A Study of the Safety and Effectiveness of Ustekinumab in Patients With Psoriatic Arthritis

An ACR 20 response is defined as a greater than or equal to 20 percent improvement from baseline in swollen (66 joints) and tender (68 joints) joint counts and greater than or equal to 20 percent improvement in 3 of the following 5 assessments: 1) Participant's assessment of pain by Visual Analog Scale (VAS) (0-10 cm), 2) Participant's global assessment of disease activity by VAS (0-10 cm), 3) Physician's global assessment of disease activity by VAS (0-10 centimeters [cm]) 4) Participant's assessment of physical function as measured by the "Disability Index of the Health Assessment Questionnaire" (HAQ-DI) (score of 0-3 in 8 functional areas) and 5) C reactive protein.

The HAQ-DI is 20-question instrument that assesses the degree of difficulty a person has in accomplishing tasks in 8 functional areas (dressing, arising, eating, walking, hygiene, reaching, gripping, and activities of daily living). Responses in each functional area are scored from 0 (no difficulty), to 3 (inability to perform a task in that area). The average score across the functional areas yields an overall HAQ-DI score which ranges from 0 (no disability) to 3 (completely disabled). In psoriatic arthritis, a decrease in score of 0.30 indicates clinically meaningful improvement.

The PASI is a physician-administered assessment tool used for assessing and grading the severity of psoriatic lesions and their response to therapy. The PASI produces a numeric score that can range from 0 (no disease) to 72 (maximal disease). A PASI 75 response is defined as greater than or equal to 75 percent improvement in PASI score from baseline.

An ACR 50 response is defined as a greater than or equal to 50 percent improvement from baseline in swollen (66 joints) and tender (68 joints) joint counts and greater than or equal to 50 percent improvement in 3 of the following 5 assessments: 1) Participant's assessment of pain by Visual Analog Scale (VAS) (0-10 cm), 2) Participant's global assessment of disease activity by VAS (0-10 cm), 3) Physician's global assessment of disease activity by VAS (0-10 cm) 4)Participant's assessment of physical function as measured by the "Disability Index of the Health Assessment Questionnaire" (HAQ-DI) (score of 0-3 in 8 functional areas) and 5) C reactive protein.

An ACR 70 response is defined as a greater than or equal to 70 percent improvement from baseline in swollen (66 joints) and tender (68 joints) joint counts and greater than or equal to 70 percent improvement in 3 of the following 5 assessments: 1) Participant's assessment of pain by Visual Analog Scale (VAS) (0-10 cm), 2) Participant's global assessment of disease activity by VAS (0-10 cm), 3) Physician's global assessment of disease activity by VAS (0-10 cm) 4) Participant's assessment of physical function as measured by the "Disability Index of the Health Assessment Questionnaire" (HAQ-DI) (score of 0-3 in 8 functional areas) and 5) C reactive protein.

The modified vdH-S score is a radiographic evaluation of hand and feet erosions and joint space narrowing (JSN) for 20 joints per hand and 6 joints per foot with a total score ranging from 0 (best) to 528 (worst = worst possible erosion score of 320 + worst possible JSN score of 208). Higher score and positive score changes indicate more radiographic damage and radiographic progression, respectively. As per protocol, analysis for this outcome measure used pooled data from 2 studies (CNTO1275PSA3001 and PSA3002) because initial power assumptions showed that 900 participants would be required to evaluate impact of ustekinumab on structural damage (SD) progression. The 2 studies, (which had similar study designs and dosing regimens with difference to prior exposure to anti-tumor necrosis factor alpha (TNFα) therapies), were intended to independently measure efficacy in terms of signs, symptoms and physical function, while effects on SD progression is provided from an integrated analysis.