Responses to ixekizumab in male and female patients with psoriatic arthritis : results from two randomized, phase 3 clinical trials

INTRODUCTION: Differences in psoriatic arthritis (PsA) treatment response between sexes for ixekizumab, an interleukin-17A antagonist, are largely unexplored. This analysis used data from randomized clinical trials (RCTs) evaluating ixekizumab to study differences in treatment response between male and female patients with PsA. METHODS: We used pooled data from patients enrolled in SPIRIT-P1 and SPIRIT-P2 (NCT01695239 and NCT02349295, respectively), phase 3 RCTs evaluating ixekizumab every 4 and 2 weeks in patients with active PsA. Subgroups of patients were defined by sex (male, female). Efficacy was measured by the proportion of male and female patients achieving American College of Rheumatology 20%/50%/70% improvement criteria (ACR20/50/70), minimal disease activity or very low disease activity (MDA/VLDA), and Disease Activity Index for Psoriatic Arthritis (DAPSA) scores representing low disease activity (LDA) or remission through week 156. Changes from baseline in components of the above measures were also assessed through week 156. RESULTS: Compared to male patients at baseline, female patients were older, had higher body mass index and lower C-reactive protein levels, and had worse tender joint count, Health Assessment Questionnaire Disability Index, and Leeds Enthesitis Index scores. Through week 156, female patients in all treatment arms had lower response rates than male patients in all analyzed composite measures (ACR20/50/70; MDA/VLDA; DAPSA LDA/remission), with significant differences observed at multiple timepoints in both ixekizumab treatment arms. Female patients also had smaller numeric changes from baseline in the composite measures’ individual components. CONCLUSION: Compared to female patients, male patients had greater response rates in ACR20/50/70, MDA/VLDA, and DAPSA LDA/remission and numerically larger improvements in these measures’ individual components, although clinical significance is unclear. Continued efforts to understand sex differences in treatment response may provide insights that can help optimize clinical decision making. TRIAL REGISTRATION: ClinicalTrials.gov identifiers, NCT01695239 and NCT02349295. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40744-022-00445-w

Efficacy and Safety of Ixekizumab in Patients with Psoriatic Arthritis and Inadequate Response to TNF Inhibitors : 3-Year Follow-Up (SPIRIT-P2)

Ixekizumab is a high-affinity monoclonal antibody that selectively targets interleukin-17A. The objective of this study was to assess the long-term efficacy and safety (to week 156) of ixekizumab in patients with active psoriatic arthritis and inadequate response or intolerance to one or two tumor necrosis factor inhibitors. In the SPIRIT-P2 study (ClinicalTrials.gov ID: NCT02349295), patients were randomized to placebo or ixekizumab 80 mg every 4 weeks (IXE Q4W) or every 2 weeks (IXE Q2W) following a 160-mg starting dose. During the extension period (weeks 24-156), patients maintained their original ixekizumab dose, and placebo patients received IXE Q4W or IXE Q2W (1:1). Exposure-adjusted incidence rates (IRs) per 100 patient-years (PY) are presented. Of 363 patients enrolled in the study, 310 entered the extension period. In all patients treated with IXE Q4W and IXE Q2W at week 0, responses persisted to week 156. At week 156, clinical responses (observed) in patients treated with IXE Q4W and IXE Q2W were assessed [American College of Rheumatology (ACR) response criteria and minimal disease activity (MDA) criteria]: 84 and 85% showed 20% improvement (ACR20); 60 and 58% showed 50% improvement (ACR50); 35 and 47% showed 70% improvement (ACR70), respectively; and 48 and 54% showed MDA. Placebo patients re-randomized to ixekizumab also demonstrated sustained efficacy, as measured by ACR and MDA responses. In the All Ixekizumab Exposure Safety Population (n = 337), with 644 PY of ixekizumab exposure, treatment-emergent adverse events (TEAEs) were reported by 286 patients (44.4 IR). The most common TEAEs were upper respiratory tract infection (9.80 IR), nasopharyngitis (8.2 IR), sinusitis (6.2 IR), and bronchitis (4.5 IR). Serious adverse events were reported by 42 (6.5 IR) patients (included 3 deaths and 10 infections). In this 156-week study of ixekizumab, improvements in signs and symptoms of psoriatic arthritis and the safety profile remained consistent with those in previous reports. ClinicalTrials.gov identifier: NCT02349295. The online version of this article (10.1007/s40744-020-00261-0) contains supplementary material, which is available to authorized users