Sarepta Plunges After FDA Spurns Its Second Duchenne Muscular Dystrophy Drug

Shares of Sarepta Therapeutics Inc SRPT are tanking Tuesday morning as a binary event turned up a negative outcome for the company.

What Happened

Sarepta announced Monday after the market close the FDA issued a complete response letter for its NDA seeking accelerated approval for golodirsen injection for treating Duchenne muscular dystrophy, or DMD, in patients with confirmed mutation amenable to exon 53 skipping.

The company noted the FDA has raised two concerns, namely risk of infections related to intravenous infusion ports and renal toxicity seen in preclinical studies

Sarepta clarified that renal toxicity was observed in pre-clinical models at doses that were ten-fold higher than the dose used in clinical studies. Also, renal toxicity was not observed in Study 4053-101 on which the application for golodirsen was based.

Why It's Important

The verdict comes as a surprise, as the drug watchword had earlier in 2016 approved Sarepta's Exondys 51 injection for DMD patients who have confirmed mutation of dystrophin gene amenable to exon 51 skipping, which affects about 13% of the population with DMD. Both Exondys 51 and golodirsen have similar mechanism of action.

"We are very surprised to have received the complete response letter this afternoon. 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," said CEO Doug Ingram.

What's Next

The company said it will immediately seek a meeting with the FDA to determine the next steps. Sarepta has another DMD drug in the pipeline, which skips exon 45.

The stock traded down 17% to $99.81 per share Tuesday morning.

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