Merck...announced that the European Commission has approved KEYTRUDA, Merck’s anti-PD-1 therapy, as monotherapy for the treatment of microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) tumors in adults with...unresectable or metastatic gastric, small intestine or biliary cancer, who have disease progression on or following at least one prior therapy.