A Study Comparing Risankizumab to Placebo in Participants With Active Psoriatic Arthritis (PsA) Who Have a History of Inadequate Response to or Intolerance to at Least One Disease Modifying Anti-Rheumatic Drug (DMARD) Therapy

Percentage of Participants With an ACR20 Response at Week 16

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 16

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 ≤ 15 (VAS from 0 to 100) * Patient's Global Assessment of disease activity ≤ 20 (VAS from 0 to 100) * 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, for an overall score range from 0 to 6)

Time frame: Week 24

Change From Baseline in Modified Nail Psoriasis Severity Index (mNAPSI) Score at Week 24

The investigator assessed each fingernail for onycholysis (separation of the nail plate from the nail bed) and oil-drop (salmon patch) dyschromia (reddish-brown discoloration under the nail plate) on a scale of 0 (none present) to 3 (\>30% of the nail), pitting (small, sharply defined depressions in the nail surface) on a scale of 0 (0 pits present) to 3 (\> 50 pits present), and nail plate crumbling on a scale of 0 (no crumbling) to 3 (\>50% of nail has crumbling) and presence (1) or absence (0) of leukonychia (white spots), splinter hemorrhages, nail bed hyperkeratosis, and red spots in the lunula. The mNAPSI score is calculated as the sum of all the components for all of the participant's fingernails giving a range of possible scores from 0 (absence of nail psoriasis) to 130 (the most severe nail psoriasis). A negative change from Baseline indicates improvement.

Time frame: Baseline and Week 24

Change From Baseline in Fingernail-Physician Global Assessment (PGA-F)

The PGA-F is a clinician-rated outcomes assessment used to measure the severity of signs and symptoms associated with fingernail psoriasis. Participant's fingernails were assessed separately for nail bed signs and nail matrix signs of disease on a scale from 0 (clear) to 4 (severe). A participant's overall global score is the worse of the nail bed score and nail matrix score. For example, if a participant had a nail bed score '2' and a nail matrix score of '4,' this participant's overall score was '4.' A negative change from Baseline indicates improvement.

Time frame: Baseline and Week 24

Percentage of Participants With Resolution of Enthesitis at Week 24

Resolution of enthesitis is defined as a Leeds Enthesitis Index (LEI) score = 0. LEI is an enthesitis measure developed specifically for PsA and assesses the presence or absence of tenderness at the following 3 bilateral enthesial sites: medial femoral condyles, lateral epicondyles of the humerus, and Achilles tendon insertions. Tenderness on examination is recorded as either present (coded as 1), absent (coded as 0), or not assessed for each of the 6 sites. The LEI is calculated by taking the sum of the scores from the 6 sites. The LEI ranges from 0 to 6 (worst). To increase the sample size due to the smaller number of participants with enthesitis at Baseline, the pre-specified analysis of the resolution of enthesitis included pooled data from KEEPsAKE 1 (this study) and the companion study KEEPsAKE 2 (M15-998; NCT03671148).

Time frame: Week 24

Percentage of Participants With Resolution of Dactylitis at Week 24

Resolution of dactylitis is defined as a Leeds Dactylitis Index (LDI) score = 0. LDI basic is a score based on finger circumference and tenderness, assessed across all digits. The LDI basic measures the ratio of the circumference of the affected digit to the circumference of the digit on the opposite hand or foot, using a minimum difference of 10% to define a dactylitic digit. The ratio of circumference is multiplied by a tenderness score (1 for tender, 0 for non-tender). If both sides of a digit are considered involved, or the circumference of the contralateral digit cannot be obtained, a standard reference table is used. Scores from each digit are summed to provide the final LDI. A higher LDI indicates worse dactylitis. To increase sample size due to the smaller number of participants with dactylitis at Baseline, the pre-specified analysis of the resolution of dactylitis included pooled data from KEEPsAKE 1 (this study) and the companion study KEEPsAKE 2 (M15-998; NCT03671148).

Time frame: Week 24

Change From Baseline in PsA Modified Total Sharp Score (mTSS) at Week 24

The Sharp-van der Heijde modified scoring method for PsA measures the level of joint damage from radiographs of the hands and feet, and was assessed by 2 independent, blinded readers. Joint erosion severity was assessed in 20 joints in each hand and wrist and 6 joints in each foot. Each joint was scored from 0 (no erosion) to 5 for hands/wrists or to 10 for feet (complete collapse). The total erosion score ranges from 0 to 320 (worst). Joint space narrowing (JSN) was assessed in 20 joints of each hand and wrist, and 6 joints of each foot, from 0 (normal) to 4 (complete loss of joint space, bony ankylosis, or luxation). The total JSN score ranges from 0 to 208 (worst). Joints with gross osteolysis or pencil in cup were assigned the maximum score for both erosions and JSN. The total mTSS score is the sum of the joint erosion and JSN scores and ranges from 0 (normal) to 528 (worst).

Time frame: Baseline and Week 24

Change From Baseline In 36-Item Short Form Health Survey (SF-36) Physical Component Summary (PCS) Score at Week 24

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 summary is a weighted combination of the 8 subscales with positive weighting for physical functioning, role-physical, bodily pain, and general health. The SF-36 PCS ranges from 0 to 100. A linear algorithm was applied to the calculation of the PCS which has a normative mean value of 50. Higher scores are associated with less disability; a score of 100 is equivalent to no disability and a score of 0 is equivalent to maximum disability. A positive change from Baseline score indicates improvement.

Time frame: Baseline and Week 24

Change From Baseline In Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-Fatigue) Score at Week 24

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 score ranges from 0 to 52, where higher scores represent less fatigue. A positive change from Baseline indicates improvement.

Time frame: Baseline and Week 24

Percentage of Participants With an American College of Rheumatology 50% (ACR50) Response at Week 24

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 24

Percentage of Participants With an American College of Rheumatology 70% (ACR70) Response at Week 24

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 24