Fsn0503h

Fsn0503h is a humanized monoclonal antibody developed by Fusion Antibodies Ltd for the treatment of solid tumors. It specifically targets cathepsin S (Cat-S), a lysosomal cysteine protease that is frequently overexpressed and secreted into the tumor microenvironment, where it promotes tumor progression by degrading the extracellular matrix and facilitating angiogenesis and metastasis. Fsn0503h works by neutralizing the extracellular proteolytic activity of cathepsin S and inducing antibody-dependent cellular cytotoxicity (ADCC) through the recruitment of CD16-positive immune effector cells, such as natural killer (NK) cells. Preclinical studies have demonstrated its antitumor efficacy as both a monotherapy and in combination with chemotherapy agents like irinotecan across various cancer models, including colorectal, pancreatic, breast, prostate, and glioblastoma.