WASHINGTON, DC—At the 2016 ACR/ARHP Annual Meeting, researchers presented data which showed treatment with subcutaneous guselkumab resulted in more patients with psoriatic arthritis achieving at least a 20% improvement in signs and symptoms of disease (ACR20) at Week 24 compared to placebo.

Guselkumab, an anti-interleukin (IL)-23 monoclonal antibody, was evaluated in a Phase 2, randomized, double-blind, placebo-controlled multicenter trial (n=149) designed to evaluate its safety and efficacy vs. placebo in adults with active psoriatic arthritis and a body surface area (BSA) of plaque psoriasis ≥3%, despite current or prior treatment with standard-of-care therapies, including those previously exposed to anti-TNF alpha agents. 

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Study patients were randomized to either guselkumab 100mg or placebo at Weeks 0,4, and then every 8 weeks thereafter, followed by a 20-week active treatment period. Patients with <5% improvement form baseline in both swollen and tender joint counts were eligible at Week 16 for early escape to open-label ustekinumab. Then at Week 24, remaining placebo patients crossed-over to guselkumab 100mg, which was given again at Week 28, then every 8 weeks thereafter through Week 44. 

In the study, 58% of patients receiving guselkumab achieved ≥20% improvement in signs and symptoms of disease (ACR20) at Week 24, the primary endpoint, vs. 18.4% of patients receiving placebo (P<0.001). 

Statistically significant improvements were also seen for all secondary endpoints compared to placebo, which included physical function, psoriatic skin lesions, and other health-related outcomes. 

Treatment with guselkumab led to significantly greater improvements in enthesitis and dactylitis, and in health-related quality of life as measured by SF-36 physical component summary scores and mental component summary scores vs. patients treated with placebo at Week 24.   Also, a higher percentage of patients treated with guselkumab achieved minimal disease activity (MDA) vs. placebo at Week 24 (23% vs. 2%; P=0.001).

Lead author, Atul Deodhar, MD, MRCP, FACP, FACR, Professor of Medicine, Oregon Health & Science University added, “It’s encouraging to see how well patients responded to guselkumab in this study with respect to improvements in disease signs and symptoms, as early as week four, and in other health-related quality of life outcomes, including measures of physical and mental health.”