BMS, Ono challenge Merck in PD-1 patent suit

Bristol-Myers Squibb Co. (NYSE:BMY) and Ono Pharmaceutical Co. Ltd. (Tokyo:4528) filed suit in the U.S. District Court for the District of Delaware alleging that Keytruda pembrolizumab from Merck & Co. Inc. (NYSE:MRK) violates U.S. Patent No. 8,728,474 covering a method of using programmed cell death 1 receptor ( PDCD1; PD-1; CD279) inhibitors as cancer immunotherapies.

Ono is an assignee of the patent, and BMS is the exclusive licensee. BMS said the patent, issued in May, expires in 2023. The companies are seeking declaratory judgment and damages. Merck said it believes the suit is without merit. ...