A randomized, single-blind, single-dose, parallel-group study in healthy subjects to demonstrate the pharmacokinetic equivalence of trastuzumab and its biosimilar

Trastuzumab is a humanized anti-HER2 monoclonal antibody used in the treatment of breast cancer. This study compared the pharmacokinetics (PK), immunogenicity and safety of trastuzumab (Roche Pharma AG) and its biosimilar (Chia Tai Tianqing Pharmaceutical Group Co. Ltd) in healthy Chinese subjects. A randomized, parallel, double-blind, single-dose study was conducted. Healthy male subjects were randomized to receive trastuzumab (<i>n</i> = 43) or its biosimilar (<i>n</i> = 43) intravenously at a dose of 4 mg. Plasma drug concentrations were detected by enzyme-linked immunosorbent assay (ELISA), and PK parameters were statistically analyzed. Safety and immunogenicity were also evaluated. The geometric mean ratios (GMRs) of AUC_0-t, C_max and AUC_0-∞ for trastuzumab and its biosimilar were 92.3%, 100.77% and 92.2%, respectively. The 90% CIs were all within 80%-125%, meeting the bioequivalence standards. No serious adverse events or immunogenicity were reported, and all the adverse events reported were mild and similar between the two treatment groups. Trastuzumab was well tolerated, showed a similar safety profile to its biosimilar, and demonstrated PK equivalence. This trial was registered at the [anonymized].