Novo Nordisk (NYSE:NVO) has drawn regulatory scrutiny in the US after the Food and Drug Administration (FDA) issued the pharmaceutical giant a warning letter over failures in how it handled reports of adverse drug events linked to several of its medicines — including semaglutide, the active ingredient behind blockbuster treatments such as Ozempic.
The March 5 letter follows an FDA inspection of Novo Nordisk’s US operations between January 13 and February 7, 2025. Investigators concluded the company did not comply with key pharmacovigilance requirements governing how drugmakers monitor and report safety events once medicines are on the market.
Those rules form a crucial part of the regulatory system that tracks potential safety signals after approval — when medicines begin to be used by far larger and more diverse patient populations than in clinical trials.
Adverse event reporting failures
At the centre of the FDA’s concerns is Novo Nordisk’s handling of reports describing serious and unexpected adverse drug experiences.
Under US regulations, pharmaceutical companies must report such events to the FDA within 15 calendar days of becoming aware of them. These “15-day alert reports” allow regulators to quickly identify potential safety risks associated with approved medicines.
According to the warning letter, Novo Nordisk’s internal procedures failed to consistently ensure those reports were submitted within the required timeframe.
Among the problems identified by inspectors:
- Written procedures allowed staff or contractors to reject adverse-event reports if the reporter believed the event was unrelated to the drug — something the FDA says conflicts with US rules, which require reporting regardless of perceived causality.
- Some safety cases were invalidated because of missing patient identifiers even though identifying information existed in the underlying documents.
- Certain cases remained in internal “medical review” processes for extended periods, delaying required regulatory reporting.
- In some situations the company failed to follow up on serious adverse-event reports — including deaths and suicide — because internal procedures required explicit consent from the original reporter before additional investigation.
The agency said these issues resulted in serious adverse events not being reported to regulators within the required 15-day window.
Spotlight on pharmacovigilance systems
While the FDA inspection covered only a sample of Novo Nordisk’s medicines — including products containing semaglutide and liraglutide — regulators said the findings raise broader concerns about the company’s safety reporting systems.
Pharmacovigilance processes are among the most heavily scrutinised parts of pharmaceutical regulation. Even widely used medicines can reveal new safety risks once they reach large real-world patient populations.
Accurate and timely reporting of adverse events allows regulators to detect potential safety signals, update prescribing information and, in rare cases, impose new restrictions or warnings.
In its letter, the FDA said Novo Nordisk’s responses to earlier inspection findings did not provide enough detail to demonstrate that the underlying issues had been fully resolved.
The agency also pointed to potential weaknesses in oversight of third-party vendors responsible for handling patient safety calls and collecting adverse-event reports.
Corrective actions under review
Novo Nordisk told regulators it planned several corrective steps, including revising internal procedures, conducting retrospective reviews of previously closed safety cases and strengthening oversight of contractors handling adverse-event reports.
The company also said it was considering shifting some safety-case intake to dedicated in-house patient safety staff rather than relying solely on outsourced call-centre vendors. The FDA, however, said the information provided so far was not detailed enough to determine whether those measures would prevent similar violations in future.
Novo Nordisk, which said in a Tuesday statement ackledging the letter that it is “working diligently” to address the FDA’s concerns, now has 15 business days to respond formally to the warning letter and outline how it will correct the deficiencies. The company's shares fell nearly 3% on the day.
For investors and industry observers, the episode is a reminder that regulatory risk in biotech and pharmaceuticals doesn’t end once a drug is approved. Blockbuster medicines such as Ozempic may dominate headlines for their commercial success, but behind the scenes, regulators remain closely focused on safety — and how companies monitor it — long after those drugs reach the market.