FDA's Recent Rejections Signal Internal Shifts and New Challenges for Drugmakers

This analysis was originally informed by reporting from PharmaVoice. For daily updates on the pharmaceutical industry, subscribe to the free PharmaVoice newsletter.

The U.S. Food and Drug Administration's regulatory compass has appeared to swing unpredictably in recent months. From its initial refusal to file Moderna's mRNA flu vaccine application—a decision reversed within days—to multiple delays for drugs carrying priority review vouchers, the agency's path has been difficult to chart. This volatility, compounded by internal restructuring and evolving review panels, has left biopharma executives searching for clarity.

However, a pattern may be emerging from the noise. Three specific rejections issued in recent weeks offer a window into the FDA's current priorities and the potential new hurdles for drug developers navigating its processes.

1. The Priority Voucher That Wasn't: A Reality Check for Accelerated Reviews

Last October, Disc Medicine secured a coveted Commissioner’s National Priority Voucher (CNPV) for bitopertin, its treatment for the rare blood disorder erythropoietic protoporphyria. The program pledges a review within one to two months for drugs deemed in the "national interest." Yet, not only did the FDA miss that accelerated window, it issued a complete response letter rejecting the application altogether.

This move has sent shockwaves through the industry, undermining confidence in the voucher's value. Analysts at BMO Capital Markets noted the decision "casts doubt" on the program, suggesting the selection "must not guarantee faster reviews or approval." The rejection raises immediate questions for other CNPV holders, including Eli Lilly's weight loss candidate orforglipron, which has already seen its decision date postponed. The recent accelerated approval of Boehringer Ingelheim's lung cancer drug zongertinib—another delayed CNPV drug—offers only partial reassurance, highlighting the agency's inconsistent application of its own frameworks.

2. Rare Disease Flexibility Tested: The Placebo-Control Sticking Point

Regenxbio's gene therapy RGX-121, targeting the ultra-rare Hunter syndrome, faced a stark rejection despite a previously agreed-upon study protocol. The FDA cited the lack of a placebo-controlled arm, a demand the company called "challenging" for a global patient population of approximately 2,000 boys, for whom it had used natural history data as a comparator.

The decision appears at odds with the agency's own recent rhetoric. Just weeks after the rejection, the FDA released draft guidance advocating for greater flexibility in trial design for ultra-rare diseases, specifically endorsing the use of "well-characterized natural history data" when randomized trials are unfeasible—the very approach Regenxbio employed. This contradiction sends a mixed message to developers of treatments for small patient populations and suggests that, despite public statements, the agency's review divisions may be tightening certain evidentiary standards, particularly around placebo controls—a trend also seen in vaccine approvals.

3. Transparency as a Double-Edged Sword: CRLs Go Public

The case of Corcept Therapeutics' relacorilant for Cushing's syndrome underscores a new era of FDA transparency with sharp consequences. After a December rejection that the company's CEO called disappointing, the FDA published the complete response letter (CRL) weeks later. The public document revealed the agency had repeatedly warned Corcept during pre-submission meetings about "significant review issues" and cited concerns over drug-induced liver injury.

This public airing, part of a new policy launched in July 2023, led directly to a shareholder class-action lawsuit alleging the company misrepresented the application's status. The FDA stated the policy aims to prevent sponsors from "misrepresent[ing] the rationale" behind its decisions. Legal experts now warn life sciences firms to meticulously vet all public statements against their confidential FDA correspondence, as the published CRL can become instant fodder for litigation.

Industry Voices React

Dr. Anya Sharma, Chief Medical Officer at a mid-sized biotech: "The RGX-121 decision is particularly disheartening. It feels like we're taking two steps back on rare disease innovation. If natural history data isn't sufficient after explicit discussions, what is? This uncertainty forces us to redesign trials that are already ethically and logistically fraught."

Michael T. Reeves, Portfolio Manager at a healthcare hedge fund: "The Disc Medicine rejection is a cold shower for the market. It shows that regulatory shortcuts, even expensive ones like a CNPV, are no substitute for robust data. Investors will now heavily discount the value of these vouchers until the FDA demonstrates consistent behavior."

Sarah Chen, Patient Advocate for the National Organization for Rare Disorders: "This is bureaucracy at its worst. The FDA talks a big game about flexibility for our communities, but then slams the door on a therapy for 2,000 boys based on a technicality they previously waived. It's a devastating betrayal of trust for families who have no time to wait for perfect trials."

Robert G. Finch, Former FDA Division Director (Retired): "These cases collectively point to internal cultural shifts. Different review divisions are interpreting policies with varying strictness, and the new transparency push is clearly intended to hold sponsors more accountable. The era of private negotiations with vague public summaries is over."