The reason that Phase 3 trials are any sort of bottleneck instead of just checking boxes is that drugs that make it to that point are still extremely likely to fail and not be productized. The phase 3 trial is hard, expensive, and slow because it's the only strong filter we have! After phase 3 trials is the only point at which you become confident that this chemical doesn't do crazy unknown things to humans.
This is because the previous trials are not sufficient enough and high fidelity enough analogues of real human biology to be able to prevent that outcome!
Literal living human cells in a petri dish are not sufficient to tell you if a drug will work or not because the entire human system is extremely chaotic and interconnected. Even animals "99%" similar to humans are not similar enough to prevent unpredicted catastrophic outcomes in that full blown human trial.
We do not have enough knowledge anywhere about any of this for an LLM to be useful at all, because we have simply never collected the data necessary to be able to predict outcomes of novel interactions in the full scale system.
We haven't quantified the human system nearly enough.
You want to fix this? Don't go buy tokens, spend $2 trillion on grad bioscience students quantifying literally every protein and gene and structure and behavior and interaction in the human body. You literally have to brute force this problem.
You can't use "simulators" because there's no data for the sim to be evaluated and verified against in the first place. Our knowledge is too sparse.
LLMs cannot magic new information from limited data. Even magic "Superintelligent" AI wouldn't be able to fix fundamental deficiencies in what we know about the human body. There's this extremely silly and weird belief that it will be able to figure everything out "from first principles" and it's driving me up a wall.
Atom level simulations of anything in our reality are computationally infeasible at scales larger than "One cell", and you should expect that to not change since there's not expected to be a magic machine that can somehow undo computational complexity. Well, there is, in that our reality is that machine, but it's not very amenable to isolation for experimentation.
Fundamentally, there seems to be a serious fault among "AI" boosters of deeply believing the "Great man" theory of reality, that everything just needs a magically "smart" enough person to solve, as if someone clever enough could somehow trick physics itself. It's extremely ignorant of reality. There are problems in the current world that no amount of "intelligence" can solve, because the problem is not constrained by reasoning ability in the first place. A lot of bioscience fits that.