FDA sharply limits approval for gene‑therapy drug after two teen deaths

New restrictions target younger patients with Duchenne muscular dystrophy

The U.S. Food and Drug Administration (FDA) announced today that it is imposing strict limits on the use of a gene‑therapy treatment for Duchenne muscular dystrophy (DMD) following the deaths of two teenage patients from severe liver complications.

The therapy, a one‑time intravenous infusion that delivers a functional copy of the dystrophin gene, had been hailed as a breakthrough for a disease that primarily affects boys and leads to progressive muscle degeneration. However, the recent fatalities have prompted the agency to reevaluate the drug’s safety profile, especially in patients under the age of 12.

Key points of the FDA’s new restrictions:

• Approval is now limited to patients aged 12 years and older with confirmed DMD.
• Physicians must conduct comprehensive liver function tests before and after the infusion.
• The drug’s label now includes a boxed warning about the risk of acute liver injury.
• Manufacturers are required to submit a detailed risk‑evaluation plan within 90 days.

“The safety of patients is our top priority,” said FDA Commissioner Dr. Robert Califf in a press briefing. “While the therapy offers hope, we must ensure that its benefits outweigh the potential harms, particularly for younger children whose livers may be more vulnerable.”

The two teenagers, aged 13 and 14, were part of an ongoing post‑marketing study when they developed rapid liver failure within weeks of receiving the infusion. Both cases were classified as serious adverse events and led to the premature termination of the study’s pediatric cohort.

Company spokesperson Laura Mitchell responded, “We are deeply saddened by these tragic outcomes and are fully cooperating with the FDA’s investigation. Our team is committed to enhancing monitoring protocols and exploring strategies to mitigate liver toxicity.”

Medical experts emphasize that the decision does not affect the drug’s availability for older adolescents and young adults, who have continued to show significant improvements in muscle function. Dr. James Patel, a neurologist specializing in DMD, noted, “For many patients, this therapy remains a transformative option, but careful patient selection and vigilant follow‑up are now more crucial than ever.”

The FDA will convene an advisory committee meeting next month to discuss further data on the drug’s risk profile and to consider whether additional age‑related restrictions or dosage adjustments are warranted.

In the meantime, families of children with DMD are urged to consult with their healthcare providers about the revised guidelines and to report any unusual symptoms promptly.