Patent Exhaustion: Invention-by-Invention

Abstract

Is patent exhaustion determined on a claim-by-claim basis, or a patent-by-patent basis? In other words, where a defendant in a patent infringement suit has a viable exhaustion defense as to one claim of a patent, does it necessarily follow that the defendant has an exhaustion defense as to that entire patent? The answer may be related to whether that single patent claims multiple distinct inventions. The Federal Circuit has sent mixed signals as to whether patent exhaustion may be appropriately determined on a claim-by-claim basis, or whether it must always be determined on a patent-by-patent basis. This article attempts to reconcile recent cases with an “invention-by-invention” approach to exhaustion. Though it is sometimes said that there is no “gist” or “heart” of the invention in patent claims, this article explains that a determination of the essential inventive features of a patent claim is permitted in the exhaustion context and is in fact necessary to a proper exhaustion analysis.