If you’re interested in Alzheimer’s clinical trials, and especially in the Biogen/Eisai antibody (BAN2401) that I last wrote about here, today has been a big day. But maybe not a good day.
That last post from from July, when the two companies had released data about the BAN2401 trials, and a lot of questions were raised. The 10mg dose showed apparent beneficial changes on cognitive scores, but the lower ones were worse than placebo. And the APOE4 status of the patients was a confounding variable. There ended up being far more APOE4+ patients in the placebo group, and that’s a known risk factor for Alzheimer’s – was this making the antibody treatment group look better than it should?
Today’s data were an attempt to put those fears to rest – it compares the high-dose APOE4+ patients in the antibody treatment group with those in the placebo group, and the companies conclude that things are fine, and that the two groups saw similar rates of decline due to Alzheimer’s. But as this article at STAT shows, there’s a big problem with that analysis: because of the skew in the APOE4 patients (who were required to be removed from the treatment group because of possible side effects), this is a comparison of 113 people in the placebo group and only ten patients in the treatment group. If you want to draw conclusions from a subgroup that size in an Alzheimer’s trial, you are free to do so. But I sure don’t recommend it.
There’s more to the presentation, but it’s not good either. As @AndyBiotech pointed out on Twitter, the companies are not mentioning those bad lower-dose numbers for BAN2401 at all (and there’s certainly no breakout of their differences, if any, based on APOE4 status). Overall, this would seem to do nothing at all to put anyone’s mind at ease about the prospects for the drug. And when you look back to that early July hype about positive results, what we have now is pretty sad. If you bought Biogen stock back then on that news, you regret it. If you got your hopes up for a solid clinical trial result for Alzheimer’s disease, you regret it. Do Biogen and Eisai regret anything, you wonder?