Sarepta Therapeutics Inc shares jumped after U.S. regulators accepted supplemental New Drug Applications that seek to convert two Duchenne muscular dystrophy therapies from their accelerated approvals to standard approvals. The FDA has assigned a target action date of February 28, 2027, for the reviews of AMONDYS 45 and VYONDYS 53.
The company’s filings rely on a combination of data sources, according to the submission documents. Those include results from the Phase 3 ESSENCE confirmatory study, real-world evidence gathered from treated patients and established safety profiles for both exon-skipping treatments.
In the ESSENCE trial, which compared casimersen and golodirsen against placebo, the primary endpoint was not met. Still, numerical trends in the data favored the active treatments. By week 96 of the study, analyses showed treatment-related increases in dystrophin expression and signals of reduced decline in a four-step ascend measure across multiple evaluations.
Beyond the trial population, more than 1,800 patients worldwide have received Sarepta’s exon-skipping therapies, including EXONDYS 51, AMONDYS 45 and VYONDYS 53. Real-world observational analyses cited in the applications point to clinically meaningful outcomes: treatment with VYONDYS 53 was associated with a 7.5 year delay in the need for nighttime ventilation, and AMONDYS 45 treatment has been associated with slowing of lung function decline.
Market analysts took note of the FDA acceptance. Mizuho analyst Uy Ear reiterated an Outperform rating and a $31.00 price target for Sarepta Therapeutics. In commentary accompanying the rating, the analyst said: "We view the FDA filing acceptance as positive news, given investor concerns that the failure of the confirmatory Phase 3 ESSENCE trial to achieve statistical significance (although trending positively) could limit the regulatory path forward. We continue to believe the risk of Amondys 45/Vyondys 53 being withdrawn from the market remains low, given the clinical benefits demonstrated with real-world evidence and the ultra-rare nature of the exon 45 and exon 53 amenable DMD patient populations."
The FDA acceptance and the data supporting the submissions frame the immediate regulatory pathway for these therapies. Companies in the rare disease and biotech sectors frequently combine randomized trial results with real-world evidence and long-term safety data when seeking conversion from accelerated to traditional approvals. In this case, regulators will have until the February 28, 2027 target date to render their decisions on AMONDYS 45 and VYONDYS 53.
Contextual note - The filings under review and the ESSENCE study outcomes provide the basis for regulatory evaluation, while real-world outcomes and safety records are cited to support continued access for the treated populations.