelagatran 36 mg bid is superior to
warfarin.
1.10.5 Conclusions on efficacy results
In this study (EXULT
290A), ximelagatran 36 mg bid showed greater efficacy than warfarin in
preventing total VTE and/or all-cause mortality in patients undergoing primary
elective TKR. The absolute reduction in the frequency of total VTE and/or
all-cause mortality was 7.3% with warfarin (27.6% warfarin vs. 20.3%
ximelagatran 36 mg), providing a relative risk reduction of 26.4% and a number
needed to treat (1/ARR) of 14 (95% C.I. 8-39). The 36 mg dose was superior to
“warfarin group”(p=0.003). The benefit was mainly due to a reduction in
asymptomatic distal DVT diagnosed by venography which is not clinically
meaningful. There were no clinically or statistically significant differences
between ximelagatran and warfarin in reducing the frequency of proximal DVT,
PE, and/or all-cause mortality in this population. Ximelagatran 24 mg bid was
effective in achieving a rate of total VTE and/or all-cause mortality
numerically better than “warfarin” (27.6% warfarin vs 24.9% ximelagatran 24
mg), but this difference did not reach statistical significance. The female
patients, older patients and patients enrolled at sites in Canada were
associated with higher rates of VTE.
There are several major problems for comparison of
ximelagatran with warfarin in this study. Warfarin is not suitable for
short-term therapy for prevention of VTE in patients with TKR surgery. Warfarin
is not approved for this indication. The comparison is unfair, because warfarin
will take about 3-5 days to reach therapeutic level, while Exanta reaches
therapeutic levels within hours. The results show that 35.2% of patients
receiving warfarin had an INR less than 1.8 by postoperative day 3, and 24% by
end of treatment (day 7 – 12). Therefore, although the study demonstrated that
the 36 mg dose of ximelagatran was superior to “warfarin group” (p=0.003) for
primary endpoints, it is unacceptable to claim that ximelagatran is better than
warfarin for this indication.
1.11 Safety Results
1.11.1 Extent of exposure
The duration of
treatment received is summarized in Table A10. The mean number of days on
treatment was approximately 8 days for each treatment group. There were no
appreciable differences in exposure to study drug among treatment groups from
Day 10 onwards, although overall warfarin administration may have been reduced
relative to ximelagatran because warfarin is often withheld if INR is elevated.
The minimum number of days on study drug was 1 day for patients in each
treatment group; the maximum was 13 days for patients in the ximelagatran 24 mg
treatment group and 14 days for patients in the ximelagatran 36 mg and warfarin
treatment groups.

1.11.2 Adverse events
A summary of adverse
events in each category of seriousness is presented in Table A11.
Table A11 Number (%) of patients with
treatment-emergent adverse events (safety
population, follow-up included)

More than 60% of
patients in each treatment group experienced at least one adverse event. There
were no appreciable differences among treatment groups in the proportions of
patients with at least one adverse event or with drug-related adverse events.
The incidence of serious adverse events and discontinuations attributed to
adverse events was higher in the ximelagatran treatment groups than in the
warfarin group. Eight patients died who had undergone surgery and were
randomized to study drug; 4 received ximelagatran 36 mg and 2 each received
ximelagatran 24 mg and warfarin.
The most common
treatment-emergent adverse events experienced by at least 5% of patients in any
treatment group are shown in Table A12 listed by preferred term in order of
decreasing total incidence.
Table A12 Number (%) of patients with adverse
events occurring with a minimum
incidence of 5% of all patients (safety population)

The most common adverse
event was postoperative complications (for events such as anemia; pain; wound
infection; bleeding and delayed wound healing) as experienced by 20.4% of all
patients. The remaining common adverse events experienced by at least 5% of the
patients were fever (7.0%), nausea (6.9%), increased serum levels of gamma
glutamyl transferase (6.4%) and constipation (5.0%). There were no appreciable
differences among treatment groups in the incidence of adverse events.
The common
treatment-emergent adverse events attributed to study drug by the investigator
were increased serum levels of gamma glutamyl transferase (4.3%), postoperative
complications (3.1%), alkaline phosphatase (2.8%), ALAT (2.6%) and ASAT (1.7%).
Bleeding events
Bleeding events were
categorized as major/minor/no bleeding. The most common treatment-emergent
reported bleeding events were coded under postoperative complications (5.1%).
Treatment-emergent bleeding complications reported by at least 1% of patients
in any treatment group are summarized in Table A13. Hemoptysis was experienced
by 5 patients (0.7%) randomized to ximelagatran, all on the 36 mg dose, and by
1 patient (0.1%) randomized to warfarin.
minimum
incidence of 1% of all patients (safety population)

The frequencies of
adjudicated bleeding events on treatment are summarized by event type in Table
A14.
Table A14 Frequency of ICAC adjudicated
on-treatment bleeding events by event
type (safety population)

Approximately 5% of
patients in each treatment group had major or minor bleeding events while
receiving study medication; approximately 1% of patients in each treatment
group had major bleeding events, 0.8% in each of the ximelagatran treatment
groups and 0.7% in the warfarin treatment group. Approximately 5% to 6% of
patients in each treatment group had major or minor bleeding events during the
entire study, including the period from the last administration of study
medication until the follow-up visit. Most bleeding events occurred while the
patients were receiving study medication. There were no statistically
significant differences between the ximelagatran and warfarin treatment groups
in the frequency of major, minor, or combined major or minor bleeding events
while receiving study medication (p>0.461). Similarly, there were no
statistically significant differences between ximelagatran 24 mg and 36 mg in
the frequencies of these bleeding events while receiving study medication (p>0.490).
The frequency of
on-treatment bleeding events for patients treated with warfarin by INR range is
summarized in Table A14.
Table A14 Frequency of on-treatment
bleeding events for patients treated with warfarin by
international normalized
ratios (safety population)

The frequency of
bleeding events increased from postoperative Day 3 to the End of Treatment
Period Study Visit for patients within the therapeutic INR range, from 36.4% to 60.6%, and decreased from
postoperative Day 3 to End of Treatment Period Study Visit for patients below
the therapeutic INR, from 57.6% to 30.3%.
For all warfarin treated
patients with INR values within the therapeutic range (1.8 to 3.0), 37.1% had
confirmed bleeding events at postoperative Day 3 versus 58.8% at End of
Treatment Period Study Visit. Mean INRs of warfarin treated patients with
bleeding events were lower at postoperative Day 3 and the day of the End of
Treatment Period Study Visit than for patients with no confirmed bleeding (1.9
versus 2.3, and 2.1 versus 2.4, respectively).
There were no
appreciable differences in mean melagatran levels between patients with
confirmed on-treatment major/minor bleeding events and with no confirmed
bleeding at the postoperative Day 3 and End of Treatment Period study visits
suggesting that the bleeding events occurred independently of melagatran plasma
concentrations.
Subgroup analyses of adjudicated bleeding events
For the majority of
subgroups examined, the pattern of results was consistent with that of the
overall population and the incidences of bleeding events in the ximelagatran
groups were comparable to or slightly higher than those in the warfarin group.
A logistic regression analysis examining on-treatment bleeding events found
that there was a statistically significant effect of gender and location of the
study site on the incidence of major/minor bleeding events, with male patients
and patients enrolled at sites in Canada associated with an increased risk of
bleeding (p<0.001). The interaction of each subgroup factor with
treatment was also analyzed and indicated no statistically significant
interactions between treatment and any examined subgroup (p>0.096).
The frequency of on-treatment major/minor bleeding events by selected subgroup
factors is summarized in Table A15.

