Potential Risk of Cancer from Zantac Known By Drug Maker For Decades: Report

Court records indicate GlaxoSmithKline knew Zantac's active ingredient could chemically change into a cancer-causing agent as early as 1982, and that the potential risk was there before the drug was even developed

Following an analysis of court records and other documents, Bloomberg News reports that GlaxoSmithKline knew about the potential risk of cancer from Zantac for decades, but failed to disclose information about problems with their blockbuster heartburn drug to federal regulators or the medical community.

The report was published this week, highlighting how scientists working with the drug maker suspected that the active ingredient in Zantac, ranitidine, posed a potential cancer risk since the drug was first developed and marketed in the late 1970s.

While the risk concerned investigators at the U.S. Food and Drug Administration (FDA) at the time, Bloomberg indicates the manufacturer failed to share critical study data, which may have raised even more health concerns about the potential Zantac side effects.

Zantac (ranitidine) was used by millions of Americans for treatment of heartburn and acid reflux, before it was removed from the market in late 2019, following a discovery that the active pharmaceutical ingredient is inherently unstable, and produces high levels of the chemical byproduct N-Nitrosodimethylamine (NDMA), which is a potent human carcinogen.

GlaxoSmithKline, Boehringer Ingelheim, Pfizer, Sanofi and various other manufacturers, distributors and retailers involved in the sale of brand name or generic ranitidine pills have faced more than 100,000 Zantac lawsuits brought by former users who indicate they have been diagnosed with bladder cancer, esophageal cancer, liver cancer, pancreatic cancer, stomach cancer or other injuries, as NDMA moved through their body.

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Zantac Lawsuits

Side effects of Zantac may increase the risk of cancer, due to chemical impurities found in the heartburn drug.


According to Bloomberg News, an analysis of court records revealed that one cancer researcher working for the U.S. government, William Lijinsky, determined that nitrosamines could form in the stomach as early as 1969, when ranitidine was still in development. He warned that certain foods and drugs might become cancer-causing agents due to the body’s natural processes.

In 1980, shortly after Zantac was introduced, a report from a pharmaceutical analyst at a British investment firm warned investors that ranitidine could become cancer-causing nitrosamines due to the body’s natural processes.

Numerous reports and studies followed, beginning in the early 1980s, many of which warned that ranitidine could turn into N-Nitrosodimethylamine (NDMA) in the body. However, high-level researchers at Glaxo say the company never asked them to test whether ranitidine would turn into NDMA in the human body, even after studies began to come out suggesting that as a possible risk.

Court records indicate that in 1982, Glaxo asked one of its scientists, Richard Tanner, to investigate the risk of ranitidine changing into NDMA in the human body. He found some samples of ranitidine contained as much as 232,000 nanograms (ng) of NDMA. The FDA would later determine that 96 ng was the highest acceptable amount of NDMA in any drug.

However, Glaxo did not give the FDA what became known as the Tanner study, according to court records. Many even in the company were not told, including the associate director of clinical research in the U.S. and the company’s senior medical advisor for gastrointestinal research.

Zantac would go on to become a blockbuster drug for years, until it was recalled due to the presence of high levels of NDMA decades later.

Zantac MDL Cases Dismissed

Given common questions of fact and law raised in cases brought in U.S. District Courts nationwide, the federal Zantac litigation was centralized before Judge Robin L. Rosenberg in the Southern District of Florida, for coordinated discovery and pretrial proceedings. However, thousands of claims have also been filed in various state courts nationwide, including California, Delaware and other venues.

Following several years of discovery and pretrial proceedings, Judge Rosenberg issued an unexpected ruling in December 2022, determining that all of the plaintiffs’ expert witnesses were excluded from testifying at trial under the federal standards for admissibility of causation evidence, which left federal plaintiffs without any means of proving the recalled Zantac pills caused their cancer. As a result of the ruling, all Zantac lawsuits pending in the federal court system have been dismissed, and plaintiffs have initiated a lengthy appeals process to challenge the ruling.

February 2023 Zantac Lawsuit Update

The federal court ruling did not result in the dismissal of claims pending in various different state courts, each of which follows variations on the standards for expert testimony to be admissible and presented to juries.

There are an estimated 50,000 Zantac lawsuits still pending in state courts nationwide, with the first cases expected to before juries in various different venues throughout 2023.

Several California state court Zantac trials are expected to begin later this year, with cases previously scheduled to go before juries on May 1, 2023, August 7, 2023 and October 23, 2023.

These trials will be closely watched by parties involved in the litigation, and may provide a “bellwether” to help gauge how juries will respond to certain evidence and testimony that will be repeated throughout the remaining state court cases.

If plaintiffs can establish that they can succeed with their claims before state juries, it will increase pressure on the drug makers to negotiate Zantac settlements, including potential resolutions for claims that are pending on appeal and may later be reinstated and returned back to the trial court if the MDL judge’s controversial decision to exclude plaintiffs’ expert testimony is reversed.


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