[authors: Pavan K. Agarwal, Andrew S. Baluch, Jeanne M. Gills]

On March 15, 2012, the U.S. Court of Appeals for the Federal Circuit issued its en banc decision in Marine Polymer Technologies, Inc. v. HemCon, Inc., upholding the district court’s $29 million verdict in favor of the patent owner, Marine Polymer, and denying defendant HemCon’s intervening rights defense where Marine Polymer had never formally amended the asserted patent claims during reexamination. The en banc ruling overturns an earlier decision by a three-judge panel, which held that intervening rights accrue when the patent owner limits the claim scope by argument rather than by formal amendment to the claims.

While the en banc decision is a victory for patent owners whose arguments alone will no longer trigger intervening rights (rights that eliminate some or all of the damages period), patent owners must still be mindful, as the court pointed out, because such arguments can still affect the proper interpretation and effective scope of their claims.

Background

Marine Polymer sued HemCon for infringement of a patent that claims “biocompatible” compositions for use in various industrial, pharmaceutical, and biomedical applications. The meaning of the term “biocompatible” was relevant in the infringement litigation, as well as in the parallel reexamination proceeding that HemCon initiated against the same patent in the USPTO. The district court and USPTO examiner initially adopted different meanings for the term “biocompatible.” At the urging of Marine Polymer, the examiner eventually adopted the district court’s narrower interpretation and confirmed the validity of the original patent claims without any change to the claim language. In the parallel litigation, a jury found in favor of Marine Polymer, resulting in a $29 million damages award and a permanent injunction against HemCon.