By Sarepta Therapeutics Inc. shares plunged 37% on Tuesday after the biotechnology company reported disappointing trial results for two of its treatments targeting Duchenne muscular dystrophy (DMD).
The stock fell to $15.28 on Tuesday’s open, compounding a steep 80% decline in 2025 before the latest selloff.
The company said that a confirmatory trial evaluating the effectiveness of its therapies, Amondys 45 and Vyondys 53, failed to achieve statistical significance.
The study was designed to provide the additional data needed to secure full regulatory approval for the two drugs, which currently hold accelerated approvals from the US Food and Drug Administration (FDA).
Duchenne muscular dystrophy is a rare genetic disorder that primarily affects boys, causing progressive skeletal and heart muscle weakness that worsens with age.
Sarepta, a longtime leader in developing treatments for DMD, attributed the trial’s disappointing outcome in part to dose interruptions that occurred during the COVID-19 pandemic.
“It is certainly believable that dose interruptions diluted the effect size, but the fact remains that the results from this post-hoc analysis are also not especially compelling,” said Bernstein analyst William Pickering, in a note commenting on the findings.
Broader concerns over Sarepta’s pipeline
The failed trial adds to Sarepta’s ongoing challenges as it faces growing scrutiny from regulators and investors.
The company is already under investigation by the FDA following deaths linked to its top-selling gene therapy, Elevidys.
Earlier this year, three patients who had received the Elevidys treatment reportedly died from liver failure, prompting regulatory review and intensifying pressure on Sarepta’s safety oversight.
Monday’s disclosure represents a significant setback for the company’s broader strategy.
Confirmatory trials like the one conducted for Amondys 45 and Vyondys 53 are a critical step in securing full FDA approval, validating the long-term safety and efficacy of drugs that were initially cleared under accelerated pathways.
Sarepta emphasized that despite the trial’s shortcomings, it intends to meet with the FDA to discuss the path forward for converting the drugs’ accelerated approvals into full approvals.
The company noted that it does not expect the FDA to withdraw the therapies from the market.
Brokerage Mizuho echoed that view, saying, “We do not anticipate the FDA pulling Vyondys and Amondys from the market.”
However, analysts warned that the outcome may still increase regulatory, payer, and physician scrutiny over the company’s treatment portfolio.
Financial results and market reaction
Alongside the trial update, Sarepta reported its third-quarter results, posting an adjusted loss of $0.13 per share.
That was narrower than analysts’ expectations for a $0.32 per-share loss, according to FactSet.
Despite the smaller-than-expected loss, the market reaction was overwhelmingly negative.
The latest results underscore the mounting challenges Sarepta faces in maintaining investor confidence amid regulatory uncertainty and mixed clinical outcomes.
While analysts noted that the trial failure was not entirely unexpected, they cautioned that the setback could further cloud the company’s growth outlook and delay progress toward full FDA approvals.
With its shares already down sharply for the year, Sarepta now faces the difficult task of rebuilding credibility with investors and regulators alike, while navigating an increasingly complex environment for gene therapy development.
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