BAXALTA INC. v. GENENTECH, INC., Appeal No. 2019-1527 (Fed. Cir. August 27, 2020).  Before Moore, Plager, and Wallach.  Appealed from D. Del. (Judge Dyk).  (Claim Construction)


Baxalta sued Genentech for infringement of its patent directed to preparations for treating hemophelia.  The claims were directed to “an isolated antibody or antibody fragment thereof” that binds to a clotting factor in the enzymatic coagulation cascade responsible for blood clotting and increases the procoagulant activity of that factor.

The district court narrowly construed the term “antibody” based on a passage in the specification, which described antibodies as molecules that only bind to antigens that induce their synthesis or to very similar antigens.  The passage also described antibodies as being molecules that consist of two identical heavy chains and two identical light chains.  Even though this construction would exclude embodiments recited in the dependent claims, the court held that this inconsistency was insufficient to overcome what it considered to be an express definition in the specification.  The court considered the non-encompassed embodiments recited in the dependent claims to be “antibody derivatives,” which the patentee disclaimed during prosecution by amending the claims to replace the term “antibody derivative” with “antibody fragment.”

Based on the court’s construction, the parties stipulated to non-infringement.  Baxalta appealed, arguing that the claim construction was improper.


Did the district court properly construe the claim term “antibody”? (continue reading)

Summary by:  Molly Chen

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