A Study of Guselkumab Administered Subcutaneously in Bio-naive Participants With Active Psoriatic Arthritis Axial Disease

The purpose of this study is to evaluate the efficacy of guselkumab treatment in participants with active psoriatic arthritis (PsA) axial disease by assessing reduction in axial symptoms and inflammation.

PsA is a chronic inflammatory musculoskeletal disease that has 6 disease domains, and axial disease represents one of the domains. Guselkumab is a fully human immunoglobulin (Ig) G1 lambda monoclonal antibody (mAb) that by binding to the p19 protein subunit of interleukin (IL)-23, blocks the binding of extracellular IL-23 to the cell surface IL-23 receptor, inhibiting IL-23-mediated intracellular signaling, activation, and cytokine production. This study will consist of a screening phase (up to 6 weeks), a treatment phase (up to 48 weeks, including a placebo-controlled period from Week 0 to Week 24 and an active-controlled treatment phase from Week 24 to Week 48), and a safety follow-up phase (up to Week 60). The efficacy assessments will include assessment such as Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score and the safety assessments will include evaluations of physical examinations, vital signs, electrocardiograms, clinical laboratory tests, and adverse events. The overall duration of the study will be up to 14 months.

Inclusion Criteria: * Have a diagnosis of psoriatic arthritis (PsA) for at least 6 months prior to the first administration of study intervention and meet classification criteria for psoriatic arthritis (CASPAR) criteria at screening * Have active PsA as defined by: a) at least 3 swollen joints and at least 3 tender joints at screening and at baseline and b) C-reactive protein (CRP) greater than or equal to (\>=) 0.3 milligram/deciliter (mg/dL) at screening from the central laboratory, and despite previous non-biologic disease modifying antirheumatic drug (DMARD), apremilast, and/or nonsteroidal anti-inflammatory drug (NSAID) therapy * Have magnetic resonance imaging (MRI)-confirmed PsA axial disease (positive MRI spine and/or sacroiliac \[SI\] joints, shown by a Spondyloarthritis Research Consortium of Canada \[SPARCC\] score of \>= 3 in either the spine or the sacroiliac joints) * Have a Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score of at least 4, and have a spinal pain score (on a visual analog scale \[VAS\]) of at least 4 * Have active plaque psoriasis, with at least 1 psoriatic plaque of \>= 2 centimeter (cm) diameter and/or nail changes consistent with psoriasis, or documented history of plaque psoriasis Exclusion Criteria: * Has known allergies, hypersensitivity, or intolerance to guselkumab or its excipients * Has other inflammatory diseases that might confound the evaluations of benefit of guselkumab therapy, including but not limited to rheumatoid arthritis (RA), ankylosing spondylitis (AS)/non-radiographic-axial spondyloarthritis (this does not include a primary diagnosis of PsA with spondylitis), systemic lupus erythematosus, or Lyme disease * Has previously received any biologic treatment * Has ever received a Janus kinase (JAK) inhibitor including but not limited to tofacitinib, baricitinib, filgotinib, peficitinib, decernotinib, upadacitinib or any other investigational JAK inhibitor * Has received any systemic immunosuppressants (example, azathioprine, cyclosporine, 6 thioguanine, mercaptopurine, mycophenolate mofetil, hydroxyurea, tacrolimus) within 4 weeks of the first administration of study intervention