INTELLECTUAL PROPERTY CLIENT ALERT: The Intervening Rights Defense Applies Only Where Claim Language was Actually Changed During a Reexamination

    16 April 2012
    The Federal Circuit, in Marine Polymer Tech., Inc. v. HemCon, Inc., clarified the scope of intervening rights for accused patent infringers. Intervening rights are a defense to patent infringement where the accused infringer, prior to completion of a reexamination proceeding, made, imported, purchased, offered to sell or used within the United States, anything patented by the claims resulting from the reexamined patent. Intervening rights are typically invoked when claim language is changed during a reexamination proceeding, as this changes the scope of the patent being enforced.