Our CD137 FAP agonist is undergoing clinical investigation as a monotherapy and in combination with a PD-1 inhibitor (ezabenlimab [BI 754091]* or pembrolizumab) for the treatment of patients with metastatic or unresectable recurrent head and neck squamous cell carcinoma (HNSCC).^1–3

CD137 FAP bispecific agonist antibody clinical trial

CD137 FAP bispecific agonist antibody mechanism of action

Our CD137 FAP bispecific agonist antibody is designed to selectively reactivate T cells within the tumor microenvironment in a tissue-dependent manner via concomitant binding to FAP on CAFs and CD137 on T cells, potentially avoiding systemic activation of T cells and associated cytotoxicity.^1,2,4–6

CD137 FAP bispecific agonist antibody mechanism of action⁶

Combination therapy

The combination with a PD-1 inhibitor may boost tumor-specific T-cell activity further by both counteracting tumor-mediated suppression of T cells and simultaneously activating the T cells through CD137 agonism.^4,7

CD137, also known as 4-1BB, is a receptor expressed on immune cells such as T cells, NK cells, and dendritic cells that functions as an important regulator of immune responses, and is an essential pathway for maximal CD4 and CD8 T-cell responses.⁵ FAP is a protein expressed on cancer-associated fibroblasts (CAFs).⁴

*This is an investigational compound and has not been approved. Its safety and efficacy have not been established. 
CAF, cancer-associated fibroblast; CD, cluster of differentiation; FAP, fibroblast activation protein; HNSCC, head and neck squamous cell carcinoma; NK, natural killer.