The U.S. Food & Drug Administration (FDA) has identified the source of cancer-causing nitrosamines behind recent recalls involving valsartan and other potentially-tainted blood pressure drugs.
Last Friday, the agency confirmed that the compounds – N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) – were likely chemical byproducts of the manufacturing process used to synthesize the medications’ active ingredients.
Apparently, the problem went undetected for years because regulators and manufacturers did not know what impurities the method would inadvertantly create.
Zhejiang Huahai Pharmaceutical Co., one of the overseas companies responsible for the supplying the ingredients to generic drug makers around the world, instituted the process in 2014. This means contaminated valsartan, losartan, and irbesartan were likely in circulation for more than four years.
All three of these drugs belong to a medication class called angiotensin II receptor blockers (ARBs), which are indicated to treat patients suffering from heart failure or high blood pressure.
NDEA and NDMA are both considered probable human carcinogens. Specifically, tests involving rats and mice have linked the compounds to kidney cancer, liver cancer, colorectal cancer, respiratory cancer, stomach cancer, and bladder cancer. The contaminants were first detected in active ingredients supplied by China-based Zhejiang Huahai Pharmaceutical, and would later turn up in ingredients manufactured by Hetero Labs of India.
Medications affected by the subsequent ARB recalls include:
The recalled drugs were marketed by numerous generic manufacturers, including, Mylan Pharmaceuticals, Teva Pharmaceuticals, Sandoz, Prinston Pharmaceuticals, ScieGen, and Torrent Pharmaceuticals.
According to The Washington Post, some of these companies also sold recalled medications under different names. For example, Prinston marketed some of its recalled batches under the Solco Healthcare label, while Teva recalled medications bearing labels for Actavis and Major Pharmaceuticals.
The FDA estimates that as many as 2 million patients may have been exposed to contaminated valsartan, losartan, or irbesartan drugs. According to the agency’s scientists, one additional case of cancer would occur if 8,000 people took the highest dose of valsartan for four years.
Consumers should contact their pharmacy to determine if their ARB is included in one of these recalls. They can also check regularly-updated lists of recalled valsartan products , losartan medications, and irbesartan products posted on the FDA’s website.
Individuals with a recalled medication should get in touch with their doctor or pharmacist to arrange for a replacement. It’s important, however, that patients continue using their ARB until they obtain an alternative, as stopping treatment entirely could lead to serious adverse health events.
Unfortunately, finding a replacement ARB could be difficult, as the ongoing recalls have already created a valsartan shortage. On Friday, the FDA warned that other products could soon be in short supply.
Since last June, more than a dozen valsartan lawsuits have been filed in federal courts throughout the United States. Although many of the filings are class actions that seek reimbursement for consumers who purchased recalled medications, a growing number of individual lawsuits involve patients who allegedly developed cancer because of contaminated valsartan.
On Thursday, the U.S. Judicial Panel on Multidistrict Litigation will hear oral arguments on a motion to centralize the federal valsartan litigation before a single judge in one U.S. District Court. If the panel agrees, all currently pending lawsuits, as well as any filed in the future, will be transferred to the designated jurisdiction for coordinated discovery and motions practice.
At some point, a small number of representative valsartan lawsuits will be chosen for bellwether trials. Verdicts in these cases could provide insight into how other juries might decide similar claims. In many previous multidistrict litigations, bellwether trial verdicts provided the parties with a path towards a global settlement that resolved all or nearly all of the pending cases. Any lawsuits that aren’t settled or otherwise resolved during the multidistrict litigation process are returned to their original court of filing for trial.