
 

Response to FDA Request for Information - Provenge, November 29, 2006


 
(System Info - 126774 Kim Helen 04/22/2010 19:02:55 TULL)


BlankFrom: Kim, Helen [hkim@Dendreon.com]
 Sent: Wednesday, November 29, 2006 1:30 PM
 To: Tull Lori; Zhen, Boguang (CBER)
 Cc: Smith, Liz; Yuh, Lianng
 Subject: Response to FDA Request for Information

Importance: High

Attachments: Blank Bkgrd.gif

Lori -

 Provided below are our responses to the list of questions sent by Bo Zhen on
 11/28/2006.

 Please do not hesitate to contact me at (206) 829-1464 or Ms. Elizabeth Smith 
at
 (206) 829-1556 with any questions.

 Sincerely,

 Helen Kim
 Sr. Regulatory Affairs Manager
 Dendreon Corporation
 (P) 206.829.1464
 (F) 206.441.4070

 **************************************************************


 1. In the attached SAS program, I tried to duplicate the results
 presented in Figure 8 of your study report (p79) and to repeat the same 
analysis
 using all available follow-up data (not just cut-off at 36 months as in Figure
 8). Could you check the program to make sure that I used the right
 variables/datasets?

 DNDN Response: The variables/datasets you used are correct, however, we applied
 the rule "divide by 365 and multiply by 12" to calculate MONTHS of survival for
 the clinical study report (CSR) table. Thus, our results are slightly different
 from yours.


 2. In Figure 3 of your study report, it shows that one patient lost to
 follow-up. However, from the results of the above survival analysis program and
 Figure 8, we could not see a censored patient before 36 months. Could you tell
 us this patient's ID and how you dealt with this patient in survival analysis?

 DNDN Response: In Figure 3 of the D9901 clinical study report (CSR), the one
 subject noted as ?lost to follow-up? (ID 9126-154) is specific for the time to
 disease progression endpoint. However, survival information was subsequently
 provided by the clinical study center upon the subject?s death, and thus this
 subject was not censored in the survival analysis.


 3. Patient 9124-152 had death date, but the cause of death (DCUASEDC in
 DEATH.XPT) for this patient is missing. Does it mean the cause of death for
 this patient is unknown?

 DNDN Response: The cause of death for all subjects was to be collected on the
 Death Summary Report case report form (CRF). Collection of death certificates
 or other source documentation verifying cause of death was retrospectively
 requested from all clinical study centers.

 For the subject in question (ID 9124-152), the source documentation used to
 verify the cause of death came from a mortuary record (BLA: refer to Item 12,
 CRFs for Subject 9124-152, Certification of Death), which was obtained after 
the
 clinical database was locked. This record indicates that the cause of death was
 prostate cancer.


 4. Do you have more follow-up data beyond 36 months for the 25 patients
 who were still alive based on the last contact information, especially the five
 in the placebo control?

 DNDN Response: The protocol was not designed to collect survival data beyond 36
 months. Survival data beyond 36 months were not systematically collected; any
 additional survival data that Dendreon received from the clinical study centers
 were not disregarded but included in the D9901 listing entitled ?Deaths Known 
to
 have Occurred After the 36 Month Follow-up Period? (BLA: refer to Item 8, D9901
 CSR, Appendix 16.2.7.7).

 It is important to note that data contained in this listing were not used in 
any
 of the survival analyses in the BLA.


 5. I also tried to start running Cox regression model. It would be very
 helpful if you could tell me the datasets you used to obtain all covariates for
 the analysis. I tried to look at your SAS program, but it seems not quite easy
 for me to understand the program due to many macro procedures (though fully
 understandable why you were using macros).

 DNDN Response: Dendreon intends to provide a response to this question within
 the next 3-5 business days.


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