Replies to post #49924 on Biotech Values

[bladerunner1717]

re: GPCB/SPPI

GPC Biotech Shares Plunge on FDA Concern
Friday July 20, 10:24 am ET
GPC Biotech Shares Dive on FDA Committee Concerns Over Prostate Cancer Drug Application


NEW YORK (AP) -- Shares of GPC Biotech AG nosedived Friday after a Food and Drug Administration advisory committee questioned the methods GPC used to test and study its prostate cancer drug candidate Orplatna, or satraplatin.
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The Oncology Drugs Advisory Committee, in a brief ahead of a July 24 meeting with the company, raised several issues and pondered whether the FDA should wait on making a decision until final data from a late-stage study is available. That survival data isn't expected until the end of the year.

GPC shares plummeted $13.15, or 41.4 percent, to $18.65 in morning trading. The stock has traded between $13.53 and $37.79 over the last 52 weeks. Development partner Pharmion Corp., which has exclusive European rights, also saw shares fall $2.13, or nearly 8 percent, to $25.02 on more than quadruple average volume.

The committee questioned the measurements in the study that GPC used to determine the drug's effectiveness, including a main goal defined as a "composite endpoint". The committee said the FDA has no prior experience with that type of endpoint, an issue which was "clearly communicated" to GPC Biotech.

Also, two independent reviewers disagreed on the progress made by 39 percent of patients in the study, raising the issue of whether the main goal of the study could be reliably assessed.

The committee said a final issue is whether the FDA should wait for final survival analysis before taking action.

The company said it will hold a conference call on July 25 to discuss the outcome of the FDA meeting.



Bladerunner

[Jonathan Robinson]

FDA briefing doc - the other was the company's.


http://www.fda.gov/ohrms/dockets/ac/07/briefing/2007-4309b1-03-GPC.pdf


Jon

[p3analyze]

This is an accelerated approval - unlike provenge - it would be easy for FDA to pull the approval if OS is not significant.
Of course if FDA really cared for the OS endpoint, it should have never allowed it to be submitted first.

My reason for being long:

1. The The rumor that OS was harmed turned out to be false.
2. FDA stats criticism about PFS was regarding the inclusion of stuff other than radiological progression, however, the sensitivity analysis (although informative censoring) which stripped off non-radiological events confirmed the primary analysis.
3. Pain progression data, although unconventional, did provide tangible measurement of patient benefit, which is crucial for an AA based on surrogate endpoint.
4. Like Walldiver said, this is a dog and pony show to set a counter example to DORB and DNDN. There is no mechanism of action issue, there is no alpha error issue, and Maha - the quartile lady would be more than pleased to learn there is no "beta error" issue, and it is a large study.
5. I like how the company rationalized Single-trial approval strategy - they must have copied it from the DNDN IV board.

[biomund]

As a relative newbie to analysis of clinical results, the fact that 6.3.4 of briefing documents states that the interim analysis on OS failed to show a significance difference between treatment arms and that final analysis of Overal Survival not performed pending pre-specified number of deaths occuring, how can drug receive approval at this time? Would appreciate comments on the briefing documents suggestion that overal survival appears to be tending toward final significance