Recent Federal Circuit Decisions Address the “Tangential Relation” Exception to Prosecution History Estoppel
Ajinomoto Co., Inc. v. Int’l Trade Comm’n, Appeal No. 2018-1590 (Fed. Cir. Aug. 6, 2019)
Eli Lilly & Co. v. Hospira, Inc., Appeal No. 2018-2128 (Fed. Cir. Aug. 9, 2019)
Prosecution history estoppel typically forecloses a patent owner’s ability to claim infringement on equivalents in the territory between the original claim language and the finalized claim language.[1] In two recent cases, however, the Federal Circuit showed its willingness to apply the tangential relation exception to prosecution history estoppel and find infringement under the doctrine of equivalents.