Deaths
Eight patients died who
had undergone surgery and were randomized to treatment; 4 patients had received
ximelagatran 36 mg, 2 patients had received ximelagatran 24 mg, and 2 patients
had received warfarin. Of the eight deaths, 1 occurred in each treatment group
during the study treatment period; none of these was adjudicated as due to
fatal PE or fatal bleeding (2 MIs and 1 ischemic bowel with perforation). The
other five deaths occurred after study treatment was discontinued and up until
the end of the study.
The 2 warfarin treated
patients died as a result of myocardial infarction. Deaths of patients who
received ximelagatran 36 mg resulted from PE (Patients 93/144 and 217/3259),
myocardial infarction (Patient 112/154), and hypotension, gastrointestinal
bleeding, and multiorgan failure (Patient 401/7037). Patient 46/2236, who
received ximelagatran 24 mg, died as a result of intestinal perforation. The
cause of death for Patient 215/3776, who also received ximelagatran 24 mg, was
unknown.
Narratives for patient 401/7037, Patient 46/2236 and Patient 215/3776 are listed below.
·
Patient
401/7037 was a 79 yeas old female Caucasian. The subject had a history of
hypertension, deafness, congestive obstructive pulmonary disease, appendectomy,
and renal lithotripsy. She underwent left TKR for osteoarthritis. Operative
blood loss was 130 mL, and postoperative drainage was 100 mL. The subject
received the first dose of warfarin placebo approximately 10 hours after
surgery. She received 1 day of treatment with ximelagatran 36 mg for a total of
2 doses. On postoperative day 1 at 17: 50 hour, the subject experienced
paleness, nausea, and vomiting. She was found to have hypotension (80/ 50 mm
Hg), a respiratory rate of 20/ min, and a temperature of 35.8 oC.
Therapy with the study drug was discontinued, and the patient was transferred
to intensive care. She was evaluated again at 00: 30 hour and diagnosed with
arrhythmia, seizures, disorientation, paleness, and hypotension (90/ 60 mm Hg).
The subject’s hemoglobin was low, and she had bleeding via her nasogastric tube.
Hemodynamic instability, hydroelectrolytic and acid- base disorder, and upper
gastrointestinal bleeding were diagnosed. She was intubated, and mechanical
ventilation was necessary. Acute renal failure was diagnosed. The subject was
treated with intravenous plasma, two units of blood, and potassium chloride. On
postoperative day 3, the subject’s upper gastrointestinal bleeding continued
with hypotension and tachycardia. Her central venous pressure was 10.5 to 23 mm
Hg. On postoperative day 5, the subject became unstable and underwent
exploratory laparotomy for the upper gastrointestinal bleeding. During the
procedure, multiple gastric ulcers were found. Her condition worsened, and she
died on postoperative day 46. The probable cause of death was acquired hospital
pneumonia and multiple organ failure. An autopsy was not performed. The
mandatory venography was not performed for this subject because she was in
intensive care. The study investigator assessed the acute renal failure as
medically significant and assessed all of the events as not related to the
study drug. The upper gastrointestinal bleeding was adjudicated as a major
bleeding event.
·
Patient
46/2236 was a 79 years old female Caucasian. The subject’s medical history
included anemia, hypertension, depression, left bundle branch block,
hyperlipidemia, colonic stricture and arteriovenous malformations of the cecum,
and left eye cataract removal. The subject underwent left TKR for
osteoarthritis. Operative blood loss was 250 mL, and postoperative drainage was
500 mL. The subject received the first dose of warfarin placebo approximately
11 hours after surgery. She received 7 days of treatment with ximelagatran 24
mg for a total of 13 doses. On postoperative day 5, she complained of
constipation. On postoperative day 6, a flat plate of the abdomen revealed a
possible early ileus. The subject was put on enteral nutrition and started on
Reglan (metoclopramide) therapy. On the morning of postoperative day 7, she had
cold clammy skin with gray pallor. The subject was tachypneic, and her abdomen
was distended. A nasogastric tube was inserted. Study drug was discontinued.
Laboratory results showed an increased white blood cell count. On postoperative
day 8, abdominal obstruction series results were consistent with a bowel
perforation. The subject was taken to surgery, and a subtotal colectomy was
performed. She remained in critical condition following surgery and expired on
postoperative day 9 due to multiple complications of sepsis. The mandatory
venography was not performed for this subject. The study investigator assessed
the event as not related to the study drug.
·
Patient
215/3776 was a 70 years old male Caucasian. The subject had a history of
asthma, cancer of the prostate, fractured wrist, influenza, and tonsillectomy.
The subject underwent left TKR for osteoarthritis. Operative blood loss was not
reported, and postoperative drainage was 365 mL. The subject received the first
dose of warfarin placebo approximately 8 hours after surgery. He received 2
days of treatment with ximelagatran 24 mg for a total of 4 doses. On
postoperative day 2, the subject became diaphoretic, pale, and tachycardic. An EKG revealed atrial
fibrillation, and a chest x- ray revealed pulmonary edema. Cardiac enzymes were
subsequently negative. He was treated with digoxin, nitro- paste, and oxygen.
At 02: 00 on postoperative day 3, the subject vomited coffee ground material
and had bright red stools. The subject was transferred to the intensive care
unit, and therapy with the study drug was discontinued and unblinded. He was
diagnosed with a gastrointestinal bleed. He was treated with pantaloc, fresh
frozen plasma, and packed red blood cells. On postoperative day 7, the subject
was started on Fragmin (dalteparin). He was discharged to home recovered on
postoperative day 12. The mandatory venography was not performed for this
subject because he withdrew from the study due to the adverse event. The
subject was re- hospitalized on postoperative day 18 with shortness of breath.
On postoperative day 21, he was transferred to another hospital and was lost to
follow- up. The subject died secondary to an unknown cause on postoperative day
25. The study investigator assessed the upper and lower gastrointestinal bleed
as related to the study drug and the shortness of breath and death as not
related to the study drug. The Adjudication Committee classified this cause of
death as pulmonary embolism, due to lack of information to the contrary and
based on the pre- specified Adjudication Committee charter. The
gastrointestinal bleed was adjudicated as a major bleeding event.
Serious adverse events
The frequency of serious
adverse events experienced by at least two patients who were treated with
ximelagatran or with warfarin is summarized in Table A16.
Table A16 Number (%) of patients with serious
adverse events occurring in at least 2
patients treated with either ximelagatran or warfarin (safety
population)

The most common serious
adverse events experienced by at least 0.5% of patients were postoperative
complications (0.8%) and myocardial infarction (0.6%).
Eleven randomized
patients underwent surgery and dosing with study medication (warfarin or
placebo) on Day 0 but discontinued before dosing with active study drug
(ximelagatran or placebo) on Day 1. Of these 11 patients, 7 patients were
randomized to warfarin, 3 patients to ximelagatran 24 mg and one patient to
ximelagatran 36 mg. Therefore, four patients did not receive active study drug
before discontinuing from the study. All 11 patients have been included in the
safety analyses.
Serious postoperative
complications were experienced by 18 patients, 13 (0.9%) randomized to
ximelagatran and 5 (0.7%) to warfarin. Serious myocardial infarctions were
experienced by 13 patients, 11 (0.7%) randomized to ximelagatran and 2 (0.3%)
to warfarin.
Five patients
experienced serious gastrointestinal hemorrhage; all five were randomized to
ximelagatran, 4 (0.5%) to the 24 mg dose and 1 (0.1%) to the 36 mg dose. One
patient in the ximelagatran 24 mg dose group, experiencing a serious
gastrointestinal hemorrhage, discontinued study medication prior to receiving
an active dose of study medication on postoperative Day 1. This patient was one
of the eleven patients described in the previous paragraph. There were no other
appreciable differences in the incidence of serious adverse events among
treatment groups.
1.11.3 Discontinuations due to adverse events
The frequency of
discontinuations of study drug attributed to adverse events experienced by at
least 0.2% patients is summarized in Table A17.
adverse events (greater than or equal to 0.2% of patients) (safety
population)

The two most common
adverse events leading to discontinuation of study drug were postoperative
complications (7 patients [0.3%]) and myocardial infarction (6 patients
[0.3%]). Other adverse events that led to discontinuation of study drug by at
least 0.2% of all patients were atrial fibrillation, nausea, gastrointestinal
hemorrhage, and vomiting. The incidence of discontinuations attributed to
adverse events was higher in the ximelagatran treatment groups than in the
warfarin group.
1.11.4 Clinical laboratory evaluation
Hematology
Changes from baseline in
hemoglobin levels were greatest within the first 3 days following surgery and
returned to near baseline levels by the end of the follow-up period. Changes
from baseline in platelet counts were greatest between baseline and End of
Treatment Period Study Visit and returned to above baseline levels by the end
of the follow-up period. There were no appreciable differences in changes from
baseline in hemoglobin levels or platelet counts among treatment groups at any
evaluation. Changes from baseline in other hematology parameters tended to be
smaller at follow-up than at End of Treatment Period Study Visit, but no
appreciable differences were seen over time or among treatment groups.
Clinical chemistry
Changes from baseline in
liver enzymes and total bilirubin were greater at End of Treatment Period Study
Visit than at follow-up. There were no appreciable differences in mean baseline
values or in changes from baseline in liver enzymes and total bilirubin among
treatment groups at any evaluation.
Changes in individual patients over time in
selected liver function parameters
The frequencies of
measures of liver function outside the extended reference ranges for liver
enzymes (ASAT, ALAT, and alkaline phosphatase) and total bilirubin are
summarized in Table A18. The only hepatic parameter with values at least 3X ULN
with an incidence exceeding 1% in any treatment group was ALAT (ranging to
1.7%) at venography. There were no appreciable differences in the frequency of
the measures of liver function at least 3X ULN among treatment groups for any
hepatic parameter. It should be noted that there were 5 additional patients
with ALT elevation (> 3ULN) in the ximelagatran groups (1 patient in
24 mg group and 4 patients in 36 mg group) and none in the warfarin group
during the following up period. This may indicate that ximelagatran may cause
late occurrence of liver toxicity and 4-6 weeks of follow-up may not be
adequate to assess the safety for short-term use of ximelagatran.
Table A18 Frequency of selected liver function
test values elevated above upper limits of
normal (safety population)

