A Phase 3 Multicenter, Open-label Study to Evaluate the Efficacy, Pharmacokinetics, Safety, and Immunogenicity of Subcutaneously Administered Ustekinumab or Guselkumab in Pediatric Participants With Active Juvenile Psoriatic Arthritis

1. >=5 to <18 years of age, inclusive.
2. Diagnosis of jPsA by Vancouver inclusion criteria, with exclusion of ERA.
Diagnosis made >= 3 months (ie. 90 days) prior to screening. Arthritis plus
psoriasis, or arthritis plus >=2 of the following: dactylitis, nail pits, family
history of psioriasis in a first or second-degree relative, psoriasis-like
rash.
3. Active disease in >=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.
4. Medically stable on the basis of physical examination, medical history, and
vital signs performed at screening. Any abnormalities must be determination
must be recorded in the participant's source documents and initialed by the
investigator.
5. Medically stable on the basis of clinical laboratory tests performed at
screening. If the results of the serum chemistry panel or hematology are
outside the normal reference ranges, the participant may be included only if
the investigator judges the abnormalities or deviations from normal to not be
clinically significant or to be appropriate and reasonable for the population
under study. This determination must be recorded in the participant's source
documents and initialed by the
investigator.

1. Participants with enthesitis-related arthritis (ERA; see definition in
Appendix 17 of the study protocol)
2. Taken any disallowed therapies as noted in Section 6.8, Concomitant Therapy
within the timeframe specified before the planned first dose of study
intervention.
3. If participants were non-responders to previously received IL-23 blockers
including guselkumab, tildrakizumab (MK3222) and risankizumab (BI-655066).
Prior non-response to an anti-TNFα inhibitor, an IL-17 inhibitor or a Janus
kinase (JAK) inhibitor is not an exclusion.
Participants who previously discontinued ustekinumab for intolerance or
inadequate response may be enrolled into the guselkumab cohort.
Patients who previously discontinued guselkumab due to intolerance may be
enrolled into the ustekinumab cohort. Participants who previously discontinued
tildrakizumab or risankizumab due to
intolerance may be enrolled into either cohort.
4. Received an investigational intervention (including investigational
vaccines) or used an invasive investigational medical device within 4 weeks or
5 half-lives (whichever is longer) before the planned first dose of either
study intervention or is currently enrolled in another study using an
investigational intervention or procedure. Receipt of an investigational
vaccine for COVID-19 is not an automatic exclusion criterion; discuss with
medical monitor.
5. Have a history of latent or active granulomatous infection, including TB,
histoplasmosis, or coccidioidomycosis, prior to screening. An exception is made
for participants currently receiving treatment for latent TB with no evidence
of active TB, or who have a history of latent TB and documentation of having
completed appropriate treatment for latent TB prior to the first administration
of either study intervention (Section 5.2, Exclusion criterion 14b of the study
protocol).