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Biotech / Medical : XOMA. Bull or Bear? -- Ignore unavailable to you. Want to Upgrade?

To: Cacaito who wrote (9298)	3/20/1999 4:13:00 PM
From: aknahow	Read Replies (2) \| Respond to of 17367

Check with Ellen Martin. I do not believe there are three arms. Xoma has clearly said two arms. But the treatment arm is stratified into two severity group, 8 through 11 and above 12 thru ? 15 ? I believe it would be very difficult to try to accumulate the same number in both severity groups. They take anyone at 8 or above for the trial. They prospectively have done this and probably did assume a higher mortality for the 12 and over severity group. This would explain why the the target number is probably over 30. They could have assumed 20% mortality for the first severity class and 30% for the second class, in the placebo arm. In the treatment arm I would think 12% and perhaps 15% Since I do not know what they did why am I posting this? Because the stratification, means that my previous estimate of the target is too low. For some portion of the original 200 planned accruals the mortality rate was higher than the assumption used for the first severity class. This would be true in both arms. But since we do not know what level they are at now, it does not matter in terms of determination of how soon the trial could end. It could matter in terms of calculation of p ratio.

To: Cacaito who wrote (9298)	3/21/1999 8:40:00 AM
From: StockDoc	Read Replies (3) \| Respond to of 17367

Hello everybody, just visiting from the past. Interesting discussion and calculation. Be aware that the mortality of bacterial meningitis averages 11% with current treatment modalities and should drop below 10% as soon as some novel and apparently helpful ICU procedures (e.g, peritoneal ventillation in D.I.C., etc.) gain wider acceptance. Could you recalculate with 10% in the "placebo" arm and assume a 10% improvement by BPI arm? By the way, what's the thinking on this board about the apparent efficacy of protein C, antithrombin III and, maybe, activated protein C (Baxter, Genzyme, and Eli Lilly) in bacterial sepsis?