The US Food and Drug Administration has sent reminders to more than 2,200 medical product companies and researchers about federal requirements to submit certain trial results to ClinicalTrials.gov, underscoring gaps in reporting that can leave the public record incomplete.
According to an internal FDA analysis, 29.6% of studies highly likely to be subject to mandatory reporting requirements had no results posted to the database. Those studies include interventional trials involving an FDA-regulated product with a US nexus that are past the reporting deadline; phase 1 trials and device feasibility studies are excluded. The agency said such gaps can contribute to publication bias by overrepresenting positive outcomes and underrepresenting failures, potentially distorting perceptions of product safety and efficacy.
On March 30, 2026, the FDA sent messages to more than 2,200 companies and researchers associated with more than 3,000 registered clinical trials, including some that were publicly funded. According to the agency, the recipients appeared either not to have submitted required information or not to have completed the National Library of Medicine’s quality control review process. Federal requirements generally call for results to be submitted within 1 year of trial completion. The FDA said the messages were intended to seek voluntary compliance.
“Far too often, companies are suppressing unfavorable clinical trial results and keeping them secret from patients and the scientific community. Those sponsoring clinical trials have an ethical obligation to make results public regardless of the data’s influence on the company’s share price,” said FDA Commissioner Marty Makary, MD, MPH. “Too many clinical trial sponsors and researchers are failing to report their results, leaving important information unavailable to clinicians and other researchers. If you are a doctor deciding whether or not to prescribe a medication to a patient, you deserve to have the best data about clinical studies on that medication.”
The agency said it may send Pre-Notices of Noncompliance and Notices of Noncompliance as part of its risk-based compliance efforts related to ClinicalTrials.gov. The March 30 messages, FDA said, were an added step intended to give responsible parties an opportunity to comply with federal law before the agency considers further regulatory action.
“I fully support this new initiative to increase the prompt publication—as required by law—of results information from interventional studies of the medical products we regulate,” said Tracy Beth Hoeg, MD, PhD, acting director of the Center for Drug Evaluation and Research. “We hope that the thousands of messages sent to sponsors and investigators reminding them to publicly report their findings will improve patient safety and keep researchers and the public better informed of benefits and risks of new and investigational products.”
Source: FDA