To: Zvi Steinberg who wrote (593 ) 4/15/1998 9:09:00 PM From: Cacaito Read Replies (2) | Respond to of 1491
My speculation based on the 67 patients and the 12.5% mortality from the Pharmos web site reference: Ideally this should correspond to 33.5 patients in placebo group (no dexanabinol), and 33.5 patients in the dexanabinol group (But ramdomization does not usually comes to even numbers, and of course one could not have a 0.5 patient in the real world). There are no complains from the "safety board", the patients are not being harm. It is very important, check recent halted trials due to harm to the treatment group including lysophilline for ARDS, Hextend for blood loss and several others in the last 6 months. 1rst Scenario: If one assumes the expected mortality of 25% happens in the placebo group then 8.38 died out of 33.5 patients. This number is precisely 12.5% of the total number of patients so far in the study (12.5% of 67 is 8.38 ) Coincidence? We are left with no deaths in the dexanabinol group. This is a perfect outcome for the trial. 2nd Scenario: But, one should be cautious, lets assign 2 deaths to the treatment group (in a study with a small number of patients moving one or two patients to the not wanted outcome could uncover a poor performance in the intervention being study), if one assigns 2 deaths to the dexanabinol group then one should reduced 2 deaths from the placebo group and this results in: 2 out of 33.5 = 6% deaths for dexanabinol 8.38 - 2 = 6.38 out of 33.5 = 19% deaths for placebo One still has a 68.42% reduction (2/3) in number of deaths for dexanabinol vs. placebo (19% - 6% = 13%, and 13 is 68.42% of 19). This is a very important reduction due to the severity of the non wanted outcome (death) and of high clinical significance. I do not have the calculations to say if this is statistically significant, probably more subjects will be necessary to show statistical significance. I do not have access today to statistical software ( I go to the library for that). 3rd Scenario Even more one could assign 3 full deaths to the dexanabinol group and still get: 3 out of 33.5 = 8.96% deaths for dexanabinol VS. 5.38 out of 33.5 = 17.3% deaths for placebo This is a 48% reduction of deaths for dexanabinol vs. placebo, (17.3% - 8.96% = 8.34%, and 8.34 is 48% of 17.3) this is a almost a one half reduction in deaths. But this is surely not statistically significant and even if so, it has a very poor POWER to discriminate a real difference from chance. The number of subjects is probably good to justify a full phase III study to determine the real efficacy of the drug. I hope for at least the second case scenario. CAVEAT: These are my speculations, not real numbers, not real news. except for the numbers at the Pharmos website.