By Donald Zuhn --
On April 1st, the Federal Circuit affirmed the judgment of the District Court for the Western District of Wisconsin that Defendant-Cross Appellant Third Wave Technologies, Inc. did not infringe U.S. Patent No. 5,643,715, owned by Plaintiff-Appellant Digene Corp. The panel also affirmed the District Court's grant of summary judgment dismissing Third Wave's antitrust counterclaims.
The '715 patent relates to the diagnosis of human papillomavirus (HPV) type 52, which is one of several HPV strains known to cause cervical cancer. The '715 patent describes the differentiation of HPV type 52 from other HPV types using "nucleic acid hybridization probes which are specific for HPV type 52." Both Digene and Third Wave make HPV testing systems; Third Wave's system utilizes a nucleic acid molecule that includes a sequence that is homologous to HPV type 52 and an additional sequence that serves as "an indicator of the HPV's presence."
In January 2007, Digene brought suit against Third Wave for infringement of claims 8, 10-12, and 18-27 of the '715 patent. Asserted claims 18 and 21 include all of the limitations that were contested on appeal (contested limitations are underlined):
(i) HPV 52 DNA labelled with a detectable label, and
(ii) HPV 52 RNA labelled with a detectable label,
wherein the length of the HPV 52 DNA or HPV 52 RNA is between approximately 15 and 8000 nucleotide bases,
wherein the HPV 52 DNA consists of all or a fragment of an HPV DNA, wherein the HPV DNA cross-hybridizes to the HPV portion of clone pCD15 to greater than 50% under moderately stringent conditions,
wherein the HPV 52 RNA consists of all or a fragment of an HPV RNA, wherein the HPV RNA cross-hybridizes to the HPV portion of clone pCD15 to greater than 50% under moderately stringent conditions, and
wherein the HPV 52 DNA and HPV 52 RNA do not hybridize to DNA from HPV types 1 through 51 under stringent conditions.
21. An HPV hybridization probe composition comprising
(a) a member selected from the group consisting of
(i) HPV 52 DNA labelled with a detectable label and
(ii) HPV 52 RNA labelled with a detectable label,
wherein the length of the HPV 52 DNA or HPV 52 RNA is between approximately 15 and 8000 nucleotide bases,
wherein the HPV 52 DNA consists of all or a fragment of an HPV DNA, wherein the HPV DNA cross-hybridizes to the HPV portion of clone pCD15 to greater than 50% under moderately stringent conditions,
wherein the HPV 52 RNA consists of all or a fragment of an HPV RNA, wherein the HPV RNA cross-hybridizes to the HPV portion of clone pCD15 to greater than 50% under moderately stringent conditions, and
wherein the HPV 52 DNA and HPV 52 RNA do not hybridize to DNA from HPV types 1 through 51 under stringent conditions, and
(b) DNA or RNA of at least one other HPV type labelled with a detectable label.
The District Court construed the contested limitations as follows:
• "HPV 52 DNA labelled with a detectable label" (claims 18 and 21) means "HPV 52 DNA that has a detectable label that is not DNA" (since, given the Court's other constructions, the label could not be DNA);
• "between approximately 15 and 8000 nucleotide bases" (claims 18 and 21) means "between 15 and approximately 8000 nucleotide bases" (since the applicant disavowed fewer than 15 bases during prosecution);
• "HPV hybridization probe" (claim 21) means a "nucleic acid molecule that is specific for the DNA of any one type of HPV and differentiates the DNA of that type from DNA of all other HPV types"; and
• "HPV 52 DNA consists of all or a fragment of an HPV DNA" (claim 21): "HPV 52 DNA" means "a DNA molecule that is only type 52 HPV" (since the applicant disclaimed a molecule including fragments of later-discovered HPV types by stating during prosecution that "the claimed HPV 52 DNA must be derived from only type 52 HPV DNA") and "consists of all or a fragment of an HPV DNA" means "consists of all or a fragment of one HPV DNA that does not contain any other DNA" (since "an" means "one and only one" when following the transitional phrase "consists of").
On appeal, Digene argued that the District Court misconstrued the phrase "HPV 52 DNA consists of all or a fragment of an HPV DNA" by disregarding the inventor's definition of "HPV 52 DNA" in the prosecution history and claims themselves. In particular, Digene argued that in the context of the '715 patent, "HPV 52 DNA" is defined by length (approximately 15 and 8000 nucleotides), cross-hybridization with a deposited clone under moderately stringent conditions, and failure to cross-hybridize with HPV types 1-51 under stringent conditions (as opposed to being defined by nucleotide sequence). In other words, Digene contended that HPV 52 sequences in which "certain" nucleotides had been replaced were still HPV 52 DNA sequences. As for the statement made during prosecution (i.e., "the claimed HPV 52 DNA must be derived from only type 52 HPV DNA"), Digene argued that it referred to the origin of the DNA and not its specific structure.
Digene also argued that the District Court erroneously limited the term "an HPV DNA" in the contested claim 21 limitation "HPV 52 DNA consists of all or a fragment of an HPV DNA" to "one HPV DNA that does not contain any other DNA." With respect to this claim term, Digene contended that the overall transitional phrase in the claim was "comprising," and therefore, the term "an" in "an HPV DNA" should have been construed as "one or more." Digene also argued that the District Court's construction would result in the exclusion of mutations, subtypes, and synthesized DNA.
Third Wave, not surprisingly, took an opposite position with respect to each of Digene's arguments. In addition, Third Wave asserted that because claim 21 recites both "HPV 52 DNA" and "DNA . . . of at least one other HPV type," the term "HPV 52 DNA" must be limited to DNA of only type 52 and not include DNA of another HPV type.
Siding with Third Wave, the Federal Circuit found that the District Court reasonably construed the phrase "HPV 52 DNA consists of all or a fragment of an HPV DNA." In particular, the panel agreed that by reciting both "HPV 52 DNA" and "DNA . . . of at least one other HPV type" in claim 21, Digene distinguished HPV 52 DNA from the DNA of other HPV types, thereby supporting Third Wave's position that "HPV 52 DNA" means "a DNA molecule that is only type 52 HPV." The Court also found that applicant's statement that "the claimed HPV 52 DNA must be derived from only type 52 HPV DNA" indicated that applicant had disclaimed a meaning of "HPV 52 DNA" that was derived from anything but HPV 52 DNA. In addition, the panel noted that the District Court had been correct in construing "an" after the transitional phrase "consisting of" as meaning "one," stating that "[i]f the term 'consists of' appears in the body of a claim, it does not limit the entire claim as such, but it does limit the clause for which it acts as a transition to only those elements found in that particular clause." Finally, the Court agreed with Third Wave that the District Court's construction did not exclude possible mutations or subtypes. With respect to the other claim terms, the panel noted that because "Digene candidly conceded that it could not prove infringement under the district court's claim constructions of 'HPV 52 DNA consists of all or a fragment of an HPV DNA'" at oral argument, the panel did not need to address the remaining terms in light of Digene's concession."
Nonprecedential disposition
Panel: Circuit Judges Lourie, Rader, and Prost
Opinion by Circuit Judge Lourie
For additional information regarding this case, please see:
• "Digene Files Infringement Suit against Third Wave Technologies," January 17, 2007
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