Background/Purpose: Psoriatic arthritis (PsA) is a chronic immune-mediated inflammatory disease associated with psoriasis, peripheral arthritis, enthesitis, dactylitis, and spondylitis. PsA has a significant negative impact on patients’ quality of life, physical function, and work productivity. Ixekizumab is an IgG4 monoclonal antibody that binds with high affinity and specificity to the proinflammatory cytokine IL-17A, currently under investigation for the treatment of PsA.

Methods: In this phase 3 trial, 417 biologic disease-modifying antirheumatic drug (bDMARD)-naive patients with active PsA were randomized to receive up to 24 weeks of placebo (N=106); adalimumab 40 mg once every 2 weeks (Q2W; N=101) (active control); or ixekizumab 80 mg every 4 weeks (Q4W; N=107) or Q2W (N=103) following a 160 mg starting dose at Week 0. Patient Reported Outcomes (PROs) included, but were not limited to, Health Assessment Questionnaire – Disability Index (HAQ-DI), Short Form-36 Health Survey Physical Component Score (SF-36 PCS), European Quality of Life 5 Dimensions Visual Analog Scale (EQ-5D VAS), and Work Productivity and Activity Impairment-Specific Health Problem (WPAI-SHP), and were analyzed using the intent-to-treat population. Continuous PRO data were evaluated using a mixed-effects model for repeated measures. The model included data up to Week 24 for all patients except inadequate responders (IRs) for whom data after Week 16 were excluded. Categorical PRO data were compared using a logistic regression model; missing values were imputed with the non-responder imputation method, treating IRs as non-responders.

Results: Across treatment groups, baseline demographics and clinical characteristics were generally similar; population mean baseline scores for HAQ-DI, SF-36 PCS, and EQ-5D VAS were 1.17, 33.63, and 55.4, respectively, indicating reduced physical function and quality of life. Mean baseline scores for the individual components of the WPAI-SHP assessment were 8.6 for Absenteeism, 36.6 for Presenteeism, 38.9 for Work Productivity, and 47.0 for Activity Impairment. At Week 12, patients treated with either ixekizumab 80 mg Q4W or Q2W reported significantly greater improvements compared to placebo in HAQ-DI, SF-36, EQ-5D VAS, and WPAI-SHP (all components, except Absenteeism); improvements were maintained through Week 24 for all treatment groups (Table). Additionally at Weeks 12 and 24, the percentage of patients with a baseline HAQ-DI score ≥0.35 achieving minimally clinically important difference (MCID) for HAQ-DI (improvement from baseline in HAQ-DI ≥0.35) was significantly greater in both ixekizumab treatment arms compared to placebo (Table).

Conclusion: In bDMARD-naive patients with active PsA, ixekizumab significantly improved quality of life, physical function and work productivity.

Table. PROs at Weeks 12 and 24 by treatment group.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/ixekizumab-improves-physical-function-quality-of-life-and-work-productivity-in-biologic-disease-modifying-antirheumatic-drug-naive-patients-with-active-psoriatic-arthritis/