(Reuters) -GSK Plc on Friday said it reached a confidential settlement of a litigation in the United States over claims that the British pharmaceutical giant's heartburn drug Zantac caused cancer.

The case, brought by California resident James Goetz in Alameda County Superior Court, was to go to trial on July 24 and mark the first test of how Zantac cancer claims will fare before a jury.

It will now be dismissed, GSK said.

First approved in 1983, Zantac became the best-selling medicine in the world in 1988 and one of the first-ever drugs to top $1 billion in annual sales.

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 is found in low levels in food and water, it is known to cause cancer in large amounts.

The U.S. Food and Drug Administration in 2020 pulled all remaining brands of Zantac and its generic versions off the market, triggering a wave of lawsuits.

GSK has, however, repeatedly denied that Zantac can cause cancer.

(Reporting by Eva Mathews in Bengaluru; Editing by Dhanya Ann Thoppil)