GSK set to face jury trials over heartburn drug Zantac

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GSK and other pharmaceutical groups are set to face jury trials in cases brought by more than 72,000 cancer sufferers who allege a heartburn drug caused their condition, after a judge in Delaware ruled that plaintiffs’ scientific evidence could be heard.

The ruling by Judge Vivian Medinilla means that scientific experts will be able to testify before a jury that there is a link between the plaintiffs’ cancers and their exposure to NDMA, a probable human carcinogen, through Zantac. GSK and other companies dispute these claims.

GSK, which developed the drug, could face costly compensation payouts if juries find it liable for the plaintiffs’ cancers. So could other companies that marketed Zantac including Boehringer Ingelheim and Sanofi.

The companies involved have seen tens of billions of dollars wiped off their market capitalisations because of the cases and have settled several; the vast majority of the remainder are in Delaware.

Although Medinilla’s ruling is not an endorsement of the plaintiffs’ evidence, it exposes the companies to the unpredictability of a jury trial.

In her conclusion, Medinilla said: “In Delaware . . . trial courts entrust questions of science to the scientists . . . it would be improper to simply dismiss these experts as ‘poseurs or witnesses for hire’.”

Brent Wisner, co-lead counsel in cases brought by plaintiffs in the Delaware and California state courts, said the ruling “moves us one step closer to justice for our clients”.

“This case has always been about getting the science in front of a jury . . . Now the writing is on the wall. GSK, Boehringer Ingelheim, and Sanofi will need to answer for their 40 years of misconduct,” he said.

GSK said it “will immediately seek an appeal”. “[The] scientific consensus is that there is no consistent or reliable evidence that ranitidine increases the risk of any cancer and GSK will continue to vigorously defend itself against all claims,” the company said, referring to the generic name for Zantac.

In 2022 a Florida federal court decided that other scientific experts’ findings about the carcinogenic nature of Zantac were based on “unreliable methodologies”.

Zantac was a best-seller for GSK after its US approval in 1983. It was the first drug to achieve blockbuster status by generating more than $1bn in revenue, and was later also sold by other pharma groups.

But in 2019 Valisure, an independent laboratory in Connecticut, reported that it had discovered “extremely high levels” of NDMA in ranitidine. NDMA is a substance also found in cigarettes and processed foods that is classed as a probable human carcinogen. The companies have challenged the lab’s methods.

The US Food and Drug Administration and the European Medicines Agency recommended suspension of the use of ranitidine products and the FDA asked all manufacturers to withdraw products based on the drug.

This was largely unnoticed by investors until 2022, when an analyst note published by Morgan Stanley estimated the potential liability at up to $45bn. Companies linked to the drug lost a combined $40bn in value in days.

GSK, Sanofi and Pfizer have sought to settle numerous cases relating to Zantac. Last month Pfizer offered up to $250mn to settle more than 10,000 lawsuits. In the first instance to go before a jury, GSK and Boehringer Ingelheim last month won a case in Illinois.