Lab at center of Zantac saga claims GSK hid drug's risks for decades

Even as GSK defends itself against thousands of personal injury lawsuits relating to its sale of heartburn pill Zantac, a whistleblower lawsuit from the laboratory that first raised alarm bells about the med’s carcinogenic risks could introduce a sharp twist in the yearslong controversy.

Valisure, a Connecticut-based quality assurance laboratory, first flagged the link between Zantac (ranitidine) and the carcinogenic N-nitrosodimethylamine (NDMA) in 2019 after routine batch testing. Along with alerting the FDA, the company also filed a complaint on behalf of U.S. taxpayers and 25 states.

The case, which was sealed until Monday following the U.S. government’s decision not to take action, unleashes a host of serious accusations on the Zantac maker.

The crux of Valisure’s argument is that GSK “knowingly and deliberately lied to the FDA” to secure Zantac’s 1983 approval. Valsiure claims GSK knew of the NDMA risk from prior studies but concealed the connection with a different study and “false data." 

A GSK spokesperson called the lawsuit meritless and described Valisure as "a private, litigation-driven laboratory whose 2019 Zantac tests were determined scientifically flawed and unreliable by the FDA and by a U.S. MDL federal judge in Florida."

The company's representative further emphasized that the government decided not to take up the case.

“We will continue to vigorously defend against all claims, including this action and the false claims in it,” the spokesperson continued. “There have been 16 epidemiological studies analyzing human data regarding the use of ranitidine. The scientific consensus continues to be that there is no consistent or reliable evidence that ranitidine increases the risk of any cancer."

Last year, a Bloomberg report corroborated some of Valisure’s claims with a deep dive into the critical 1982 study and the company’s subsequent efforts to keep the findings under wraps.

Valisure, for its part, claims that once GSK's 40 years of alleged deception began to unravel, the company destroyed pills and batches of active pharmaceutical ingredients despite ongoing litigation and a court order to preserve potential evidence.

The 212-page complaint serves as a timeline to the Zantac safety claims, spanning from scientists’ concerns over the potential of drug compounds to form into NDMA in the 1970s to the swarm of Zantac-related litigation in recent years.

Valisure, on behalf of taxpayers, seeks what could amount to billions of dollars to recoup from alleged false reimbursements on the drug.

Despite striking several settlement deals across the country, GSK still faces thousands of lawsuits that analysts have estimated would cost around $5 billion to resolve, Reuters reported in February.