Summary
Shares of Novo Nordisk A/S (NYSE:NVO) fell 2.8% on Tuesday after the U.S. Food and Drug Administration sent a warning letter that identified deficiencies in the company's postmarketing adverse drug experience reporting processes. The FDA said the problems affect multiple products and that prior responses from the company were not adequate to show the issues would not recur.
Inspection and warning letter
The FDA issued the warning letter on March 5, 2026. The action followed an inspection of Novo Nordisk Inc. that took place from January 13 through February 7, 2025. The inspection found serious violations related to postmarketing adverse drug experience reporting for a list of products, including semaglutide, liraglutide, nedosiran sodium, and estradiol.
Regulatory findings
According to the warning letter, the FDA concluded that Novo Nordisk failed to develop adequate written procedures covering surveillance, receipt, evaluation, and reporting of postmarketing adverse drug experiences. The agency found that the company and some contractors did not submit serious and unexpected adverse events to the FDA within the required 15-day timeframe.
The FDA also noted that the company’s written procedures permitted adverse events to be rejected or cancelled if the original reporters believed the events were unrelated to the product. The agency said this approach is inconsistent with FDA regulations. Examiners identified multiple instances in which serious adverse events - including stroke, death, and suicidal ideation - were either not reported within the 15-day window or were invalidated despite containing valid patient identifiers.
Investigation process concerns
The warning letter further states that Novo Nordisk did not promptly investigate adverse events that should have triggered 15-day alert reports. The FDA attributed part of that delay to an internal requirement that reportedly insisted on obtaining consent from reporters before conducting follow-up, which the agency characterized as unnecessary and a factor in slowed investigations.
Company responses and FDA reaction
Novo Nordisk submitted multiple responses to the FDA between March 2025 and January 2026. The company described corrective measures including revisions to written procedures, retrospective case reviews, and moving safety case intake to dedicated insourced patient safety agents. Despite those submissions, the FDA judged the responses to be inadequate, saying the company did not provide sufficient detail to determine whether the actions would prevent similar violations going forward.
Next steps
The FDA has requested that Novo Nordisk provide a response within 15 business days that outlines the actions the company has taken to prevent recurrence of the cited violations.