Merck found the source of Januvia contamination, plans to fix the issue this year: report

In a report to the FDA, Merck says it has figured out how its blockbuster Type 2 diabetes drugs have become contaminated with nitrosamine. And the company has told the regulator that it can fix the issue by the end of this year, a source told Bloomberg.

Five months ago, the FDA detected Nitroso-STG-19 (NTTP) in Januvia and Janumet, the franchise which generated sales of $5.3 billion for Merck in 2021.

While it wasn’t clear whether Merck or a third-party manufacturer was responsible for the contamination, the agency temporarily allowed sales of the drug to continue even though some samples exceeded the 37 nanogram (ng) threshold for daily intake.

The FDA’s decision also was influenced by a shortage of the injected blood-sugar-reducing drug, which if discontinued by a patient can have dangerous consequences.

"(Merck) has already instituted additional quality controls and expects to be able to consistently reduce NTTP levels to meet the long-term acceptable daily intake level this year," the company said in a statement to Fierce Pharma. "The specific timeframe will be based on the progress of timing to institute process modifications and on engagement with FDA and other health authorities."

Over the last few years, nitrosamines have turned up in a variety of commonly used medicines, including Sanofi, Pfizer, Boehringer Ingelheim and GSK’s blood pressure drug Zantac, Pfizer’s smoking cessation therapy Chantix and another Type 2 diabetes treatment, metformin, which is sold by several companies as a generic.

The contamination has triggered recalls, shortages and—in the case of Zantac—lawsuits. Last month, a judge in Florida sided with the sellers of Zantac, saying claims did not have sound scientific basis.

While the FDA has pointed out that nitrosamines can cause cancer, the compounds are a part of life as they are commonly found in water and in foods—particularly dairy products, vegetables and grilled and cured meats. The risk of cancer comes with high-level exposure over extended periods of time.