June 10 (Reuters) -

GSK and other drugmakers on Monday asked a Delaware

court for permission to appeal a

ruling allowing more than 70,000 lawsuits claiming that

heartburn drug Zantac causes cancer to go forward.

If Judge Vivian Medinilla of Delaware Superior Court

grants

the petition

, which is also joined by Pfizer ( PFE ), Sanofi

and Boehringer Ingelheim, the appeal will go directly to the

Delaware Supreme Court. If she denies it, GSK said, the

companies will ask the Supreme Court directly to hear the case.

The companies, which all sold Zantac at different times,

argue that Medinilla should have granted their motion to block

plaintiffs from presenting expert testimony that Zantac causes

cancer. That would have effectively ended all of the lawsuits in

Delaware, where the vast majority of Zantac lawsuits nationwide

are pending.

Also on Monday, GSK announced that a woman who alleged that

she developed breast cancer as a result of taking Zantac dropped

her case shortly before it was set for trial.

GSK said in a statement that it did not settle with the

woman, Eugenia Kasza. A lawyer for Kasza did not immediately

respond to a request for comment.

Kasza's case would have been the second over Zantac to go to

trial, after the first ended last month with a victory for GSK

and Boehringer Ingelheim. Another case was dismissed by a judge

shortly before a trial was set to begin on May 23.

Sanofi has settled about 4,000 Zantac cases, and the

Financial Times reported last month that Pfizer ( PFE ) had settled more

than 10,000 cases.

First approved in 1983, Zantac became the world's

best-selling medicine in 1988 and one of the first to top $1

billion in annual sales. It was originally marketed by a

forerunner of GSK and later sold successively to other

companies.

In 2019, some manufacturers and pharmacies halted Zantac

sales after a chemical called NDMA, which is known to cause

cancer, was detected in some pills. Some tests showed that

Zantac's active ingredient, ranitidine, could degrade into NDMA

over time or when exposed to heat.

The U.S. Food and Drug Administration asked manufacturers to

pull the drug off the market in 2020. In the face of mounting

lawsuits, the drugmakers have maintained that there is no

evidence Zantac exposed users to harmful levels of NDMA.

The companies notched a significant win in 2022, when

another judge rejected about 50,000 lawsuits making similar

claims that had been consolidated in federal court in Florida.

Some plaintiffs are appealing that ruling.

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