<em>Baxalta Inc. v. Genentech, Inc.</em>

972 F.3d 1341 (Fed. Cir. 2020)

The Federal Circuit affirmed the district court’s ruling that Baxalta’s patent for antibodies that treat Hemophilia A was invalid for lack of enablement and applied the Supreme Court’s 2023 decision in Amgen Inc. v. Sanofi to reach its determination.

Baxalta sued Genentech, Inc. alleging Genentech’s Hemlibra (emicizumab) product infringed Baxalta’s Patent No. 7,033,590 (’590 patent). The ’590 patent provided an alternative means to treat Hemophilia A, particularly in patients who develop Factor VIII inhibitors. The patent claimed a process for creating antibodies or antibody derivatives that bind to Factor IX/IXa and allow Factor IXa to activate Factor X without Factor VIII/VIIIa. Emicizumab is a humanized bispecific antibody that binds to Factor IXa with one arm and Factor X with the other arm, thereby mimicking the function of Factor VIIIa.

The ’590 patent claims “[a]n isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.” It further discloses the amino acid sequences of eleven antibodies that bind to Factor IX/IXa and increase the procoagulant activity of Factor IXa. The ’590 patent explains that a skilled artisan may use the hybridoma technique, a well-known antibody engineering process, to transform the resulting antibody into different structural formats.

Baxalta sued Genentech in the United States District Court for the District of Delaware, where the district court construed the claim terms “antibody” and “antibody fragment” to exclude bispecific antibodies. The parties stipulated to non-infringement subject to appeal. On a prior appeal, the Court of Appeals for 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.” The Federal Circuit remanded back to the district court to decide the dispute with their new term constructions. The instant case arose after the district court granted summary judgment for Genentech, holding claims 1–4, 19, and 20 of Baxalta’s ’590 were invalid for lack of enablement.

The Federal Circuit reasoned that the ’590 patent’s claims were not enabled because a person skilled in the art would not have been able to implement “the full scope of the claimed antibodies without undue experimentation.” The court cited 35 U.S.C. § 112(a), which states that “[a] patent’s specification must describe the invention and ‘the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains . . . to make and use the same.’”

Section 112(a) has been interpreted to require inventors to enable the full scope of the claimed invention without unreasonable experimentation. Here, Baxalta's experts testified that the only way for skilled artisans to identify a new embodiment of the genus was “to make antibodies and test them.” This is the definition of trial and error and leaves future skilled artisans no better equipped to make and use the claimed antibodies than the original inventors were when they set out to discover the antibodies over which they now claim an exclusive right. Therefore, on statutory grounds alone, Baxalta’s claims were insufficient to enable the patent.

The court further cited the Supreme Court’s unanimous holding in Amgen Inc. v. Sanofi, 598 U.S. 594 (2023), as having “materially indistinguishable” facts from the instant case. Baxalta’s patent claims covered potentially millions of antibodies, but the patent only disclosed eleven antibodies. Thus, to find undisclosed, but claimed, antibodies, a skilled artisan would have to undergo extensive trial-and-error testing. The Federal Circuit reiterated the Supreme Court’s holding in Amgen: providing a step-by-step, trial-and-error type of research summary in a patent claim is insufficient to “enable” the patent because even skilled artisans would have to “engage in ‘painstaking experimentation’ to see what works.”

After comparing the patent claims at issue in Amgen to Baxalta’s, the Federal Circuit wrote, “[j]ust like the roadmap rejected by the Supreme Court in Amgen, the ’590 patent’s roadmap simply directs skilled artisans to engage in the same iterative, trial-and-error process the inventors followed to discover the eleven antibodies they elected to disclose.” The court continued that “[i]n both cases, ‘nothing in the specification [teaches] how to identify any antibodies complying with the claim limitations other than by repeating the same process the inventors used to identify the . . . examples disclosed in the specification.’” 

Baxalta argued that the district court’s decision on enablement was inconsistent with In re Wands, 858 F.2d 731 (1988), which listed numerous factors that aid a court in determining whether the enablement requirement was met and if any necessary experimentation was excessive or undue. In the instant case, the Federal Circuit stated that Amgen did not disrupt Wands or its factors, and the factual distinctions between Amgen and Wands were responsible for their different outcomes. Finally, the Federal Circuit reiterated that the facts in this case were so analogous to Amgen that Amgen was a better guide than Wands.

Amgen made clear that a general instruction in a patent claim, without more, was not enough to enable the broad claims at issue. This case is a textbook application of Amgen v. Sanofi and affirms the lineage of patent enablement cases that explain section 112(a). A patent must have specific claims so that a person skilled in the art could make and use the patented work without experimentation. Here, Baxalta’s claims did not meet that test.

Thus, the Federal Circuit affirmed the district court’s grant of summary judgment that claims 1–4, 19, and 20 of Baxalta’s ’590 patent were not enabled because a person with skill in the art could not implement the patent without excessive experimentation.