Baxalta Inc. v. Genentech, Inc., No. 22-1461 (Fed. Cir. 2023)Annotate this Case
In a “key step” of the "coagulation cascade" that forms blood clots, an enzyme (Factor VIIIa) complexes with another enzyme (Factor IXa) to activate Factor X. Hemophilia A is a disorder where the activity of Factor VIII is functionally absent, impeding the body’s ability to effectively form blood clots. Historically, Hemophilia A has been treated by intravenously administering Factor VIII. Approximately 20–30% of Hemophilia A patients cannot benefit from that treatment because they develop Factor VIII inhibitors. Baxalta’s patent provides alternative means to treat Hemophilia A.
Baxalta sued, alleging Genentech’s Hemlibra® (emicizumab) product infringes the patent. Emicizumab is a humanized bispecific antibody that binds to Factor IXa with one arm and Factor X with the other arm, mimicking the function of Factor VIIIa. Following the district court’s construction of the claim terms “antibody” and “antibody fragment” to exclude bispecific antibodies, the Federal Circuit held the proper construction of “antibody” was “an immunoglobulin molecule having a specific amino acid sequence comprising two heavy chains (H chains) and two light chains (L chains),” and the proper construction of “antibody fragment” was “a portion of an antibody” and remanded. On remand, Genentech successfully moved for summary judgment of invalidity of multiple claims for lack of enablement. The Federal Circuit affirmed. The patent fails to teach skilled artisans how to make and use the full scope of claimed antibodies without unreasonable experimentation.