Today, Thu., Mar. 15, 2012, in Marine Polymer v. Hemcon, No. 2010-1548, the Federal Circuit en banc (Opinion by Lourie; Dissent by Dyk) in a split decision ruled that intervening rights do not arise for claims that were not amended or added in reexamination even if arguments during reexamination changed the claim scope.  The Majority ruled that the first step in assessing intervening rights is to determine whether claims were amended or added in reexamination.  If not, then the court should not proceed to the second step of determining whether there were substantive changes to claim scope.

The Majority ruled on the intervening rights issue even though it was based on reexamination activity that occurred after – and was not considered by – the district court decision.  The Dissent urged that this rendered the intervening rights decision dicta.