July 10 (Reuters) - Delaware's highest court ruled on

Thursday that patients suing drugmakers GSK, Pfizer ( PFE )

, Sanofi and Boehringer Ingelheim cannot

introduce reports from several experts to support their claim

that the heartburn drug Zantac causes cancer.

The decision by the Delaware Supreme Court is a victory for

the drugmakers, in a case closely watched by business groups

that fear an adverse outcome could erode Delaware's reputation

as a business safe haven by encouraging mass tort litigation.

(Reporting by Jonathan Stempel in New York)