Sen. Ron Johnson is turning up the heat on the Food and Drug Administration after parents of boys with Duchenne muscular dystrophy told him the agency's recent decisions cut off access to a drug they believe kept their sons on their feet. The probe follows PTC Therapeutics' decision to withdraw its U.S. approval bid for ataluren, sold as Translarna, and a public Capitol Hill event where families made emotional pleas. Johnson says he plans to collect internal records and press the FDA to explain why certain rare-disease therapies have been rejected.
Senate probe: what Johnson is seeking
As chair of the Senate Permanent Subcommittee on Investigations, Johnson says he will go after the FDA's complete response letters, the formal written denials that spell out why an application did not make the cut. He is also signaling he may invite or subpoena senior FDA officials to walk through how they reached those decisions. As reported by Bloomberg Law, Johnson says he wants to see those letters to understand exactly why the agency is saying no. His office also issued a media advisory for a March 10 press conference where families were invited to share their stories; the advisory appears on Sen. Ron Johnson.
Families: "Ataluren kept him walking"
At the Capitol event, parents and a 15-year-old patient told Johnson they saw very real benefits from Ataluren, including prolonged walking ability, more independence, and better day-to-day strength. Losing access, they said, has been crushing. "If I could start taking Ataluren again, I may be able to live longer," Ben Bumgarner said after describing how he lost the ability to walk on Christmas Eve, according to Spectrum News. A Department of Health and Human Services spokesperson told Spectrum that the FDA "stands by the scientists evaluating these applications" and said the agency lays out its rationale in complete response letters.
Why the company pulled its application
In February, PTC Therapeutics said it had withdrawn its resubmitted New Drug Application for Translarna (ataluren) after the FDA signaled that the data were unlikely to clear the agency's bar for substantial evidence of effectiveness. The company described the decision as the product of unresolvable differences over how to interpret the data in a statement posted to PR Newswire. Trade and industry coverage have noted that the withdrawal closes out years of regulatory back-and-forth in both the United States and Europe and leaves U.S. patients with fewer options.
A fraught European history
Ataluren's track record overseas has been complicated. The European Medicines Agency's committee concluded that the drug's effectiveness had not been confirmed, and the European Commission formally declined to renew Translarna's conditional marketing authorization on March 28, 2025. That European call has fueled a broader debate over how much weight regulators should give to trial data versus real-world evidence when it comes to rare-disease therapies, and it has made U.S. resubmission strategies trickier, as summarized by the European Medicines Agency.
Legal and regulatory angle
Complete response letters, or CRLs, are the FDA's way of saying an application cannot be approved in its current form. They typically spell out the shortcomings a drug sponsor needs to fix, according to the FDA. A CRL does not automatically kill a drug's chances, but PTC's withdrawal suggests the company and the agency were still far apart on what the data actually show. Johnson has argued that instead of cutting off access, the FDA could allow the drug to remain available with a prominent safety warning, a position families have embraced and critics say could keep marginal medicines on the market, as reported by Spectrum News.
What comes next
Johnson's office says the investigation will start with gathering CRLs and could lead to hearings where FDA officials are asked to defend their review decisions and walk through the agency's thinking in detail. PTC's public filings state that after the February withdrawal, further development of Translarna for nonsense-mutation DMD in the United States is not planned. That leaves families and clinicians weighing other approved therapies along with clinical-trial options. Advocacy groups and parents say they will keep pressing Congress and regulators for clearer explanations, continued access where possible, and a more transparent decision-making process.
