Amid continuing concerns about the risk of cancer from recalled valsartan tablets, new research indicates that an impurity found in generic versions of the blood pressure medications does not appear to increase the short-term cancer risk, but the findings can not rule out a long term cancer risk from NDMA in valsartan.

In a study published this week in the medical journal The BMJ, researchers with the University of Southern Denmark and the Danish Medicines Agency published findings of a cancer risk assessment involving valsartan contaminated with N-nitrosodimethylamine (NDMA).

The assessment comes following a series of valsartan recalls issued after it was discovered that NDMA contaminated the ingredients for years, leaving consumers nationwide with concerns about the cancer risk they may now face.

The research involved data from 5,150 Danish patients ages 40 and older, who used valsartan between January 2012 and June 2017. The researchers looked at cancer rates and likely exposure to NDMA.

According to the findings, there was a 9% increased risk of cancer among those exposed to NDMA for a median of 4.6 years, and there was no evidence of a dose-response relationship. However, the researchers also found that when they looked at single cancer outcomes linked to valsartan and NDMA, there were increased risks for colorectal cancer and uterine cancer.

“The results do not imply a markedly increased short term overall risk of cancer in users of valsartan contaminated with NDMA,” the researchers concluded. “However, uncertainty persists about single cancer outcomes, and studies with longer follow-up are needed to assess long term cancer risk.”

The first valsartan recalls were announced in Europe on July 5, after batches of the active ingredient supplied by Zhejiang Huahai Pharmaceuticals in China, tested positive for NDMA. That initial recall affected about 2,300 batches of valsartan and valsartan HCT shipped throughout Europe and Canada. The same manufacturer made the recalled Torrent Pharmaceutical pills.

The FDA followed with its own recall announcement on July 13, indicating that the agency had launched an investigation to determine the scope of the contamination and the potential risk to consumers.

According to the FDA’s valsartan findings, a specific combination of conditions, which include the use of certain chemicals in the right processing conditions and production steps can lead to the formation of NDMA in the active pharmaceutical ingredient. The formation of the impurity occurs if the steps are done in a certain sequence, and the FDA indicates that this is the first time scientists and experts have come to understand how NDMA is formed accidentally.

Now, the FDA can evaluate other drug manufacturing processes that could lead to the formation of NDMA, and valsartan testing will be required in situations where the agency believes NDMA could form. It also allows the agency to determine whether other valsartan manufacturers have processes that could lead to NDMA, which may result in additional recalls.

The FDA has assigned a group of pharmacists and nurses to answer consumer’s questions about the recalls. Since the first recalls, the agency indicates it has received more than 6,000 inquiries from patients, doctors, nurses, pharmacists and academics. Inquiries can be made by calling 855-543-3784 or by sending an email to druginfo@fda.hhs.gov.

A number of consumers are now pursuing valsartan cancer lawsuits against the manufacturer, alleging that use of the contaminated drug resulted in their diagnosis.

Tags: Cancer, Colorectal Cancer, Drug Recall, Hypertension, NDMA, Uterine Cancer, Valsartan