Current drug patents are unpatentable---PTAB invalidated anti-body drug conjugates under section 112.
Gregory Gutierrez 24. JD from Suffolk University Law School and PhD from the Massachusetts Institute of Technology. “PTAB Issues Final Written Decision Finding Seagen Antibody-Drug Conjugate Patent Claims To Be Unpatentable.” Gale Onefile. 1-30-2024. https://www.goodwinlaw.com/en/insights/blogs/2024/01/ptab-issues-final-written-decision-finding-seagen-antibodydrug-conjugate-patent-claims-to-be-unpaten
On January 16, 2024, the Patent Trial and Appeal Board (PTAB) of the United States Patent and Trademark Office issued a Final Written Decision in a post-grant review (PGR) (PGR2021-00030) of claims in US Patent No. 10,808,039 ("the '039 patent") owned by Seagen. The PGR, filed by Daiichi Sankyo, Inc. and AstraZeneca Pharmaceuticals, LP, requested review of claims 1-5, 9, and 10 of the '039 patent, which are directed to antibody-drug conjugates (ADC) capable of intracellular cleavage. The '039 patent is at issue in a patent infringement lawsuit brought by Seagen against Daiichi Sankyo over Daiichi's FDA-approved ADC cancer therapy ENHERTU®. Previously, a federal jury has found that ENHERTU infringed the '039 patent and awarded $41.8 million in royalty revenue to Seagen.
Issues raised in the PGR included whether claims 1-5, 9, and 10 of the '039 patent were not patentable for lack of written description and enablement under 35 U.S.C. §112(a), indefiniteness under 35 U.S.C. §112(b), and anticipation under 35 U.S.C. §102.
On the issue of written description, Daiichi argued that the claims were not sufficiently supported because (a) the disclosure lacked descriptive support for the claimed gly/phe tetrapeptide component (Ww) of the ADC, and (b) the disclosure did not describe a representative number of species for the genus of "drug moiety" nor did the disclosure demonstrate common structural features for the "drug moiety" component.
On enablement, Daiichi argued that the '039 patent does not enable the full scope of the claimed ADCs. Specifically, it noted that "[c]omplex chemical interactions among ADC components affect its structure and properties," and that "[w]hile the claim does limit one aspect of the linker ... the structural limitations of the claim still encompass an astronomical number of structurally and functionally disparate compounds."
In the Final Written Decision, the PTAB held that claims 1-5, 9, and 10 are unpatentable for failing to comply with the written description and enablement requirements under Section 112(a).