InterMune Trading Halts, Pending FDA Review of Respiratory Drug

InterMune (ITMN) trading was halted Tuesday, as a Food and Drug Administration panel reviews its experimental drug pirfenidone for treatment of idiopathic pulmonary fibrosis, a fatal disease in which the lungs scar for no apparent cause.

Shares on Friday soared some 56% ahead of the review, despite FDA concerns over the uncluear trial results for pirfenidone, also known by the proposed brand name of Esbriet. Only one of the two trials showed efficacy, according to the FDA, and even there, the clinical significance was uncertain.

The FDA also expressed concerns about side effects including gastrointestinal events, dizziness, fatigue, anorexia, and syncope. Many pirfenidone users dropped out of the trial due to complications, the FDA said.

Investors on Friday seemed prepared for bad news, Reuters reported. Today's FDA panel meeting, featuring InterMune's and experts' testimony, will close at 5:00 p.m., and an FDA decision is expected by May 4.

'Urgent, Unmet Medical Need'

IPF afflicts about 90,000 people in the U.S., making breathing progressively difficult and typically leading to fatal respiratory failure within five years. The disease, InterMune said, "represents an urgent, unmet medical need, for which there are no medicines approved by the FDA. While reversal of the disease may not be feasible due to the presence of fixed and irreversible fibrosis, the slowing of progression in loss of lung volume constitutes a clear benefit to patients.

"The safety profile of pirfenidone," according to the company, "indicates that adverse events are primarily related to tolerability rather than morbidity, are readily monitored, are typically reversible, and are nonlethal."

Pirfenidone would be InterMune's second approved drug. The FDA has granted the drug orphan-drug and fast-track designation, and it has orphan-drug status in Europe as well.