FPT155

FPT155 is a first-in-class recombinant fusion protein composed of the extracellular domain of human CD80 fused to the Fc domain of human immunoglobulin G1. It is designed as an immune modulator for cancer immunotherapy. The drug acts by directly engaging and stimulating the CD28 receptor on T cells to enhance co-stimulatory T-cell activation in the presence of antigenic T cell receptor (TCR) signaling. Additionally, it blocks CTLA-4 from competing for endogenous CD80, allowing sustained CD28 signaling and promoting anti-tumor immunity. Unlike superagonist antibodies targeting CD28, FPT155 does not induce non-specific or spontaneous cytokine release and requires concurrent TCR engagement for activity. Preclinical studies demonstrated potent anti-tumor effects even in models resistant to PD-1/PD-L1 or CTLA-4 blockade[1][5][6]. Developed by Five Prime Therapeutics (now a subsidiary of Amgen), clinical development reached Phase 1 trials in advanced solid tumors but was discontinued[2][3].

Other names

CD80-FcCD-80-FcCD 80-Fc