United States: Claim Construed According To Accepted Scientific Meaning Where Specification And Prosecution History Did Not Justify Alternative Construction

In Bayer CropScience AG v. Dow AgroSciences, LLC, No. 13-1002 (Fed. Cir. Sept. 3, 2013), the Federal Circuit affirmed the district court's SJ of noninfringement because it did not accept the patent owner's proposed claim construction.

U.S. Patent No. 6,153,401 ("the '401 patent"), owned by Bayer CropScience AG ("Bayer"), relates to genetically modifying plants to render them resistant to the commonly used herbicide, 2,4-dichlorophenoxyacetic acid ("2,4-D"). The method involves inserting into plant cells a gene encoding an enzyme that can break down the 2,4-D herbicide into harmless products by converting it to 2,4-dichlorophenol ("2,4-DCP"). The '401 patent discloses the first identified gene encoding such an enzyme and describes a "growth test" for isolating it.

The enzymatic reaction requires the presence of an oxygen molecule (O2), and the inventors understood at the time of filing that one of the oxygen atoms combined with 2,4-D to form 2,4-DCP and glyoxylate by "bringing about the cleavage of the side chain of 2,4-D." Slip op. at 4 (citation omitted). The inventors did not know what happened to the second oxygen atom, but relied on an unverified belief that it ended up in water (H2O) and thus characterized the enzyme as a monooxygenase. While the application was pending, Bayer learned that the second oxygen atom did not actually end up in water such that the enzyme was not correctly characterized as a monooxygenase. Bayer did not change the language of its pending claim 1, which recited "[a] recombinant gene, comprising a DNA sequence encoding a polypeptide having the biological activity of 2,4-D monooxygenase . . . ." Id. at 5-6 (citation omitted).

Bayer sued Dow AgroSciences, LLC ("Dow") for infringement based on Dow's genetically modified seeds that are resistant to 2,4-D and other herbicides. Dow's accused seeds use resistance genes that are different from the gene identified in the '401 patent, but which also code for dioxygenases that catalyze the conversion of 2,4-D to 2,4-DCP. Bayer asserted that claim 1 encompasses any enzyme with "the biological activity of 2,4-D monooxygenase," meaning any enzyme that triggers cleaving of the side chain of 2,4-D to produce 2,4-DCP. After a Markman hearing and cross-motions for SJ, the district court rejected Bayer's proposed claim construction and granted SJ of noninfringement for Dow. Bayer appealed.

On appeal, the Federal Circuit noted that the case turned on whether Bayer's proposed construction of the term "the biological activity of 2,4-monooxygenase" as "bringing about the cleavage of the side chain of 2,4-D" was correct. The Court disagreed with Bayer's proposed construction for two reasons: (1) familiar aspects of textual analysis pointed strongly the other way; and (2) it would read independent claim 1 so broadly as to raise serious doubts about validity.

First, the Federal Circuit concluded that Bayer's "efforts fight a facially straight-forward textual analysis." Id. at 8. The Court noted that the meaning of "monooxygenase" as an enzyme catalyzing a reaction in which one oxygen atom is incorporated into water and the other is incorporated into something other than water was undisputed. The Court concluded that putting "2,4-D" in front of "monooxygenase" appeared to be a standard way of conveying that the enzyme acts on 2,4-D, and that "the biological activity of" was naturally understood to refer to the activity that makes the identified enzyme a monooxygenase that acts on 2,4-D, namely, the attachment of one oxygen atom to the 2,4-D molecule to trigger cleaving with the other oxygen atom going to water. The Court found no indication that the '401 patent used the term "monooxygenase" differently from its accepted scientific meaning, which would be required for Bayer's position. The Court stated, "Familiar claim-construction policies regarding public notice and patentee drafting duties make it appropriate to demand such clarity here: Bayer chose the language based on an unverified belief that it accurately described its enzyme, learned that the belief was false while the application was pending, had seven years before its patent issued to alter the language, but never did." Id. at 9. The Court also disagreed with Bayer's position that the specification defined "biological activity" as "bringing about the cleavage of the side chain of 2,4-D." Id. at 11. The Court concluded that "the claim language has a strong accepted scientific meaning," and that "Bayer's alternative construction strips the monooxygenase half of the claim phrase of its accepted descriptive meaning and then asserts a specification 'definition' of the biological-activity half." Id. at 12. The Court held that these steps were not justified by the specification or prosecution history.

Second, the Federal Circuit concluded that Bayer's proposed construction would call into serious doubt the claim's validity under 35 U.S.C. § 112(a). According to the Court, Bayer's proposed construction went far beyond the identified enzyme and monooxygenases "to capture the broad functionally defined genus of enzymes that cause cleaving of the 2,4-D side chain." Id. The Court noted that the '401 patent disclosed a single embodiment, and that "neither the patent nor the knowledge in the art showed that what Bayer offered in place of a description of the shared structure—the growth test—correlated closely with an enzyme's structure." Id. at 14. According to the Court, the '401 patent provided at best a "roadmap" of how to complete the unfinished invention, and even with this "roadmap," not all members of the genus could be reliably discovered. The Court stated that "the significant invalidity troubles that accompany Bayer's construction substantiate our rejection of it." Id.

The Court noted that neither party presented a reason to go beyond rejecting Bayer's proposed claim construction, stating, "All we need and do say is that, because we do not accept the only claim construction under which Bayer has alleged infringement, we affirm the summary judgment of non-infringement." Id. at 16.

Judges: Prost, Bryson, Taranto (author)

[Appealed from D. Del., Judge Bumb]

This article previously appeared in Last Month at the Federal Circuit, October 2013.

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