Thousands of US lawsuits claiming that the heartburn drug Zantac caused cancer have been dismissed on the basis that they are not backed by sound science.
The ruling against around 50,000 claims was made by US District Judge Robin Rosenberg in West Palm Beach, Florida. The manufacturers have repeatedly asserted that Zantac does not cause cancer.
Following the decision, shares of GSK and Sanofi surged, adding more than $20 billion in combined value. The gains meant the companies almost recouped all the losses caused by the uncertainty of potential litigation.
The ruling can still be appealed and does not directly affect tens of thousands of similar cases pending in state courts around the country. In a statement GSK said it would continue to defend itself vigorously, including against all claims brought at the state level.
Originally marketed by a forerunner of GSK, the medicine has been sold by several companies at different times, including Pfizer, Boehringer Ingelheim and Sanofi, as well as several generic drugmakers.
Cancer risk rumours
Zantac, first approved in 1983, became the world’s best-selling medicine in 1988.
Concerns around Zantac containing potential cancer-causing impurities started to emerge in 2018. By 2019, some manufacturers and pharmacies halted sales of the drug over concerns that its active ingredient, ranitidine, degraded over time to form a chemical called NDMA.
While NDMA is found in low levels in food and water, it is known to cause cancer in larger amounts. In 2020, the US health regulator pulled all remaining Zantac versions off the market, citing research showing the amount of NDMA in the products increases the longer the drug is stored and could potentially become unsafe.
