We do not understand the human body well enough to be able to directly jump from drug design to effect on the human body. Hell, I'm not even sure you could even do that on a single cell level, apart from the obvious "this kills the cell". The whole field of biology is a huge mess, and it is very hard to generalize results from the different scales (protein -> proteins -> single cell -> tissue -> living creature -> human). Not only that, long-term effects take, by definition, a long time to surface and cannot be accelerated.

This is what AI companies either have a hard time understanding, or choose to ignore.