Have a look here:
https://patentscope.wipo.int/search/en/search.jsf if you search things like combination therapy, there are many examples of companies that hold the IP for use of using treatments together.
Also, I have seen cases where company 'a' owns a drug, but company 'b' discovers another use of it and puts a patent on its use. Company 'b' now has the rights to that treatment domain. As I understand it, it was up to company 'a' to discover and protect its IP for all practical uses. if they missed something, fair game.
E.g. if EmtinB is good for treating 'z, but they only have patents to cover use in 'x' & 'y' someone else can claim that use.
You don't own the molecule, just the treatment involved with it's use.
Please correct if I am wrong. I am not a patent lawyer, or any other kind.
