This month, a fourth Indian drug company involved in the manufacture of valsartan and another angiotensin II receptor blockers (ARBs) received an FDA warning letter over NDEA and NDMA found in its products. Lantech joins Hetero Labs, Aurobindo and Emtech Pharmaceuticals on the list of drug manufacturers that supply the active ingredient in valsartan that has been found to be contaminated with cancer-causing industrial chemicals.
Last year, a Chinese facility operated by Zhejiang Huatai Pharmaceuticals (ZHP) also received a warning for its failure to investigate NDMA contamination.
NDMA (N-Nitrosodimethylamine) is an industrial by-product resulting from the manufacture of aviation and rocket fuel, while NDEA (N-Nitrosodiethylamine) is a nitrosamine found in tobacco fumes and is used as an additive for gasoline and machine lubricants. Both of these chemicals are known carcinogens and can cause tumors to form anywhere in the body.
According to the FDA warning letter, Lantech failed to investigate traces of the contaminants found on their equipment. They were also unaware of conditions and inadequacies in the manufacturing process under which chemical contamination could occur. According to the letter, Lantech does not “understand all the potential risks associated with the drug manufacturing processes conducted” at the factory.
In addition to NDEA and NDMA contamination, FDA investigators discovered “solid and liquid material of unknown origin…pooling at the bottom of a non-dedicated receiving tank.” To make matters worse, Lantech has admitted to “routinely deleting” inspection records after 90 days.
Earlier this summer, Lantech was put on the FDA import alert for failing to investigate contamination of their valsartan after receiving notification from a customer. The FDA reports that valsartan contamination may be due to the practice of reusing solvents that are employed in the manufacturing process.
Concerns about valsartan emerged in July of 2018 after the European Medicines Agency and Health Canada ordered recalls of valsartan after NDMA contamination was discovered in the active ingredient made in China by ZHP. The contaminated valsartan was used by a number of generic drug makers around the world. A month after the initial recall, the FDA cited Hetero Labs and another Chinese drug company, Zhejiang Tianyu Pharmaceuticals, for similar contamination.
Over the past year, nitrosamine contamination has been discovered in other drugs of the ARB class, including losartan, irbesartan, Olmesartan, and telmisartan. All of these medications are used for the treatment of hypertension. The primary difference between them is how long they remain in a patient's system. These medications work by blocking the angiotensin receptors in the smooth (involuntary) muscle cells of blood vessels. Angiotensin is a hormone that among other things causes blood vessels to constrict. Blocking the receptors allows the blood vessels to relax and dilate, lowering blood pressure. According to estimates, nearly 67 million prescriptions per year are written for ARB medications.
Not all ARB medications have been found to be contaminated. Patients who are concerned can check the FDA website, which now has a list of 40 ARBs that have tested negative for contamination.