Speed and Cumulative Responses According to Body Regions in Patients with Moderate-to-Severe Plaque Psoriasis Treated with Ixekizumab (Interleukin-17A Antagonist) versus Guselkumab (Interleukin-23p19 Inhibitor)

Introduction When assessing the effect of a therapy for psoriasis (PsO), it is important to consider speed of response and cumulative response. However, responses among biologics may differ by body regions. This post hoc analysis compares speed of response and cumulative response for ixekizumab (IXE), an interleukin-17A antagonist, and guselkumab (GUS), an interleukin-23p19 inhibitor, in different body regions of patients with moderate-to-severe plaque PsO participating in the IXORA-R study, up to week 24. Methods The IXORA-R design has been previously described. Patients received the respective on-label dosing of IXE or GUS. The median time to first Psoriasis Area and Severity Index (PASI) 50, 75, 90, and 100 response (50%, 75%, 90%, and 100% improvement from baseline, respectively) and the cumulative days with clear skin for PASI 50, 75, 90, and 100 responses were assessed in four body regions: head, trunk, upper extremities, and lower extremities. Results A total of 1027 patients were enrolled and received IXE ( N = 520) or GUS ( N = 507). Median time to first PASI 50, 75, 90, and 100 response was shortest in the head region, followed by the remaining body regions in both IXE and GUS cohorts. In each body region, IXE was significantly faster than GUS ( p < 0.001) in achieving PASI 50, 75, 90, and 100. Through 24 weeks, the number of days with clear skin for PASI 90 and 100 was greater in the head region, followed by trunk, upper extremities, and lastly lower extremities in both IXE and GUS cohorts. In each body region, through 24 weeks, patients on IXE experienced a significantly higher number of days with clear skin for PASI 50, 75, 90, and 100 than patients on GUS ( p < 0.01). Conclusions As compared to GUS, IXE provided a faster skin clearance and more days with clear skin in all body regions of patients with moderate-to-severe plaque PsO through 24 weeks. Trial Registration Number https://www.clinicaltrials.gov/ : NCT03573323 (IXORA-R).