Noble et al report results of two Phase III placebo-controlled trials in N. America and Europe, with 779 patients total. In one trial, pirfenidone reduced FVC decline by ~4% at 72 weeks; in the other, it did not; pooling all the data, pirfenidone reduced FVC decline by 2.5% compared to placebo. There were abundant mild side effects in the treated arms (GI, photosensitivity and rash). Authors conclude the drug is "an appropriate treatment option" in IPF patients, but the FDA disagreed. (n=779) Lancet 2011;377:1760-1769.

In an earlier trial in Japan of 275 patients with IPF, pirfenidone reduced FVC decline by 70 mL and improved progression-free survival, resulting in its approval there. The FDA has indicated it will not approve pirfenidone for U.S. use without another clinical trial. InterMune, pirfenidone's manufacturer, launched the phase 3 ASCEND trial in mid-2011 in response.