Promising results from study of Pirfenidone in idiopathic pulmonary fibrosis (IPF) patients

InterMune today announced that the American Journal of Respiratory and Critical Care Medicine (AJRCCM) published results from a double-blind, randomized, placebo-controlled Phase II trial evaluating pirfenidone for the treatment of patients with idiopathic pulmonary fibrosis (IPF).

This 107- patient study with a planned 12-month treatment period was conducted in Japan by Shionogi & Co., LTD and was terminated after only nine months based on the recommendation of the Data Safety Monitoring Board following an interim analysis. This analysis suggested favorable effects of pirfenidone on acute exacerbations and other efficacy parameters, prompting the decision to stop the trial.

In the 9-months of treatment, acute exacerbations had occurred in 14% and 0% of placebo and pirfenidone patients, respectively (p=0.0031). All of these patients required hospitalization and one patient died. The analysis of the primary endpoint, change from baseline in the lowest oxygen saturation during a 6-minute exercise test, revealed a trend in the overall population (p=0.072) with a more pronounced treatment effect in a pre-specified subgroup of patients with milder disease (p=0.0305). Pirfenidone had a favorable effect on vital capacity, analyzed as both a change from baseline (p=0.0366) and a categorical assessment of the proportion of patients who improved, were stable, or declined (p=0.0028). Changes in total lung capacity, carbon monoxide diffusing capacity, resting partial pressure of arterial oxygen, dyspnea, and quality of life were not statistically significant after nine months of treatment. Gastrointestinal symptoms, photosensitivity and fatigue occurred more frequently in the pirfenidone group, although rates of treatment adherence were similar between the two groups. The main cause for patients discontinuing from study treatment was photosensitivity in the pirfenidone group (6.8% vs. 0%) and acute exacerbation (0% vs. 14%) in the placebo group.

"This study suggests that treatment with pirfenidone may prevent acute exacerbation of IPF and reduce the rate of decline in vital capacity," said Dan Welch, InterMune's President and CEO. "We are encouraged by these promising results and are moving forward with our discussions with the U.S. Food and Drug Administration and the European Medicines Agency regarding the design of a Phase III development program for pirfenidone in IPF, which we expect to initiate in the first half of 2006."

InterMune acquired an exclusive license relating to the manufacture, use and sale of pirfenidone for antifibrotic use worldwide, excluding Japan, Korea, and Taiwan, where rights are held by Shionogi & Co., LTD.

IPF is a disabling and ultimately fatal disease that affects approximately 83,000 people in the United States, with an estimated 30,000 new cases developing each year. Those diagnosed with IPF are usually between the ages of 50 and 70, and the disease tends to affect men more than women. IPF causes inflammation and scarring (fibrosis) in the lungs, hindering a person's ability to process oxygen and causing shortness of breath (dyspnea) and cough. IPF is a progressive disease, meaning that over time, lung scarring and symptoms increase in severity. Median survival time from diagnosis is two to five years in patients with IPF. There are currently no drugs approved by the FDA for the treatment of IPF.

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