InterMune Inc announced that data from a Phase II trial of pirfenidone for pulmonary fibrosis suggests the drug may be more efficacious than prednisone in patients with idiopathic pulmonary fibrosis (IPF).

"This proof-of-concept study provides intriguing evidence regarding the potential clinical impact of pirfenidone across a number of IPF clinical endpoints, and is consistent with U.S. open-label and Japanese clinical trial data reported previously," said James E. Pennington, Executive Vice President of Medical and Scientific Affairs at InterMune. "We intend to meet with the FDA to discuss these data and our plans for implementing a larger scale clinical development program with pirfenidone in IPF."

This randomized, double-blind, multi-center Phase II trial enrolled 53 patients with moderate to severe IPF (n = 46) or secondary pulmonary fibrosis (n = 7). Patients received either 40 mg/kg/day of oral pirfenidone or 0.33 mg/kg/day of oral prednisone administered in three divided daily doses.

There was evidence of a positive treatment effect for pirfenidone in the IPF patients compared to prednisone across several efficacy endpoints, although given the exploratory nature of this study there was not a predefined primary efficacy endpoint. The change from baseline to 12 months in the minimum oxygen saturation, a measure of a patient's ability to maintain oxygen concentrations in their blood, during the six-minute walk test was significantly better in the pirfenidone group compared to that of patients treated with prednisone (p=0.014).

Several other efficacy outcomes measured at 12 months compared to baseline in this relatively small study tended to favor the pirfenidone-treated group, including distance walked in the six-minute walk test, forced vital capacity (FVC) measurement, and resting A-a gradient, although these did not achieve statistical significance.

Pirfenidone was generally well tolerated overall. The most common treatment-related adverse events were gastrointestinal symptoms and rash, which were typically mild in severity and consistent with prior clinical experience. Fewer patients experienced one or more serious adverse events in the pirfenidone arm (26.9%) of the trial than in the prednisone arm (42.3%), including fewer serious infections.