InterMune Inc. has discontinued the phase 3 Inspire clinical trial evaluating Actimmune (interferon gamma-1b) in patients with idiopathic pulmonary fibrosis (IPF) based upon the recommendation of the study's independent data monitoring committee (DMC).

In a planned interim analysis that included a total of 115 deaths, the DMC found the overall survival result crossed a predefined stopping boundary for lack of benefit of Actimmune relative to placebo. Among the 826 randomised patients, there was not a statistically significant difference between treatment groups in overall mortality. Based on a preliminary review of the interim safety data, the adverse events associated with Actimmune therapy appear generally consistent with prior clinical experience, including constitutional symptoms, neutropenia and possibly pneumonia.

Inspire was a randomised, double-blind, placebo-controlled phase 3 study designed to evaluate the safety and efficacy of Actimmune in IPF patients with mild to moderate impairment in lung function. The primary endpoint was survival time. The lack of benefit stopping boundary was developed to allow for early study termination in the event interim data were statistically inconsistent with a clinically meaningful treatment effect of Actimmune.

InterMune plans to submit the data from the phase 3 Inspire trial for presentation at an appropriate medical meeting and for publication in a peer-reviewed journal.

"The interim results of the Inspire trial and our decision to discontinue the trial are disappointing," said Steve Porter, MD, PhD, chief medical officer at InterMune. "We are extremely grateful for the strong support we received from physicians, healthcare providers and especially the patients who participated in the clinical evaluation of Actimmune. The overall conduct of the study by investigators and the participation by patients were exemplary."

Dan Welch, President and CEO of InterMune, said, "Although we are disappointed by this result with Actimmune, we remain committed to addressing the significant unmet medical need in IPF with pirfenidone through our phase 3 capacity program. A positive treatment effect of pirfenidone on lung function has been supported in several phase 2 studies and in a phase 3 study as recently reported by Shionogi & Co., Ltd. We also are focused on advancing our novel hepatitis C virus drug candidate, ITMN-191. In collaboration with our partner Roche, our phase 1a study of ITMN-191 is proceeding as planned."

Welch continued, "We will promptly evaluate the implications of the Inspire study termination on our corporate strategy and our infrastructure. We expect to provide an update on this evaluation, including revised financial guidance, in the near future."

Actimmune is a synthesized version of interferon gamma, a naturally occurring protein believed to stimulate the immune system. InterMune markets Actimmune for the treatment of two life-threatening congenital diseases: chronic granulomatous disease and severe, malignant osteopetrosis.