(Reuters) -GSK on Wednesday said it would confidentially settle another lawsuit in California alleging its discontinued heartburn drug Zantac caused cancer, as the British drugmaker sought to end costly litigation.
Citi and J.P. Morgan estimate GSK's total liability related to the lawsuits to amount to about $5 billion.
The trial for the Cantlay/Harper case, which was set to begin on Nov. 13, will now be dismissed, GSK said, adding it had also settled three remaining breast cancer cases in California related to the same drug.
The latest settlements in California related to cases due to go to trial in November, with a further set scheduled to begin in Delaware courts in January, GSK said. The company still faces about 79,000 cases related to Zantac in the United States, with 73,000 of them in Delaware.
Shares in GSK ticked up 2% to a 10-month high of 1,559 pence on Wednesday, making it the best performer on London's blue-chip FTSE 100.
First approved in 1983, Zantac became the world's best selling medicine in 1988 and one of the first-ever drugs to top $1 billion in annual sales.
Originally marketed by a forerunner of GSK, it was later sold successively to Pfizer, Boehringer Ingelheim and finally Sanofi. Those companies also face lawsuits over the drug.
In 2019, some manufacturers and pharmacies halted Zantac sales over concerns that its active ingredient, ranitidine, degraded over time to form a chemical called NDMA. While NDMA can be present in low levels in food and water, research has found it causes cancer in larger amounts.
The FDA in 2020 pulled all brand name Zantac and generic versions of the drug off the market, triggering a wave of lawsuits.
Concerns about protracted legal wrangling and compensation wiped almost $40 billion off the market value of GSK, Sanofi, Pfizer and GSK-spinoff Haleon over roughly a week in August last year.
Late in June, the company agreed to settle a similar lawsuit with California resident James Goetz who alleged he developed bladder cancer after taking Zantac. The trial was due to start on July 24.
J.P Morgan analysts said the company's decision to again settle suggests it is likely to have to pay out on many of the outstanding cases.
The settlement could be read that GSK sees a risk that these Zantac cases are strong enough that the company might lose at trial, J.P Morgan added.
(Reporting by Eva Mathews in Bengaluru and Maggie Fick in London; Editing by Nivedita Bhattacharjee and Bernadette Baum)