FDA delays decision on Sarepta's Duchenne muscular dystrophy therapy eteplirsen; shares jump

Sarepta Therapeutics announced Wednesday that the FDA will not be able to complete its review of the company's marketing application for eteplirsen for the treatment of Duchenne muscular dystrophy (DMD) by May 26. Sarepta indicated that the agency is "continuing their review and internal discussions," adding that the regulator "will continue to work past the PDUFA goal date and strive to complete their work in as timely a manner as possible." Shares in the company jumped more than 25 percent on the news. 

Last month, an FDA advisory panel voted 7-3, with three abstentions, that clinical data backing Sarepta's submission for eteplirsen provided insufficient evidence of the efficacy of the drug in treating patients with DMD amenable to exon 51 skipping. In documents released ahead of the panel vote, FDA staff echoed prior concerns that the drugmaker had failed to provide sufficient evidence of the effectiveness of the treatment. 

Commenting on the news, RBC Capital Markets analyst Simos Simeonidis explained that the delay was unlikely to improve the likelihood of approval for eteplirsen. The postponement is "extending the agony [and the hope] in DMD,"remarked Simeonidis, adding "we continue to see only a small chance of an approval." SunTrust Robinson analyst Edward Nash, who anticipates a final decision from the FDA in mid-June, agreed, stating "we continue to expect no near-term approval." 

Meanwhile, Ritu Baral of Cowen & Co. noted that despite the steep cost, Sarepta could elect to conduct additional clinical trials of the therapy. "When there are investors who believe in the activity and investors that believe there’s a market, there’s always a price," Baral noted, continuing " it's a vanishingly small probability that they will walk away from this drug," The analyst estimated that a study assessing the effect of eteplirsen on a critical protein could be completed in the second half of next year. 

Earlier this year, the FDA issued a refuse-to-file letter to PTC Therapeutics concerning its marketing application for Translarna (ataluren) in the treatment of nonsense mutation DMD. Previously, the agency declined to authorise BioMarin Pharmaceutical's Kyndrisa (drisapersen) for use in DMD after delaying a final decision on whether to approve the therapy last year (for related analysis, see ViewPoints: BioMarin’s bullish guidance may imply the end is near for Kyndrisa). 

For additional analysis, read ViewPoints: Sarepta's AdCom - plenty of emotion, not enough data.



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