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

Inclusion Criteria:

• Have a diagnosis of psoriatic arthritis (PsA) for at least 6 months prior to thefirst administration of study intervention and meet classification criteria forpsoriatic arthritis (CASPAR) criteria at screening

• Have active PsA as defined by: a) at least 3 swollen joints and at least 3 tenderjoints at screening and at baseline and b) C-reactive protein (CRP) greater than orequal to (>=) 0.3 milligram/deciliter (mg/dL) at screening from the centrallaboratory, 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 MRIspine and/or sacroiliac [SI] joints, shown by a Spondyloarthritis ResearchConsortium of Canada [SPARCC] score of >= 3 in either the spine or the sacroiliacjoints)

• 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 historyof plaque psoriasis

Exclusion Criteria:

• Has known allergies, hypersensitivity, or intolerance to guselkumab or itsexcipients

• Has other inflammatory diseases that might confound the evaluations of benefit ofguselkumab therapy, including but not limited to rheumatoid arthritis (RA),ankylosing spondylitis (AS)/non-radiographic-axial spondyloarthritis (this does notinclude 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 totofacitinib, baricitinib, filgotinib, peficitinib, decernotinib, upadacitinib or anyother investigational JAK inhibitor

• Has received any systemic immunosuppressants (example, azathioprine, cyclosporine, 6thioguanine, mercaptopurine, mycophenolate mofetil, hydroxyurea, tacrolimus) within 4 weeks of the first administration of study intervention