PTC Therapeutics Withdraws Ataluren NDA for Duchenne Muscular Dystrophy
PTC Therapeutics has withdrawn its New Drug Application resubmission for ataluren (Translarna) for nonsense mutation Duchenne muscular dystrophy after the FDA indicated the submission lacked substantial evidence of effectiveness.
Following discussions with the Food and Drug Administration, PTC Therapeutics has made the decision to withdraw its New Drug Application resubmission for ataluren (Translarna) for the treatment of nonsense mutation Duchenne muscular dystrophy (nmDMD). The FDA indicated that, based on its review thus far, the submission lacked the substantial evidence of effectiveness required for regulatory approval.
The withdrawal represents a major setback for PTC Therapeutics regarding its US commercialization efforts for Translarna. PTC Therapeutics shares dropped 5.2% to $67.05 after market close when the announcement was made.
"We have therefore made the decision to withdraw the NDA submission," said the Chief Executive Officer of PTC Therapeutics. "We have worked tirelessly for over two decades to develop a safe and effective therapy for boys and young men affected by nonsense mutation DMD in the US and are disappointed that FDA approval cannot be achieved."
Ataluren is an oral protein restoration agent that was designed to enable the formation of a functioning protein in patients with nonsense mutation genetic disorders. In 2017, PTC Therapeutics had received a Complete Response Letter from the FDA indicating that additional clinical trial data would be needed in order to substantiate the effectiveness of the therapy in nmDMD patients.
A resubmitted NDA was accepted for review in October 2024 though no action date was provided by the Agency. The updated submission included data demonstrating that ataluren slowed muscle function decline and delayed the loss of ambulation in nmDMD patients. However, the ataluren NDA did not meet the Agency's expectations.
The latest setback looks like it could finally spell the end for Translarna in the US, after around a decade of attempts by PTC to bring it to market there. Its first attempt resulted in a refusal-to-file letter in 2016, which was successfully appealed, but nevertheless followed by a rejection by the FDA in 2017.
The drug was approved in Europe in 2014, but in 2024, the European Commission decided not to renew its conditional marketing authorization after multiple reviews of its safety and efficacy.
In a letter to the DMD community in the US, PTC said "differences in data interpretation" between the company and the FDA could not be resolved, adding that it would be deciding in the next few weeks what the implications would be on the supply of ataluren for those currently receiving therapy. In a statement posted on the company's website, PTC Therapeutics said it was determining the best course of action for those currently receiving treatment with ataluren.
In its third-quarter 2025 results, PTC reported sales of around $50 million for Translarna, down from $72 million a year earlier. The company's other DMD therapy, steroid-based Emflaza (deflazacort), is also in decline after losing patent protection.
PTC will now have to focus its attention on the rollout of Sephience (sepiapterin), its new treatment for people living with the rare disorder phenylketonuria, in the US and Europe. Third-quarter 2025 sales were around $20 million. Its pipeline also includes Novartis-partnered votoplam for Huntington's disease, which generated mid-stage data last year, and vatiquinone for Friedreich's ataxia, which was turned down by the FDA in 2025 with a request for more efficacy data.