A federal judge dealt a blow to plaintiffs after dismissing thousands of Zantac cancer lawsuits in multidistrict litigation in Florida.

The ruling absolves pharmaceutical giants Pfizer, Sanofi, GSK and Boehringer Ingelheim of some 50,000 claims, according to FiercePharma. This includes class-action claims and individual Zantac lawsuits among the 2,056 pending actions in multidistrict litigation in the Southern District of Florida.

In a 300-page ruling, U.S. District Judge Robin Rosenberg found plaintiff’s experts didn’t use reliable methodologies to connect Zantac to cancer. 

Plaintiff’s experts “systemically utilized unreliable methodologies with a lack of documentation on how experiments were conducted, a lack of substantiation for analytical leaps, a lack of statistically significant data and a lack of internally consistent, objective, science-based standards for the evenhanded evaluation of data,” according to the judge’s ruling. 

People began filing lawsuits against Zantac makers in 2020 following a massive 2019 recall based in part on the findings of Valisure, an online pharmacy. Valisure found high levels of N-nitrosodimethylamine, or NDMA, in Zantac tablets. 

As of 2020, no ranitidine products remain on U.S. store shelves after the U.S. Food and Drug Administration requested a market withdrawal. 

Zantac Decision Likely Headed to Appeals Court

While Rosenberg’s decision is a win for defendants, attorneys for plaintiffs will likely be appealing the decision. Defendants still face tens of thousands of Zantac lawsuits in state courts across the country. New cases may still be filed. 

In its statement, GSK said it will “continue to defend itself vigorously, including against all claims brought at the state level.” 

Likewise, Sanofi and Boehringer are committed to fighting the remaining Zantac cases. 

In an email to FiercePharma, Sanofi said, “This ruling significantly decreases the scope of the litigation potentially by over 50%.”

GSK: Evidence ‘Unreliable’ and ‘Litigation-Driven’

Zantac lawsuits claimed drugmakers knew ranitidine, the active ingredient in Zantac, was unstable and could turn into NDMA in the human body. NDMA has been shown to be a carcinogen in animal studies and a probable human carcinogen. 

The science connecting ranitidine to cancer in humans was “unreliable and litigation-driven science,” according to GSK.

“Following the 12 epidemiological studies conducted looking at human data regarding the use of ranitidine, the scientific consensus is that there is no consistent or reliable evidence that ranitidine increases the risk of any cancer,” GSK said in a statement. 

Sanofi and GSK stock climbed after the lawsuit dismissal news. Bernstein analysts called the ruling a “nice early Christmas present for the defendants,” Reuters reported.