Pharmacokinetic equivalence of CT‐P39 and reference omalizumab in healthy individuals: A randomised, double‐blind, parallel‐group, Phase 1 trial

BACKGROUND: CT‐P39 is being developed as a biosimilar of reference omalizumab. This study aimed to assess the pharmacokinetic equivalence of CT‐P39 to European Union‐approved and United States‐licensed reference omalizumab (EU‐ and US‐omalizumab, respectively). METHODS: This two‐part, randomised, parallel‐group, double‐blind Phase 1 trial (NCT04018313) was conducted in healthy individuals with a total immunoglobulin E (IgE) level ≤100 international units (IU)/ml at screening. In part 2, described herein, participants were randomised (1:1:1) to receive a single 150 mg subcutaneous dose of CT‐P39, EU‐omalizumab, or US‐omalizumab. The primary endpoint was pharmacokinetic equivalence in terms of area under the concentration–time curve (AUC) from time zero to the last quantifiable concentration (AUC(0–last)), AUC from time zero to infinity (AUC(0‐inf)), and maximum serum concentration (C (max)). Equivalence was concluded if 90% confidence intervals (CIs) of the geometric least‐squares means ratios were contained within the predefined 80%–125% equivalence margin. Additional pharmacokinetic parameters, pharmacodynamics, safety, and immunogenicity were also evaluated. RESULTS: Overall, 146 participants were randomised (CT‐P39, N = 47; EU‐omalizumab, N = 49; US‐omalizumab, N = 50). For all primary pharmacokinetic parameters, 90% CIs for pairwise treatment comparisons were within the 80%–125% equivalence margin, demonstrating pharmacokinetic equivalence. Decreases in free IgE and increases in total IgE serum concentrations were comparable across groups. CT‐P39 was well tolerated. Safety endpoints were comparable across groups: there were no treatment‐related serious adverse events, deaths, or discontinuations due to treatment‐emergent adverse events. CONCLUSIONS: CT‐P39 was well tolerated and demonstrated pharmacokinetic equivalence with EU‐omalizumab and US‐omalizumab following administration of a single dose in healthy individuals.