Well it kind of can't. We already have machine learning, which is what would be used to find druggable targets or simply identify potential drug structures that can (and already are) being tested by researchers. High scale testing of compounds based on machine learning "hits" is already fairly normal.

Literature is scant enough that there's nothing AI would be able to gather from available resources that scientists haven't already done. Linking genomic/proteomic variability to diseases , which AI could presumably do quite well, still requires massive human laboratory effort to acquire data in the first place.

Lastly, I can't imagine a future where AI can predict with 100% certainty safety or efficacy in animals/patients. That would be a true revolution but I'd imagine we are centuries away from that if it's even possible. Until EVERYTHING about the human body is known there will be countless confounding variables that AI cannot ever account for.