A Phase 1 randomized study compare the pharmacokinetics, safety and immunogenicity of HLX02 to reference CN- and EU-sourced trastuzumab in healthy subjects.

PURPOSE This study evaluated the bioequivalence of China-manufactured biosimilar, HLX02, to reference China (CN)- and European Union (EU)-sourced trastuzumab. METHODS This was a two-part Phase 1 study conducted in healthy Chinese males. Part 1 evaluated the safety of different doses of HLX02 (2, 4, 6 or 8 mg/kg; intravenous infusion over 90 min, n = 3 per group). Part 2, a randomized, double-blind study, investigated the pharmacokinetics (PK), safety and immunogenicity of study drugs (HLX02 [n = 37], CN-trastuzumab [n = 35] or EU-trastuzumab [n = 37] at the dose suggested by Part 1 results). The primary PK endpoint was the area under the serum concentration-time curve from time 0 to infinity (AUCinf). Equivalence was concluded if the 90% confidence interval (CI) for the geometric least squares mean ratio (GLSMR) fell in the equivalence criteria of 0.80-1.25. RESULTS In Part 1, all doses of HLX02 were well tolerated and 6 mg/kg was suggested for Part 2. The GLSMRs and 90% CIs for AUCinf were: 0.950 (0.891-1.013), 0.914 (0.858-0.973) and 0.962 (0.902-1.025) for HLX02 versus CN-trastuzumab, HLX02 versus EU-trastuzumab and CN-trastuzumab versus EU-trastuzumab, respectively. Secondary endpoints comparisons also fell in the equivalence criteria. Treatment-emergent adverse events were reported in 75.7, 86.5 and 70.3% of the subjects in HLX02, CN-trastuzumab, and EU-trastuzumab groups, respectively. No serious adverse events or deaths occurred. No treatment-related anti-drug antibodies were detected. CONCLUSION This study demonstrated comparable safety profiles and PK bioequivalence among HLX02, CN-trastuzumab and EU-trastuzumab in healthy Chinese male subjects. CLINICAL TRIAL REGISTRATION ClinicalTrials.gov, NCT02581748, registered at October 19, 2015.