A patent applicant dissatisfied by an patent examiner's rejection of that applicant's claims in ex parte prosecution has recourse by appeal to the Patent Trial and Appeal Board (PTAB) under 35 U.S.C. § 134, and to the Federal Circuit thereafter under 35 U.S.C. § 141. While there is no right without a remedy (ubi jus ibi remedium) that remedy can be fleeting, as illustrated by In re BAC IP B.V. (non-precedential) (albeit illuminative).
Appellant's appeal was from a decision by the PTAB affirming an Examiner's Final Rejection of claims 77-83 and 85-94 in U.S. Application No. 16/282,082* that were directed to a method for purifying mammalian immunoglobulin antibodies, for failing to satisfy the written description requirement of 35 U.S.C § 112(a). Claim 77 is representative:
A method for the purification of a molecule comprising an epitope present in the Fc domain of a human IgG antibody, the method comprising the steps of:
(a) bringing a sample comprising the molecule comprising the epitope present in the Fc domain of a human IgG antibody into contact with an immunoadsorbent material comprising a variable heavy-heavy (VHH) antigen-binding protein under conditions that allow for binding of the molecule to the immunoadsorbent material;
(b) optionally, performing a washing step; and
(c) eluting the bound molecule comprising the epitope present in the Fc domain of a human IgG antibody under conditions that decrease the affinity between the molecule and the VHH antigen-binding protein,
[(i)] wherein the VHH antigen-binding protein has binding affinity for the Fc domain of the human IgG molecule but does not have binding activity for the Fc domain of a mouse, a bovine, a rat, a Syrian hamster, a guinea pig, a dog, a cat, a goat, or a sheep IgG molecule, and
[(ii)] wherein the VHH antigen binding protein comprises four framework regions, FR1 to FR4, and three complementarity determining regions, CDR1 to CDR3, that are operably linked in the order FR1-CDR1-FR2-CDR2-FR3- CDR3-FR4, wherein the CDR3 region comprises the amino acid sequence Arg Arg Phe Gly Ser Ser Glu Trp Asp Tyr (SEQ ID NO: 108).
(wherein the italicized portion of the claims raised the written description issues that were the basis for the examiner's final rejection). The bases for the PTAB's decision (which adopted the Examiner's reasoning) were, first, that "the claims cover a large genus of VHH antigen-binding proteins"; second, that "the specification of the '082 application discloses only one VHH antigen-binding protein meeting each requirement of claim 77"; and third, that "the specification does not disclose a structural feature shared by each member of the species of claim 77."
The Federal Circuit affirmed, in a decision by Judge Lourie joined by Judges Prost and Stoll. The panel rejected Appellant's argument that the Board's determination was not supported by substantial evidence. As the Court saw it, the Examiner was correct in the three bases affirmed by the Board. Regarding the "large genus of VHH antigen binding proteins," the opinion asserts that this conclusion was based on correct claim construction which was consistent with the language of claim 77 and the specification. The specificity of the amino acid sequences recited in claim element (c)(ii) for CDR3 of the VHH protein did not overcome the lack of such specificity for CDRs 1 or 2. The disclosure of 49 different species of amino acid sequences for CDRs 1 and 2 in the specification also did not suffice for the panel, because the scope of claim 77 was not limited to those sequences. The Court opined that "the claims and specification place effectively no constraints on the amino acid sequences that can constitute the CDR1 and CDR2 regions, and therefore the claimed VHH antigen-binding proteins," which supported the Examiner's conclusion that the claimed genus is broad, and was supported by substantial evidence. The panel rejected BAC's argument that the genus was narrow because the specification only disclosed 15 VHH antigen-binding proteins defined by function and only one having the sequence recited in claim element (c)(ii). According to the Court, the proper determination of written description satisfaction is not limited to what is disclosed in the specification but rather depends upon the scope of the claim as properly construed, which in this instance encompassed a broad genus having unspecified (and broad) amino acid sequences for CDRs 1 and 2.
The Court also rejected BAC's arguments that the specification disclosed "how to identify VHH antigen-binding proteins" by functional and structural characteristics. This is insufficient to satisfy the written description requirement in view of the specification only disclosing a single VHH antigen-binding protein species, according to the panel.
The opinion also notes that "BAC does not challenge the Board's findings that the '082 application discloses only one VHH antigen-binding protein that meets each of the limitations claim of 77, and that the '082 application does not disclose a common structural feature for the claimed VHH antigen-binding proteins" as grounds for affirming the Board's rejection of BAC's appeal of the examiner's final rejection.
The decision in many ways is a "garden variety" written description rejection based on thirty years of written description jurisprudence that began with Judge Lourie's decision in Regents of the University of California v. Eli Lilly & Co. (indeed, the decision recites the standard from that case that satisfaction of the requirement can be achieved by disclosing a "representative number of species" in a claimed genus or a structure/function relationship for species falling within the scope of the claimed genus). If nothing else, decisions such as these illustrate the continuing consistency of the Court's written description jurisprudence.
* The opinion notes that at least one claim would be allowable, if amended so as not to depend on a rejected base claim; that claim recited a specific VHH species.
In re BAC IP B.V. (Fed. Cir. 2025)
Nonprecedential disposition
Panel: Circuit Judges Lourie, Prost, and Stoll
Opinion by Circuit Judge Lourie
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