Hunter Keeton

Divided patent infringement—also called “joint infringement”—is a doctrine plaintiffs can use to allege infringement where more than one party may have participated in a patent’s claimed steps. While the fundamental rules here have been set since 2015, a few recent district court cases set out some new considerations for both plaintiffs and defendants. A handful of U.S. Court of Appeals for the Federal Circuit decisions have been instrumental in shaping this area of law. The Akamai v. Limelight Networks case clarified that a single entity can be found liable for infringement if it “directs or controls” another’s action or forms a joint enterprise. It also created a new test for finding joint infringement, if an entity conditions participation or receipt of a benefit on performance of the patented method, and controls the manner and timing of the performance. Later cases Eli Lilly & Company v. Teva Parenteral Medicines and Travel Sentry v. Tropp clarified how this “conditions or benefits” test applies in the context of pharmaceutical and mechanical method patents.