The FDA's controversial fast-track drug approval program is hitting some speed bumps. According to internal documents reviewed by Reuters, agency scientists have delayed reviews of several drugs selected for the Trump administration's expedited approval initiative after raising concerns about safety, efficacy, and trial data quality.

The program in question is the FDA's Commissioner's National Priority Voucher (CNPV) initiative, designed to accelerate drug reviews for products addressing critical U.S. health priorities. We're talking about compressing timelines from the typical 10 to 12 months down to a blistering one or two months. The pilot currently has 16 drugs under review, with two more potentially joining the queue.

In December 2025, Merck & Co. Inc. (MRK) reportedly had two treatments selected for the CNPV program: enlicitide decanoate for cholesterol and sacituzumab tirumotecan (sac-TMT) for cancer. If finalized, they would become the 17th and 18th drugs to enter the program, according to internal documents.

The Delays Are Piling Up

Disc Medicine Inc. (IRON) got hit with the first reported delay. FDA reviewers postponed their decision on bitopertin, an experimental treatment for erythropoietic protoporphyria (a rare blood disorder causing extreme sun sensitivity), by roughly two weeks to February 10.

The holdup? Regulators are questioning whether "pain-free time in the sun," a secondary endpoint in the clinical trials, actually provides statistically reliable evidence of effectiveness. They're considering whether biomarker data might be a better foundation for approval instead.

But it gets more complicated. Internal documents show FDA staff responsible for evaluating drugs with abuse potential were asked to examine whether bitopertin posed any risk of misuse or addiction, adding yet another layer to the review process. When the agency first announced the CNPV program, it noted that FDA scientists reserve the right to extend review times if an application is incomplete, there are manufacturing violations, or as they otherwise deem appropriate.

The Serious Safety Concerns

Then there's Sanofi SA (SNY), which saw its review for Tzield (teplizumab) delayed by more than a month. Tzield is currently used in late-stage type 1 diabetes, and Sanofi is seeking expanded use approval.

This delay has more serious undertones. Documents cited by Reuters point to adverse event reports including seizures, blood-clotting issues, and what regulators described as a treatment-related death. The FDA's public adverse-event database references a September 2025 case involving a 30-year-old man who experienced a seizure and other complications.

A Sanofi spokesperson told Reuters that the company carefully evaluates serious adverse events and continues working closely with the FDA on Tzield's expanded-use application. But this is exactly the kind of safety signal that makes compressed review timelines nerve-wracking.

Other drugs in the fast-track program have also seen their timelines slip. A decision on zongertinib, a lung cancer drug from privately held Boehringer Ingelheim, is now expected in mid-February. Meanwhile, Eli Lilly and Co. (LLY) said its weight-loss pill orforglipron could receive a decision in the second quarter, with current FDA guidance pointing to an April 10 target date versus the late March timeline anticipated earlier.

Are These Delays Actually Good News?

Here's the twist: two regulatory experts told Reuters the delays were actually reassuring. The program's aggressive one- to two-month targets had raised serious concerns about whether reviews could remain thorough enough to catch safety issues. Apparently, they can, because the FDA is taking extra time when questions arise.

Not everyone's convinced the program is a good idea to begin with. U.S. Representative Frank Pallone and Senator Bernie Sanders have criticized the CNPV program as opaque, arguing it risks favoritism, rushed reviews, and threats to public confidence in the drug approval process.

The debate basically boils down to this: faster drug approvals could get life-saving treatments to patients sooner, but only if cutting review times doesn't compromise the quality of safety and efficacy evaluations. These delays suggest the FDA is trying to balance speed with caution, though whether they can maintain that balance with such compressed timelines remains an open question.

Price Action: In premarket trading on Thursday, IRON shares slid 9.83% to $69.50, while LLY dipped 0.48% to $1,068.16 and SNY edged 0.50% lower to $47.65, at last check.