The hardest problem in CAR-T is moving from blood cancers to solid tumors, which requires a binder for a solid-tumor antigen. US11707487B2 - "EpCAM antibody and CAR-T cells," issued July 25, 2023 to AffyImmune Therapeutics, Inc. - claims a binder for EpCAM and the CAR cells built around it.
In a chimeric antigen receptor, the antigen-binding domain is the module that decides what the engineered T cell attacks. This claim fixes that domain to EpCAM (epithelial cell adhesion molecule), a marker expressed on many carcinomas. The CPC tags - C07K 16/30 (anti-tumor antibody), C07K 14/7051 (CAR component), A61K 35/17 (T-cell therapy) - capture both the antibody and its incorporation into the receptor.
The claim's two-part structure matters. It covers the EpCAM antibody itself and the CAR-T cells that use it as their binding domain. That dual coverage means a competitor could infringe either by making the antibody or by building CAR cells with a binder falling within the claimed EpCAM-targeting domain - two distinct infringement theories from one grant.
The scope question is the binder's sequence and specificity. EpCAM is expressed on healthy epithelium as well as tumors, so the on-target-off-tumor risk is real, and the value of a particular EpCAM binder lies in its affinity and selectivity profile. A competitor's EpCAM CAR infringes only if its binding domain falls within the claimed antibody's scope - which turns on the CDR sequences, not the antigen name.
For the landscape, solid-tumor CAR-T antigens like EpCAM each anchor their own small estate of binder-and-construct claims. Freedom-to-operate for a solid-tumor cell therapy means clearing the specific antigen-binder claims for its target, separately from the foundational CAR-architecture layer - a reminder that 'CAR-T patent' fractures by antigen as much as by construct.