The US Court of Appeals for the Federal Circuit expanded the Markush doctrine, determining that the claim language “comprising . . . [at least] . . . a group consisting of . . .” absent some basis or extrinsic evidence for limiting the group, such a group could capture an alleged infringement  having an additional component  present, as long as the additional component is “functionally similar” to the component identified in the Markush group limitation. ,Amgen Inc. v. Amneal Pharm. LLC, Case No. 18-2414 (Fed. Cir. Jan. 7, 2020) (Lourie, J).

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