Effectiveness and Continuous 2-Week Dosing of Ixekizumab in Practice: A Multicenter Study

Ixekizumab, an IL-17A monoclonal antibody, is administered in Japan as 160 mg initially, then 80 mg every 2 weeks (Q2W) through Week 12 and every 4 weeks thereafter. Continued Q2W dosing is allowed if response is insufficient at Week 12. This study evaluated long-term effectiveness and factors associated with sustained Q2W dosing in real-world practice. Data from the Western Japan Psoriasis Registry were analyzed for patients treated > 1 year. Outcomes included achievement of body surface area (BSA) ≤ 3% and physician global assessment (PGA) 0/1. Logistic regression adjusted for age, sex, and psoriatic arthritis identified predictors of Q2W maintenance. Among 114 patients (35 for 1 year, 79 for > 1 year; mean duration 35 months), BSA ≤ 3% was achieved by 88.6% and 79.7%, and PGA 0/1 by 82.9% and 75.9%, respectively. Q2W dosing continued in 44 patients (38.6%). Higher body mass index (OR 1.11, 95% CI 1.01-1.23) and prior biologic therapy (OR 2.37, 95% CI 1.01-5.58) were significant predictors; smoking, alcohol, baseline severity, and nail involvement were not. Ixekizumab showed durable effectiveness, and sustained Q2W dosing was a practical option for patients with higher BMI or prior biologic exposure.