FDA Implements Cautious Review Strategy on Key Drugs Under Accelerated Approval Program

The U.S. Food and Drug Administration (FDA) has exhibited a notably cautious stance by delaying the evaluation of several pharmaceuticals enrolled in a fast-track approval initiative aimed at expediting access to treatments aligned with national health priorities. Internal documents reviewed indicate that FDA scientists are scrutinizing safety data, clinical trial results, and the robustness of efficacy measures, leading to postponements that extend review durations beyond the program's aggressive timelines. The FDA's Commissioner’s National Priority Voucher (CNPV) pilot program, launched during the previous administration, targets a significant reduction in drug review timelines by compressing the standard 10- to 12-month process down to as little as one to two months. Currently, the program encompasses 16 drugs under active review, aiming to accelerate patient access to therapies addressing critical conditions. Notably, two drugs from Merck & Co. Inc. — a cholesterol-lowering agent, enlicitide decanoate, and a cancer therapy, sacituzumab tirumotecan (commonly referred to as sac-TMT) — have been preliminarily nominated to join the initiative, potentially marking the 17th and 18th entries by December 2025, pending finalization. Among the medications experiencing delays is bitopertin, an experimental compound developed by Disc Medicine Inc., intended to treat erythropoietic protoporphyria (EPP). This rare hematologic disorder manifests as severe phototoxicity, resulting in intense sensitivity to sunlight. The FDA has deferred its decision on bitopertin by approximately two weeks, setting a new target date of February 10. Regulatory reviewers have raised issues concerning the validity of "pain-free time in the sun," a secondary endpoint in the clinical trials, questioning whether this metric reliably demonstrates therapeutic effect. There is deliberation over whether biomarker data might better substantiate efficacy for regulatory approval. The FDA reserve the right to extend review timelines if applications are incomplete or manufacturing practices are inadequate, as was noted during the program’s initial announcement. Further complicating the review process, FDA personnel specializing in abuse potential have been tasked with assessing bitopertin for any risks related to misuse or addiction. This additional evaluation step adds complexity and length to what was intended to be a streamlined review pathway. Sanofi SA’s Tzield (teplizumab), a treatment targeting advanced type 1 diabetes, has also encountered extended scrutiny, with its review postponed for over a month. Documents highlight concerns arising from adverse event reports, including incidences of seizures, blood clotting complications, and at least one death suspected to be related to the treatment. An example cited is that of a 30-year-old male patient who experienced a seizure and subsequent complications in September 2025, recorded in the FDA’s public adverse-event repository. Sanofi officials have emphasized ongoing collaboration with the FDA and assert rigorous internal evaluation of the serious adverse events linked to Tzield, particularly in the context of applications to broaden the drug’s use. Several other fast-tracked therapies have likewise faced timeline shifts. The lung cancer candidate zongertinib, developed by privately held Boehringer Ingelheim, now expects a regulatory decision around mid-February, whereas Eli Lilly and Co.’s weight management medication, orforglipron, anticipates a verdict in the second quarter of the year. The present FDA schedule assigns an April 10 target date for orforglipron, a modest delay from earlier expectations targeting late March. Industry analysts who have evaluated these developments consider the FDA’s deliberative approach reassuring, given the original plan’s one- to two-month review window raised concerns about maintaining thorough scientific evaluation standards. Elected officials, including Representative Frank Pallone and Senator Bernie Sanders, have criticized the CNPV program, highlighting its lack of transparency and warning that the accelerated timeline could foster favoritism or erode public trust if rushed approvals compromise safety assessments. Following the news of extended reviews, the stock market response saw shares of Disc Medicine (tied to bitopertin) reduce by nearly 10% pre-market, retreating to around $69.50 per share. Eli Lilly’s share price declined slightly by approximately 0.5%, trading just above $1,068, while Sanofi’s stock slipped half a percent to $47.65 during early trading sessions. These delays underline the tension between expedited access to novel therapies and the rigorous evaluation needed to ensure patient safety and drug efficacy. The FDA’s cautious navigation of this balance reflects a prioritization of comprehensive data review despite the political and public pressures to accelerate the availability of critical therapies. The situation remains dynamic, and stakeholders await further decisions as agencies and companies continue to address regulatory concerns.