A Recent Clarification on Intervening Rights by the Federal Circuit

The Federal Circuit recently found that intervening rights can apply to a claim that has been narrowed by argument only during a reexamination. In Marine Polymer Technologies, Inc. v. HemCon, the Federal Circuit recently found that narrowing a claim by argument only changes the substantive scope of the claim for purposes of intervening rights. Specifically, a claim term that is changed during reexamination without changing a word in the claim can still substantively narrow the scope of a claim. Therefore, upon reissue of the patent, an infringer would have “… absolute intervening rights with respect to products manufactured before the date of reissue.”