This article from Science Translational Medicine shows excellent results in a phase-1 trial of a new hepatitis C vaccine. This is a huge deal: hepatitis C infects 170 million globally, and causes a great deal of the world's liver damage. It kills more people in the US annually than HIV/AIDS.
The new vaccine was developed using chimpanzees as research subjects. I submit that this is exactly the sort of research for which the IOM's recent report on use of chimps in research left room. But I submit, also, that there aren't many more examples of this sort.