A randomized, double-blind, single-dose, phase 1 study comparing the pharmacokinetics, pharmacodynamics, safety, and immunogenicity of denosumab biosimilar CT­P41 and reference denosumab in healthy males.

BACKGROUND: This study's objective was to demonstrate pharmacokinetic (PK) similarity and safety of denosumab biosimilar, CT­P41, and United States-licensed reference denosumab (US-denosumab) in healthy male Asian adults, considering also pharmacodynamic (PD) outcomes. RESEARCH DESIGN AND METHODS: This double-blind, two-arm, parallel-group, Phase 1 study randomized (1:1) healthy males to a single (60-mg) subcutaneous dose of CT­P41 or US-denosumab. Primary endpoints were area under the concentration - time curve (AUC) from time zero to infinity (AUC0-inf), AUC from time zero to the last quantifiable concentration (AUC0-last), and maximum serum concentration (Cmax). PK equivalence was determined if 90% confidence intervals (CIs) for ratios of geometric least-squares means (gLSMs) were within the predefined 80-125% equivalence margin. Secondary PK, PD, safety, and immunogenicity outcomes were also evaluated. RESULTS: Of 154 participants randomized (76 CT­P41; 78 US-denosumab), 151 received study drug (74 CT­P41; 77 US-denosumab). Primary and secondary PK results, PD results, safety, and immunogenicity were comparable between groups. Ninety percent CIs for ratios of gLSMs were within the predefined equivalence margin for AUC0-inf (100.4-114.7), AUC0-last (99.9-114.3), and Cmax (95.2-107.3). CONCLUSIONS: Following a single dose in healthy males, CT­P41 demonstrated PK equivalence with US-denosumab. TRIAL REGISTRATION: ClinicalTrials.gov: NCT06037395.