Some 30% of clinical trials that are mandated to report their findings have not posted results to clinicaltrials.gov, the federal government’s public repository for studies, according to internal data from the FDA.
The FDA has written to more than 2,200 study sponsors reminding them of their obligation to make their results publicly available on a federal clinical trials database—a move that falls in line with the agency’s aim of improving transparency across the industry.
Certain researchers and companies—including those that have received federal funding for their programs—are required by law to post their study results on clinicaltrials.gov within a year after completion, the regulator said in a news release on Monday. An internal accounting, however, has found that 29.6% of these studies have failed their reporting requirements—corresponding to more than 2,200 responsible parties.
Failure to completely report findings, often negative outcomes, leads to “significant gaps in the public record,” the FDA said Monday, and “obscures the true landscape of drug development outcomes—overrepresenting successes and underrepresenting failures.”
The FDA is seeking voluntary compliance from these parties. Companies and researchers that fail to comply with reporting requirements are at risk of receiving the FDA’s Notice of Noncompliance, which could incur civil monetary penalties or open them up to injunctions or even criminal prosecution.
The letters, issued March 30, are “an extra step” extended to these trial sponsors, giving them an additional opportunity to fulfill their obligations “before the agency considers whether to take further regulatory action,” according to the FDA’s news release.
“Far too often, companies are suppressing unfavorable clinical trial results and keeping them secret from patients and the scientific community,” Commissioner Marty Makary said Monday in a prepared statement. Trial sponsors have an “ethical obligation” to make their results publicly available, “regardless of the data’s influence on the company’s share price.”
The FDA is in the midst of a campaign for “radical transparency” across the pharma industry—an initiative that in July 2025 pushed the agency to publish more than 200 complete response letters to give the public a peek into the regulator’s thinking behind drug rejections.
While the rejection letters often feature redactions to help protect intellectual property, they still have helped foster “a level of accountability and professionalism” to the industry, TD Cowen senior biotechnology analyst Ritu Baral told BioSpace in an interview earlier this month.
The transparency has been particularly good for investors, who previously were mostly left in the dark about why a certain drug had been rejected. Drugmakers now can’t easily misrepresent the FDA’s reasoning for a rejection because the CRL would easily contradict them, Baral said.
“The reception from the investment community has been unanimously positive,” she told BioSpace.
