Sarepta Pauses DMD Gene Therapy Trial After Second Death; Retail Traders Brush Off Risk

Retail investor chatter around Sarepta Therapeutics surged on Sunday after the company announced it had suspended shipments and paused a clinical trial of its gene therapy Elevidys for non-ambulatory patients with Duchenne muscular dystrophy following a second patient death from acute liver failure.

Sarepta shares closed down 3% at $36.18 on Friday, but edged 0.5% higher to $36.36 in after-hours trading.

The company said it is developing an improved immunosuppressive regimen, in consultation with clinical experts and regulators, to mitigate the risk of liver injury. 

The move comes after two reported cases of fatal liver failure, both in non-ambulatory individuals with Duchenne. The previous adverse event had happened in March to a 16-year-old DMD patient.

As part of the changes, Sarepta has temporarily halted dosing in its Envision study, a Phase 3 confirmatory trial required under the FDA’s accelerated approval pathway. 

The company said the trial will remain paused while it seeks protocol amendments to include additional immunosuppression.

Sarepta said it is working with an expert panel to evaluate a revised regimen that includes sirolimus, citing preclinical data supporting its use in managing liver enzyme elevations. 

The recommendations will be submitted to the U.S. Food and Drug Administration (US FDA) for review.

Treatment protocols for ambulatory patients remain unchanged, the company said.

More than 900 individuals have been treated with Elevidys to date, according to Sarepta. 

The company said it is also evaluating potential updates to Elevidys’ label to reflect the newly identified risks.

Additionally, BMO Capital Markets downgraded Sarepta to ‘Market Perform’ from ‘Outperform’ and slashed its price target to $70 from $120. 

In a note to investors, Analyst Kostas Biliouris said the death highlights known risks associated with adeno-associated virus (AAV)-based gene therapies.

While the benefit-risk profile of Elevidys remains favorable in ambulatory patients, BMO warned that the event could increase regulatory uncertainty, potentially leading to a withdrawal of non-ambulatory approval, missed 2025 revenue guidance, or additional reported fatalities.

On Stocktwits, retail sentiment was ‘extremely bullish’ amid a 2,078% surge in 24-hour message volume.

One user suggested the decline was an "overreaction in low volume" and predicted a rebound after the market open. 

Another user expressed confidence that Sarepta shares would stabilize in the next session.

The stock has declined 70.8% so far in 2025.

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