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

Inclusion Criteria * Diagnosed to have psoriatic arthritis (PsA) of at least 3 months duration at screening. * Meets the Classification Criteria for Psoriatic Arthritis at Screening. * Active plaque psoriatic skin lesion(s) or documented medical history of plaque psoriasis (PsO) at screening. * Active arthritis as shown by ≥ 3 swollen joints and ≥ 3 tender joints at Screening and day 1. * Participant has high sensitivity C-reactive protein (hsCRP) ≥ 3 mg/L at Screening. * ≥ 1 PsA-related hand and/or foot joint erosion on X-ray during Screening Period that is confirmed by central reading. * Must have completed the week 52 treatment for the optional open-label long-term extension period. Exclusion Criteria * Nonplaque psoriasis at screening or day 1. * Other autoimmune condition such as systemic lupus erythematous, mixed connective tissue disease, multiple sclerosis, or vasculitis. * History of or current inflammatory joint disease other than PsA (e.g., gout, reactive arthritis, rheumatoid arthritis, ankylosing spondylitis, Lyme disease). * Active fibromyalgia. * Received an approved or investigational biologic therapy for the treatment of PsA or PsO. * Other protocol-defined Inclusion/Exclusion criteria apply.