Shares of GSK, Sanofi and Haleon all sold off sharply this week, shedding tens of billions in market value, amid investor fear over potential U.S. litigation charges focused on popular heartburn drug Zantac.
This has been a known issue bubbling in the background for years but investor concern exploded this week in the lead-up to the first scheduled legal proceeding on Aug 22.
Zantac is the brand name for a drug called ranitidine, a medicine used to relieve heartburn. It was originally invented and sold by GSK as a prescription drug in the 1980s before transitioning to an over-the-counter medicine.
In 2019, regulators launched a safety review amid concern the drug contains a probable carcinogen called NDMA, prompting manufacturers to pull it from shelves. And by 2020, the U.S. FDA and the European Medicines Agency requested all versions of the treatment be withdrawn from…