July 1 (Reuters) - A Delaware judge rebuffed a request

by GSK and other drugmakers to appeal a ruling allowing

more than 70,000 lawsuits claiming that the heartburn drug

Zantac caused cancer to go forward.

The ruling by Judge Vivian Medinilla of the Delaware

Superior Court means that the drugmakers, which also include

Pfizer ( PFE ), Sanofi and Boehringer Ingelheim, will

have to ask the Delaware Supreme Court directly for permission

to appeal. GSK said it already submitted its appeal to that

court.

If the state high court declines to take the appeal, it will

clear the way for the Zantac lawsuits to go to trial.

"Judge Medinilla resoundingly rejected GSK, Boehringer

Ingelheim, Pfizer ( PFE ), and Sanofi's attempt to end run around the

jury system in Delaware," said Jennifer Moore, a lawyer for the

plaintiffs.

GSK in a statement said "the scientific consensus remains

that there is no consistent or reliable evidence that ranitidine

increases the risk of any cancer." Ranitidine is the active

ingredient in the now discontinued drug.

Lawsuits began piling up after the U.S. Food and Drug

Administration in 2020 asked manufacturers to pull the drug off

the market over concerns that ranitidine could degrade into a

cancer-causing chemical called NDMA over time or when exposed to

heat.

The drugmakers say Medinilla should have kept the plaintiffs

from introducing expert testimony that Zantac can cause cancer,

as a federal judge did in 2022 in about 50,000 claims

centralized in Florida.

The plaintiffs' cases depend on that testimony, and cannot

go to trial without it.

Industry groups including the U.S. Chamber of Commerce

backed the drugmakers' appeal in a filing last month, saying

letting Medinilla's ruling stand had relaxed the standards for

evidence in the traditionally business-friendly state and

threatened to turn it into "a hotbed of products-liability and

mass-tort litigation."

Medinilla wrote on Monday that she had not adopted a

different standard from the Florida federal judge, but simply

reached a different conclusion about the evidence in the case.

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.

The vast majority of pending cases are in Delaware. Only one

case, against GSK and Boehringer Ingelheim in Illinois, has gone

to trial, ending in a victory for the companies last month.