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For a drug expected to top $7B in annual sales, even a partial success looks like a failure to me. I’ve talked about the efficacy in modulating APP for the treatment of Alzheimer’s a few times and Derek Lowe @ has some great articles, so if you’re not familiar, I‘d check them out to catch up.
On to the news. I’m going to try and summarize the press release from Elan and Wyeth without all the spin. Bapineuzumab failed to reach significance on the primary endpoint in a phase 2 trial.
Simple, right? Maybe not. The trial did show efficacy, though magnitude wasn’t released, in a small subgroup of patients (in non-carriers of the ApoE4 allele, estimated to be ~40% of Alzheimer’s patients).
So, right off the bat, this should cut analyst expectations by 60% right?
Interestingly, in trying to explain away not hitting the primary endpoint for the general population, the release mentions that the study wasn’t powered to detect changes in ADAS-cog.
Fantastic. Let me just break down this flow and see if we can make more sense of it.
1.) Run a trial that is not powered to detect primary endpoint changes.
2.) Fail primary, ADAS-cog endpoint.
3.) Release that you succeeded in a subgroup of patients on many endpoints (that you admittedly aren’t powered to detect)
4.) Conclude with statements like, “bapineuzumab appeared to have clinical activity in treating Alzheimer’s disease“, and “…the Phase 2 study are a continued validation of the amyloid approach to Alzheimer’s disease”.
Fundamentally, I’m happy that there are companies with deep-pockets attempting to treat debilitating diseases in novel ways but doing things over and over, expecting different results is foolish.