ARX-F01 (Ambrx)

ARX-F01 is an investigational antibody-drug conjugate (ADC) targeting Folate Receptor Alpha (FRα), a cell-surface protein frequently overexpressed in solid tumors such as ovarian, lung, and endometrial cancers. Developed by Ambrx Biopharma (now a subsidiary of Johnson & Johnson), the drug utilizes Ambrx's proprietary expanded genetic code technology to incorporate non-natural amino acids into the antibody sequence. This allows for the site-specific conjugation of a cytotoxic payload, typically a microtubule inhibitor, resulting in a highly homogeneous drug-to-antibody ratio (DAR). By precisely controlling the conjugation site, ARX-F01 aims to achieve superior stability and a wider therapeutic window compared to conventional ADCs, delivering the toxin directly to FRα-expressing malignant cells while sparing healthy tissue.