Second Teenage Boy Dies From Liver Failure After Sarepta Gene Therapy Treatment

(Bloomberg) — Sarepta Therapeutics Inc. plummeted after reporting a second patient died of acute liver failure while being treated with its gene therapy for a rare muscle disorder.

The death of the 15-year-old boy comes only three months after another teenage boy who received the one-time treatment, Elevidys, died. Both cases occurred in people with Duchenne muscular dystrophy who are unable to walk, the company said.

The development casts a pall over Sarepta’s most important drug. As a result, the company suspended its 2025 revenue guidance and will “take a careful look” at its costs going forward, Chief Executive Officer Doug Ingram told analysts.

The loss will also intensify scrutiny on the Food and Drug Administration over its decision to approve Elevidys. The therapy was cleared through the agency’s expedited review process despite a lack of data showing it slowed overall progression of the disease, and only after an FDA official overrode staff objections.

“We think a second death is going to dramatically impact physician, caregiver and patient decisions moving forward,” said Cantor Fitzgerald analyst Kristen Kluska.

The FDA said in a statement that it is “treating this situation with the highest level of concern” and that the agency will “take all appropriate regulatory actions,” without specifying what that might entail.

Shares in Sarepta fell 42% in New York on Monday, the most since October 2023, as at least two analysts downgraded their rating on the stock. Roche Holding AG, Sarepta’s partner on the treatment, dropped 2.5% in Zurich. 

After the first Elevidys patient died European authorities put studies of the drug on hold. Roche, which is marketing the drug outside the US, said those holds are still in effect. Patients in the US were still being enrolled. 

The teenager who most recently died was in the US, Roche said, adding he died about seven weeks after receiving treatment. 

Sarepta has paused a clinical trial, suspended shipments of the drug for non-ambulatory patients and is considering an enhanced immunosuppression regimen for them. Elevidys has been given to about 140 patients who are unable to walk, according to Roche.

The dosing restrictions will also go into effect for commercial patients around the world, Roche said in a statement.

FDA Test

The fatalities pose one of the first big tests for Vinay Prasad, the new head of the FDA’s gene therapy division, who as an academic at University of California San Francisco has been highly critical of the FDA’s expedited approval process and about Sarepta’s gene therapy approvals in particular.

In social media posts in March, Prasad questioned Sarepta’s treatment, saying it “seems to be killing kids” with Duchenne and “destroying their livers.”

Although early trials of Elevidys didn’t show it slowed the disease, it was originally approved based on its ability to raise patients’ production of dystrophin, the protein missing in people with muscular dystrophy. 

The $3.2 million gene therapy won broad full US approval last year for patients who could still walk. It got an additional accelerated approval for patients unable to walk, such as older patients who have had the disease for years.

Approved drugs by law are supposed to be safe and effective, or in the case of expedited approvals, reasonably likely to benefit patients. Yet it’s now unclear whether the FDA will seek to limit Sarepta’s approval or to restrict the age range it can be given to.

It’s “unlikely” that Elevidys will be removed from the commercial market, though its label may be changed to reflect its risk, William Blair analyst Sami Corwin said.

About 15,000 Americans have Duchenne muscular dystrophy, a genetic disorder mainly affecting boys that interferes with the production of the protein dystrophin used by muscle cells. It causes severe muscle weakening and atrophy, with patients needing to use wheelchairs as they get older. Most die in their 20s, though some are living longer due to various treatment options.

–With assistance from Robert Langreth.

(Adds FDA comment in sixth paragraph. An earlier version corrected story to reflect patient was in the US.)

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