Good post upchuck but I suspect the FDA do have enough statistical nous to realise that a replica P3 achieves little except perhaps greater sensitivity due to sample size - which is not really their beef. They seem to want to know more about the physiology of any liver effects and (I'm a biologist not a medic) the best way to do that could be a small-scale study focussed on the liver physiology, perhaps using something like TMT and Mass Spec to examine closely what might be going on in selected patients. And, on their other shoulder, and not often mentioned, is the pressure from kidney-impaired patients who would like a better treatment. I don't know if it's ever happened but could there be class-action against the FDA for failure to approve something life-changing without good reason??
Latino, That's correct. And it's important to note, as others have pointed out, that the approval does not demand NO toxicity but the understanding of any toxicity that may exist. Pretty well everything you eat sends the liver into overdrive but, given the risks of prescription medicines that already exist, an understanding of anything yet unexplained is what they are after. I'm sure this ab has a role in life, just not sure how we get there and how long... and whether I can afford the process!