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U.S. Department of Health and Human Services

Vaccines, Blood & Biologics

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Vaccines

STN 125265 Rotarix

MEMORANDUM

 

DATE: February 21, 2008
FROM: S. M. Feinstone
TO: Laraine Henchal
THROUGH: Jerry Weir
CC: Robin Levis, Loris McVittie, Phil Krause, Luba Vujcic
SUBJECT: STN 125265 Rotarix
SPONSOR: GSK

Background: GSK had always used the standard ----- assay from ----------- to test for antibody to HBsAg. However, in 2002, ------ began to discontinue ------ ---- because they had gone to ------------------------------------. GSK looked for alternatives to --------- and found that all ------------------------- of anti-HBsAg test kits were lacking in one way or another. -------------------------------------------------- ------------------------------------------------------------------------------------- ------------------------------------------------------------------------------- ------------------------------------------------------------------------------------ ---------------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------------- ----------------------------------------------------------------------------------- The test was calibrated using reference standards from --- and from the ------------- -----------------------------------------------

The limit of detection (LOD) and limit of quantitation (LOQ) and a cut off value were determined. The LOD was set at ---- mIU/mL and the LOQ at --- mIU/mL and the cut off was set at --- mIU/mL based on the best sensitivity where specificity was not compromised. The analytic range was set at ---- mIU/mL for the lower limit and ------ for the upper limit. Precision was determined by measuring the coefficient of variation (CV) on -------------- and with ------------------- working in both ---------------- --------- sample testing. The CV total was ---- for ------- sample testing and ---- for ---------- testing. These are very good numbers for an ELISA.

Other parameters tested were linearity, specificity, accuracy-recovery, interferences and robustness. The assay performed well for all these characteristics.

A comparison was made with the reference method, ------- EIA in a -------- comparison.

 

Anti-HBs -------- Assay

Total

----- ---

-

+

-

---

---

---

+

---

---

---

Total

---

---

---

Sensitivity: -------------------------
Specificity: ----------------------
Agreement: -----------------------------

The specificity, sensitivity and agreement in comparison to the standard assay was reasonable.

A larger sample was tested in the --- assays in which sera from other GSK studies were evaluated. In this analysis, 1649 sample that tested positive in ---- assays were analyzed ------------------------------------------------------. The correlation coefficient was ------- -------------------. However, it was shown that the --------------- assay gave ------------ antibody concentrations at the ------- and ---------------------.

---------
(mIU/mL)

Anti-HBs -- -----
(predicted mIU/mL)

Ratio ----------/
----- RIA

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

----

The discrepancies between the assays at the ------------------- of antibody are a potential problem because the cut-off value that is accepted for sero-protection is 10mIU/mL. If the new assay is giving ------ results around the level of 10 mIU, there may be the possibility to ------------- the number of subjects who developed antibody at the sero-protective level.

Conclusions and recommendations: The -------- assay compares well with the standard ---------------- with the one problem of the potential for -------------- --------------. For use in the evaluation of the concomitant administration of Rotarix and hepatitis B vaccine in comparison to a placebo, the -------- assay should perform adequately.

Based on the information presented, I recommend that the FDA accept the data from the clinical trials of the concomitant administration of Rotarix with hepatitis B vaccine


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