Opinion: Limb girdle muscular dystrophy patients face a maddening reality
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- FDA awarded Sarepta a platform technology designation in June 2025 for the viral vector behind its muscular dystrophy gene therapies, then revoked it and held all Sarepta trials after three nonambulatory patients died — two Duchenne patients and one LGMD 2D/R3 patient.
- Sarepta's LGMD2E/R4 Phase 3 trial was nearing completion with the company preparing to file for approval within weeks, but FDA placed the program on clinical hold for both ambulatory and nonambulatory patients.
- FDA later allowed dosing to resume for the related Duchenne therapy on the same platform for ambulatory patients, but kept the LGMD2E/R4 hold in place, preventing the treatment from moving toward approval even for patients who can still walk.
- FDA placed a January clinical hold on a Hurler syndrome gene therapy after a tumor was found in a young patient, then extended the hold to a Hunter syndrome therapy citing shared risk, though none of the 32 Hunter syndrome patients treated (some dosed nearly seven years earlier) had shown similar outcomes.
- New FDA leadership recently lifted the Hunter syndrome hold and reconsidered the program's approval pathway, a reversal the author says still underscores the need for a consistent framework governing risk transfer across platform programs.
- Author Kat Bryant Knudson is urging Congress, during the Prescription Drug User Fee Act reauthorization, to direct FDA to properly apply the platform technology designation created by FDORA of 2022 and provisions from the 21st Century Cures Act.
Why it matters: The FDA's inconsistent application of platform technology designation has produced a one-way ratchet in which risk transfers quickly across diseases but accumulated safety and efficacy data does not — leaving ultra-rare LGMD2E/R4 patients with no alternative drug developer likely to step in while their muscles deteriorate. The upcoming PDUFA reauthorization gives Congress a specific window to codify how platforms should work.
