The Conversation Continues: Some Post-Patent-Termination Royalties Are Acceptable

For the second time in less than two weeks, a circuit court decided an appeal hinging on the Brulotte rule, which holds that patent royalties are impermissible when based on payments for the use of expired patents. Like the US Court of Appeals for the Ninth Circuit, the Fourth Circuit upheld a royalty agreement that purported to require payments after patent expiration. Ares Trading S.A. v. Dyax Corp., Case No. 23-1487 (4th Cir. Aug. 14, 2024) (Krauser, Porter, Chung, JJ.)

Dyax is a biotechnology company engaged in "phage display" research – a laboratory process used to identify antibody fragments for use in developing medications. Dyax holds multiple patents related to phage display, including licenses to patents owned by Cambridge Antibody Technology (CAT). Dyax and Ares entered a licensing agreement. Dyax's main obligation was to use its phage display technology to identify antibody fragments and then provide those fragments to Ares so that Ares