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.