Pharmacokinetics, Safety, and Efficacy of Ixekizumab in Chinese Patients with Moderate-to-Severe Plaque Psoriasis: A Phase 1, Single- and Multiple-Dose Study

IntroductionWe evaluated the pharmacokinetics (PK), safety, and efficacy of ixekizumab, a high-affinity monoclonal antibody that selectively targets interleukin-17A, in Chinese patients with moderate-to-severe psoriasis.MethodsIn this phase 1, multicenter, open-label study, adults (& GE; 18 years) diagnosed with moderate-to-severe plaque psoriasis for & GE; 6 months involving & GE; 10% of their body surface area received ixekizumab 80 mg by subcutaneous injection and were observed for 20 weeks (single-dose phase) and then an initial dose of 160 mg followed by randomization (1:1) to 80 mg ixekizumab every 2 weeks (IXE Q2W) or every 4 weeks (IXE Q4W) for an 8-week treatment period (multiple-dose phase).ResultsThe median time to maximum observed ixekizumab concentrations occurred 2-4 days after dosing and the geometric mean half-life was 15-16 days, after single (n = 12) and multiple (n = 29) doses. Approximately linear pharmacokinetics were observed between the 80 and 160 mg single doses. Steady-state systemic exposure to ixekizumab during a dosing interval was similar with the IXE Q2W and IXE Q4W regimens, with estimates of 224 & mu;g & BULL;day/mL and 213 & mu;g & BULL;day/mL for the area under the concentration-time curve from time 0 to 14 days post-dose and 0 to 28 days post-dose, respectively. Safety was consistent with the established safety profile of ixekizumab. At week 12 after multiple doses, the proportions of patients achieving a 75% or 90% improvement in Psoriasis Area and Severity Index score were 100% and 86% for IXE Q2W, respectively, and 93% and 80% for IXE Q4W, respectively. A Static Physician's Global Assessment score of 0 or 1 was achieved in 100% and 87% with IXE Q2W and IXE Q4W, respectively.ConclusionsThe PK of ixekizumab in Chinese patients with moderate-to-severe plaque psoriasis was comparable to findings in global populations. After IXE Q2W or IXE Q4W for 12 weeks, clinically relevant treatment responses and an acceptable safety profile were observed.