Expected postoperative
changes were observed: elevations were seen in measures of hepatic function
(ASAT, ALAT, GGT, alkaline phosphatase, and LDH) and white blood cell counts,
and reductions in RBCs, all at the time of venography, which generally returned
to near baseline values at the follow-up visit. Hemoglobin levels diminished in
all treatment groups following surgery and returned to near baseline at the
follow-up visit. Platelet counts diminished in all treatment groups following
surgery and returned to above baseline at the follow-up visit. There were few
appreciable differences in clinical laboratory values among treatment groups. These changes are consistent
with surgical intervention and postoperative recovery.
1.11.5 Conclusions on safety results
There were no
statistically significant differences between either the ximelagatran treatment
group and warfarin in the frequency of major bleeding events, the frequency of
minor bleeding events, or the frequency of any (major and minor) bleeding
events on treatment or over the entire study. Five patients experienced serious
gastrointestinal hemorrhage; all five were randomized to ximelagatran, 4 (0.5%)
to the 24 mg dose and 1 (0.1%) to the 36 mg dose (One patient discontinued
study medication prior to receiving an active dose of study medication on
postoperative Day 1).
No appreciable
differences were detected among the treated groups in regard to adverse events.
The incidences of serious adverse events (5.7-5.9% vs. 4.3%), deaths (6 vs. 2)
and discontinuations attributed to adverse events (3% vs. 1.7%) were
numerically higher in the ximelagatran treatment groups than in the warfarin group.
There was a statistically significant effect of gender and location of the
study site on the incidence of major/minor bleeding events, with male patients
and patients enrolled at sites in Canada associated with an increased risk of
bleeding (p<0.001).
Serious myocardial
infarctions were experienced by 13 patients, 11 (0.7%) randomized to
ximelagatran and 2 (0.3%) to warfarin. Three additional patients in
ximelagatran group reported angina.
There were no
appreciable differences in the frequency of the measures of liver function at
least 3X ULN among treatment groups for any hepatic parameter. However, it
should be noted that there were 5 additional patients with ALT elevation (>
3ULN) in ximelagatran groups and none in the warfarin group during the following
up period. This may indicate that ximelagatran may cause late occurrence of
liver toxicity and 4-6 weeks of follow-up may not be adequate to assess the
safety for short-term use of ximelagatran. A study incorporating at least 6
months of follow-up will be needed to assess liver toxicity following
short-term use of ximelagatran.
2: STUDY SH-TPO-0012 (EXULT B)
Exult B was studied
between June 2002 and April 2003. Title of the protocol was “Safety and
Efficacy of H 376/95 (Oral Direct Thrombin Inhibitor) Compared to Warfarin
(COUMADIN) for the Prevention of Venous Thromboembolism Following Total Knee
Arthroplasty.
2.1 Study objectives
Primary objectives
The purpose of this
study was to confirm the superior efficacy of ximelagatran compared to warfarin
for the prevention of VTE in patients after TKR. The primary analysis was to
focus on the primary composite endpoint of proximal and distal DVT and/or PE
and/or all-cause mortality, according to independent central adjudication.
Secondary objectives
The secondary objectives of this study were to compare
ximelagatran with warfarin for the incidence of:
·
the
secondary composite endpoint of proximal DVT and/or PE and/or all-cause
mortality during the
study drug treatment period
·
the
secondary composite endpoint of total DVT and/or PE and/or all-cause
mortality according to
local on-site evaluations during the study drug treatment period
·
major and
any bleeding during the study drug treatment period.
2.2 Study design
This (EXULT B) was a multi-center, randomized,
double-blind, double-dummy, parallel-group active comparator study in patients
who had undergone primary elective TKR. Patients were randomized to 1 of 2
treatment groups: ximelagatran 36 mg twice daily (bid) (initiated as early as
possible on the morning after surgery) or warfarin once daily (initiated the
evening of surgery), administered for 7 to 12 days. Independent Central
Adjudication Committee (ICAC) evaluation of mandatory bilateral venography
(performed at the End of Treatment Period Study Visit) in conjunction with
objectively confirmed, symptomatic VTE events and/or all-cause mortality were
used to determine the primary endpoint. Symptomatic events or deaths occurring
within 2 days following mandatory venography or up to Day 12, if no mandatory
venography was done, were included in the primary analysis of efficacy.
2.3 Selection of study population
Inclusion criteria
For inclusion in the
study, patients had to fulfill all of the following criteria:
1. Be scheduled for
elective primary unilateral or bilateral TKR
2. Be at least 18 years
old
3. Weigh between 88 lbs
(40 kg) and 300 lbs (136 kg)
4. Be a male, or a
female that was either a) surgically sterile, b) at least 2 years
postmenopausal, or c) using a reliable form
of contraception.
5. Provide written
informed consent.
Exclusion criteria
Any of the following was
regarded as a criterion for exclusion from the study:
1. Be scheduled for
hemiarthroplasty or surface repair or revisionary surgery
2. Have had a traumatic epidural/spinal puncture
for this surgery (> 3 attempts or gross bleeding)
3. Have any condition resulting in immobilization
for > days within the 30 days prior to surgery
4. Have treatment with anticoagulant or
antiplatelet drugs within 7 days prior to surgery. Acetylsalicylic acid up to 500 mg daily and
non-steroidal anti-inflammatory drugs (NSAIDs) were allowed.
5. Have a known disorder
associated with an increased risk of bleeding
6. Have had an ischemic
stroke or MI within the 30 days prior to surgery
7.
Have had any major surgical procedure within 30 days prior to surgery
8. Have significant
renal impairment (CrCL<30 mL/min)
9. Have abused drugs
and/or alcohol within the last 6 months
10. Have malignancy currently under active
cytotoxic treatment, or being the reason for joint replacement surgery
11. Have a known clinically significant liver
disorder, or ASAT and/or ALAT > 2 times ULN.
12. Have
thrombocytopenia (platelet count <100 x 109 /L)
13.
Have a known allergy to contrast media or iodine
14. Have any condition
that would preclude venography
15. Have been previously randomized into this
study or any other study of melagatran or
ximelagatran
16. Be mentally or
legally incapacitated
17. Be in a situation or condition that, in the
opinion of the investigator, may interfere with full participation in the study
or produce a significant risk to the patient
18. Have received any investigational agent (drug
or device) for any therapeutic reason within 30 days prior to surgery
19. Have planned use of intermittent pneumatic compression
or foot pump device (Passive anti-embolism stockings and continuous passive
motion devices are acceptable.)
20. Have a
contraindication to warfarin.
2.4 Doses and treatment regimens
Patients were randomized
in a double-dummy fashion to 1 of 2 treatment groups:
·
Ximelagatran
36-mg tablet given twice daily in the morning and evening with doses taken at
intervals as close to 12 hours as possible and placebo capsule(s) matching
warfarin given in the evening,
or
·
Warfarin 2.5
mg capsule(s) given once daily in the evening and titrated to a target INR of
2.5 (range: 1.8 to 3.0) and 1 placebo tablet matching ximelagatran 36 mg given
twice daily in the morning and evening.
2.5 Criteria for evaluation (main variables)
Efficacy
·
Primary
endpoint: The number of patients with verified distal and/or proximal DVT,
and/or symptomatic PE with objective confirmation, and/or all-cause mortality
during the treatment period according to central evaluations.
·
Secondary
endpoints: The number of patients with proximal DVT/PE (venographic assessment
of the proximal veins + symptomatic, objectively confirmed proximal DVT and/or
PE during the treatment period) + all-cause mortality during the treatment
period.
And
The number of patients with verified distal and/or proximal DVT, and/or
symptomatic PE with objective confirmation, and/or all-cause mortality during
the treatment period according to local on-site evaluations.
Safety
Safety assessments
included bleeding complications occurring after TKR; surgical site evaluations;
adverse event (AE) reports; clinical laboratory data (hematology and clinical
chemistry) and vital
signs. An independent Data Safety Monitoring Board was in place during the
performance of the study.
2.6 Statistical methods
The presence or absence
of DVT, PE, and all-cause mortality was assessed locally at each
investigative site and
by the ICAC. The primary statistical analysis was performed using central
evaluations. To address the primary objective of this study, ximelagatran 36 mg
was compared to warfarin. Treatment differences were tested using the
Cochran-Mantel-Haenszel (CMH) chi-square test, stratified by type of surgery
(unilateral and bilateral). All objectives were assessed at a significance
level of 0.05. A secondary analysis, in which the local venography assessments
were substituted for the central venography assessments and analyzed, was also
performed. Sub-group analyses were also performed on the frequency of
thromboembolic events (total VTE and proximal VTE). The main analysis of efficacy
was performed on the efficacy intention-to-treat (ITT) population, ie, all
randomized and treated patients with a venogram adequate for evaluation or
objectively confirmed, symptomatic DVT/PE and/or all-cause mortality while on
treatment.
The frequency of
adjudicated bleeding events (major and/or minor) was determined for each
treatment group by the type of surgery performed. Differences among treatment
groups were tested using the CMH chi-square test, stratified by type of surgery
(unilateral/bilateral). Liver function test results (alanine aminotransferase
[ALAT], aspartate aminotransferase [ASAT], alkaline phosphatase, total
bilirubin) were summarized according to the proportion of patients with results
greater than 2, 3, 5, and 7 times the upper limit of normal (ULN). Analyses of
AEs, laboratory parameters (including hemoglobin and platelet count), and vital
signs were summarized descriptively.
2.7 Summary of patients
Of 2813 patients
enrolled in 115 centers, 2303 were randomized to study drug at 113 centers.
Four randomized patients were excluded from the safety analysis population
because they did not receive study drug. Of the 2299 patients included in the
safety population, data from 982 and 967 patients in the ximelagatran and
warfarin groups, respectively, were analyzed for efficacy in the ITT population
while data from 941 and 883 patients, respectively, were included in the PP
population. The discrepancy in the number of patients in each treatment group
evaluable for the PP population was primarily due to a higher proportion of
patients in the warfarin group compared with the ximelagatran group who were
noncompliant (did not have a minimum INR of 1.5) with study drug or who did not
receive their first dose of study drug on schedule.
Approximately 94% of
patients in each treatment group completed the study (ie, completed the 4- to
6-week follow-up visit). The proportion of patients who discontinued study drug
early for any reason was comparable in the ximelagatran group (n=53, 4.6%) and
the warfarin group (n=52, 4.5%). The most common reason for early
discontinuation of study drug in the ximelagatran and warfarin groups was AEs
(29 and 34 patients, respectively). Other reasons for discontinuation of
treatment across both treatment groups included consent withdrawn (17
patients), confirmed VTE event (14 patients), other (10 patients), and
eligibility criteria not fulfilled (1 patient).
An additional 19 patients (9 ximelagatran; 10 warfarin)
discontinued the study during the 4- to 6-week follow-up period. The reason for
discontinuation of the study following completion of treatment was consent
withdrawn (6 patients in each treatment group), AE (2 ximelagatran; 1
warfarin), and other (1 ximelagatran; 3 warfarin).
2.8 Protocol deviations
The numbers of patients
with protocol deviations that resulted in data being excluded from the analyses
are provided in Table B1.
Table B1 Number (%) of patients with protocol
deviations (randomized population)

Three primary patient
populations were analyzed in this study, the safety population, the efficacy
ITT population, and the PP population.
More patients (44, 3.8%)
in warfarin group than ximelagatran group (11, 1.0%) did not receive first dose
of study drug on schedule.
2.9 Summary of demographic and baseline
characteristics
The demographic and key
baseline characteristics of patients included in the safety population are
summarized in Table B2.
Table B2 Demographic and baseline characteristics
(safety population)



