A phase I dose-escalation study of a biosimilar trastuzumab in Chinese metastasis breast cancer patients

Trastuzumab has been widely used among the breast cancer patients with human epidermal growth factor receptor 2 (HER2) overexpression. The genetically engineered trastuzumab traded as Cipterbin® was developed in China since 2003. We have disclosed the phase I clinical trial data of safety, pharmacokinetic profile (PK) in patients with metastasis breast cancer. Subjects identified as HER2 strong positive received single intravenously doses of 100, 250 or 500 mg Cipterbin® in dose-escalation manner. The safety evaluations were recorded and plasma concentration profiles for the drug were analyzed. 27 Chinese metastatic breast cancer patients were enrolled in this study. Patients in each group of different dosage were well-tolerated. The most frequently drug-related adverse events were fever (59.3 %), transaminase increased (22.2 %), chills (18.5 %) and arrhythmia (18.5 %). Only one patient with severe adverse event was observed in 250 mg group revealing brachycardia. PK profile analysis showed that sera steady concentration could be reached in dose-proportional manner, except volume of distribution (V(d)) and clearance (CL), which reached peak values at 250 mg administration cohort. This genetically engineered HER2-target antibody had demonstrated the accepted safety with well-tolerated.