Five months after reporting a survival benefit from a Phase III trial of Actimmune in the treatment of idiopathic pulmonary fibrosis, InterMune Inc. reported preliminary survival data from a follow-up observation period.

The results, which were not as positive as initially expected, sent the Brisbane, Calif.-based company's stock (NASDAQ:ITMN) down sharply Tuesday. Its shares closed at $22.21, down $5.41, or 19.6 percent.

In the overall intent-to-treat patient population through the follow-up period, there were 26 deaths in the 162-patient, Actimmune-treated group (16 percent) compared to 36 deaths in the 168-patient placebo group (21.4 percent), a 25 percent relative reduction in mortality in favor of Actimmune (p=0.17).

InterMune said exploratory subgroup analyses nevertheless suggest that Actimmune may have a more favorable effect in patients with mild to moderate disease. In those patients with forced vital capacity (FVC) greater than or equal to 55 percent at study entry, there were 13 deaths in the 126-patient, Actimmune-treated group (10.3 percent) vs. 26 deaths in the 128-patient placebo group (20.3 percent), a 49 percent relative reduction in mortality in favor of Actimmune (p=0.02). In those patients with FVC greater than 60 percent at study entry, there were 10 deaths out of 90 in the Actimmune-treated group (11.1 percent) vs. 16 deaths in the 92-patient placebo group (17.4 percent), representing a 36 percent relative reduction in mortality in favor of Actimmune (p=0.15). For the FVC subgroups less than 55 percent and FVC less than or equal to 60 percent, the "p" values equaled 0.45 and 0.61, respectively.

The preliminary survival data are part of exploratory analyses of safety and efficacy that the company is conducting based on a three- to five-month follow-up of patients who participated in the double-blind, placebo-controlled Phase III trial.

Late in the summer, InterMune reported top-line results showing that the drug failed to meet its primary endpoint of progression-free survival in treating the debilitating and fatal lung disease. (See BioWorld Today, Aug. 29, 2002.)