FDA pauses fast-track reviews after safety and efficacy questions arise

Internal U.S. Food and Drug Administration documents show the agency has postponed reviews of two medicines selected for the Commissioner’s National Priority Voucher program after scientists raised safety and efficacy concerns, including reports linked to a patient death. The timetable changes highlight the political and regulatory strains of compressing drug reviews to unusually fast windows while safeguarding public health.

Sanofi’s Tzield (teplizumab), a therapy used in late-stage type 1 diabetes and the subject of an expanded-use application, was pushed back by more than a month as reviewers flagged reports of serious adverse events. The agency’s public adverse-event database references a September 2025 case in which a 30-year-old man suffered a seizure and subsequent complications. Internal records also note seizures, blood-clotting issues and what regulators described as a treatment-related death. Sanofi said it “carefully evaluates serious adverse events and continues to work closely with the FDA on Tzield’s expanded-use application.”

Disc Medicine’s bitopertin, described in the documents as a blood-disorder medicine, had its review delayed by two weeks amid questions at the agency about efficacy and potential abuse. The shorter delay for bitopertin underscores different risk profiles across products that have been placed on an accelerated path.

Two additional drugs in the voucher program have seen schedule shifts. A decision on Boehringer Ingelheim’s lung cancer candidate zongertinib is now expected in mid-February; a company spokesperson said a decision is expected “in the near future” but declined to comment on the delay. Eli Lilly’s oral weight-loss drug orforglipron has a revised FDA decision target of April 10, 2026. A Lilly spokesperson said “approval could land in the second quarter based on current FDA guidance.”

The voucher initiative, established during the Trump administration, compresses standard review timelines that often run 10 to 12 months into windows as short as one to two months by mobilizing interdisciplinary agency resources. Internal materials show the program covers a wide array of priorities, from label expansions to complex biologics and neglected-disease therapies, including treatments for multidrug-resistant tuberculosis and a gene therapy for sickle cell disease. Agency announcements indicate more than a dozen medicines are in active review, though only one product, a generic antibiotic, has been approved under the program to date.

Public health experts say the recent pauses are consequential for both safety assurance and public trust. Holly Fernandez Lynch, a health policy professor at the University of Pennsylvania, said the pauses signal the agency is not automatically rubber-stamping voucher recipients. That willingness to slow an accelerated track has been welcomed by some regulators and patient safety advocates who feared compressed timelines could sacrifice thorough evaluation.

Critics in Congress, including Representative Frank Pallone and Senator Bernie Sanders, have warned the program risks favoritism, rushed reviews and diminished public confidence. Those concerns intersect with equity issues: expedited pathways that favor high-profile products could divert attention and resources from therapies that address diseases affecting marginalized communities unless transparent criteria and consistent standards are maintained.

The agency’s decision to delay reviews in response to safety and efficacy signals an attempt to balance rapid access with regulatory rigor. The ultimate credibility of the voucher program will hinge on the FDA’s ability to apply standards consistently, communicate clearly with sponsors and the public, and ensure that acceleration does not come at the expense of safety or equitable access to meaningful therapies.