"When a drug comes out [that's broadly prescribed] there are going to start to be a lot of people on it [in a million person cohort] and you might get therefore an early signal of something unexpected that hadn't come through in the clinical trials. And I'm sure [drug companies] would love it if, in fact, FDA, recognizing that, would say, OK, maybe you don't have to do your trial with 30,000 people because we're going to find out shortly after registration because we'll have a lot of people taking the drug and we'll be able to see what happened using PMI."