GSK plays defense after California judge approves plaintiff's expert testimony in high-stakes Zantac trial

After eluding thousands of federal lawsuits because a U.S. district judge rejected the science behind plaintiffs’ claims, GSK will be forced to defend itself against allegations that its fallen heartburn med Zantac causes cancer in state court this summer.

Late this week, California judge Evelio Grillo said he’d allow expert testimony to proceed after what’s known as a Sargon hearing, in which Evelio weighed the validity of claims on both sides of the argument.

The outcome of the Sargon proceedings simply means both parties can call on expert witnesses at the upcoming trial, slated for July. It is not a ruling on the evidence itself.

GSK “respectfully disagrees” with the ruling, the company said in a statement. The British drugmaker called on 13 epidemiological studies that suggest “the scientific consensus is that there is no consistent or reliable evidence that ranitidine increases the risk of any cancer.” Ranitidine is Zantac's generic moniker. 

The British drug giant stressed that litigation is still at an “early stage."

This initial case is being brought by California resident James Goetz. GSK says it will “press additional defenses” and notes that Goetz “still needs to prove his case at trial.”

The outcome differs from that in some 50,000 similar Zantac claims in federal court, which U.S. District Judge Robin Rosenburg tossed after ruling that plaintiffs’ experts leveraged “unreliable methodologies” to reach their conclusions.

At the time of the ruling late last year, the federal court said no scientist outside the litigation had concluded Zantac causes cancer.

Naturally, GSK welcomed that ruling. The company has elected to play defense in the Goetz case, unlike its peers in the Zantac litigation Sanofi and Pfizer, which settled their cases with the plaintiff last year, though it remains unclear for how much.

A Sanofi spokesperson told Fierce Pharma at the time that the company resolved the case “not because it believes these claims have any merit, but rather to avoid the expense and distraction of a trial in California.”

GSK, for its part, noted in a December 2022 press statement that it will continue to “defend itself vigorously, including against all claims brought at the state level.”

Despite GSK’s arguments on a lack of “consistent or reliable evidence” linking its heartburn drug to cancer, a recent report in Bloomberg Businessweek suggested GSK’s own scientists had long known about the risks.

Zantac was pulled from the market in 2020 when it was linked to unacceptable levels of N-nitrosodimethylamine, a potential cancer-causing agent. Aside from GSK, Pfizer and Sanofi, the litigation has swept up Boehringer Ingelheim and several generic manufacturers.