IP Law Daily, PATENT—Fed. Cir.: Invalidity of hemophilia drug patent affirmed under Amgen, (Sep 20, 2023)

By George Basharis, J.D.

Baxalta patent asserted against Genentech was invalid for lack of enablement.

The U.S. Court of Appeals for the Federal Circuit has refused to revive an antibody patent that was invalidated in 2021 by the federal district court in Delaware. The district court had ruled that Baxalta Inc.’s patent, which pertains to antibodies that bind to a protein important for blood coagulation, was invalid for lack of enablement. The Federal Circuit affirmed, finding the process outlined in the patent employed the same type of trial-and-error method that the U.S. Supreme Court recently rejected in Amgen Inc. v. Sanofi (Baxalta Inc. v. Genentech, Inc., September 20, 2023, Moore, K.).

Baxalta Inc. owns U.S. Patent No. 7,033,590 (the ’590 patent). The ’590 patent claims a method for treating hemophilia A in patients who do not respond to conventional hemophilia treatments, which typically involve the administration of a specific enzyme to facilitate blood clotting. The ’590 patent encompasses antibodies that bind to a different enzyme to reestablish blood clotting in these patients.

The antibodies were produced by the inventors of the ’590 patent using a method known as the “hybridoma” technique. They conducted numerous hybridoma experiments to identify antibodies that could bind to the relevant enzyme. Out of thousands of antibodies screened, they found eleven that could bind to the enzyme in question and enhance blood coagulation.

Baxalta sued Genentech, Inc., alleging that Genentech’s Hemlibra (emicizumab) hemophilia drug infringed the ’590 patent. Emicizumab is based on an antibody Baxalta claimed was covered by its patent. Genentech moved for summary judgment, asserting that Baxalta’s patent was invalid for lack of enablement. The district court agreed with Genentech, ruling that the ’590 patent was invalid because it did not provide sufficient instruction for a skilled artisan to create or use the full scope of the claimed invention without excessive experimentation.

The Federal Circuit affirmed after evaluating the ’590 patent using the standard articulated by the U.S. Supreme Court in Amgen, Inc. v. Sanofi, 598 U.S. 594 (2023). In Amgen, the Court dismissed Amgen’s “trial-and-error” method of identifying functional antibodies from potentially millions of antibodies for treating high cholesterol. The Federal Circuit found that the claims made in the ’590 patent were nearly identical to those made by Amgen in its cholesterol patent. Like Amgen, Baxalta’s approach involved millions of potential antibodies, but only 11 were effective for treating hemophilia. The ’590 patent would require skilled artisans to engage in the same iterative, trial-and-error process that was rejected the U.S. Supreme Court to discover the eleven antibodies disclosed by the ’590 patent. Furthermore, the only guidance provided by the ’590 patent to discover these eleven antibodies was “to create a wide range of candidate antibodies and then screen each to see which happen to bind” to the relevant enzyme.

Baxalta contended that the hybridoma technique disclosed in the ’590 patent did not involve trial and error because an effective antibody would be discovered every time the technique was performed. However, the Federal Circuit dismissed this argument, stating that even if skilled artisans could generate at least one claimed antibody each time they followed the disclosed process, it still involved the trial-and-error approach rejected in Amgen. To practice the full scope of the claimed invention, skilled artisans would need to create candidate antibodies and screen each one to determine if it performed the claimed functions. According to Amgen, such random discovery constituted unreasonable experimentation.

The Case is No. 2022-1461.

Attorneys: William R. Peterson (Morgan, Lewis & Bockius LLP) for Baxalta Inc., and Baxalta GmbH. Eric Alan Stone (Groombridge, Wu, Baughman & Stone LLP) for Genentech, Inc.

Companies: Baxalta Inc.; Baxalta GmbH.; Genentech, Inc.

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