Cases & Deals

Merial Limited and Merial SAS obtain favorable ruling from U.S. Court of Appeals for Federal Circuit in biotechnology patent suit

Clients Merial Limited and Merial SAS

On August 4, 2010, the U.S. Court of Appeals for the Federal Circuit ruled in favor of Jones Day's clients Merial Limited and Merial SAS (Merial) in a biotechnology patent suit.

Merial, a world-leading animal health company, is the owner of a patent directed to DNA constructs encoding a type of pig virus known as porcine circovirus type 2 (PCV-2) on which Merial based the world's first vaccine aimed at preventing a devastating disease impacting the pork industry, Postweaning Multisystemic Wasting Syndrome (PMWS).

The appeal arose from a declaratory judgment action brought in the District of Columbia by Intervet Inc. denying that its vaccine against PMWS infringed Merial's patent. The district court had entered summary judgment of noninfringement based on its construction of the disputed claim terms. On appeal, the Federal Circuit agreed with Merial that the district court erred in its construction of the disputed claim terms. In particular, the Federal Circuit held that the district court erred in limiting claim terms directed to Open Reading Frames (ORFs) or epitopes of the PCV-2 virus to only DNA sequences having strict identity with the DNA sequences of the PCV-2 viruses deposited in conjunction with Merial's patent. Because the Federal Circuit recognized that the PCV-2 viruses deposited in conjunction with the patent were merely representative of the scope of the invention, the Federal Circuit held that Merial was entitled to broader constructions that allow for some variation of the DNA sequences at issue. Accordingly, the Federal Circuit vacated the judgment of noninfringement, and remanded for a finding of whether the accused Intervet vaccine infringes under the Federal Circuit's constructions.

Additionally, the Federal Circuit held, although Merial had amended the asserted claims during prosecution, that prosecution history estoppel did not foreclose Merial from arguing infringement under the doctrine of equivalents. Specifically, the Federal Circuit clarified that a narrowing amendment, even if adopted for a substantial reason related to patentability, does not completely bar the benefit of the doctrine of equivalents. Because the Federal Circuit agreed with Merial that the rationale for the amendments at issue bore only a tangential relationship to the question of whether the accused Intervet vaccine sequences are properly characterized as PCV-2, the Federal Circuit instructed the district court to consider on remand arguments related to both literal infringement and infringement under the doctrine of equivalents.

Partner J. Patrick Elsevier, Ph.D., of Jones Day's San Diego Office argued the appeal.

Intervet Inc. v. Merial Limited and Merial SAS, Appeal No. 2009-1568 (Fed. Cir. Aug. 4. 2010)

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