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Just days after agreeing to review the scope of the enablement requirement in Amgen Inc. v. Sanofi, Aventisub LLC, the Supreme Court denied Juno Therapeutics, Inc.’s (Juno) request to review the scope of the written description requirement. Interestingly, both cases involved similar questions – whether the respective portion of 35 U.S.C. §112(a) is governed by the statutory language or whether enablement and written description apply to the “full scope” of the claimed invention.

Section 112 of the Patent Act requires a patent’s specification to “contain a written description of the invention, and of 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, or with which it is most nearly connected, to make and use the same.” 35 U.S.C. §112(a). A specification is said to provide adequate written description when it “reasonably conveys to those skilled in the art that the inventor had possession of the claimed subject matter as of the filing date.” Ariad Pharms., Inc. v. Eli Lilly & Co., 598 F.3d 1336, 1351 (Fed. Cir. 2010) (en banc). In Juno Therapeutics, Inc. v. Kite Pharma, Inc., the Federal Circuit stated that written description is satisfied when the inventors convey that they possessed all known and unknown parts of the claimed invention. 10 F.4th 1330, 1338 (Fed. Cir. 2021), cert. denied, No. 21-1566, 2022 WL 16726060 (U.S. Nov. 7, 2022). Thus, Juno requested that the Court address the following question:

Is the adequacy of the “written description of the invention” to be measured by the statutory standard of “in such full, clear, concise, and exact terms as to enable any person skilled in the art to make and use the same,” or is it to be evaluated under the Federal Circuit’s test, which demands that the “written description of the invention” demonstrate the inventor’s “possession” of “the full scope of the claimed invention,” including all “known and unknown” variations of each component?

Claims 3, 5, 9, and 11 of U.S. Patent No. 7,446,190 (the ’190 patent) were at issue in the case. Claim 1 of the ’190 patent reads as follows:

1. A nucleic acid polymer encoding a chimeric T cell receptor, said chimeric T cell receptor comprising

(a) a zeta chain portion comprising the intracellular domain of human CD3 ζ chain,

(b) a costimulatory signaling region, and

(c) a binding element that specifically interacts with a selected target,

wherein the costimulatory signaling region comprises the amino acid sequence encoded by SEQ ID NO:6.

Claims 3 and 9 require that the antibody is a single chain antibody (scFv), and claims 5 and 11 require that the single chain antibody bind to CD19.

Kite Pharma, Inc., argued that the claims at issue encompass “millions of billions” of scFvs but that only a fraction of those satisfy the functional requirement of the claims – the ability to bind to a target. Juno Therapeutics, Inc., 10 F.4th at 1336. Juno, on the other hand, argued that scFvs are well-known molecules, that making scFvs was well known, that multiple scFvs for specific targets are well known, and that the ’190 patent provides two working examples of scFvs, which “are representative of all scFvs.” Id. The Federal Circuit did not agree with Juno’s arguments, stating that the ’190 patent “fails to provide a representative sample of species within, or defining characteristics for, that expansive genus.” Id.

The Federal Circuit first evaluated whether the patent provides a representative number of species falling within the scope of the claimed genus. The court found that although the ’190 patent discloses two scFvs – one derived from the SJ25C1 antibody that binds CD19 and the other derived from the J591 antibody that binds PSMA – claims 3 and 9 encompass a limitless number of targets. Id. According to the Federal Circuit, the disclosure of one scFv that binds to CD19 and one scFv that binds to a PSMA “in the manner provided in this patent does not provide information sufficient to establish that a skilled artisan would understand how to identify the species of scFvs capable of binding to the limitless number of targets as the claims require.” Id. at 1337.

The Federal Circuit then evaluated whether the patent discloses structural features common to the members of the genus so that one of skill in the art can visualize or recognize the members of the genus. The court noted that the ’190 patent fails to provide the amino acid sequence of either of the disclosed scFvs. Id. And although the court stated that “[i]t is not fatal that the amino acid sequences of these two scFvs were not disclosed” (id.), it noted that written description requires “other means of identifying which scFvs would bind to which targets, such as common structural characteristics or shared traits,” which the patent was said to lack. Id. According to the Federal Circuit, to satisfy written description “the inventors needed to convey that they possessed the claimed invention, which encompasses all scFvs, known and unknown, as part of the claimed CAR that bind to a selected target.” Id. at 1338.

The Federal Circuit reversed the district court’s ruling that claims 3, 5, 9, and 11 are not invalid for lack of written description, finding that the ’190 patent “does not disclose representative species or common structural features to allow a person of ordinary skill in the art to distinguish between scFvs that achieve the claimed function and those that do not.” Id. at 1342.

It is unclear why the Supreme Court denied Juno’s petition just days after granting Amgen’s. For now, the Federal Circuit’s ruling that written description requires applicants to convey that they possessed all known and unknown aspects of the claimed invention will stand. Time will tell if the Supreme Court will require a similar level of disclosure to satisfy the enablement requirement.