GSK Plc, Pfizer Inc. and other drugmakers must face trials in State court in Delaware after a judge found the evidence backing up claims the companies’ former Zantac heartburn treatment causes cancer is legitimate and can be heard by juries.

Superior Court Judge Vivian Medinilla concluded late Friday that consumers aren’t relying on flawed science to support allegations Zantac — owned by different companies at different times – caused a variety of cancers. She also found disputes over experts’ analyses of those health risks can be properly debated at trial.

About 75,000 consumers have filed suit in Delaware targeting former makers of the treatment.

Delaware law shows a “deep deference for the role of juries as the ultimate fact finders,” Medinilla said in a 102-page ruling. “Delaware courts are loath to step into the heart of technical debate between opposing scientists.” She hasn’t yet set a trial date for any of the cases. Other companies targeted by the suits include French drugmaker Sanofi and Berlin-based Boehringer Ingelheim GmbH.

The ruling is a major blow to GSK and other former Zantac makers, which hoped to persuade Medinilla to follow the lead of a federal judge in Florida who rejected the cancer evidence as unreliable in 2022. California and Illinois judges have signed off on the validity of much of the same evidence, leading GSK and Pfizer to settle some cases. Still, an Illinois jury last month rejected a woman’s claim that Zantac caused her colon cancer in the first US case to go to trial.

UK-based GSK said Saturday it disagreed with Medinilla’s ruling and would appeal it. “The ruling does not mean that the court agrees with plaintiffs’ experts’ scientific conclusions, and it does not determine liability,” GSK said in a release. Sanofi officials said they face about 25,000 cases in Delaware and believe none are worthy for trial.

Pfizer said it’s implicated in “only a fraction” of the Delaware cases, adding that it continues to see no material impact from Zantac litigation. The company intends to appeal, it said in a statement Saturday. 

“Sanofi remains committed to its defense and to the safety of Zantac, and will vigorously defend itself against these claims, which the medical, scientific, and regulatory communities have extensively evaluated and have found to be without merit,” the company said in a statement.

Representatives of Boehringer did not immediately return emails seeking comment.

Ex-Zantac users have sued branded and generic drugmakers that made the heartburn medicine over the years alleging the product caused breast, stomach and colon cancer, among others.

Cancer Link

Plaintiffs have argued the companies knew ranitidine — the drug’s active ingredient — turned into the potential carcinogen NDMA under certain conditions. In 2020, the US Food and Drug Administration asked companies to remove all ranitidine-based drugs from the US market after some versions were found to be contaminated with NDMA. 

Medinilla cited the FDA recall in her decision to allow consumers’ experts to testify about studies showing NDMA can cause cancer and ranitidine can transform itself into carcinogen in certain circumstances. The judge noted regulators ordered the ranitidine version of Zantac off the market after concluding NDMA is a “substance that can cause cancer.”

The companies and consumers will get a chance to present their experts to juries, who will make the final call on Zantac’s cancer risks, the judge noted. “This dispute presents a classic battle of the experts,” Medinilla wrote. The companies “can take up their challenges” to plaintiffs’ scientific evidence on cross-examination at trial, she added.

Zantac in the US market

Zantac hit the US market as a prescription drug in 1983 before transforming into an over-the-counter heartburn treatment in 1995. GSK and Warner Lambert developed it as part of a joint venture, and the drug was owned by several companies through the years before Sanofi, which acquired it in 2017.

After the FDA recall, Sanofi won approval to return Zantac to US store shelves, but without ranitidine. It’s now made with famotidine, the active ingredient in competitor Pepcid, which is marketed jointly by Merck & Co. and Johnson & Johnson spinoff Kenvue Inc.

Zantac makers got a boost in 2022 when a federal judge threw out more than 5,000 suits filed in federal court in Florida, saying the science behind the cancer claims was flawed. That decision also applied to about 50,000 unfiled cases covered by the so-called multi-district litigation (MDL), according to court filings. 

After the federal cases were thrown out, many were refiled in Delaware, where the pharma companies’ US units are incorporated.

The companies’ attorneys argued the Delaware cases relied on the same science rejected in Florida, and plaintiffs sought to have Medinilla ignore her function to weigh the legitimacy of evidence presented to juries. Consumers’ attorneys countered that they’d offered different expert witnesses in the Delaware cases who’d based their opinions on “reliable materials.”

The case is IN RE: Zantac (Ranitidine) Litigation, N22C-09-101 ZAN, Delaware Superior Court (Wilmington).

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