A Study of Guselkumab in Participants With Active Psoriatic Arthritis and an Inadequate Response to Anti-Tumor Necrosis Factor Alpha (Anti-TNF Alpha) Therapy

The purpose of this study is to evaluate guselkumab efficacy versus placebo in participants with active psoriatic arthritis (PsA) and an inadequate response to Anti-Tumor Necrosis Factor Alpha (TNF-alpha) therapy by assessing the reduction in signs and symptoms of joint disease.

Psoriatic arthritis is a multi-faceted disease that impacts the joints, soft tissues, and skin, all of which not only results in functional disability and impaired quality of life, but participants with this disease also have increased mortality. Guselkumab is a monoclonal antibody that binds to human interleukin 23 (IL-23) and inhibits IL-23 specific intracellular signaling and subsequent activation and cytokine production. Investigation of guselkumab in this Phase 3b PsA clinical study is supported by the favorable efficacy and safety results from Phase 2 study of guselkumab in PsA and Phase 2 and Phase 3 studies in psoriasis including the subset of participants with PsA. The primary hypothesis is that guselkumab 100 milligram (mg) at Weeks 0, 4, and every 8 weeks (q8w) thereafter is superior to placebo which will be assessed by the proportion of participants achieving an American College of Rheumatology (ACR 20) response at Week 24. The study includes 2 periods: A 24-week double-blind, placebo-controlled period for the primary analysis of the efficacy and safety of guselkumab, compared with placebo and a 32-week active-treatment and safety follow-up period for additional analysis of the efficacy and safety of guselkumab. Safety will be monitored throughout the study (Up to Week 56).