Intervet Inc v. Merial Ltd.

• Decision Date: 04 August 2010
• Docket Number: No. 2009-1568.,2009-1568.
• Citation: 617 F.3d 1282
• Parties: INTERVET INC., Plaintiff-Appellee,v.MERIAL LIMITED and Merial SAS, Defendants-Appellants.
• Court: U.S. Court of Appeals — Federal Circuit

617 F.3d 1282

INTERVET INC., Plaintiff-Appellee,v.MERIAL LIMITED and Merial SAS, Defendants-Appellants.

No. 2009-1568.

United States Court of Appeals Federal Circuit.

Aug. 4, 2010.

COPYRIGHT MATERIAL OMITTED

William G. James, II, Kenyon & Kenyon LLP, of Washington, DC, argued for plaintiff-appellee. With him on the brief were John R. Hutchins and Yariv Waks; Richard L. Delucia and Michael D. Loughnane, of New York, NY. Of counsel was Patrice P. Jean, of New York, NY.

J. Patrick Elsevier, Jones Day, of San Diego, CA, argued for defendants-appellants. With him on the brief were Frank G. Smith, III and Kristen L. Melton, Alston & Bird LLP, of Atlanta, GA; Madison C. Jellins, of Palo Alto, CA. Of counsel on the brief were Judy Jarecki-Black, Merial Limited, of Duluth, GA; Edgar H. Haug, and Thomas J. Kowalski, Frommer Lawrence & Haug LLP, of New York, NY.

Before BRYSON, DYK, and PROST, Circuit Judges.

Opinion for the court filed by Circuit Judge PROST.

Opinion concurring-in-part, dissenting-in-part filed by Circuit Judge DYK.

PROST, Circuit Judge.

The present patent infringement case arises from a declaratory judgment action brought in the United States District Court for the District of Columbia on April 11, 2006. Plaintiff Intervet Inc. (“Intervet”) denies infringing U.S. Patent No. 6,368,601 (“'601 patent”), owned by Defendants Merial Limited and Merial SAS (collectively “Merial”), directed to DNA constructs encoding a type of porcine circovirus. The district court entered summary judgment of noninfringement based on its construction of six disputed claim terms. Merial appeals the district court's claim construction for three of the terms, and, in the alternative, appeals the district court's summary judgment of noninfringement based on the doctrine of equivalents.

Because we agree with Merial that the district court erred in its construction of two disputed claim terms, we reverse the district court's claim construction, vacate the judgment of noninfringement, and remand for a finding of whether the accused device infringes under the claim construction articulated herein. Additionally, because we agree with Merial that the district court misapplied the law of prosecution history estoppel, we instruct the district court to consider on remand arguments related to literal infringement and to infringement under the doctrine of equivalents, consistent with the analysis herein.

Background

Postweaning Multisystemic Wasting Syndrome (“PMWS”) is a disease affecting livestock pigs. Researchers at Merial learned that PMWS is associated with a particular type of porcine circovirus.¹ The scientific community was aware of porcine circoviruses prior to Merial's findings. Known porcine circoviruses, however, were not observed to be pathogenic, meaning they did not appear to cause disease in infected pigs. Merial filed for the ' 601 patent pertaining to the discovery of what it described as a previously unknown pathogenic type of porcine circovirus that the inventors dubbed “PCV-2.” PCV-2 stands for “porcine circovirus type II.” Merial's patent categorizes previously known, nonpathogenic porcine circoviruses as belonging to “type I” or “PCV-1”. The patent identifies a particular known DNA sequence isolated from pig kidney cells called PK/15 as being representative of type I. The ' 601 patent then identifies five isolated pathogenic porcine circovirus strains as being representative of type II.

The patentee placed the five representative strains on deposit with the United States Patent and Trademark Office (“PTO”) as part of the description of the invention. The written patent disclosure provides the full DNA sequence for four of these strains, as well as the full sequence of PK/15.

The disclosure explains that the deposited PCV-2 strains had been detected in lesions of pigs with PMWS, but not in healthy pigs. The patent description observes that the sequenced strains exhibit 96% nucleotide homology with each other, and only 76% nucleotide homology with PK/15.² The description concludes from these observations that there are two types of porcine circoviruses, and that nonpathogenic “type I,” as represented by PK/15, is “thus” distinct from pathogenic “type II,” as represented by the five isolated strains. ' 601 patent col.1 ll.48-62. The disclosure then identifies the subject of the present invention as “the group II porcine circovirus, as defined above, isolated or in the form of purified preparation.” Id. at col.1 ll.63-65.

