A second Chinese company has been flagged by the European Medicines Agency after low levels of a cancer-causing substance were again detected in batches of valsartan, the main ingredient in certain high blood pressure and heart drugs.
The EMA said Aug. 10 that valsartan manufactured by Zhejiang Tianyu Pharmaceutical Co. Ltd. was determined to contain low levels of an impurity known as N-nitrosodimethylamine, or NDMA. The EU regulator, however, noted that patients are not at immediate risk, and they should not stop taking any valsartan medicines without consulting their doctor or pharmacist.
While NDMA has been classified as a carcinogen by European regulators, little evidence is available to confirm the substance causes cancer in humans. Recalls and other measures are taken out of precaution, the EMA has previously said.
Zhejiang Tianyu is the second Chinese company to be named by the EMA after NDMA was detected in valsartan manufactured by Zhejiang Huahai Pharmaceutical Co., Ltd. Zhejiang Huahai issued a voluntary recall of the drug in July.
The EMA, however, said that NDMA levels detected in batches of valsartan from Zhejiang Tianyu were much lower than levels seen in the active substance from Zhejiang Huahai. The EMA said it is working closely with international partners to review the impact of the NDMA detected in valsartan from Zhejiang Tianyu and will provide updates as additional information is available.
Valsartan, which was developed by Novartis AG and sold under the brand name Diovan, now has many generic versions and a variety of manufacturers. Earlier in August, Novartis stated that it was working with authorities in 23 countries to shore up supplies of valsartan after a recall of the medicine was initiated by the European regulator. Companies manufacturing valsartan using active pharmaceutical ingredients from Zhejiang Huahai have already been directed by the EMA to test available samples to identify NDMA levels.
In the U.S., the Food and Drug Administration on Aug. 10 updated its list of recalled valsartan products to include the compound manufactured by Indian drugmaker Hetero Labs Ltd, after the cancer-causing impurity was found in the company's products.