I won’t justify huge valuations like that, I agree, but as for Merck, it’s biggest drug is Keytruda, but it does not hold a monopoly on PD1/PD-L1 blockers AND it’s patent is coming up on end of life.
So while the share price has done well, it has a few factors that undermine full valuation in the same context as a company that would have the sole drug in its class, and that can very likely work well with almost all of the other immune therapies and many of the other treatments likely as well.
Obviously, those things need to ultimately be validated. But if it works with solid tumors across the board using various strategies and combinations, it has quite a lot of potential to generate huge ultimate revenues. In the possession of a Merck, it is worth a lot more than by itself. So such a company should have to pay for that privilege.