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 at least 12 weeks 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
Inadequate response (>= 4 weeks) or intolerance to >=1 non-steroidal anti-inflammatory drug (NSAID)
Inadequate response (>=12 weeks) or intolerance to >=1 non-biological disease modifying anti-rheumatic drug (DMARD)
If using corticosteroids; must be on a stable dose of less than or equal to (<=) 10 milligrams (mg) prednisone equivalent or 0.20 mg per kilograms (kg) per day (whichever is less) for >=4 weeks before first administration of study intervention. If currently not using corticosteroids, the participant must have not received corticosteroids (intra articular, intramuscular, or intravenous [IV] corticosteroids [including intramuscular corticotropin]) for >=4 weeks before the first dose administration

Exclusion Criteria:

Participants with ERA
Have a history of latent or active granulomatous infection, including tuberculosis (TB), histoplasmosis, or coccidioidomycosis prior to screening
Have a history of, or ongoing, chronic or recurrent infectious disease
Has evidence of herpes zoster infection within 8 weeks prior to Week 0
Have a known history of hepatitis C infection or test positive at screening