Can you point to someone who developed a useful medicine for 3rd-world diseases and failed to make money?

Few diseases are confined to only extremely poor areas. Medicines against malaria, for example, are a robust business. If you developed a good vaccine, you could make a lot of money selling it in Brazil, China, India, and other developing countries. The reason there is no vaccine isn't because there's no money to be made, but people have actually tried pretty hard and been unable to develop vaccines that aren't as risky as the disease itself.

I would argue that if a medical device/drug was developed for the third-world as opposed to being a developed world hand-me-down, it would be profitable. Good book on the topic "Fortune at the bottom on the pyramid".