Thursday, July 20, 2023

Tidbit: Alzheimer Study Observed Much Larger Effects in Men

 Recently, the FDA gave full approval to the Alzheimer drug lecanemab (Leqembi), based on a pivotal trial published in January in NEJM - van Dyck et al. Here.

On the edge of the news, but cited in a few places, Axios reported that there was quite a difference observed between the male response (slowing 43%) and the female response (slowing 12%).  See page 19 of the Supplement here.  While the result did not meet p< 0.05, and results in such large lists of covariates can accidentally reach significance, the groups were large (900 women, 800 men randomized) and the absolute difference was large (almost 4X).  

Another way of saying this, the statistical significance of drug effect in men on its own was very large, but on the other hand, if taken by itself, the error bars for women "crossed zero," e.g. error bars overlapped 0.

Variation in blacks is very large, because the "n" was so small.

click to enlarge

While genotype was also not a primary variable, the benefit in ApoE4 homozygotes was "negative," as observed in 260 such patients randomized.


For a brief blog on exclusion criteria, here.