Merck & Co Manufacturing Mishap Leads to Carcinogen in Diabetes Medication

Last week, Merck & Co made the FDA aware of the presence of nitrosamine in its type 2 diabetes drug, Januvia. Merck’s analysis of the drug found nitrosamine levels higher than allowed by the FDA, but the agency has decided not to withdraw the drug from the market for fears of a shortage.  

The decision to leave Januvia — Merck’s brand name for sitagliptin — on the market was based on the importance of the drug for maintaining patients’ safety and the likelihood of harm if it was temporarily pulled. The once-daily prescription pill helps lower blood sugar levels in adults with type 2 diabetes by increasing insulin release.  

Januvia is exclusively sold by Merck and has become one of their top earning pharmaceuticals since its introduction in 2006. In 2021, the drug was responsible for $5.3 billion in revenue, making it Merck’s third best-selling drug and one of the most popularly prescribed Medicare Part-D medications. The drug will lose its patent exclusivity in January of 2023, and while there are no generic alternatives to Januvia, several companies manufacture similar drugs that improve blood sugar control for people with type 2 diabetes.   

Nitrosamine is classified as a possible human carcinogen in the United States, with an acceptable intake level of 246.7 nanograms per day. The chemical is primarily found in tobacco products, tobacco smoke, fried foods, cured and grilled meats, and beer. Nitrosamines can also be produced spontaneously during pharmaceutical manufacturing, making them difficult to monitor and necessitating testing. Long-term exposure to high levels of the chemical is thought to lead to cancer in humans, although there aren’t conclusive scientific studies to prove the causal effects of exposure.  

Last year, Pfizer found nitrosamine in its popular smoking cessation drug Chantix and decided to halt the production of pills until they could fix their manufacturing issues. One year prior, the FDA requested the removal of all prescription and over-the-counter ranitidine drugs — including Zantac — after finding nitrosamine in independent laboratory tests. Consequently, a class action lawsuit was filed against former Zantac manufacturer Pfizer and other Zantac distributors after some users of the drug developed cancer.  

And in a situation similar to that of Januvia’s, an extended-release version of the widespread diabetes drug metformin was voluntarily recalled after nitrosamine was discovered in some pills.  

Merck is now working with health authorities to ensure their medications’ quality and compliance with maximum limits of cancer-causing chemicals.