En Banc Court Holds That Intervening Rights Are Invoked For New Or Amended Claims Only

This article previously appeared in Last Month at the Federal Circuit, April 2012

Judges: Rader, Newman, Lourie (author), Bryson, Gajarsa, Linn, Dyk (dissenting-in-part), Prost, Reyna, and Wallach

[Appealed from D.N.H., Judge DiClerico, Jr.]

In Marine Polymer Technologies, Inc. v. HemCon, Inc., No. 10-1548 (Fed. Cir. Mar. 15, 2012) (en banc), the Federal Circuit, sitting en banc, held that intervening rights do not apply to claims that have not been amended and are not new, and affirmed the judgment of the district court that HemCon, Inc. ("HemCon") infringed U.S. Patent 6,864,245 ("the '245 patent") assigned to Marine Polymer Technologies, Inc. ("Marine Polymer").

Marine Polymer accused HemCon of infringing the '245 patent, which claims preparations of "biocompatible" poly-β-1→4-N-acetylglucosamine ("p-GlcNAc") used to treat serious wounds. The district court found the patent valid and infringed, and awarded Marine Polymer $29.4 million in damages. Initially, HemCon appealed to the Federal Circuit ("the panel") and argued that the verdict should be overturned under the doctrine of intervening rights. While the litigation was in progress, HemCon initiated an ex parte reexamination of the patent, where, according to HemCon, Marine Polymer amended the claims thus giving rise to intervening rights. During the reexamination proceeding, Marine Polymer argued for a narrower construction of the term "biocompatible" and canceled claims that might be inconsistent with this narrower construction. Marine Polymer neither added any new claims nor amended any existing claim. The examiner in the reexamination proceeding subsequently upheld the patentability of the remaining claims.

The panel agreed that HemCon had acquired intervening rights and overturned the district court decision. Marine Polymer filed a petition for rehearing en banc, which was granted, and a majority of the en banc Court held that HemCon had not acquired intervening rights, because Marine Polymer had not amended claims nor added new claims during the reexamination proceeding. While the Court was split as to whether the district court's claim construction was correct, it nevertheless affirmed the district court's decision of infringement.

With respect to claim construction, HemCon argued that the district court's construction of "biocompatible"—to mean no detectable biological reactivity—was erroneous. In supporting this assertion, HemCon relied primarily on the presence of the six dependent claims in the original '245 patent (eventually cancelled in reexamination) that required elution test scores of one or two, as well as passages in the specification characterizing certain biocompatibility tests as being satisfied despite detectable bioreactivity.

The Court ultimately found HemCon's focus on...