InterMune weighs the odds

FDA's rejection of an NDA for Esbriet pirfenidone to treat idiopathic pulmonary fibrosis, and its request for additional clinical data, present InterMune Inc. with a critical question as it determines whether to invest more resources in the compound: How likely is it that another trial will produce results that would convince FDA to approve Esbriet?

Clinicians who specialize in treating IPF, including some who believe FDA should have announced an approval last week, suggest the odds aren't good. Esbriet has an unknown mechanism of action, modest efficacy and is being targeted at a disease with unknown etiology and a heterogeneous patient population. There is no consensus about appropriate surrogate endpoints, and mortality trials could take four or more years and require thousands of patients...