TAA013

TAA013 is an investigational HER2‑targeted antibody–drug conjugate (ADC) composed of the monoclonal antibody trastuzumab linked via a non‑cleavable succinimidyl 4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC) thioether linker to the maytansinoid microtubule inhibitor DM1 (trastuzumab‑MCC‑DM1), with an average drug‑to‑antibody ratio of about 3.5.[3][5][7][9] Designed as a T‑DM1–like ADC, it retains trastuzumab’s HER2 binding and Fc‑mediated functions while delivering intracellular DM1 to HER2‑overexpressing tumor cells, causing mitotic arrest and apoptosis.[3][5][9] In early clinical studies in heavily pretreated HER2‑positive metastatic breast cancer, TAA013 has shown a manageable safety profile and preliminary antitumor activity, and it has progressed into phase III evaluation versus lapatinib plus capecitabine in HER2‑positive breast cancer.[1][2][3][6][9]