The US Food and Drug Administration (FDA) has issued a warning letter to Novo Nordisk over failures in reporting suspected adverse side effects linked to the GLP-1 drugs Ozempic and Wegovy.
The warning letter was issued on March 5 following an inspection of the company’s facility in Plainsboro, New Jersey, conducted in 2025.
The FDA said some serious adverse events linked to semaglutide, the active ingredient in Ozempic and Wegovy, were not investigated or reported within required timelines.
The agency said three deaths were not reported within the required timeframe. One case involved suicide and another referenced suicidal thoughts. The FDA said it has not concluded that the drugs caused these events.
In the letter and an accompanying inspection report, the FDA said Novo Nordisk did not report all suspected side effects in patients taking Ozempic. The agency said the cases included two deaths and a suicide.
According to the inspection report, Novo Nordisk identified in April 2024 that serious adverse events involving Ozempic and other medicines had not been properly reported since 2020.
FDA investigators at the company’s US headquarters in Plainsboro said they found more than 300 adverse event reports that had not been submitted to the agency. Some reports were more than 1,000 days late. The cases included at least four deaths and a suicide.
The FDA said the company did not promptly investigate a report in which a doctor told a company representative that a patient taking semaglutide was depressed and later committed suicide.
In another case, the company did not investigate a reported death because the person who submitted the report was not a healthcare professional. A third death was not reported because the company said it could not identify the patient. The FDA said it was able to identify the patient during its investigation.
The agency also said some company procedures did not comply with regulations. One policy allowed information about a potential adverse event to be withheld if the person reporting it believed the complication was unrelated to the drug. FDA regulations require companies to report all serious and unexpected adverse events.
The FDA said Novo Nordisk has not yet demonstrated that its planned changes will prevent similar violations in the future.
Novo Nordisk said it has reviewed the cases and ensured they were processed and reported appropriately. The company said it plans to address the FDA’s concerns “expeditiously and holistically.” It added that it has been working with the regulator on a corrective action plan since an inspection early last year.
The warning letter comes as Novo Nordisk competes in the growing market for obesity and diabetes medicines, where rival Eli Lilly has gained market share. The United States is the largest market for these drugs.
Novo Nordisk shares fell as much as 3.3% in Copenhagen following the news. The stock has declined about 22% this year through Monday’s close.
In a separate review, the FDA said there is no increased risk of suicidal ideation or behaviour linked to GLP-1 drugs such as Ozempic. In January, the agency asked companies to remove warnings about suicide risk from the labels of weight-loss medicines.
Analysts said the impact in India is expected to be limited as semaglutide goes off patent and generic versions enter the market in March.
They added that if regulatory pressure increases, it could benefit Eli Lilly’s GLP-1 portfolio, including tirzepatide and the upcoming drug retatrutide. Analysts also said this could be positive for suppliers such as Divi’s Laboratories.
(With input from agencies)