A Study to Determine the Efficacy and Safety of Deucravacitinib Compared With Placebo in Participants With Active Psoriatic Arthritis (PsA) Who Are Naïve to Biologic Disease Modifying Anti-rheumatic Drugs or Had Previously Received TNFα Inhibitor Treatment

Inclusion Criteria:

1. Diagnosed to have psoriatic arthritis (PsA) of at least 3 months duration at Screening
2. Meets the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria at Screening
3. Active plaque psoriatic skin lesion(s) or documented medical history of plaque psoriasis (PsO) at Screening
4. Active arthritis as shown by ≥ 3 swollen joints and ≥ 3 tender joints at Screening and Day 1
5. Participant has high sensitivity C-reactive protein (hsCRP) ≥ 3 mg/L at Screening
6. Must have completed the week 52 treatment for the optional open-label long-term extension period

Exclusion Criteria:

1. Nonplaque psoriasis at Screening or Day 1
2. Other autoimmune condition such as systemic lupus erythematous, mixed connective tissue disease, multiple sclerosis, or vasculitis
3. History of or current inflammatory joint disease other than PsA (e.g., gout, reactive arthritis, rheumatoid arthritis, ankylosing spondylitis, Lyme disease)
4. Active fibromyalgia
5. Received an approved or investigational biologic therapy for the treatment of PsA or PsO

Other protocol-defined inclusion/exclusion criteria apply