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

Change From Baseline in Health Assessment Questionnaire Disability Index (HAQ-DI) at Week 12

The Health Assessment Questionnaire - Disability Index is a patient-reported questionnaire that measures the degree of difficulty a person has in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and errands and chores) over the past week. Participants assessed their ability to do each task on a scale from 0 (without any difficulty) to 3 (unable to do). Scores were averaged to provide an overall score ranging from 0 to 3, where 0 represents no disability and 3 represents very severe, high-dependency disability. A negative change from Baseline in the overall score indicates improvement.

Time frame: Baseline and Week 12

Percentage of Participants Achieving a Static Investigator Global Assessment (sIGA) of Psoriasis of 0 or 1 and at Least a 2-point Improvement From Baseline (sIGA 0/1) at Week 16

The sIGA is a 5 point scale ranging from 0 to 4, based on the investigator's assessment of the average elevation, erythema, and scaling of all psoriatic lesions at the current visit. A lower score indicates less severe psoriasis (0 = clear, 1 = almost clear, 2 = mild, 3 = moderate and 4 = severe).

Time frame: Baseline and Week 16

Percentage of Participants Achieving Psoriasis Area Severity Index (PASI) 75 Response at Week 16

PASI is a composite score based on the percentage of the body surface area (BSA) affected by psoriasis and the intensity of erythema (reddening), induration (thickening or hardening of the skin), and desquamation (peeling of the skin) of lesions assessed at 4 anatomic sites (head, upper extremities, trunk, and lower extremities). At each location, the percentage of BSA involvement is assigned a score from 0 (no involvement) to 6 (90% to 100% involvement), and erythema, induration, and desquamation are scored on a scale from 0 (no symptoms) to 4 (very marked). The PASI score ranges from 0 (no psoriasis) to 72 (very severe psoriasis). A PASI-75 response is the percentage of participants who achieved at least a 75% reduction (improvement) from Baseline in PASI score.

Time frame: Baseline and Week 16

Change From Baseline in Short-Form 36 (SF-36) Physical Component Score (PCS) at Week 12

The Short Form 36-Item Health Survey (SF-36) Version 2 is a self-administered questionnaire that measures the impact of disease on overall quality of life during the past 4 weeks. The SF-36 consists of 36 questions in eight domains (physical function, pain, general and mental health, vitality, social function, physical and emotional health). The physical component score is a weighted combination of the 8 subscales with positive weighting for physical functioning, role-physical, bodily pain, and general health. The PCS was calculated using norm-based scoring so that 50 is the average score and the standard deviation equals 10. Higher scores are associated with better functioning/quality of life; a positive change from Baseline score indicates an improvement.

Time frame: Baseline and Week 12

Change From Baseline in Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) Score at Week 12

The FACIT-Fatigue questionnaire is a self-administered patient questionnaire that consists of 13 questions designed to measure the degree of fatigue experienced by participants in the previous 7 days, including physical fatigue (e.g., I feel tired), functional fatigue (e.g., trouble finishing things), emotional fatigue (e.g., frustration), and social consequences of fatigue (e.g., limits social activity). Participants respond to the questions on a scale from 0 'not at all' to 4 'very much'. The FACIT Fatigue score is computed by summing the item scores, after reversing those items that are worded in the negative direction. The FACIT-Fatigue subscale score ranges from 0 to 52, where higher scores represent less fatigue. A positive change from Baseline indicates improvement.

Time frame: Baseline and Week 12

Percentage of Participants Achieving Minimal Disease Activity (MDA) at Week 24

A participant was classified as achieving MDA if 5 of the following 7 criteria were met: * Tender joint count (out of 68 joints) ≤ 1 * Swollen joint count (out of 66 joints) ≤ 1 * PASI score ≤ 1 (score ranges from 0 - 72) or percent BSA involved with psoriasis ≤ 3% * Patient's assessment of pain ≤ 1.5 (NRS from 0 to 10) * Patient's Global Assessment of disease activity ≤ 2 (NRS from 0 to 10) * HAQ-DI score ≤ 0.5 (index score ranges from 0 to 3) * Leeds Enthesitis Index ≤ 1 (assesses the presence or absence of enthesitis at 3 bilateral sites, with an overall score range from 0 to 6)

Time frame: Week 24

Change From Baseline in Self-Assessment of Psoriasis Symptoms (SAPS) Score at Week 16

The SAPS is an 11-item self-assessment of psoriasis symptoms that includes questions on: pain, itching, redness, scaling, flaking, bleeding, burning, stinging, tenderness, pain due to skin cracking, and joint pain. Each item is scored from 0 to 10, with 0 being least severe and 10 being most severe. The total score is generated by summing the 11 items and ranges from 0 to 110 (worst). A negative change from Baseline in the total score indicates improvement.

Time frame: Baseline and Week 16

Percentage of Participants With an American College of Rheumatology 50% (ACR50) Response at Week 12

Participants who met the following 3 conditions for improvement from Baseline were classified as meeting the ACR50 response criteria: 1. ≥ 50% improvement in 68-tender joint count; 2. ≥ 50% improvement in 66-swollen joint count; and 3. ≥ 50% improvement in at least 3 of the 5 following parameters: * Physician global assessment of disease activity * Patient global assessment of disease activity * Patient assessment of pain * Health Assessment Questionnaire - Disability Index (HAQ-DI) * High-sensitivity C-reactive protein (hsCRP).

Time frame: Baseline and Week 12

Percentage of Participants With an American College of Rheumatology 70% (ACR70) Response at Week 12

Participants who met the following 3 conditions for improvement from Baseline were classified as meeting the ACR70 response criteria: 1. ≥ 70% improvement in 68-tender joint count; 2. ≥ 70% improvement in 66-swollen joint count; and 3. ≥ 70% improvement in at least 3 of the 5 following parameters: * Physician global assessment of disease activity * Patient global assessment of disease activity * Patient assessment of pain * Health Assessment Questionnaire - Disability Index (HAQ-DI) * High-sensitivity C-reactive protein (hsCRP).

Time frame: Baseline and Week 12

Percentage of Participants With an American College of Rheumatology 20% (ACR20) Response at Week 2

Participants who met the following 3 conditions for improvement from Baseline were classified as meeting the ACR20 response criteria: 1. ≥ 20% improvement in 68-tender joint count; 2. ≥ 20% improvement in 66-swollen joint count; and 3. ≥ 20% improvement in at least 3 of the 5 following parameters: * Physician global assessment of disease activity * Patient global assessment of disease activity * Patient assessment of pain * Health Assessment Questionnaire - Disability Index (HAQ-DI) * High-sensitivity C-reactive protein (hsCRP).

Time frame: Baseline and Week 2