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Vaccines, Blood & Biologics

SAS Programs/Outputs - Provenge, December 14, 2006

(System Info - 125400 TULL LORI 04/07/2010 09:17:39 TULL)

From: Zhen, Boguang (CBER)
Sent: Thursday, December 14, 2006 2:39 PM
To: 'Harmon, Matt'
Cc: Liu, Ke; 'Yuh, Lianng'; 'Smith, Liz'; Tull Lori
Subject: SAS programs/outputs


Dear Matt,

Thanks for your help in understanding the data structure and the SAS programs
attached in BLA 125197. As ?promised? in the previous telecon, I have more
questions regarding the data analysis and need your further assistance.

1. Cox model -- for Study 9901
I conducted several additional sensitivity analyses with different set of
covariates in Cox model. In one of the analyses, I used localization of
disease (bone and soft tissue vs. bone only or soft tissue only), PSA (<20,
20-<100, >=100), and Gleason score (<=6, 7, >=8) as covariates . Could you
check the program ( to make sure that I used the right
[Note: would like to let you know that this is just one of the many
sensitivity analyses -- although p-value for treatment effect from this
particular sensitivity analysis is 0.0788, p-values from many of my other
sensitivity analyses are below the 0.05 level]
2. Time to objective disease progression as measured by imaging -- for
Study 9901
I tried to repeat your analysis in 11.4.2 Time to objective disease
progression confirmed by imaging studies (p74 of the study report) and tried
to generate Kaplan-Meier curves for this endpoint as suggested by our medical
reviewers . However, I was unable to do so due to failure in identifying the
right variables/datasets. Could you generate Kaplan-Meier curves for us and
tell me which variables you used for this analysis?
3. Survival analysis in Study 9902a
When I run my program for Kaplan-Meier curves and log-rank test for the
overall survival endpoint, I found that the median survivals, CIs, number of
events from my analysis matched with those in the study report (, page
69 of the study report) except p-value. P-value = 0.3482 from my analysis
while p=0.331 in the study report.
Again, when I tried to duplicate the results in Table 13: Proportional Hazards
Regression Models of Survival (page 72), I could not match my results with
those in the table . However, I could duplicate the results for Cox model
using the same variables/datasets as you recommended for Study 9901.
Could you please check my program ( to see if the program is
correct? If not, please show me how to duplicate the results.

Thanks again for your help.

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