PITTSBURGH — The University of Pittsburgh Medical Center and health insurer Highmark have ended four years of antitrust litigation by dismissing their dueling lawsuits in accordance with a federal judge’s order earlier this month.

The companies dismissed their lawsuits with prejudice, which means they cannot be refiled.

U.S. District Judge Joy Flowers Conti on Dec. 19 ordered Highmark to compel its West Penn Allegheny Health System board to drop the original 2009 lawsuit and ordered UPMC to drop the competing suit it filed last year.

UPMC is Western Pennsylvania’s dominant hospital system, with more than 20 hospitals and 3,200 physicians, and has a health insurance plan that competes with Highmark, the region’s largest insurer.

A third antitrust lawsuit names both companies as defendants.