Bayer CropScience AG v. Dow AgroSciences LLC
Addressing the negative consequences of poor or erroneous claim drafting, the U.S. Court of Appeal for the Federal Circuit affirmed a narrow interpretation of a functional claim and a grant of summary judgment of non-infringement in favor of the defendant, finding that a narrow description of one species does not support a broader construction of the genus. Bayer CropScience AG v. Dow AgroSciences LLC, Case No. 13-1002 (Fed. Cir., Sept. 3, 2013) (Taranto, J.).
Bayer filed a patent application with claims directed to an enzyme that, when genetically incorporated into plants, could make them resistant to the herbicide 2,4-D. According to the application, the enzyme catalyzed the breakdown of 2,4-D into something harmless in plants. As a result, the 2,4-D herbicide could be used to destroy weeds with no adverse effects on the genetically engineered plants. The application described the enzyme as having a 2,4-D monooxygenase function. This function was merely an assumption and unverified at the time. Later, while Bayer's application was still pending, scientists determined that the enzyme was in fact a dioxygenase not a monooxygenase. However, Bayer failed to take appropriate steps to correct the error or to establish on record that the discovered enzyme functioned as a 2,4-D dioxygenase. On the contrary, Bayer pursued claims that were directed to the erroneously claimed function. The application issued as a patent with broad functional claims drawn to any and all recombinant genes encoding polypeptides having biological activity of 2,4-D monooxygenase.
In the meantime, Dow AgroSciences produced a line of genetically modified seeds resistant to 2,4-D, which expressed two dioxygenase (i.e., aryloxyalkanoate dioxygenase) enzymes. Bayer sued Dow for infringing its patent. In a Markman hearing that followed, Bayer sought a broad claim construction that would cover the Dow products. Bayer wanted the claims to be construed as covering any oxygenase enzyme that bring about the cleavage of the side chain of 2,4-D. The district court applied the "plain and ordinary meaning" to the term "2,4-D monooxygenase," which based on the established scientific meaning functioned differently from a 2,4-D dioxygenases including the dioxygenases of Dow. Bayer appealed.
The Federal Circuit affirmed, reasoning that "public notice and patentee drafting duties make it appropriate to demand such a clarity here: Bayer chose the language based on an unverified belief that it accurately described its enzyme, learned that the belief was false while its application was pending, had seven years before its patent issued to alter the language, but never did."
Moreover, by acknowledging that validity analysis is not a regular component of claim construction, the Federal Circuit indicated that if it were to adopt the Bayer's broad claim construction, the claims could be invalid for failing to meet the written description requirement. The Court acknowledged that it had not articulated a comprehensive and precise formulation for identifying how the broad construction could be found invalid under the written description requirement, but was of the opinion that disclosing one enzyme without sufficient correlation between its structure and function did not provide adequate written description support for a broad genus claim. Thus the Federal Circuit affirmed the district court's summary judgment of non-infringement in favor of Dow.
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