S3F-CL-MMAE

S3F-CL-MMAE is an experimental **antibody-drug conjugate (ADC)** targeting the cancer-associated antigen Sialyl-Tn (STn). It consists of the anti-STn monoclonal antibody S3F conjugated via a cathepsin B-cleavable maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-vc-PAB) linker to the cytotoxic payload **monomethyl auristatin E (MMAE)**. The ADC selectively binds cell-surface STn, leading to internalization and intracellular release of MMAE, which disrupts microtubules and induces cell death. Preclinical studies have demonstrated significant anti-tumor activity in vitro and in vivo, particularly in ovarian cancer models, with selectivity for STn-positive cancer cells and cancer stem-like cells.