The 2 treatment groups
were well matched with respect to demographic and baseline characteristics. Of
the 2299 patients included in the safety population, slightly more than 60% in
each treatment group were female, approximately 94% in each treatment group
were Caucasian, and approximately two-thirds of the patients were enrolled at
centers in the United States or Canada. At baseline, slightly more than 60% of
patients in the ximelagatran and warfarin groups were non-smokers and
approximately 67% of patients in each treatment group did not consume alcohol.
The mean age of patients
in the ximelagatran and warfarin groups was approximately 67 years and between
41% and 44% of patients in both groups were between 65 and 74 years of age. The
estimated creatinine clearance was normal (>80 mL/min) for comparable
proportions of patients in the ximelagatran (65.4%) and warfarin (62.8%)
groups.
The proportions of
patients included in the efficacy ITT population who entered the study
with risk factors for
DVT were generally comparable in the 2 treatment groups. More patients in the
ximelagatran group (n=11, 1.1%) compared with the warfarin group (n=6, 0.6%)
entered the study with a known history of PE, while comparable proportions of
patients in the 2 groups had a history of DVT (n=35, 3.6% and n=29, 3.0%,
respectively). Approximately one-quarter of patients in both the ximelagatran
and warfarin groups (24.2% and 25.9%, respectively) had a history of varicose
veins. No patient in either treatment group was reported to have known APC
resistance, protein-C, protein-S, or antithrombin III deficiencies. Three
patients (2 ximelagatran, 1 warfarin) entered the study with another known
coagulation disorder.
In the efficacy ITT
population, the most common reason for TKR was osteoarthrosis, with comparable
percentages of patients in the ximelagatran and warfarin groups (94.2% and
95.4%, respectively) presenting with this reason.
Approximately 95% of
patients in each treatment group underwent unilateral knee surgery, most
(>94%) for osteoarthrosis. Prostheses were cemented in place in
approximately 90% of the patients in each treatment group. There were no
appreciable differences between treatment groups in the use of prior,
concomitant, or follow-up therapies or in the proportion of patients using an
anticoagulant for extended prophylaxis. The population of patients studied was
suitable for the purpose of this study and representative of the general TKR
population.
2.10 Efficacy results
2.10.1 Primary variable: Incidence of total
venous thromboembolism and/or all-cause mortality (blinded ICAC assessment)
In this study, frequency
rates of total VTE included patients with a confirmed DVT of the
distal or proximal veins
by mandatory venography as well as any patient who had clinical
signs/symptoms of DVT or
PE that were objectively confirmed and centrally adjudicated by the ICAC.
Frequency rates of proximal VTE included patients with a confirmed DVT of the
proximal veins by mandatory venography as well as any patient with objectively
confirmed and adjudicated signs/symptoms of proximal DVT or PE. All-cause
mortality included all deaths occurring during treatment or within 2 days
following venography or up to postoperative Day 12, if mandatory venography was
not performed. Symptomatic events occurring within 2 days following mandatory
venography or up to Day 12, if no mandatory venography was done, were included
in this analysis. Patients adequate for evaluation for the presence of total
VTE may not have been adequate for evaluation for the presence of proximal
DVT/PE.
The frequency of total
VTE and/or all-cause mortality among patients undergoing TKR was 22.5% for
patients in the ximelagatran group and 31.9% for patients in the warfarin group
(Table B3).
Table B3 Frequency of total venous thromboembolism
and/or all-cause mortality (efficacy ITT population; blinded ICAC assessment)

Ximelagatran 36 mg was
superior to warfarin group (p<0.001) in reducing total VTE and/or all-cause
mortality among patients with TKR according to blinded ICAC assessment. The absolute reduction in the frequency of total
VTE and/or all-cause mortality was 9.3% with ximelagatran (31.9% warfarin vs
22.5% ximelagatran 36 mg) (p<0.001); the number needed to treat to obtain
benefit (1/ARR) was 11 (95% CI: 8 to 19).
Results obtained from
data in the efficacy ITT population were confirmed by analyses of data from
patients in the PP population. The frequency rates of total VTE and/or
all-cause
mortality in the PP
population were 22.6% and 33.3% among patients in the ximelagatran and warfarin
groups, respectively (p<0.001).
2.10.2 Secondary variables
Incidence of proximal deep vein thrombosis,
pulmonary embolism, and/or all-cause mortality (blinded ICAC assessment)
The frequency of
proximal DVT, PE, and/or all-cause mortality using blinded ICAC
assessments among
patients undergoing TKR was 3.9% for patients randomized to
ximelagatran 36 mg and
4.1% for patients randomized to warfarin (Table B4).
Table B4 Frequency of proximal DVT, pulmonary
embolism, and/or all-cause mortality (efficacy ITT population; blinded ICAC
assessment)

There was no difference
for reduction in the frequency of proximal DVT, PE, and/or all-cause mortality
between the patients in ximelagatran 36 mg group and warfarin group (p=0.802).
Incidence of total VTE and/or all-cause mortality
(local assessment)
The frequency of total
VTE and/or all-cause mortality assessed locally at study centers was slightly
higher in both treatment groups (<10% difference) than when assessed
centrally by the ICAC. The locally assessed frequency of total VTE and/or
all-cause mortality among patients undergoing TKR was 30.1% in the ximelagatran
group and 35.8% in the warfarin group (Table B5).
Table B5 Frequency of total venous
thromboembolism and/or all-cause mortality
according to local assessments (safety population
with evaluable local assessments)

Ximelagatran 36 mg was
superior compared to warfarin in reducing total VTE and/or all-cause mortality
among patients with TKR according to local assessments (p=0.007). Using local
assessments, the absolute reduction in the frequency of total VTE and/or
all-cause mortality in the ximelagatran group was 5.7% in relation to patients
in the warfarin group, providing a relative risk reduction of 15.9 (95% CI: 4.6
to 2.58).
The rate of proximal VTE
and/or all-cause mortality was numerically higher using local versus central
assessments, 6.8% in the ximelagatran group compared with 5.7% in the warfarin
group (p=0.298; 95% CI of -1.0 to 3.3 surrounding the between-group difference
of 1.1%).
2.10.3 Subgroup analysis
The results of the
subgroup analysis were generally consistent with the overall pattern of results
seen the total efficacy ITT population, with the incidence of total VTE and/or
all-cause mortality consistently lower in the ximelagatran group compared with
the warfarin group. The frequency of total VTE and/or all-cause mortality is
shown for selected subgroups in Table B6.
Table B6 Impact of selected subgroups on the
frequency of total VTE and/or all-cause mortality (efficacy ITT population;
blinded ICAC assessment)

A higher frequency of
total VTE and/or all-cause mortality was observed across both treatment groups
for female patients (relative to males), older patients (relative to younger
patients), patients enrolled at sites in Canada (relative to those in the
United States and the rest of the world), patients with bilateral surgery
(relative to unilateral surgery), patients with a history of VTE (relative to
no VTE history), and patients with earlier scheduled venograms (relative to
later venograms) (p‹0.016 across all factors).
2.10.4 Symptomatic and asymptomatic
thromboembolic events
Over the entire study
period (treatment and follow-up), there were 45 objectively confirmed,
symptomatic thromboembolic events in the efficacy ITT population occurring in
20 (2.0%) patients in the ximelagatran 36 mg group and 24 (2.5%) patients in
the warfarin group (Table B7).
Table B7 Objectively confirmed symptomatic and
asymptomatic thromboembolic events over the entire study (efficacy ITT
population)

The proportions of
patients with objectively confirmed, symptomatic total DVT and proximal DVT
were low in both treatment groups (1.1% and 0.4% in the ximelagatran group,
respectively; and 1.7% and 0.2% in the warfarin group, respectively). During
the treatment period, the incidence of any confirmed thromboembolic event was
lower in the ximelagatran group (n=14, 1.4%) compared with the warfarin group
(n=22, 2.3%).
Among patients included
in the efficacy ITT population, 21.8% of ximelagatran-treated and 31.1% of
warfarin-treated patients had asymptomatic DVTs detected at mandatory
venography. Corresponding proportions of patients with proximal DVTs at
mandatory venography were 3.1% and 3.4%. Venograms were not evaluable for 15.2%
of all patients. The most common reasons provided by the sites for not
performing the venogram included failed venous access and withdrawal of patient
consent. There was no appreciable difference in the number of patients without
central venogram assessments between the ximelagatran and warfarin groups
(14.7% and 15.8%, respectively).
2.10.5 International normalized prothrombin time
ratios (INR) in the warfarin treatment arm
At the End of Treatment
Period Study Visit, 54.6% of patients in the warfarin treatment group had INR
values within the therapeutic range of 1.8 to 3.0 (Table B8).
Table B8 Proportion of patients in the warfarin
treatment group with INR within 1.8 and 3.0 (efficacy ITT population)

