B003 in Patients With HER2-positive Recurrent or Metastatic Breast Cancer

"Usage: Intravenous infusion; Dose escalation stage: doses 0.6, 1.2, 2.4, 3.6, 4.8 mg / kg, 1-6subjects each. Dose expansion stage: 20 subjects are enrolled and take the recommended dose based on the result of dose escalation stage.~Infusion time：90 minutes(90min-106min suggested) for the first time; if no infusion reaction happens, the follow-up time is adjusted to at least30 minutes(30min-40min suggested).Dose escalation stage: treatment cycle is administered every 21days,the infusion is taken at the first day of each treatment cycle.Observation period of DLT is the 21st day of the first treatment cycle."