Dozens of lawsuits have been filed against drug makers and sellers over widely prescribed generic heart medications tainted with potential carcinogens, the first claims in what some lawyers expect to be a wave of litigation.

Millions of Americans have taken the drugs, which are at the center of a widening recall being overseen by the U.S. Food and Drug Administration, and have been for decades used to treat high blood pressure, heart failure and other common conditions.

A lawyer involved in an effort to combine about 50 lawsuits, including at least 27 by patients who say they contracted cancer by using the recalled medicine, told a U.S. federal court he expects a surge of legal action. 

“My best estimate sitting here today is I expect that we will have approximately 2,000 personal-injury cases on file in the next two years,” Daniel Nigh, who has filed 12 such lawsuits so far, told judges at a conference in the U.S. District Court in New Jersey last month, according to a transcript.

The FDA has been coordinating a recall of adulterated heart medications since last July, when the carcinogen NDMA was discovered in valsartan manufactured by Zhejiang Huahai Pharmaceutical Co. The contaminated valsartan was sold to a number of major drugmakers and used as an ingredient in other popular cardiovascular therapies.

Zhejiang Huahai and its affiliates are the primary targets of the lawsuits. Other companies named in the complaints include generic-drug giants Teva Pharmaceutical Industries Ltd. and Mylan NV, as well as CVS Health Corp., which operates large pharmacy and drug-benefit management businesses. Almost 40 defendants have been sued so far.

The FDA has said that the pills may have been contaminated with NDMA for as long as four years before the problem was found. The number of patients, if any, who developed cancer as a result of taking valsartan is unknown.

Earlier this year, Bloomberg News reported wide-ranging problems with testing data used to assure drugs’ safety and effectiveness. Bloomberg found that FDA inspectors who'd expressed concerns about data integrity at some manufacturing facilities were at times overruled by senior officials at the agency.

At a Zhejiang Huahai plant in Linhai that's at the center of the recall, an FDA inspector determined that some of the drugs produced there were substandard — 14 months before the agency took steps to facilitate the removal of valsartan and its combinations from the U.S. market.

A spokeswoman for Zhejiang Huahai declined to comment. Representatives for Teva, Mylan and CVS didn’t immediately respond to requests for comment. Shares of Zhejiang Huahai lost 2.5 percent on Wednesday in Shanghai.

The FDA said last month it plans to revamp rules governing how medicines are manufactured to ensure the safety of the nation's drug supply, in response to what former Commissioner Scott Gottlieb said were inadequate quality controls that have led to “a lot of instances” of contaminated products.

“I expect that we will have approximately 2,000 personal-injury cases on file in the next two years.”

Andres Rivero, an attorney for MSP Recovery, a Florida-based claims recovery service, told judges at the New Jersey hearing last month that his client represents insurers covering 73,311 people who took valsartan and that their claims were worth more than $91m. In 2018, 1.5 million people in the U.S. took contaminated valsartan, said Nigh.

Other drugs that are similar to valsartan — losartan and irbesartan — have also been recalled. It’s unclear if those drugs will be included in the combined litigation, plaintiffs’ lawyers told the court, because not as much is known about the degree of contamination of those pills. Other carcinogens, NDEA and NMBA, have been found in the drugs as well.

Zhejiang Huahai didn’t make all of the valsartan found to be tainted, though carcinogen levels were highest in its drugs, according to the FDA. The U.S. agency has said it’s looking into how the chemicals could have been created during the manufacturing process.

Proving the link between exposure to the contaminated medication and the plaintiffs’ cancers may be difficult, Senior U.S. District Judge Robert Kluger told the lawyers at the March 27 hearing.

“There’s a number of people who claim, I understand, that they’ve contracted cancer from taking this drug,” Kluger said. “It’s probably going to be a heavy lift to prove that, but you know, we’ll see what happens.”

NDMA, which is also found in cured and grilled meat, has long been known as a carcinogen. Plaintiffs’ lawyers said in the complaints that the amount contained in valsartan was far above accepted levels. Shortly after the recalls started in July, the FDA said that it’s reasonably safe to consume up to 0.096 micrograms of NDMA a day. FDA test results released Oct. 5 found NDMA levels in recalled valsartan ranging from 0.3 micrograms to 17 micrograms.

“Thus the pills contained somewhere between 3.1 and 177 times the level of NDMA deemed safe for human consumption,” lawyers for plaintiff Priscilla Kleinman, who has esophageal cancer, said in her lawsuit filed in February.

There is more NDMA in a single pill of valsartan than a person could consume in a month, said plaintiffs’ attorney John Boundas, who is reviewing medical records of dozens of potential claimants. “One pill is the equivalent of 30 pounds of bacon,” he said.

Shortly after it announced the start of the recall in July, the FDA estimated that for every 8,000 people who took the highest dose of valsartan, there would be one additional case of cancer.

In addition to the personal-injury cases, attorneys in the federal-court cases in New Jersey are also proposing class actions to cover economic losses, including allegations by consumers and third-party payers such as health-insurance companies that they spent millions of dollars for tainted drugs.

MSP Recovery is suing on behalf of health insurers including New York Group Health Inc. and SummaCare Inc., an Ohio provider, according to its lawsuit, filed in February. Greg Hansel, an attorney for the Maine Automobile Dealers, told the court the group has been in touch with “a number of larger health insurers” that are “actively monitoring what’s happening.”

A separate class action was filed with the New Jersey court on April 5 on behalf of patients who may not exhibit symptoms until years from now. Those patients took contaminated valsartan and may have sustained cellular damage, suffered genetic harm or developed cancer but haven’t yet been diagnosed, according to the complaint. The suit seeks to create a fund to finance independent medical monitoring, including examinations and preventive screening, and provide cancer treatment.

All the cases have been combined before Judge Kluger in federal court in Camden in a so-called multidistrict litigation, where he will oversee selection of plaintiffs’ leadership, pretrial motions and evidence-gathering, as well as any initial trials. At a hearing in Camden on Wednesday, U.S. District Magistrate Judge Joel Schneider said he plans to order the defendants to produce all FDA inspection reports related to facilities that manufacture valsartan dating back to 2010. He also asked the companies to produce any communications they had with the FDA about how carcinogens got into the drugs.

The information covered by the order would come in addition to material that the defendants have already agreed to produce.

MDLs can include thousands of claims, some of which would never pan out or even be brought if filed separately, said law professor Carl Tobias of the University of Richmond law school. As such, it can attract weaker cases that piggyback on strong ones, he said.

“You can never tell with MDLs on the number of viable or strong cases as opposed to the weak ones,” Tobias said.