A166

A166 is an antibody-drug conjugate developed by Sichuan Kelun-Biotech Biopharmaceutical. Its target is HER2 (the sponsor names HER2). The sponsor states: A166 is a HER2-targeted antibody-drug conjugate with a microtubule inhibitor payload, administered intravenously at 4.8 mg/kg every three weeks (Q3W) to HER2-positive breast cancer patients. It is the investigational product in 2 recruiting or active industry-led phase 2 and phase 3 interventional cancer trials, including the phase 3 study NCT06968585 (A Study of A166 Versus Trastuzumab Emtansine (T-DM1) in Patients With HER2-Positive Unresectable or Metastatic Breast Cancer Previously Treated With Trastuzumab and Taxane Therapy), in HER2-positive breast cancer. The largest, NCT06968585, plans to enrol 365 participants (actual) with primary completion expected 2026-11-30. Status reflects the highest phase registered on ClinicalTrials.gov at the 2026-09-11 check; no efficacy results are recorded here.