Additional Relevant Details
AB154 is a monoclonal antibody that potently and selectively blocks a novel immune checkpoint called TIGIT. As are the targets (e.g., PD-1 and CTLA-4) of some of the first-generation immune checkpoint inhibitors, TIGIT is expressed on exhausted effector T cells, which may reside within tumors but are unable to mount an effective attack against the cancer cells. TIGIT is also expressed on a wide range of other tumor-infiltrating immune cells, such as NK cells and regulatory T cells. AB154 blocks the interaction between TIGIT and CD155, which is highly expressed on many cancer cells, an interaction that results in an inhibitory signal in immune cells. CD155 can also bind to CD226 on T cells and NK cells, which results in a stimulatory signal. Therefore, by binding to TIGIT, AB154 not only blocks an inhibitory signal but also frees up CD155 to bind to CD226, thereby selectively activating the immune system against cancer cells. Based on results from the Company’s preclinical assays, the Company believes this will result in a powerful anti-tumor effect.