InterMune (UNKNOWN:ITMN.DL) was health care's top performing stock, thanks to positive phase 3 trial results for its lead drug Esbriet in idiopathic pulmonary fibrosis. Shares popped nearly 15% as Esbriet compared favorably with a competing drug also in late-stage develpment, by Boehringer Ingelheim.

This caused a rash of upgrades from Wall Street analysts, who insist InterMune is now a full-fledged takeover target. However, deep-pocketed competitors like Biogen Idec (NASDAQ:BIIB) and Bristol-Myers Squibb (NYSE:BMY) are lurking with mid-stage drugs using completely different methods of action that could pose a threat to Esbriet's blockbuster potential.

In this episode of Market Check-Up, The Motley Fool's health-care-focused investing show, analysts David Williamson and Michael Douglass discuss the trial results, IPF drug competition, and ultimately why InterMune investors should be exited about their stock.