On postoperative Day 3
and at the End of Treatment Period Study Visit, 66.9% and 73.1% of warfarin
patients, respectively, had INR values of 1.8 or greater.
There was no appreciable
difference in mean INR between patients in the warfarin group with confirmed
VTE or no confirmed VTE at the postoperative Day 3 and End of Treatment Period
Study visits. The mean INR for patients with confirmed vs no confirmed VTE was
2.319 and 2.393, respectively at postoperative Day 3 and 2.342 and 2.445,
respectively, at the End of Treatment Period Study Visit.
There were no
appreciable differences between the distribution of INR values in patients with
and without confirmed VTE, with approximately one-third of patients with a
confirmed event within the therapeutic range of 1.8 to 3.0 on both
postoperative Day 3 and at the End of Treatment Period Study Visit.
There are several major problems in this study using
warfarin as a comparator. Warfarin is not suitable for short-term therapy for
prevention of VTE in patients with TKR surgery. Warfarin is not approved for
this indication. The comparison is unfair, because warfarin will take about 3-5
days to reach therapeutic level, while Exanta reaches therapeutic levels within
hours. The results show that 33.1% of patients receiving warfarin had an INR
less than 1.8 by postoperative day 3, and 26.9% by end of treatment (day 7 –
12). Therefore, although the study demonstrated that the 36 mg dose of
ximelagatran was superior to “warfarin group” (p<0.001) for primary
endpoints, it is unacceptable to claim that ximelagatran is better than
warfarin for this indication.
2.10.6 Conclusions on efficacy results
In this study (EXULT B),
an oral treatment regimen of ximelagatran 36 mg bid begun at least 12 hours
following TKR and continued for 7 to 12 days was associated with a low rate of
VTE (22.5%) in comparison with warfarin (31.9%). According to blinded ICAC
assessment, the absolute reduction in the frequency of total VTE and/or
all-cause mortality was 9.3% with ximelagatran (31.9% warfarin vs 22.5%
ximelagatran 36 mg, p<0.001), providing a relative risk reduction of 29.3%
(95% CI: 18.1 to 39.1) and a number needed to treat to obtain benefit (1/ARR)
of 11(95% CI: 8 to 19). The benefit was mainly due to a reduction in
asymptomatic distal DVT diagnosed by venography which is not clinically
meaningful. There were no clinically or statistically significant differences
between ximelagatran and warfarin in reducing the frequency of proximal DVT,
PE, and/or all-cause mortality in this population. The incidence of proximal
DVT, PE, and/or all-cause mortality was low in both treatment groups, 3.9% for
ximelagatran and 4.1% for warfarin (p=0.802).
The reduction in total
VTE and/or all-cause mortality observed for the efficacy ITT population was
confirmed by analyses of data from patients in the PP population (p<0.001)
and using local assessments (p=0.007). The locally assessed frequency of total
VTE and/or all-cause mortality among patients undergoing TKR was 30.1% for
ximelagatran and 35.8% for warfarin (absolute reduction of 5.7%).
A higher frequency of
total VTE and/or all-cause mortality was observed across both treatment groups
for female patients (relative to males), older patients (relative to younger
patients), patients enrolled at sites in Canada (relative to those in the
United States and the rest of the world), patients with bilateral surgery
(relative to unilateral surgery), patients with a history of VTE (relative to
no VTE history), and patients with earlier scheduled venograms (relative to
later venograms) (p‹0.016 across all factors).
There are several major problems for comparison of
ximelagatran with warfarin in this study. Warfarin is not suitable for
short-term therapy for prevention of VTE in patients with TKR surgery. Warfarin
is not approved for this indication and has not been used for this purpose in
medical practice. The comparison is unfair, because warfarin will take about
3-5 days to reach therapeutic level, while Exanta reaches therapeutic levels
within hours. The results show that 33.1% of patients receiving warfarin had an
INR less than 1.8 by postoperative day 3, and 26.9% by end of treatment (day 7
– 12). More patients (44, 3.8%) in the
warfarin group than the ximelagatran group (11, 1.0%) did not receive first
dose of study drug on schedule. Therefore, although the study
demonstrated that the 36 mg dose of
ximelagatran was superior to warfarin group (p<0.001) for the primary
endpoint efficacy analysis, it is unacceptable to claim that ximelagatran is
better than warfarin.
2.11.1 Extent of exposure
Of the 2303 patients
randomized to study drug in this study, 4 patients (1 ximelagatran, 3 warfarin)
never received study drug following surgery and were therefore excluded from
the safety population.
The duration of exposure
to study drug is summarized in Table B9 for the safety population.
Table B9 Overview of exposure in the safety
population

The mean number of days
on treatment was 8.2 days in the ximelagatran group and 7.6 days in the
warfarin group. There was a disparity between the 2 treatment groups, with a
higher percentage of patients in the warfarin group treated for only 1 to 6
days (19.0%) compared with patients in the ximelagatran group (4.9%). Of the
218 patients recorded as receiving 1 to 6 days of warfarin treatment, most (n=171)
were reported to have completed therapy. The remaining 47 patients discontinued
study drug prematurely, most commonly due to AEs (n=30) and a confirmed VTE
event (n=6). The above discrepancy resulted in a higher proportion of patients
in the ximelagatran group (71.7%) compared with the warfarin group (58.7%) who
were treated for 7 to 9 days; there were no appreciable differences in exposure
to study drug between the treatment groups from postoperative Day 10 onwards.
2.11.2 Adverse events
A summary of
treatment-emergent AEs in each category of seriousness is presented for the
safety population in Table B10.
Table B10 Number (%) of patients with
treatment-emergent adverse events (safety population, follow-up included)

The overall tolerability
profiles for ximelagatran and warfarin were similar, with approximately 61% of
patients in each treatment group reporting at least 1 treatment-emergent AE and
approximately 14% of patients reporting drug-related AEs. There were no
appreciable differences between treatment groups in the proportions of patients
with bleeding-related and non-bleeding-related AEs. In addition, the
proportions of patients who experienced an SAE or who discontinued treatment
prematurely for an AE were similarin the ximelagatran and warfarin groups. Ten
patients, 7 in the ximelagatran group and 3 in the warfarin group, died during
treatment or within the study-defined 4- to 6-week follow-up visit.
2.11.2.1 Most common treatment-emergent adverse
events (safety population)
The most frequently
reported AE in both treatment groups was postoperative complications (preferred
term coding for events such as anemia, pain, wound infection, and bleeding)
which was reported by 18.6% of patients in the ximelagatran group and 17.0% of
patients in the warfarin group. The remaining common AEs experienced by at
least 5% of the patients in either treatment group were fever, nausea, and
increased levels of GGT. The types and incidence rates of common AEs in the
study were generally comparable in the ximelagatran and warfarin groups.
Among the less commonly
reported AEs, there was at least a 2-fold higher incidence of chest pain in the
ximelagatran group (1.9%) compared with the warfarin group (0.8%). None of the
episodes of chest pain were considered related to study drug. No additional AEs
occurred with at least a 2-fold higher incidence in the ximelagatran group
compared with the warfarin group.
Drug-related
treatment-emergent AEs were reported for comparable percentages of patients in
the ximelagatran (13.6%) and warfarin (14.7%) groups. The types and incidence
rates of treatment-emergent drug-related AEs were generally comparable between
treatment groups. The most frequently reported treatment-emergent, drug-related
AEs in the ximelagatran and warfarin groups were increased serum levels of GGT
(4.8% and 3.6% for ximelagatran and warfarin, respectively), postoperative
complications (3.7% and 2.9%, respectively), increased SGPT (2.6% and 2.3%,
respectively), and increased alkaline phosphatase (2.6% and 2.5%,
respectively).
2.11.2.2 Treatment-emergent adverse events
(modified safety population)
The modified safety
population included patients who had TKR performed and received at least 1 dose
of active study medication at any point on or after postoperative Day 1.
Seven patients (4
ximelagatran, 3 warfarin) were excluded from the modified safety
population. Each of the
4 ximelagatran-treated patients received warfarin placebo on the day of surgery
but were discontinued from the study prior to receiving the morning dose of
ximelagatran on Day 1. Similarly, the 3 warfarin-treated patients received a
single dose of warfarin on the day of surgery but were discontinued prior to
receipt of study medication on Day 1 (ximelagatran placebo or warfarin).
The percentage of
patients included in this population who reported at least 1 treatment-emergent
AE (60.8% and 61.5% for the ximelagatran and warfarin groups, respectively) was
almost identical to that of the overall safety population (60.7% and 61.6%,
respectively).
Of the 4 patients in the
ximelagatran group who were excluded from the modified safety
population, 1(6/10829)
died as the result of ventricular fibrillation and cardiomyopathy on
postoperative Day 1. One additional patient in the ximelagatran group
(29/10944) and the 3 patients in the warfarin group (105/10382, 207/12335, and
210/12327) discontinued treatment prematurely as the result of AEs that began
on postoperative Day 1.
2.11.2.3 Bleeding events
As seen in Table B11,
the majority of bleeding-related AEs in the ximelagatran and warfarin groups
were assessed by the ICAC as a minor bleeding event or no bleeding event. A
higher incidence of major bleeding events was found in the ximelagatran group
than warfarin group, 1.1% and 0.5% of patients, respectively.
Table B11 Number (%) of patients with
treatment-emergent bleeding-related AEs
by ICAC adjudication (safety population)

Five patients (0.4%) in
each treatment group had GI hemorrhage reported as a bleeding-related AE. For 3
of these patients (2 ximelagatran, 1 warfarin), the ICAC assessed the GI
hemorrhage as a major bleeding event. One patient in the ximelagatran group
(227/12588) died as a result of the GI hemorrhage following attempted
cardiopulmonary resuscitation due to loss of melenic stool, sudden volume
depletion, and peripheral shut down.
Incidence of adjudicated bleeding events
The frequencies of
adjudicated bleeding events on treatment are summarized by event type in Table
B12.
Table B12 Frequency of ICAC adjudicated on-treatment
bleeding events by event
type (safety population)

Major bleeding events
were uncommon during the treatment period and were reported for only 12 of the
1151 (1.0%) patients treated with ximelagatran 36 mg and 5 of the 1148 (0.4%)
of the patients treated with warfarin. Minor bleeding events were reported
during treatment for 4.2% and 3.4% of patients in the ximelagatran and warfarin
groups, respectively, while 5.0% and 3.8% of patients, respectively, were
reported to have any bleeding event (major or minor). Only 7 additional
patients (3 ximelagatran, 4 warfarin) experienced adjudicated major or minor
bleeding events between administration of the last dose of study medication and
the follow-up visit. Although there were no statistically significant differences
between the 2 treatment groups in the frequency of major, minor, or combined
major or minor bleeding events while receiving study medication (p>0.087)
or during the entire study (p>0.105), a numerically higher incidence
of major bleeding events in the ximelagatran group was found.
The frequency of
on-treatment bleeding events for patients treated with warfarin by INR range is
summarized in Table B13.
Table B13 Frequency of on-treatment bleeding
events for patients treated with warfarin by international normalized ratios
(safety population)

