IAM Publishes Rachel Elsby Article on Federal Circuit Ruling in Doctrine of Equivalents Case

IAM has published “CAFC creates blueprint for early stage challenges to claims brought under doctrine of equivalents,” written by Rachel Elsby, counsel in the intellectual property practice at Akin Gump. The article examines a decision by the U.S. Court of Appeals for the Federal Circuit involving the doctrine of equivalents and prosecution history estoppel.

Elsby writes that the decision in Amgen Inc. v Coherus Biosciences Inc., in which the plaintiff alleged infringement of one of its patents, “highlights the importance of taking a conservative approach in prosecution to avoid making unnecessary statements that can later limit claim scope.” Notably, she said, “Amgen made several arguments during prosecution and the argument found to be a disclaimer was not one that resulted in allowance of the claims.”

In reaching its decision, Elsby observed that the court “noted that prosecution history estoppel applies even though Amgen only included the ‘particular combinations’ argument in its response to the examiner’s first rejection, and not the second rejection.” The result, she said, “may provide support for future early challenges to claims brought under a doctrine of equivalents theory.”