PTC calls time on FDA filing for Duchenne’s

Edited by Robert McTiernan··2 min read

PTC Therapeutics, headquartered in Warren, New Jersey, issued notice that its New Drug Application (NDA) with the US FDA for Translarna (ataluren) as a treatment for nonsense mutation Duchenne muscular dystrophy (nmDMD) would be withdrawn. The decision follows recent communications with the agency indicating that the current data package, despite containing results from multiple late-stage trials and real-world evidence, was unlikely to support an approval at this time. PTC Therapeutics stated it does not plan to pursue further US FDA registration efforts for Translarna in the foreseeable future.

The company indicated it would redirect resources toward its other pipeline assets, including its splicing platform and gene therapy programs. Translarna previously gained a conditional marketing authorization in the EU in 2014. However, that regional authorization also faced significant challenges; the European Commission (EC) issued a final decision in March 2025 not to renew the marketing authorization across the EU, following a series of negative opinions from the Committee for Medicinal Products for Human Use (CHMP).

Decision context

Translarna is a small molecule orally administered therapy designed to promote “read-through” of premature stop codons, allowing for the production of functional dystrophin protein in patients with nmDMD. The molecule is thought to interact with the ribosomal RNA, specifically targeting the ribosome to reduce its sensitivity to premature stop codons.

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The US FDA’s skepticism toward the asset has centered on the consistency of clinical trial results. While the Phase III ACT DMD and Study 041 trials showed trends in efficacy, they failed to meet their primary endpoints with statistical significance. The US FDA had previously issued multiple Refuse to File letters and Complete Response Letters to PTC regarding this asset over the last decade.

PTC now shifts toward its later-stage pipeline, such as sepiapterin for PKU and its Huntington’s disease program.

The regulatory environment for Duchenne therapies remains highly divided between different modalities and regions. While the US FDA has shown flexibility toward gene therapies and exon-skipping agents, it has maintained a high bar for “read-through” small molecules like ataluren. Other recent regulatory activities in the DMD space include:

  • Elevidys (delandistrogene moxeparvovec-rokl): Received expanded traditional approval from the US FDA in June 2024 for a broad DMD population, despite missing its primary endpoint in the EMBARK study.
  • Duvyzat (givinostat): An HDAC inhibitor from Italfarmaco approved by the US FDA in March 2024 for all DMD genetic variants.
  • Agamree (vamorolone): A dissociative steroid approved by both the US FDA and EMA in late 2023/early 2024 as a replacement for standard-of-care corticosteroids.
  • Exondys 51, Vyondys 53, and Amondys 45: A suite of antisense oligonucleotides from Sarepta Therapeutics that remain on the US market under accelerated approval pathways for specific exon-skipping mutations.