There were no
appreciable differences between the distribution of INR values in patients
without a confirmed bleeding event at postoperative Day 3 or the End of
Treatment Period Study Visit or with a confirmed bleeding event at the End of
Treatment Period Study Visit. On postoperative Day 3, however, most patients
with a confirmed bleeding event had an INR value of <3.0.
Subgroup analyses of adjudicated bleeding events
The frequency of adjudicated on-treatment major/minor
bleeding events was examined by subgroup factors relating to pre-specified
demographic and other patient characteristics (Table B14). For the majority of
subgroups examined, the pattern of results was consistent with that of the
overall population, with the incidence of bleeding events in the ximelagatran
group comparable to or slightly higher than that in the warfarin group. A
logistic regression analysis examining on-treatment bleeding events found that
across both treatment groups there was a statistically significant effect of
age and gender on the incidence of major/minor bleeding events, with male
patients and older patients associated with an increased risk of bleeding
(p‹0.02 for both factors). The interaction of each subgroup factor with
treatment was also analyzed and indicated a statistically significant
interaction between treatment and age and treatment and body mass index
(p‹0.048). In the warfarin group, the rate of on-treatment bleeding events was
highest in patients aged >75 years and those with a body mass index of
<30 kg/m2. By comparison, rates of on-treatment adjudicated
major/minor bleeding events in the ximelagatran group were similar across all 3
age and body mass index subcategories.
Table B14 Impact of selected subgroups on the
frequency of on-treatment bleeding events (combined major and minor) (safety
population)

2.11.2.4
Deaths, serious adverse events, discontinuation due to adverse events,
and other significant adverse events
Deaths
Among all randomized patients,
10 died, including 7 in the ximelagatran group and 3 in the warfarin group. One
death was considered by the investigator to be related to study drug: Patient
227/12588 in the ximelagatran group died as the result of a GI hemorrhage on
postoperative Day 8 while receiving study medication. Six of the 10 deaths
occurred while patients were receiving treatment, including 4 in the
ximelagatran group and 2 in the warfarin group. Deaths while on treatment with
ximelagatran included ventricular fibrillation with cardiomyopathy, MI, sudden
death, and GI hemorrhage, while those occurring on treatment with warfarin
included cardiac arrest with AV block and MI. The remaining 4 deaths occurred
during the 4- to 6-week follow-up period.
Of the 7 patients in the
ximelagatran group who died, the ICAC could not rule out that the death was
associated with a PE for 3 patients; 2 had experienced a MI (401/15134 and
507/14091) and 1 died
suddenly and the exact cause of death was unknown (510/14366). One of these
deaths occurred on treatment (507/14091), while the other 2 deaths occurred
during follow-up. None of these 3 patients had an objectively confirmed
clinical PE. The ICAC assessed 1 death to be the result of a major bleeding
event; Patient 227/12588 in the ximelagatran group died as the result of a GI
hemorrhage on postoperative Day 8 following his morning dose of study
drug. The remaining 3 deaths in the
ximelagatran group were not associated with a VTE or bleeding event as assessed
by the ICAC. Of the 3 deaths occurring in the warfarin group, none were
associated with a VTE or bleeding event as assessed by the ICAC. All patients
who died are listed in Table B15.
Table B15 Listing of all patients who died


Narratives for patients
6/10829, 227/12588, 235/12122 and 510/14366 are presented below:
·
Patient
6/10829 was a 43 year old male Caucasian. The subject had a history of
hyperlipidemia, coronary angiogram, type II diabetes mellitus, ischemic
colitis, obstructive sleep apnea, ear infection, H. pylori, right knee
arthroscopy, laminectomy and fusion, adenoidectomy and septoplasty. He
underwent right total knee replacement for osteoarthritis. Operative blood loss
was 400 mL, and no postoperative drainage volume was reported. The subject
received the first dose of warfarin placebo approximately 8 hours after surgery
but did not receive any doses of ximelagatran. On postoperative day 1, the
subject died suddenly. Based on an autopsy performed the next day, cardiac
arrhythmia (ventricular fibrillation) due to hypertrophic cardiomyopathy was
the primary cause of death, and hepatomegaly and obesity were secondary causes
of death. No embolism, infarction, or hemorrhage was reported as contributing
to death. The mandatory venography was not performed for this subject because
he died before venography was performed. The study investigator assessed these
events of cardiac arrhythmia (ventricular fibrillation) and hypertrophic
cardiomyopathy as not related to the study drug.
·
Patient
227/12588 was an 80 year old male Caucasian. The subject had a history of
cardiomegaly, abnormal electrocardiogram (EKG), bifascicular block, right
bundle branch block with left axis deviation, benign microhematuria, rotator
cuff tear, hiatal hernia, right hand tremors, bilateral glaucoma, and umbilical
hernia repair. He underwent right total knee replacement for osteoarthritis.
Operative blood loss was 50 mL, and postoperative drainage was 400 mL. The
subject received the first dose of warfarin placebo approximately 10 hours
after surgery. He received 8 days of treatment with ximelagatran 36 mg for a
total of 13 doses. Postoperatively, the subject had agitation and intermittent
confusion. On postoperative day 2, the subject developed a decreased level of
consciousness. Study drug was withheld until the neurologist assessed the
subject. A computed tomography (CT) scan was negative for bleed, lesion, or
cerebrovascular accident. Study drug continued to be withheld due to
drowsiness. Hemoglobin and hematocrit were 85 g/ L and 24.1%, respectively.
Lasix (furosemide) was given intravenously per blood transfusion protocol. On
postoperative day 7, some non- progressive bruising on the subject’s thigh was
noted. Hemoglobin and hematocrit were 98 g/ L and 28.6%, respectively. PT and
PTT were elevated above normal reference ranges. Cardiac enzymes were within
normal range. Red blood cell count was below normal limits at 3.24x109/
L. That same day, the subject became diaphoretic, pale, and weak, and a large
amount of melenic stool was found in the bed. He became unresponsive, and his
blood pressure dropped significantly. Thirty minutes later, hemoglobin was
decreased to 84 g/ L; red blood cells and hematocrit decreased to 2.74x109/
L and 24.9%, respectively. PT, PTT, and BUN were above normal limits at 1.4, 40
seconds, and 10.2 mmol/ L, respectively. Cardiac enzymes were within normal
range. The subject’s condition continued to deteriorate. Cardiopulmonary
resuscitation was performed, but the subject expired one hour after onset of
symptoms. The study investigator and hospital physician thought that a massive
gastrointestinal bleed had occurred due to symptoms of the large melena stool
immediately before the event, the sudden volume depletion, and peripheral shut
down. The autopsy assessment note and a review with the coroner concluded the
cause of death to be a massive upper gastrointestinal bleed due to a chronic
duodenal ulcer perforation due to anticoagulation. The mortality classification
status was fatal bleed. The upper gastrointestinal bleed was centrally adjudicated
as a major bleeding event. The study investigator assessed the upper
gastrointestinal bleed as related to the study drug.
·
Patient
235/12122 was an 81 years old male Caucasian. The subject had a history of
coronary artery disease, hyperlipidemia, prostate cancer, non- insulin
dependent diabetes, hiatal hernia, alcoholism (21 drinks/ week), and right
total knee replacement. He underwent left total knee replacement for
osteoarthritis. Operative blood loss was 75 mL, and no postoperative drain was used.
The subject received the first dose of warfarin placebo approximately 4 hours
after surgery. He received 3 days of treatment with ximelagatran 36 mg for a
total of 5 doses. On postoperative day 1, the subject received a blood
transfusion for decreased hemoglobin of 83 g/ L. The subject developed
confusion after the transfusion (approximately 24 hours postoperatively), which
the study investigator attributed to alcohol withdrawal. The subject was
treated with a benzodiazepine medication. On postoperative day 2, the subject
became aggressive and violent, assaulted one of the nurses, and had to be
restrained. On postoperative day 3, his confusion was still fairly significant.
The study investigator noted the subject to be improved, fairly lucid, and
denying any problems in regard to the knee replacement. On postoperative day 4,
the subject was discovered unresponsive with absent vital signs. Resuscitation
was attempted but was unsuccessful, and the subject expired. An autopsy was
performed. The coroner stated the subject’s death was due to cardiac
arrhythmia, on the basis of extensive coronary artery disease with no evidence
of any thromboembolic events. Cardiac arrhythmia was therefore the cause of
death recorded on the death certificate. The study investigator assessed the
sudden death as not related to the study drug. The mandatory venography was not
performed for this subject due to his death.
·
Patient
510/14366 was an 80 years old female Caucasian. The subject had a history of
hypertension, gastritis, varicose veins, perineoplasty, and removal of dorsal
sebaceous cyst. She underwent right total knee replacement for osteoarthritis.
Operative blood loss was 300 mL, and postoperative drainage was 1340 mL. The
subject received the first dose of warfarin placebo approximately 5 hours after
surgery. She received 7 days of treatment with ximelagatran 36 mg for a total
of 13 doses. The subject was discharged to home on postoperative day 4. On
postoperative day 7, the subject had a mandatory bilateral venogram assessed as
positive for intraluminal- filling defects in the left muscular and right
fibular veins. Both legs were classified as having any deep vein thrombosis
(DVT) distally. The subject received Clexane (heparin- fraction, sodium salt)
and open- label warfarin sodium for treatment of the DVT. On postoperative day
19, the subject’s family reported to the study investigator that the subject
had died at home on postoperative day 15. The cause of death was unknown. No
autopsy was performed. Based on central adjudication, the mortality
classification status was fatal pulmonary embolism (PE), as PE could not be
excluded as the cause of the unexplained, undescribed death at home two weeks
after surgery. The study investigator assessed the death (unknown reason) as not
related to the study drug.
Serious adverse events other than deaths
Of the 2299 patients
included in the safety population, 158 patients had a treatment-emergent SAE,
and the proportion of patients with an SAE was identical in the ximelagatran
and warfarin groups (n=79, 6.9% for each). A summary of the SAEs (including
death) experienced by at least 2 patients in either treatment group is provided
in Table B16 by preferred term.
Table B16 Number (%) of patients with SAEs
occurring in at least 2 patients

