How to Tell When A Drug Company Fibs About Clinical Trial Results
The canned quote from management: Always positive and optimistic. I usually ignore this fluff but in this case, Debrabandere reminds me that Osiris conducted a previous phase I study of Prochymal in patients suffering from a first heart attack. This study enrolled 53 patients and randomized them to treatment with either Prochymal or placebo. In other words, the older phase I study is very similar to the more current phase II study.
The phase I study, "A Randomized, Double-Blind, Placebo-Controlled, Dose-Escalation Study of Intravenous Adult Human Mesenchymal Stem Cells (Prochymal) After Acute Myocardial Infarction" was published the Journal of the American College of Cardiology in December 2009. You can download the study here for free. I won't go into too much detail about the results, but suffice to say, investigators found no statistically significant difference between Prochymal and placebo in ejection fraction or a six-minute walk test.
Debrabandere's comment that Osiris is extending the current phase II study to capture the long-term clinical benefit of Prochymal is most perplexing because the phase I study was notable in that measures of cardiac improvement between Prochymal and placebo narrowed and in some cases disappeared with longer follow up. Why results would be different in the phase II study is a mystery, particularly since patients in the study are only treated with single infusion of Prochymal.
Perhaps Osiris is extending the phase II study to delay the reporting of negative results? Again, that's a pretty safe assumption absent a better explanation.
The trial also demonstrated that treatment with Prochymal was safe. There were no infusional toxicities observed in patients receiving Prochymal. Serious adverse events occurred with equal frequency in both treatment groups (31.8%). To date, there have been 5 deaths in the trial, 2 in the Prochymal group and 3 in the placebo group.
Prochymal is safe but so is placebo. That's no great comfort. Deaths in the study are essentially equivalent in both arms, a survival benefit favoring Prochymal would have been better.