Efficacy data for InterMune Inc.'s Esbriet pirfenidone are likely to be enough for U.S. approval to treat idiopathic pulmonary fibrosis, but doctors contacted by BioCentury said it may only add weeks to patient lives and hope future programs will show more dramatic outcomes.

Last week, Esbriet met the primary endpoint in the Phase III ASCEND trial. Compared with placebo, significantly fewer patients receiving Esbriet either died or saw their forced vital capacity (FVC) decline by at least 10% at 52 weeks, while significantly more saw no decline in FVC.