Marine Polymer v. HemCon – Intervening Rights

By Michael T. Ghobrial // October 20th, 2011

Arguments made to the PTO during reexamination can amend the scope of claims and trigger absolute intervening rights for the accused infringer under 35 U.S.C. §§ 252 and 307(b), thereby eliminating all damages for the period before the issuance of the reexamination certificate.

In Marine Polymer v. HemCon, Marine Polymer moved for summary judgment of literal infringement, which was granted by the district court. Slip Op at 4-5.  A jury trial was then held to determine validity and damages. The jury found that the asserted patent was valid and infringed. The jury also found that HemCon owed Marine Polymer $29.4 million for past infringement.

During the pendency of the district court proceedings, HemCon requested reexamination of the asserted patent, which did not conclude until several months after the trial had completed. In the reexamination, the Examiner had construed the term “biocompatible” broadly and issued a rejection of all the claims of the patent is invalid in light the term and the prior art. Marine Polymer argued against the rejection by canceling six dependent claims and arguing for a narrow definition of “biocompatibility.” The PTO then issued a reexamination certificate canceling the six dependent claims and validating the patentability of the claims found by the trial court to be infringed.

HemCon then appealed the trial court’s ruling to the CAFC, and argued that there infringement could not occur because Marine’s arguments in reexamination had created intervening rights.

Although the language of the independent claims did not change, the CAFC found that Marine’s arguments had narrowed the scope of the claims. Specifically, the CAFC determined that the scope of the original claims incorporated the definition of “biocompatible” that was provided by the Examiner during the reexamination. Because Marine had argued for a narrower definition of “biocompatibility” the CAFC found that the argument constituted a clear disclaimer of claimed subject and effectively amended the scope of the claims. Therefore, under 35 U.S.C. §§ 252 and 307(b), this amendment in effect granted absolute intervening rights to HemCon and eliminated all damages for the period before the issuance of the reexamination certificate.

Accordingly, the CAFC vacated the jury’s verdict. Additionally, the CAFC indicated that there could also be equitable intervening rights that would be an infringement action against product made after the reexamination certificate issue date. However, because a determination of equitable rights requires analysis of a number of factual issues not yet addressed, the CAFC remanded the case to the trial court for further consideration.

A copy of the CAFC opinion may be found here.

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