[harvestmoon]

Interestingly, a quite high amount of breakthrough treatments were discovered by accident. Antibiotics, the original antidepressants, antipsychotics, lithium, viagra and others were all found initially that way.

Which may imply that our discovery approach has benefited from happy accidents which are hard to replicate and where the basics have been found already.

[jonlucc]

I think Viagra was discovered during clinical trials for hypertension. It (and it's fellow PDE5 inhibitors) is used in cardiac care, but the market is larger for "erectile dysfunction". There are certainly programs in big pharma to screen known drugs (that are already deemed safe for humans) in assays aimed at new targets.