[entee]

One small wrinkle: what if there's an old existing compound that seems to work well for an different indication than it was originally approved for? It would be good to run the phase 3 trial (possibly phase 2 as well) but that's gonna cost a ton of money. Maybe the government does it, or maybe we let people extend a patent for a new indication, freeing up government research money for the much trickier problem of understanding fundamental disease mechanisms.

There are of course good arguments against, but there's at least some good arguments to allow limited patent extensions.

[mattkrause]

Both of your options already happen.

Basically anyone can apply to the NIH for a grant to run clinical trials. It's not easy: the funding rate for NIH grants in general is in the teens and you'll need to convince the reviews that a) the trial itself generally makes sense and b) you, specifically, can pull it off, but it can be done.

If you find a new use for an existing drug—and run a trial to prove it—the FDA will give you a period of "marketing exclusivity", wherein you will be the only one allowed to market that drug for that condition. It's not quite a patent, but it's meant to be a similar recompense/reward for doing the research.

[entee]

Yes :) I've heard of some of these mechanisms, I think they're a decent balance. All of these issues are fairly complex, it's helpful to have context.

[lojack]

Whats preventing doctors from prescribing off label?

[dekhn]

if you're in the US, doctors can do this. https://en.wikipedia.org/wiki/Off-label_use

What's preventing them? Safety, efficacy, and fear of litigation.