(Reuters) — Shares in GSK, Sanofi and Haleon fell sharply on Thursday, following declines earlier in the week, amid growing investor concern over U.S. litigation focused on a heartburn drug that contained a suspected cancer-causing agent.
Around 1400 GMT, GSK shares fell 6.8%, Sanofi’s fell 6.9% and Haleon’s 5.6%.
GSK and Sanofi at different times sold the drug – originally branded as Zantac – which US regulators ordered off the market in 2020. Haleon, which spun off as an independent publicly traded company last month, includes consumer healthcare assets once partly owned by GSK.
The prospect of impending litigation is not new. Among other disclosures, recently listed Haleon had highlighted the risk of such lawsuits in its prospectus.
The topic has “arrived in investors̵7; consciousness in the past few days it seems but has been rumbling in the background for a few years,” Deutsche Bank analysts wrote in a note.
Zantac became the world’s best-selling drug in 1988 and one of the first drugs ever to top $1 billion in annual sales.
But concerns about the compound – known chemically as ranitidine – containing potential cancer-causing impurities began to surface in 2018, long after generic versions of the drug had been launched by a variety of manufacturers.
More than 2,000 lawsuits related to Zantac have been filed in the United States, analysts say, with the first trial starting later this month.