FDA gives thumbs down to Sarepta’s next Duchenne’s muscular dystrophy drug

The decision stood in contrast with the agency’s highly controversial approval of Sarepta’s previous DMD drug, Exondys 51. The company’s shares fell sharply in after-hours trading.

A new drug for Duchenne muscular dystrophy failed to win Food and Drug Administration approval Monday.

Cambridge, Massachusetts-based Sarepta Therapeutics said that it had received a complete response letter from the FDA for golodirsen, a drug for patients with DMD who have a confirmed mutation amenable to exon 53 skipping. The company markets the drug Exondys 51 (eteplirsen), for DMD patients with a mutation amenable to exon 51 skipping.

The letter, also known as a CRL, highlighted concerns about the risk of infections related to intravenous infusion ports and kidney toxicity in preclinical models of the drug, which was observed at doses tenfold higher than the one used in clinical trials but not in the clinical trial the company used to seek approval.

Shares of Sarepta were down 13 percent after hours on the Nasdaq, trading at $95.50. Their closing price Monday was $120.31. In a statement, Sarepta CEO Doug Ingram expressed surprise at the FDA’s decision and said the company would immediately request a meeting with the agency to determine the next steps, adding “the patient community is waiting.”

“Over the entire course of its review, the agency did not raise any issues suggesting the non-approvability of golodirsen, including the issues that formed the basis of the complete response letter,” Ingram said. “We will work with the division to address the issues raised in the letter and, to the fullest extent possible, find an expeditious pathway forward for the approval of golodirsen.”

The study, 4053-101, is a randomized, placebo-controlled Phase I/II trial of 39 patients. DMD is a rare, genetic and potentially fatal disease mostly affecting boys that causes progressive muscle weakness that eventually spreads to the heart and respiratory muscles.

The FDA’s decision Monday stood in stark contrast with the one it made three years ago, when it granted accelerated approval to Exondys 51 on the basis of surrogate endpoint data for a small number of patients despite a recommendation against it by a panel of experts that the agency had convened. The FDA’s decision was highly controversial and seen as resulting at least in part from pressure by the DMD patient community, which included several boys with the disease in wheelchairs being brought in to attend the panel’s meeting. Moreover, the company has yet to release results from its confirmatory trial.

Photo: Streeter Lecka, Getty Images

CORRECTION: An earlier version of this story stated that the trial used for approval was the Phase III ESSENCE study. The story has been corrected.