WASHINGTON - InterMune Inc. failed to win FDA approval of Esbriet (pirfenidone) as a treatment for a fatal lung disease, known as idiopathic pulmonary fibrosis (IPF), despite the strong backing of an agency panel of experts.
Regulators said InterMune, whose shares plummeted more than 80 percent in afterhours trading, must provide an additional clinical trial to support Esbriet's efficacy in treating IPF, which causes irreversible honeycomb-like lesions and scarring on the lungs.
Shares of Brisbane, Calif.-based InterMune (NASDAQ:ITMN) had been halted early Tuesday afternoon at $45.44 in anticipation of the news. But by 5 p.m., the shares had dropped by more than $36.
CEO Dan Welch said it currently is unclear whether his firm would need to conduct an entirely new study or if it could submit data from a Phase III study conducted by Osaka, Japan-based Shionogi & Co. Ltd., which holds the rights to pirfenidone in Japan, where it is sold as Pirespa.
InterMune had submitted a summary of those data to the FDA with its application for Esbriet, but regulators said in March that the agency could not rely on that information since the actual results had not been provided to the FDA.
"We have a data-sharing agreement in place, and has been in place for sometime, that describes how we might access the patient-level datasets and the economics related to that access," Welch told investors and analysts late Tuesday during a conference call. "That has been negotiated, that is done, that doesn't have to be worked out," he said.
The work in front of InterMune, which Welch called "not insignificant," is to translate the Japanese patient-level dataset into electronic datasets that could be useable and in a content format acceptable by the FDA.
"We don't even know, however, at this time until we meet [with the FDA] what role if any the Shionogi Phase III data might play," Welch said. But he added that InterMune's current read of the complete response letter is unclear whether the Shionogi Phase III study would fill the FDA's request.
"That remains to be known," he said.
Welch said he expected that an after-review meeting with the FDA would likely not occur for two to three months - emphasizing the latter time period.
InterMune's development program, however, was designed independent of Shionogi, noted Steven Porter, chief medical officer at the company. "While the FDA did ask for those datasets during the review, there was no way during a six-month review period that even if we could have accessed those datasets that we could have done all of the work necessary to get them to the point where they could have been used," Porter said. "That now is an exercise we will need to develop if that looks like a pathway that can be productive."
He said InterMune must first meet with regulators to "understand exactly what FDA is looking for" not only to determine whether using the Shionogi data would fulfill the agency's requirements but also if it would be the most economical route for the firm.
In March, the FDA's Pulmonary-Allergy Drugs Advisory Committee voted 9 to 3 recommending approval of Esbriet as a therapy to reduce the decline in lung function in patients with IPF. (See Bioworld Today, March 10, 2010.)
And although one of InterMune's two Phase III studies missed its primary endpoint, the panel voted 7 to 5 that the pooled data showed substantial evidence that the drug provided a clinically meaningful efficacy benefit in reducing decline in lung function in IPF.
The committee also voted 9 to 3 that Esbriet's safety had been adequately assessed, despite some concerns about one potential case of drug-related serious liver injury and serious adverse gastrointestinal and skin events.