CLSP-1025

CLSP-1025 is a novel, half-life extended bispecific T-cell engager (TCE) developed by Clasp Therapeutics for the treatment of solid tumors harboring the p53 R175H mutation in HLA-A*02:01-positive patients. It is an asymmetric bispecific single-chain diabody Fc fusion protein that binds monovalently to the mutant p53(R175H)168-176 peptide presented by HLA-A*02:01 on cancer cells and to CD3ε on T cells. This design enables highly selective targeting of tumor cells expressing this specific neoantigen, sparing wild-type p53 and minimizing off-tumor effects. Upon binding, CLSP-1025 bridges cancer cells and T cells, activating T cell-mediated cytotoxicity against tumor cells. Preclinical studies have demonstrated potent activity in patient-derived organoids and animal models, with regression of established tumors observed in vivo. The drug is currently being evaluated in a Phase 1 clinical trial for multiple solid tumor types including colorectal, lung, pancreatic, prostate, ovarian, breast cancers and others[1][3][4][6].