A Study Evaluating the Efficacy and Safety of Guselkumab Administered Subcutaneously in Participants With Active Psoriatic Arthritis

Inclusion Criteria

• •Have a diagnosis of Psoriatic Arthritis (PsA) for at least 6 months before the first administration of study agent and meet Classification criteria for Psoriatic Arthritis (CASPAR) at screening
• •Have active PsA as defined by: at least 5 swollen joints and at least 5 tender joints at screening and at baseline, and CRP greater than or equal to (\>=) 0.6 milligram per deciLitre (mg/dL) at screening from the central laboratory
• •Have at least 1 of the PsA subsets: distal interphalangeal joint involvement, polyarticular arthritis with absence of rheumatoid nodules, arthritis mutilans, asymmetric peripheral arthritis, or spondylitis with peripheral arthritis (confirmation of sacroiliitis should be performed at the screening visit by a locally performed pelvic x-ray \[single anterior-posterior view\] unless a pelvic or SI joint x-ray or pelvic magnetic resonance imaging (MRI) has been previously performed. Results must be documented)
• •Have active plaque psoriasis, with at least one psoriatic plaque of \>= 2 centimeter (cm) diameter or nail changes consistent with psoriasis or documented history of plaque psoriasis
• •Have active PsA despite previous non-biologic disease-modifying antirheumatic drug (DMARD), apremilast, and/or nonsteroidal anti-inflammatory drug (NSAID) therapy