A Study of Ustekinumab or Guselkumab in Pediatric Participants With Active Juvenile Psoriatic Arthritis

Inclusion Criteria: * Diagnosis of juvenile psoriatic arthritis (jPsA) by Vancouver criteria with exclusion of enthesitis-related arthritis (ERA). Diagnosis made \>=3 months (that is, 90 days) prior to screening * Active disease in at least greater than or equal to (\>=) 3 joints at screening and at week 0 (defined as swelling or loss of motion with pain and/or tenderness. Swelling alone meets the criteria for an active arthritic joint. In the absence of swelling, loss of motion with pain or tenderness or both pain and tenderness meet the criteria for an active arthritic joint * Have active disease despite previous non-biologic disease modifying anti-rheumatic drug (DMARD) and/or non-steroidal anti-inflammatory drug (NSAID) therapy: Non-biologic DMARD therapy is defined as taking a non-biologic DMARD for at least 12 weeks or evidence of intolerance; NSAID therapy is defined as taking an NSAID for at least 4 weeks or evidence of intolerance * Concurrent use of methotrexate, sulfasalazine, leflunomide, oral corticosteroids or NSAIDs is permitted but must be on stable dose * Participants must be up to date with all immunizations in agreement with current local immunization guidelines for immunosuppressed patients * Prior use of anti-TNFα agents, IL-17 inhibitors and other biologics (except non-responders to IL-23 inhibitors) and JAK inhibitors are permitted with sufficient washout period Exclusion Criteria: * Participants with enthesitis-related arthritis (ERA) * Have a histo…