There has been, since the turn of the century, a steady, seemingly inexorable trend towards limiting patent rights and focusing the application of U.S. patent law towards an emphasis on preventing innovators from obtaining patent rights broader than the minimum to which they may be entitled. This focus puts putative interests the public may have in reducing present patent rights in favor of future ones, where granting such rights to present inventors (limited as they are in time) is more important that providing sufficient patent protection to permit exploitation and commercialization of the innovations disclosed in their patents. Examples of this trend can be seen in the loss patent term adjustment awarded by statute due to Patent Office delay on the principle that the public has the right to freely used a patented invention including obvious variations thereof upon earliest patent expiry, the principle being found in Federal Circuit decisions from AbbVie Inc. v. Mathilda & Terence Kennedy Institute of Rheumatology Trust and Gilead Sciences, Inc. v. Natco Pharma Ltd. and culminating in the Federal Circuit's recent In re Cellect decision. In this climate concerns quickly arose regarding how the recent Supreme Court decision in Amgen v. Sanofi would be interpreted by the Federal Circuit. The Court did not disappoint, in its decision handed down in Baxalta Inc. v. Genentech, Inc.

The case arose in litigation over U.S. Patent No. 7,033,590 (having an earliest priority date of September 14, 2000, the significance of which will become readily apparent). The claims of this patent were directed to monoclonal antibodies that could provide an alternative treatment for Hemophilia A, being immunologically specific for human blood clotting factor IX and its activated form Factor IXa that would activate Factor X in the coagulation pathway in the absense of Factor VIII lacking in these hemophiliacs. The coagulation pathway is set forth here for clarification:

In the opinion, claim 1 of the '590 patent was set forth as being representative:

1. An isolated antibody or antibody fragment thereof that binds Factor IX or Factor IXa and increases the procoagulant activity of Factor IXa.

By eliminating the need for Factor VIII these antibodies overcame the limitation of treatment by recombinant human Factor VIII (one of the triumphs of the application of recombinant DNA technology and transformation of cells to make useful amounts of the protein), wherein patients developed antibodies against the Factor that disabled its ability to support coagulation and treat patients' disease.

As discussed in the opinion, the specification of the '590 patent disclosed use of hybridoma technology to produce such antibodies, which technology was considered sufficiently robust and predictable that it was the basis for the Federal Circuit's opinion in Noelle v. Lederman (wherein the mere isolation of a novel antigen or epitope thereof was considered sufficient to enable claims directed to antibodies to that antigen or epitope with no demonstration of actual production of any such antibodies). Indeed, until recently the vulnerability of such claims was considered to be a failure to satisfy the written description requirement in light of the Federal Circuit's en banc decision in Ariad v. Eli Lilly & Co.

Here, however, the matter was before the District Court on remand from an earlier Federal Circuit decision, wherein Baxalta sued Genentech over the latter's Hemlibra® (emicizumb-kxwh) product and the Court reversed based on the District Court's incorrect claim construction (ironically, by Judge Dyk who was sitting by designation in the District of Delaware). Judge Dyk, again sitting by designation granted Genentech summary judgment that the asserted claims of the '590 patent were invalid for lack of enablement in view of the Supreme Court's intervening Amgen v. Sanofi decision.

The Federal Circuit affirmed, in an opinion by Chief Judge Moore joined by Judges Clevenger and Chen. The Court's basis for its decision, recited more than once, is that "[t]he facts of this case are materially indistinguishable from those in Amgen" (which was not strictly speaking true; the Amgen claims recited producing antibodies based on their function of PCSK9 binding that prevented PCSK9 binding to LDL receptors, which is that elicited the blood cholesterol-reducing effect rather than, as here, antibodies directed to the target itself, a distinction without a difference to the Court). Sufficiently significant for the Court to recite in the opinion were the facts that the hybridoma methods disclosed in the specification expressly disclosed eleven antibodies by amino acid sequence having the claimed binding properties, and that such functional antibodies amounted to only 1.6% of the "thousands" of screened antibodies resulting from the Kohler and Milstein hybridoma protocol employed by the inventors. The panel interpreted the Supreme Court's Amgen decision to require enablement of "the full scope of the invention as defined by its claims," allowing for "a reasonable amount of experimentation." As in Amgen, the Federal Circuit appreciated the asserted claims of the '590 patent to likewise encompass millions of potential candidate monoclonal antibodies, the screening of which itself amounted to undue experimentation. The Court considered the circumstances here to be "materially indistinguishable" from those in Amgen, including reliance on an experimental "roadmap" (here) that required the skilled artisan to "(1) immunize mice with human Factor IX/IXa; (2) form hybridomas from the antibody-secreting spleen cells of those mice; (3) test those antibodies to determine whether they bind to Factor IX/IXa; and (4) test those antibodies that bind to Factor IX/IXa to determine whether any increase procoagulant activity."

Moreover the panel discerned that the specification provides no disclosure regarding "a quality common to every functional embodiment" that would permit the skilled worker to predict which of these potential millions of antibodies would have the claimed function. This deficiency included no disclosure of a comparison of the eleven disclosed antibodies that would provide such a structural key to identifying functional species. Rather, the person of ordinary skill in the art would (as in Amgen) need to produce a surfeit of antibodies and then screen them for the desired activity. This amounted, in the panel's view, to no more than the type of "trial and error" disclosure found wanting for satisfying the enablement requirement in Amgen.

More than ten years ago Judge Lourie set forth rubrics that could satisfy that other aspect of Section 112, the written description requirement, in the Federal Circuit's en banc Ariad opinion:

[A] description of a claimed genus disclosing either (1) "a representative number of species falling within the scope of the genus," . . . or (2) "structural features common to the members of the genus," either of which must enable "one of skill in the art [to] 'visualize or recognize' the members of the genus" [emphasis in opinion].

The current emphasis on undue experimentation resonates with these requirements, which formed the reasoned basis for the Federal Circuit's decision in this case:

Moreover, it is undisputed the '590 patent contains no disclosures—such as "a quality common to every functional embodiment," Amgen, 598 U.S. at 614—that would allow a skilled artisan to predict which antibodies will perform the claimed functions. The patent does not disclose any common structural (or other) feature delineating which antibodies will bind to Factor IX/IXa and increase procoagulant activity from those that will not. Nor does the patent describe why the eleven disclosed antibodies perform the claimed functions, or why the other screened antibodies do not. The only guidance the patent provides is "to create a wide range of candidate antibodies and then screen each to see which happen to bind" to Factor IX/IXa and increase procoagulant activity. Id. Amgen makes clear that such an instruction, without more, is not enough to enable the broad functional genus claims at issue here. Id. at 614–15 ("[T]he . . . problem we see [is that] Amgen offers persons skilled in the art little more than advice to engage in 'trial and error.'").

For anyone looking for a rationale that supports a broader disclosure of biological molecules than a recitation limited to the expressly disclosed species, it seems Judge Lourie's suggestions would be a good place to start.

Baxalta Inc. v. Genentech, Inc. (Fed. Cir. 2023)
Panel: Chief Judge Moore and Circuit Judges Clevenger and Chen
Opinion by Chief Judge Moore

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