GSK Appeals Delaware Court’s Decision in Zantac Cases as Plaintiff Drops Lawsuit

Pictured: GSK's headquarters in West London/iStock

Pictured: GSK’s headquarters in West London/iStock

Tati Campelo/Getty Images

On Monday, GSK reported that a plaintiff voluntarily dropped her Zantac case against the company and that it is in the process of appealing a Delaware State Court’s decision to admit expert testimony in other cases.

Pictured: GSK’s headquarters in West London/iStock, Tati Campelo

GSK on Monday provided two updates on the legal cases surrounding its heartburn drug Zantac (ranitidine), including a voluntary plaintiff dismissal and an appeal of a recent decision by the Delaware State Court.

The company announced that the plaintiff Eugenia Kasza has voluntarily dropped her case against the pharma, which would otherwise have started trials in an Illinois state court on Monday. GSK said it did not settle Kasza’s claim “and has not paid anything in exchange for the voluntary dismissal.”

In her lawsuit, Kasza alleged that Zantac caused her breast cancer. However, GSK contends that 16 epidemiological studies of human data—taken together—show “no consistent or reliable evidence” that Zantac aggravates the risk of any cancer.

“GSK will continue to vigorously defend itself and manage this litigation in the best interests of the company and shareholders,” the company said in its statement.

As part of its defense efforts, GSK on Monday also announced that it has taken the first step to appeal the recent ruling by the Delaware State Court, which allowed plaintiff expert witnesses to testify in the Zantac cases. The ruling, released last week, sent GSK’s stocks tumbling 10%.

On Monday, the pharma said that it “strongly disagrees” with the court’s ruling, noting that it is “inconsistent with how the Daubert standard has been applied previously in Delaware and federal courts.” The Daubert standard helps courts determine whether expert testimony is admissible at a trial. It can be brought about by either the plaintiffs or defendants.

In its appeal of the court’s decision, GSK has asked for an interlocutory review which is typically granted only in exceptional situations. “GSK believes such circumstances are present here and that it is important to raise these matters now to the Delaware Supreme Court.” Pfizer, Sanofi and Boehringer Ingelheim are all part of the application.

First developed by Glaxo Holdings, which is now part of GSK, Zantac is a histamine 2-receptor antagonist that tempers the secretion of gastric acid, the main driver of heartburn. In 2019, the FDA said that it had found several samples of ranitidine to be contaminated with NDMA, an environmental impurity that the regulator classifies as a probable human carcinogen.

In April 2020, the FDA asked ranitidine manufacturers to withdraw their products as the NDMA contaminations could build over time and may expose patients to unacceptable levels of toxicity. There are still some 70,000 Zantac cases in the Delaware Superior Court, according to Reuters.

Tristan Manalac is an independent science writer based in Metro Manila, Philippines. Reach out to him on LinkedIn or email him at or

Tristan is an independent science writer based in Metro Manila, with more than eight years of experience writing about medicine, biotech and science. He can be reached at, or on LinkedIn.