The patent disclosure goes on to analyze the sequenced PCV-2 strains in more detail, providing tables comparing the sizes and alignments of the strains. The disclosure then identifies one of the sequenced strains, designated SEQ ID 4, as being further representative of the other strains, and identifies thirteen open reading frames (“ORFs”) for PCV-2 using that sequence. The '601 specification identified nine of the thirteen disclosed ORFs that are unique to PCV-2, and four that are present in both PCV-2 and PCV-1.

“ORF” is a commonly used term in molecular genetics that has a standard textbook meaning. An ORF is a portion of a gene that contains a sequence of nucleotide bases that may be translated into a protein. Each amino acid of a protein is encoded by a DNA codon. A codon consists of three adjacent nucleotide bases. The first codon in an open reading frame is the “start” codon, which encodes a modified form of methionine. Each amino acid in the polypeptide chain is encoded by a subsequent set of three base pairs, until the translation is terminated at a stop codon that does not itself encode an amino acid, but rather signals the end of translation. Thus, a double-stranded length of DNA can have six different reading frames, depending on the starting base-pair of the first codon and the direction in which the strand is read. ³ The length of an ORF is thus defined by the number of codons that lie between a start codon and a stop codon within the same frame.

Identifying the ORFs of a gene sequence differentiates the portions of the sequence that may encode a protein from the portions that do not encode a protein. It allows those skilled in the art to estimate the size and composition of potential amino acid sequences for the proteins encoded by the gene. Identifying ORFs is especially important in the context of viral or prokaryotic DNA, which can contain several overlapping ORFs in the same gene sequence.

There are two groups of claims in the '601 patent relevant to the present case. The first group can be represented by independent claim 9, which reads:

9. A vector comprising an isolated DNA molecule comprising a sequence selected from the group consisting of ORFs 1 to 13 of porcine circovirus type II.

The second group can be represented by independent claim 32, which reads:

32. An isolated DNA molecule comprising a nucleotide sequence encoding an epitope which is specific to PCV-2 and not specific to PCV-1.

An epitope is an immunodominant region of a protein, meaning it is the part of an antigen peptide that is recognized by antibodies of the immune system. The patent explains that certain epitopes found among strains of PCV-2 are not present in PCV-1. Thus, the regions of DNA encoding these epitopes are unique to PCV-2. Epitopes unique to PCV-2 are relevant to diagnostics or treatments, because antibodies specific to these epitopes will recognize and bind to the pathogenic PCV-2, but will ignore the benign PCV-1.

Merial's patent claims cover certain vectors and other DNA molecules that contain portions of the PCV-2 gene sequence. These molecules are believed to be useful in diagnosing and vaccinating against PMWS, by stimulating the production and activity of antibodies against PCV-2.

Intervet is an animal healthcare company that manufactures vaccines for livestock. Intervet developed a vaccine called “Porcine Circovirus Vaccine Type 2” that contains a porcine circovirus nucleotide sequence in a vector for treating PMWS in pigs. Merial alleges that Intervet's PMWS vaccine uses an infringing PCV-2 sequence.

At a Markman hearing, the United States District Court for the District of Columbia construed six disputed claim terms of the '601 patent. Among these constructions, the district court defined the term “porcine circovirus type II” as consisting of the five nucleotide sequences that Merial placed on deposit with the PTO. The district court construed the term “ORFs 1-13” as the DNA sequences of the thirteen ORFs of SEQ ID 4 listed in the table under Example 13 of the patent. Finally, the district court construed claim 32 in its entirety to refer (in part) to a construct comprising at least one DNA molecule that is unique to one of the five sequences on deposit with the PTO.

The district court then entered summary judgment of noninfringement based on these claim constructions. It was undisputed that Intervet's vaccine contained a nucleotide sequence that was 99.7% homologous to one of the deposited sequences. The accused product was therefore held to be outside the literal claim scope of PCV-2, which required strict identity to one of the five deposited sequences. The district court also held that the doctrine of prosecution history estoppel precluded Merial from arguing that the accused sequence infringed under the doctrine of equivalents.

Merial timely appealed to this court, arguing that the district court erred in its claim construction and erred in applying the doctrine of prosecution history estoppel to Merial's equivalence arguments for the accused product. For the reasons discussed below, we agree with Merial that the district court erred in its claim construction and application of prosecution history estoppel.⁴

Discussion

Claim Construction

Claim construction is a question of law that is reviewed de novo. Markman v. Westview Instruments, Inc., 52 F.3d 967, 978 (Fed.Cir.1995) (en banc). To the extent possible, claim terms are given their ordinary and customary meaning, as they would be...