Objective: To use data from a phase II clinical trial to evaluate the effect of ustekinumab, a human immunoglobulin monoclonal antibody that binds with high affinity to the shared p40 subunit of human interleukins-12 and -23, on physical disability and health-related quality of life (HRQoL) in patients with psoriatic arthritis (PsA).
Methods: In this multicenter, double-blind, placebo-controlled, crossover study of ustekinumab, patients with active PsA were randomized (1:1 ratio) to receive either ustekinumab at weeks 0, 1, 2, and 3 and placebo at weeks 12 and 16 (n = 76) or placebo at weeks 0, 1, 2, and 3 and ustekinumab at weeks 12 and 16 (n = 70). Physical function was assessed using the disability index from the Health Assessment Questionnaire-Disability Index (HAQ-DI) in all randomized patients. HRQoL was evaluated using the Dermatology Life Quality Index (DLQI) in a subset of patients (84.9%) with at least 3% body surface area (BSA) psoriasis involvement at baseline.
Results: At baseline, overall mean HAQ-DI and DLQI scores were 0.9 and 11.5, respectively, indicating impaired physical function and moderate effect on HRQoL. At week 12, ustekinumab patients had significantly more improvement (decrease) in the mean HAQ-DI (-0.31) and DLQI (-8.6) scores versus placebo (-0.04 and -0.8, respectively; p < 0.001 for both comparisons). At week 12, 58.7% (37/63) of ustekinumab-treated patients had a DLQI score of 0 or 1 (no negative effect of disease or treatment on HRQoL) versus 5.5% (3/55) for placebo (p < 0.001). The results also indicated a positive but weak correlation between improvement in physical function and HRQoL, pain, and skin response as well as between improvement in joint and skin responses in patients receiving ustekinumab or placebo. Potential limitations of the study include the short duration of the placebo-controlled period and the relatively small patient population.
Conclusion: Ustekinumab significantly improved physical function and HRQoL in patients with PsA and psoriasis involving at least 3% BSA.