Bristol-Myers Squibb Co. /zigman2/quotes/202559280/composite BMY -1.25% shares rallied in the extended session Wednesday after a federal judge ruled for it and Pfizer Inc. /zigman2/quotes/202877789/composite PFE -0.67% in a key patent fight over a blood thinner. Bristol-Myers shares surged 4.4% after hours, following a 0.4% rise to close at $59.69. Pfizer shares advanced 1.5% after hours, following a 0.2% gain to close at $38.45. In a ruling Wednesday, a federal judge said that products made by Sigmapharm Laboratories LLC, Sunshine Lake Pharma Co., and Unichem Laboratories Ltd. infringed patents protecting the blood-thinner Eliquis,, which is generically known as apixaban. Bristol-Myers and Pfizer have a profit-sharing agreement on the drug. "While subject to appeal, at present the generic manufacturers currently involved in the case cannot launch their apixaban products until 2031," said a Bristol-Myers Squibb spokewoman in emailed comments. "Based on settlement agreements reached with other generic manufacturers, we currently expect generic entry could occur after 2026 but before 2031, subject to appeals and future challenges." In 2019, Eliquis was Bristol-Myers's top-selling drug with sales of $2.03 billion, following its acquisition of Celgene in November.