Shares in Chapel Hill-based Pozen Pharmaceuticals (Nasdaq: POZN) declined Monday after two analysts for the stock.

The downgrades came after Pozen warned of potential challenges with the FDA over a new drug it has undergoing trials and the treat of a generic rival for its recently approved migraine drug.

Pozen shares lost 31 cents to close at $6.19. Pozen took a shellacking Friday with its share price hammered down to $5.75, a two-year low. The day’s loss: Nearly 28 percent.