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Biotech / Medical : Biotech Valuation -- Ignore unavailable to you. Want to Upgrade?

To: former_pgs who wrote (20072)	5/18/2006 2:12:52 PM
From: Ian@SI	Read Replies (1) \| Respond to of 52153

I withdraw my uninformed comment about this likely being a negative event. At most, I should have said "This is unusual.".

To: former_pgs who wrote (20072)	5/18/2006 2:52:51 PM
From: Biomaven	Read Replies (1) \| Respond to of 52153

only new news the DMB would be receiving in the interim would be bad news (deaths / toxicity) But of course those deaths could have occurred in the control arm instead of in the drug arm. I guess my point comes down to the notion that it isn't urgent to stop a trial because you have met a futility analysis. A futility analysis says that the chance of the drug being statistically superior is remote. That's a long way from the drug being clearly enough inferior to require stopping the trial urgently. If I can attempt to draw a picture: A.....B.....C.....D A= drug is statistically clearly inferior (stop trial) B= trial is futile (stop trial) C= drug is superior at say p<.05 (continue trial) D= drug is clearly superior (stop trial) We know that recently the results were between B and D. That likely means they could not have been close to A. We now can infer from the recent announcement that the results are close to A or close to D. I'm inferring that this means that "close to D" is more likely. (I'm assuming here that if the interim look was close to "B" they wouldn't ask for an expedited re-look. I could easily be wrong about that). Peter

To: former_pgs who wrote (20072)	5/18/2006 4:27:16 PM
From: former_pgs	Read Replies (2) \| Respond to of 52153

One more consideration for the satraplatin trial: The first interim analysis was at 354 PFS events. Since PFS precedes survival, it makes sense that there are few (far fewer, imo) survival events that have accrued. I think it stands to reason that any look at survival would be inherently weaker statistically. I think it is also a safe assumption that the DMB would not consider stopping the trial for success at such an early time if the survival test simply met p < 0.05. I'd have to guess that they'd have a stricter criteria to prematurely stop this trial for survival (p < 0.01 or better?). So if PFS didn't meet p < 0.005 at the interim, and the survival analysis would not be as statistically powerful as the PFS analysis, could the DMB really be thinking that they have a reasonable shot at reaching p < 0.01 or better? I'm thinking it rather unlikely. But who knows. Given this thread, it'll now be fun to see what happens. Disclosure: I got phrm in the charity portfolio (and i think i'm the only one). I'm rooting for improved survival at this look :-)