Knowledge of a newly characterized antigen for patenting a genus of its cognate antibodies is not quite enough, according to Amgen Inc. v. Sanofi (Fed. Cir. 2017). The “newly characterized antigen” test is opined to be inappropriate in determining whether a patent application for an antibody satisfies the written description requirement. Although several pharmaceutical companies concurred with Amgen and voiced strong concerns about the “narrow and inflexible rule” created by the Federal Circuit, Amgen’s petition for certiorari to the Supreme Court to take up the issue of written description was denied in early January, 2019.
The United States Patent and Trademark Office (USPTO) issued a memorandum adopting Amgen as the law on written description as it applies to antibodies and pointed out that 35 U.S.C. § 112(a) requires adequate written description of the antibody itself.
Even in light of Amgen and the USPTO memorandum, successful prosecution of patent applications directed to antibodies and therapeutic methods of using antibodies can still be achieved. Applicants are reminded that:
- Making a biological deposit of hybridomas at any time before allowance remains a viable option in many instances for a U.S. patent application to satisfy the written description requirement. For certain foreign jurisdictions, such as Europe, applicants should ensure that biological samples are deposited on or before the effective filing date of the application (i.e., before the filing date of the priority application, if one is filed), for the invention to be considered sufficiently disclosed as of the effective filing date. Under the European Patent Convention, a biological deposit made between a priority application and a subsequent European application is too late for the invention to be considered sufficiently disclosed in the priority application, resulting in a loss of the priority date.
- Amino acid sequences of the complementarity-determining regions (CDRs), if known, should be included.
- Disclosures relating to substitutions, additions or deletions of amino acids in the CDRs along with functional features such as binding affinity and therapeutic efficacy may help broaden the scope of protection.
- To protect a genus of antibodies, disclosure of a representative number of species and/or common structural features among the members of the genus should be made.
The particular nuances of each invention need to be considered on a case-by-case basis against the evolving laws in each jurisdiction of interest when formulating and revisiting one’s strategy for antibody-related patent protection.