My understanding is they had a change in strategic direction and...

My understanding is they had a change in strategic direction and no longer had an interest in antiviral agents. This happens all the time in the pharma industry - you just have to look to the recent decision by J&J to drop their dengue antiviral right in the middle of a Phase 2 field study. There is absolutely nothing wrong with the J&J drug, but J&J decided for strategic reasons to drop all further development.

If you took all the drugs that have been abandoned for non-clinical reasons and chose to sell them you would be running the largest pharmaceutical company in the world by a large margin.