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Author: keahou Big gold star, 5000 posts Old School Fool Add to my Favorite Fools Ignore this person (you won't see their posts anymore) Number: of 74275  
Subject: A new twist in 9902B Date: 4/24/2007 12:53 AM
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By walldiver/IV


I forgot to add one of the biggest factors in Provenge's favor on 9902B that differentiates it from 9901/9902A. The earlier trials were time-driven...stop patient followup at 36 months after that patient was randomized. This protocol did not give Provenge any p value credit for the length of time a patient survived beyond 36 months. For example, we do know that 28 out of 82 patients in the Provenge arm survived the full 36 months, compared to 5/45 in the control arm. We also know that as of March 2007, 8 additional patients out of those 28 survivors had died. If in fact there are still 20 survivors, every day each one survives will have improved Provenge's p value if the trial protocol is like 9902B's, which is an event-driven trial where the unblinding snapshots are taken when a certain number of patients has died. The 9901 trial ended in September 2004, three years after the last patient was randomized.

Mr. Garcia, who spoke at the advisory committee meeting, is a long-term survivor from the 9901 trial. He probably enrolled in early 2000...if so, he is a 7-year survivor. However, his dot on the Kaplan-Meier curve would therefore have been censored in early 2003...sure, it's great for the Provenge arm that he survived the full three years, but think about what a seven-year survival would have done for Provenge's p value. Now think about the 20 people in the Provenge arm who may have still been alive as of March 2007, Mr. Garcia included. This means that these guys have survived 5 1/2 to 7 years, while only 5 in the control arm survived 3 years...and some of them have probably passed away since September 2004.

Now if we look at 9902B, it's probable that the 99 patients enrolled figure in Dr. Provost's Feb 2006 CTGTAC presentation comes from 1H 2005, as we know from the 3/29 briefing docs that 179 patients were enrolled as of 2/6/06. The trial began in mid-2003. At some point in late 2008 or in 2009, 9902B could hit the 180th death trigger (if 180 is in fact the trigger). The later the better, of course. If 9902B performs similarly to 9901/9902A, there could be a number of five-year survivors in the Provenge arm at this triggerpoint, and probably very few in the control arm. These five-year survivors would have been censored out of the earlier trials once they survived three years...but won't be for 9902B... :-)
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