In both treatment
groups, the most common SAE was postoperative complications, occurring in 2.1%
of ximelagatran patients and 1.4% of warfarin patients. Pneumonia and MI were
considered serious for more patients in the ximelagatran group (n=6, 0.5% for
both) compared with the warfarin group (n=1, 0.1% and n=3, 0.3%, respectively).
Serious postoperative complications were experienced by 18 patients, 13 (0.9%)
randomized to ximelagatran and 5 (0.7%) to warfarin. In contrast, atrial
fibrillation and increased INR were considered serious for more patients in the
warfarin group (n=6, 0.5% and n=5, 0.4%, respectively) compared with the
ximelagatran group (n=2, 0.2% for each).
The proportion of
patients with SAEs considered related to study medication by the investigator
was similar in the ximelagatran (n=13, 1.1%) and warfarin (n=19, 1.7%) groups.
Few patients had serious postoperative complications that were assessed by the
investigator as related to study drug (5 in the ximelagatran group; 4 in the
warfarin group). Seventeen patients in the ximelagatran group (including 3 who
died) and 19 in the warfarin group (including 2 who died) had treatment
discontinued prematurely as the result of a SAE(s).
Treatment-emergent SAEs
were assessed by the ICAC as a major bleeding event for 8 patients in the
ximelagatran group and included GI hemorrhage (2), postoperative complications
(2), hemorrhoids (1), hemarthrosis (1), purpura (1), and intracranial
hemorrhage (1). In the warfarin group, treatment-emergent SAEs were assessed by
the ICAC as major bleeding events for 4 patients, including hemarthrosis (1),
purpura (1), GI hemorrhage (1), and postoperative complications (1).
Discontinuations due to adverse events
A summary of the
treatment-emergent AEs leading to discontinuation of study drug by at least 2
patients in either treatment group is provided in Table B17 by preferred term
in decreasing order of frequency in the ximelagatran group.
The proportion of
patients for whom the investigator coded the AE as having caused premature
discontinuation of study drug was comparable in the ximelagatran group (n=28,
2.4%) and the warfarin group (n=34, 3.0%).
Table B17 Number (%) of patients who discontinued
from treatment due to a treatment-emergent adverse event (safety population)

2.11.3 Clinical laboratory evaluation
At baseline, mean
hemoglobin levels and platelet counts were comparable in the ximelagatran and
warfarin groups. There was a steady decline in hemoglobin levels and platelet
counts during the first 3 days postoperatively in both treatment groups, with
the largest mean decrease in both parameters observed on postoperative Day 3
(mean percent reduction of 25% to 26% in both groups). By the End of Treatment
Period Study Visit, hemoglobin levels had increased slightly and had returned
to near baseline levels by the end of the follow-up period in both the
ximelagatran and warfarin groups. Mean platelet counts at the End of Treatment
Period Study Visit were elevated above baseline values, likely due to the
receipt of transfusions. Mean platelet count had returned to near baseline
levels during follow-up.
Each of the liver
function parameters and total bilirubin were increased relative to baseline in
both treatment groups at the End of Treatment Period Study Visit and there was
no difference between treatment groups in the magnitude of the increase. In
both treatment groups, the largest mean increase from baseline was observed for
ALAT (mean percent increase of approximately 55%). At follow-up, ALAT, ASAT,
and total bilirubin values were at or near baseline values while alkaline
phosphatase values remained elevated.
The frequencies in
measures of liver function outside the extended reference ranges for liver
enzymes (ASAT, ALAT, and alkaline phosphatase) and total bilirubin are
summarized in Table B18.
Table B18 Frequency of selected liver function
test values elevated above upper limits of normal (safety population)

Few patients (<3%) in
the ximelagatran or warfarin groups had abnormalities outside the extended
range at any time point for any of the liver function parameters. Less than 1%
of patients in either treatment group had increases of >3x ULN for any liver
function parameter during the study. All patients in both treatment groups with
an elevation in ALAT of >3x ULN at the end of treatment or at follow-up (ie,
more than 2 days after the last dose of study medication), had normalized
values within 4 weeks of onset. It should be noted that there were more
patients with ALT elevation (> 3ULN) in ximelagatran group (n=7) than
in the warfarin group (n=2) during the following up period. This may indicate
that ximelagatran may cause late occurrence of liver toxicity and 4-6 weeks of
follow-up may not be adequate to assess the safety for short-term use of
ximelagatran.
2.11.4 Conclusions on safety results
There were no
statistically significant differences between ximelagatran and warfarin in the
frequency of major bleeding events, the frequency of minor bleeding events, or
the frequency of any (major and minor) bleeding events on-treatment or over the
entire study (p>0.087). With the exception of a significantly higher
incidence of unusual bruising or hematoma on postoperative Day 3 in the
ximelagatran group compared with the warfarin group (p=0.015), there were no
significant differences between treatment groups at any other time point in the
incidence of any other wound assessments (p>0.245).
No appreciable
differences were detected between treatment groups in the incidence of
treatment-emergent AEs, SAEs, or discontinuations due to study drug. However, a
larger number of patients in the ximelagatran group died (n=7) compared with
the warfarin group (n=3). MI was considered serious for more patients in the
ximelagatran group (n=6, 0.5%) compared with the warfarin group (n=3, 0.3%,
respectively). It should be noted that there were more patients with ALT
elevation (> 3ULN) in ximelagatran group (n=7) than in the warfarin
group (n=2) during the following up period. This may indicate that ximelagatran
may cause late occurrence of liver toxicity and 4-6 weeks of follow-up may not
be adequate to assess the safety for short-term use of ximelagatran.
3 Study
SH-TPV-0003 (THRIVE III) for the Indication of Prolonged prophylaxis VTE after a six-month
anticoagulation treatment for VTE
The sponsor provided only one study, SH-TPV-0003
(THRIVE III) to support this indication. This was a multicentre, double-blind,
parallel-group, placebo control study.
Title: Oral Thrombin Inhibitor Ximelagatran given
to Patients as Prolonged Prophylaxis after a Six-month Anticoagulation
Treatment for Venous Thromboembolism. An International Multicentre Double-blind
Placebo Controlled Study (THRIVE
III)
3.1 Study objectives
Primary objectives
To assess whether the oral
thrombin inhibitor ximelagatran given as prolonged prophylaxis after a
six-month anticoagulation treatment for VTE reduces the recurrence rate of
symptomatic objectively confirmed VTE event compared to placebo (time to
event).
Secondary objectives
To estimate all-cause
mortality, the safety of treatment with ximelagatran with special regard to
bleeding and the pharmacokinetics of melagatran during long term treatment with
ximelagatran.
3.2 Overall study design
This was a double-blind,
randomized, placebo-controlled, parallel-group multi-center study comparing the
efficacy and safety of ximelagatran 24 mg twice daily with placebo when given
orally as long term secondary prevention for 18 months to patients after a
six-month anticoagulation treatment for VTE.
The clinical endpoints
were symptomatic objectively confirmed VTE, non-fatal or fatal, and all-cause
mortality and major bleeding. The primary variable was time to symptomatic
objectively confirmed VTE event during 18 months of treatment.
A total of 1,200
patients at approximately 150 centers in 18 countries, with roughly 10 (6-20)
patients per center, were planned to be randomized into the study.
The study comprised the
following 4 periods:
Anticoagulant and wash-out periods
Patients who had received
anticoagulation treatment for six (five to seven) months after an objectively
verified, symptomatic VTE were to be included. Dates for the bilateral
ultrasonography of the legs and the perfusion scan of the lungs (baseline) were
to be scheduled shortly before randomization. The patients were instructed to
stop treatment with vitamin K antagonist (VKA) two to seven days before the
scheduled randomization visit.
Randomization
The randomization was
stratified on the basis of the presence or absence of known active malignancy
during the past five years. The patients were randomized in equal proportions
to receive either ximelagatran tablets 24 mg or placebo tablets orally twice
daily for 18 months.
18-month randomized treatment period
Study visits were
scheduled at two weeks and four weeks and then every month (three to five
weeks) during the first six months after the randomization and thereafter every
three months (10-14 weeks).
Follow-up period
A follow-up visit was to
be planned two weeks after completing the randomized treatment period.
3.3 Selection of study population
The first exclusion
criterion (patients with a need of continuous treatment with anticoagulants)
implies that patients considered to be at high risk of recurrence were not to
be included in the study. This criterion was set for ethical reasons, since it
would not have been appropriate to randomize this type of patient to treatment
with placebo.
Inclusion criteria
For inclusion in the
study, patients had to fulfill all of the following criteria:
1. Patients with symptomatic objectively
confirmed VTE treated with anticoagulants for six months (no recurrent VTE was
allowed during this period)
2. Age >18
years
3.
Signed informed consent
Exclusion criteria
Any of the following was
regarded as a criterion for exclusion from the study:
1. Patients with a need of continuous treatment with
anticoagulants
2. Conditions associated
with an increased risk of bleeding
3. Anemia (Hb < 90
g/L)
4. Platelet count <
90x10 9 /L
5. Renal impairment
(calculated creatinine clearance < 30 mL/min)
6. Known clinically significant liver disease (as
judged by the investigator) or persistent ASAT and/or ALAT > 3 x ULN
(defined by central laboratory)
7. Pregnancy and/or
lactation
8. Childbearing potential
without reliable contraception
9. Concomitant treatment with other
anticoagulant, antiplatelet or fibrinolytic agents; continuous treatment with
acetylsalicylic acid (ASA) >500 mg per day or continuous treatment with
NSAID.
10. Participation in an
interventional clinical study during the last three months
11. Planned surgery
12. Involvement in the
planning and conducting of the study
13. Previous
randomization in the present study
14. Known drug addiction
and/or alcohol abuse
15. Mental condition preventing
understanding of the study
16. Poor compliance, as evidenced during the six
months of anticoagulation treatment before randomization, as judged by the
investigator
17. Serious illness,
with survival for 18 months being unlikely ie, terminally ill patients
3.4 Criteria for discontinuation
1. Patients for whom the treatment code was
prematurely broken were withdrawn from further study treatment and assessments.
2. Major bleeding.
3. Objectively confirmed
venous thromboembolic event.
4. Other AEs severe
enough to necessitate discontinuation of study drug administration.
5. If a pregnant woman
was included by mistake or a woman became pregnant.
Discontinuation of the
study drug should also have been considered if:
·
S-ALAT was
>7 times the ULN
·
Repeated measurements
showed that S-ALAT was 3-7 times the ULN during a 2- month period without
showing any tendency to decrease.
3.5 Doses and treatment regimens
The
patients were randomized to treatment with either one 24-mg ximelagatran tablet
twice daily or one tablet of placebo twice daily, taken orally in the morning
and in the evening for 18 months.
3.6 Efficacy variable
Primary variable
The
primary variable was time to symptomatic objectively confirmed VTE event during
the 18 months of treatment or until premature discontinuation of the study.
Secondary variable
Time to death from any
cause and time to major bleeding event, during 18 months of treatment or until
premature discontinuation of the study (ITT population).
3.7 Statistical analysis methods
In the primary analysis,
only centrally adjudicated events are considered as events. Because of the long
treatment period, the number of drop-outs in the study was expected to be
substantial. Therefore, the equality of time until event between ximelagatran
and placebo is tested with a log rank test. Due to the independent Safety
Committee monitoring for a positive trend of the pre-planned interim analyses,
the significance level for the primary analysis is 4.76%. For all other
analyses a significance level of 5% is used. Survival curves for the time to
event, based on Kaplan-Meier estimates, are presented, as is the estimated risk
for an event by 3, 6, 9, 12, 15 and 18 months. The hazard ratio between
treatments is estimated together with 95% confidence intervals using a
Cox-regression model assuming a proportional hazard.
Data from the 18-month
follow-up of prematurely discontinued patients will be presented together with
the original study data. The combined data will be analyzed as a complementary
ITT analysis using the same methods as described above. The events collected at
the 18-month follow-up will not be centrally adjudicated, however.
Time until death by any
cause, locally confirmed VTE events, the composite of VTE event and death of
any cause, major and major and/or minor bleedings are analyzed and presented
using the same methods as for the primary variable.
Descriptive statistics
and frequency tables on pertinent variables are calculated for baseline
demographics, days on study medication, compliance, laboratory variables, ECG,
physical examinations and vital signs. In addition, time to elevated ALAT is
presented using Kaplan- Meier estimates. The influence of the potential
prognostic factors mentioned above on the risk for ALAT >3 x ULN is investigated
using logistic regression. Logistic regression is used in these analyses since
an assumption of proportional hazard is unrealistic. Adverse events are
presented using frequency tables.
3.8 Disposition
Of the 1356 patients
enrolled, 1233 were randomized at 142 centers and 903 completed the study. The
most common reason for premature termination the study was adverse event.
Patient disposition and reason for premature study discontinuation are
summarized in Figure 1. In the placebo group locally confirmed VTE recurrence
was the most common reason for premature discontinuation of the study. In
general, discontinuations for other reasons than VTE were slightly more common
in the ximelagatran group.

