A Study Comparing Upadacitinib (ABT-494) to Placebo in Participants With Active Psoriatic Arthritis Who Have a History of Inadequate Response to at Least One Biologic Disease Modifying Anti-Rheumatic Drug (bDMARD)

Inclusion Criteria:

   - Clinical diagnosis of PsA with symptom onset at least 6 months prior to the Screening
   Visit and fulfillment of the Classification Criteria for PsA (CASPAR) criteria

   - Participant has active disease at Baseline defined as >= 3 tender joints (based on 68
   joint counts) and >= 3 swollen joints (based on 66 joint counts) at Screening and
   Baseline Visits

   - Diagnosis of active plaque psoriasis or documented history of plaque psoriasis

   - Participant has had an inadequate response (lack of efficacy after a minimum 12 week
   duration of therapy) or intolerance to treatment with at least 1 bDMARD.

Exclusion Criteria:

   - Prior exposure to any Janus Kinase (JAK) inhibitor (including but not limited to
   ruxolitinib, tofacitinib, baricitinib, and filgotinib)

   - Current treatment with > 2 non-biologic DMARDs or use of DMARDs other than
   methotrexate (MTX), sulfasalazine (SSZ), leflunomide (LEF), apremilast,
   hydroxychloroquine (HCQ), bucillamine or iguratimod or use of MTX in combination with
   LEF at Baseline.

   - History of fibromyalgia, any arthritis with onset prior to age 17 years, or current
   diagnosis of inflammatory joint disease other than PsA (including, but not limited to
   rheumatoid arthritis, gout, overlap connective tissue diseases, scleroderma,
   polymyositis, dermatomyositis, systemic lupus erythematosus). Prior history of
   reactive arthritis or axial spondyloarthritis including ankylosing spondylitis and
   non-radiographic axial spondyloarthritis is permitted if documentation of change in
   diagnosis to PsA or additional diagnosis of PsA is made. Prior history of fibromyalgia
   is permitted if documentation of change in diagnosis to PsA or documentation that the
   diagnosis of fibromyalgia was made incorrectly.