CT‐P39 Compared With Reference Omalizumab in Chronic Spontaneous Urticaria: Results From a Double‐Blind, Randomized, Active‐Controlled, Phase 3 Study

Abstract

BackgroundThis study compared the therapeutic equivalence of CT‐P39 (an omalizumab biosimilar) and EU‐approved reference omalizumab (ref‐OMA) in patients with chronic spontaneous urticaria.MethodsThis double‐blind, randomized, active‐controlled Phase 3 study (NCT04426890) included two 12‐week treatment periods (TPs). In TP1, patients received CT‐P39 300 mg, ref‐OMA 300 mg, CT‐P39 150 mg, or ref‐OMA 150 mg. In TP2, patients treated with ref‐OMA 300 mg were rerandomized to CT‐P39 300 mg or ref‐OMA 300 mg; patients initially randomized to CT‐P39 300 mg continued this regimen; and patients initially randomized to CT‐P39 or ref‐OMA 150 mg received 300 mg dosing with the same drug. The primary endpoint for the assessment of therapeutic equivalence of CT‐P39 300 mg and ref‐OMA 300 mg was change from baseline in weekly itch severity score (ISS7) at week 12.ResultsIn TP1, 619 patients were randomized (CT‐P39 300 mg, n = 204; ref‐OMA 300 mg, n = 205; CT‐P39 150 mg, n = 107; ref‐OMA 150 mg, n = 103). Equivalence was demonstrated between CT‐P39 300 mg and ref‐OMA 300 mg for mean change from baseline in ISS7 at week 12; confidence intervals (CIs) were within predefined equivalence margins: global analysis: treatment difference 0.77, 95% CI –0.37 to 1.90; US analysis: treatment difference 0.70, 90% CI –0.22 to 1.63. The proportion of patients experiencing ≥ 1 treatment‐related adverse event was comparable across groups. Secondary efficacy, quality of life, pharmacokinetic, safety, and immunogenicity outcomes were comparable between groups at a given dose level, with no evident impact of switching.ConclusionsEquivalent efficacy was observed between CT‐P39 and ref‐OMA, with comparable safety also evident.