There were no major
differences between treatment groups in the number of patients who had protocol
deviations that were considered serious enough to warrant exclusion of data
from the PP analyses. Overall, the treatment groups were comparable for
demographic characteristics, baseline parameters, treatment compliance and use
of concomitant medication. The major part of the patients (93%) were
Caucasians.
Patient populations analyzed
Three patient
populations were analyzed:
·
An ITT
efficacy population, which included all randomized patients who had taken at
least one dose of the study treatment and had at least one data point after
randomization. This population was the primary population for analysis.
·
A PP
efficacy population, which included all patients in the ITT population who had
no deviations from the protocol judged to affect the treatment effect. However,
some patients who had a major deviation are included in the analyses up to the
time of that deviation.
·
A safety
population, which included the same patients as in the ITT population.
The patient populations
analyzed and the number of patients in each population are summarized in Figure
2.

Of the 1233 randomized
patients, 10 patients had no data after randomization, 5 of them randomized to
ximelagatran and 5 to placebo. Of the 5 patients on ximelagatran, 3 patients
were also confirmed not to have received any study medication, as can be seen
in Figure 2.
Consequently, 1223
patients were analyzed for safety and efficacy in an ITT population. Among 1015
of the patients, all or a portion of the data was included in the PP analysis.
Among 725 of the patients, all available data were included in a complete PP
analysis. The most common reason for the exclusion of data was non-compliance
as regarded the study drug.
3.9 Demographic and other patient characteristics
Overall, the demographic
and other patient characteristics were comparable between the treatment groups.
The demographic and baseline characteristics for the ITT population are
summarised in Table C1.
Table C1 Demographics and baseline characteristics,
ITT population


Information on the
initial VTE event in the ITT population is summarized in Table C2.


The majority of the
patients (97%) in both groups started the study medication within 3 days after
randomization, and the number of days between randomization and the first dose
of medication was comparable between the treatment groups.
The median time on study
medication was slightly above 500 days, which is shorter than the anticipated
18 months (approximately 540 days). This might be explained by the flexibility
in the time interval between visits allowed according to the protocol.
The use of concomitant
medication at study entry was similar in the two treatment groups.
Conclusions on study patients
The
study population, as demonstrated by baseline characteristics, includes
important
subgroups of a general
population of patients with previous VTE. Different age groups were adequately
represented and the balance between the sexes was appropriate. Patient weights
were widely distributed and obese patients were well-represented. Fourteen
percent of the patients had a history of more than one previous VTE event.
A total of 5% of
patients with known malignancy at entry was enrolled in this study.
A limitation of the
study population is the exclusion of patients with known liver disease and/or
elevations in liver enzymes (ASAT and/or ALAT) at entry, and of patients with
severely impaired renal function, as specified in the exclusion criteria.
Consequently, the results of this study cannot safely be extended to these
subgroups of the VTE population.
3.10 Efficacy results
3.10.1 Primary variable: symptomatic
objectively-confirmed VTE, ITT population
The estimated cumulative
risk of symptomatic objectively-confirmed VTE during 18 months of treatment was
2.8% and 12.6% for patients on ximelagatran and placebo, respectively, see
Table C3.
Table C3 Estimated cumulative risk (%) of a VTE
event, ITT population

The estimated hazard
ratio between treatments is 0.16 (95% CI 0.09; 0.30 and p< 0.0001). According to the outcome of the primary analysis,
ximelagatran significantly reduced the recurrence rate of symptomatic,
objectively confirmed VTE events as compared to placebo (p<0.0001).
The number of patients
with a VTE event was 12 in the ximelagatran group and 71 in the placebo group.
The number of patients with a PE event was lower in the ximelagatran group
compared to the placebo group, 2 and 23, respectively. Number of patients with a VTE event is summarized in Table C4.
Table C4 Number of patients with a VTE event, ITT
population

Of the VTE events
described in Table C4, 3 occurred during the follow-up period i.e., after
cessation of study
medication (2 patients in the ximelagatran group and 1 in the placebo
group).
The location of DVT is
summarized in Table C5, the total numbers of proximal DVT were fewer in the
ximelagatran group than in the placebo group, 6 and 41 respectively.

3.10.2 Secondary variables
All cause mortality, ITT population
There were few deaths
and they were evenly distributed, 6 in the ximelagatran group and 7 in the
placebo group. The estimated cumulative risk of a death (all-cause mortality)
during 18 months of treatment was 1.1% and 1.4% for patients on ximelagatran
and placebo, respectively. The estimated hazard ratio between treatments is
0.83 (95% CI 0.28; 2.46, p=0.7289). According to the outcome of the secondary
analysis, there was no significant difference in all-cause mortality between
the treatment groups during the 18 months.
All-cause mortality and/or VTE events, ITT
population
The total number of
patients who died and/or experienced a VTE event was 18 in the ximelagatran
group and 75 in the placebo group. The estimated hazard ratio between
treatments is 0.23, p< 0.0001. Ximelagatran significantly reduced the
recurrence rate of the combined endpoint, all-cause mortality and/or VTE
events, compared to placebo (p<0.0001). The magnitude is similar to the
difference seen with VTE event only.
Locally confirmed VTE events, ITT population
The
agreement between the local investigator’s judgement and the central
adjudication by the independent Endpoint Committee was generally good, with few
discrepancies. Consequently, the
analysis of locally judged VTE events gave results similar to those for the
centrally adjudicated events. Patients with suspected VTE events with local
assessment versus central adjudication are summarized in Table C6.
Table C6 Patients with suspected VTE events. Local
assessment versus central adjudication, ITT population

By local assessment, the
total number of patients who experienced a VTE event was 13 in the ximelagatran
group and 75 in the placebo group. The estimated hazard ratio between
treatments is 0.17, p< 0.0001. The difference between the treatments was
statistically significant and of the same magnitude as in the case of the
centrally confirmed events used in the primary efficacy analysis.
3.10.3 Summary of efficacy results
Ximelagatran
significantly reduced the recurrence rate of symptomatic, objectively confirmed
VTE (the primary variable of the study) as compared to placebo over 18 months
of treatment (cumulative risk of 2.8% versus 12.6%; hazard ratio 0.16;
p<0.0001). The results for the
secondary variable, all-cause mortality, showed no significant difference
between the treatment groups during the 18 months. Ximelagatran also reduced the recurrence rate
of the composite endpoint, VTE and all-cause mortality, thereby supporting the
results obtained for the primary objective. Complementary intention-to-treat
analyses in randomized patients followed for the full intended 18 months
period, regardless of any premature study medication discontinuation, did not
change the aforementioned conclusions.
3.11 Safety results
See integrated review of
safety for details.