Before Moore, Plager, and Wallach. Appeal from the District of Delaware
Summary: A district court erred by interpreting a specification’s description of an “antibody” as a definition, when that description contradicted other portions of the specification and several dependent claims.
At the district court, Baxalta and Genetech disputed the construction of “antibody.” The court determined that the specification had expressly defined “antibody” consistent with the narrow construction Genentech proposed. Although the court recognized that this construction was inconsistent with several dependent claims, it ruled that the express definition controlled, rendering the dependent claims invalid. The parties stipulated to non-infringement under the district court’s narrow construction, and Baxalta appealed.
The Federal Circuit ruled that the plain language of the independent claim did not require any particular definition of “antibody,” and that the dependent claims confirmed that the independent claim used a broad meaning of “antibody.” The district court’s construction, which excluded the embodiments in the dependent claims, was “inconsistent with the plain language of the claims.” The Federal Circuit rejected the district court’s conclusion that the specification expressly defined “antibody.” Although the passage the district court relied on was plausibly definitional in isolation, a definitional reading of the passage rendered the specification as a whole internally inconsistent. The Federal Circuit therefore determined that the passage was a “generalized introduction,” not a definition. Accordingly, the Federal Circuit broadened the construction of “antibody,” vacated the judgment of non-infringement, and remanded for further proceedings.