[mwilliamson]

> The cynic in me says it's because many of them are cheap generics that have little financial upside for large pharmaceuticals.

Social impact bonds are an interesting idea that might help solve this, although I know little about the practicalities. Specifically, a company would pay for the research and trials, and if it's effective, the government (say, the NHS in the UK) would pay a portion of the money saved to the company.