Dose-finding Study of GLPG0634 as add-on to Methotrexate in Active Rheumatoid Arthritis Participants (DARWIN1)

The American College of Rheumatology (ACR) response is a measurement of improvement in multiple disease assessment criteria. The ACR20 response is defined as: 1) ≥ 20% improvement from baseline in SJC66, and 2) ≥ 20% improvement from baseline in tender TJC68, and 3) ≥ 20% improvement from baseline in at least 3 of the following 5 items: 1. Pain visual analog scale (VAS) (taken from the Health Assessment Questionnaire - Disability Index [HAQ-DI]), 2. Patient's Global Assessment of Disease Activity VAS, 3. Physician's Global Assessment of Disease Activity VAS, 4. Total HAQ-DI score, and 5. CRP. Non-responder imputation was used (ie, to impute a missing response, the participant was assumed to be a non-responder).

ACR20 response was defined as: 1) ≥ 20% improvement from baseline in SJC66, and 2) ≥ 20% improvement from baseline in TJC68, and 3) ≥ 20% improvement from baseline in at least 3 of the following 5 items: 1. Pain VAS (taken from the HAQ-DI), 2. Patient's Global Assessment of Disease Activity VAS, 3. Physician's Global Assessment of Disease Activity VAS, 4. Total HAQ-DI score, and 5. CRP. Non-responder imputation was used.

ACR50 response was defined as: 1) ≥ 50% improvement from baseline in SJC66, and 2) ≥ 50% improvement from baseline in TJC68, and 3) ≥ 50% improvement from baseline in at least 3 of the following 5 items: 1. Pain VAS (taken from the HAQ-DI) 2. Patient's Global Assessment of Disease Activity VAS 3. Physician's Global Assessment of Disease Activity VAS 4. Total HAQ-DI score 5. CRP. Non-responder imputation was used.

ACR70 response: 1) ≥ 70% improvement from baseline in SJC66, and 2) ≥ 70% improvement from baseline in TJC68, and 3) ≥ 70% improvement from baseline in at least 3 of the following 5 items: 1. Pain VAS (taken from the HAQ-DI), 2. Patient's Global Assessment of Disease Activity VAS, 3. Physician's Global Assessment of Disease Activity VAS, 4. Total HAQ-DI score, and 5. CRP. Non-responder imputation was used.

The ACR-N is the smallest percentage improvement in swollen and tender joints and the median of the remaining 5 core parameters, and is expected to be more sensitive to change than the ACR20, ACR50 or ACR70. It is a number varying between 0 and 100, with higher numbers indicating less severity of symptoms. Last observation carried forward (LOCF) algorithm was used (ie, to impute a missing value, the last preceding nonmissing value was used).

DAS28 (CRP) was categorized into EULAR response categories (none, moderate, good) as follows: None = Actual DAS28 (CRP) ≤ 3.2, > 3.2 to ≤ 5.1, or > 5.1 AND Improvement in DAS28 (CRP) from baseline ≤ 6.0 or > 0.6 to ≤ 1.2; Moderate = Actual DAS28 (CRP) ≤ 3.2 AND Improvement in DAS28 (CRP) from baseline > 0.6 to ≤ 1.2, Actual DAS28 (CRP) > 3.2 to ≤ 5.1 or > 5.1 AND Improvement in DAS28 (CRP) from baseline > 1.2, or Actual DAS28 (CRP) > 3.2 to ≤ 5.1 AND Improvement in DAS28 (CRP) from baseline > 0.6 to ≤ 1.2; Good = Actual DAS28 (CRP) ≤ 3.2 AND Improvement in DAS28 (CRP) from baseline > 1.2. LOCF algorithm was used.

A participant's disease activity status can be defined as being in remission when scores on the TJC28, SJC28, CRP (actual value in mg/dL) and Patient Global Assessment of Disease Activity (cm) are all ≤ 1. Non-responder imputation was used.

The SDAI is the numerical sum of 5 outcome parameters: TJC28, SJC28, Patient Global Assessment of Disease Activity (in cm), Physician's Global Assessment of Disease Activity (in cm), and CRP (mg/dL). The SDAI was categorized as follows:

• High disease activity: SDAI > 26 • Moderate disease activity: 11 to 26 • Low disease activity: 3.3 to 11 • Remission: ≤ 3.3. LOCF algorithm was used. The SDAI total score ranges from 0 to approximately 86.

The CDAI is the SDAI modified to exclude CRP and is the sum of the 4 outcome parameters: TJC28, SJC28, Patient Global Assessment of Disease Activity (in cm), and Physician's Global Assessment of Disease Activity (in cm). The CDAI was be categorized as follows: • High disease activity: > 22 • Moderate disease activity: 10 to 22 • Mild disease activity: 2.8 to 10 • Remission: ≤ 2.8. LOCF algorithm was used. The CDAI total score ranges from 0 to approximately 76.

FACIT-Fatigue scale is a 13-item questionnaire, each scored on a 5-point scale: 0 (Not at all) to 4 (Very much). The larger the participant's response to the questions (with the exception of 2 negatively stated that are scored reversely), the greater the fatigue. The sum of all responses resulted in the FACIT-Fatigue score for a total possible score of 0 (worse score) to 52 (better score), with a higher score indicating a better quality of life. LOCF algorithm was used.

The SF-36 is a 36-item questionnaire measuring 8 domains (physical functioning, role physical, bodily pain, general health, vitality, social functioning, role emotional, and mental health). Each domain score ranges from 0 (worst) to 100 (best), with higher scores reflecting better health-related functional status. Two summary scale scores were computed based on weighted combinations of the 8 domain scores: the Physical Component Summary (PCS) and the Mental Component Summary (MCS). LOCF algorithm was used.