MST-0300

MST-0300 is a first-in-class bispecific antibody developed by Mestag Therapeutics. It is designed to co-engage fibroblast activation protein (FAP) and lymphotoxin beta receptor (LTBR), conditionally activating LTBR in the tumor microenvironment. This dual targeting induces the formation of tertiary lymphoid structures (TLS) within solid tumors in a highly specific and localized manner. TLS are aggregates of immune cells that form as part of the body’s natural anti-cancer mechanisms, enabling improved immune cell access to tumors and driving local education and activation of anti-tumor T- and B-cells. The presence of TLS in tumors has been strongly correlated with improved outcomes for cancer patients across multiple tumor types, making this approach a novel immunotherapeutic strategy for solid tumors[5][6][9]. Preclinical data have demonstrated potent anti-tumor effects, supporting ongoing clinical development.