| Characteristic | Placebo (n = 109) | Certolizumab pegol 400 mg (n = 111) |
| Age in years, mean (SD) | 54.9 (11.6) | 52.7 (12.7) |
| Female, n (%) | 97 (89.0) | 87 (78.4) |
| RF positive (⩾14 IU/ml), n (%) | 109 (100.0) | 110 (100.0) |
| Disease duration in years, mean (SD) | 10.4 (9.6) | 8.7 (8.2) |
| No of prior DMARDs, mean (SD) | 2 (1.25) | 2 (1.19) |
| Prior MTX use, n (%) | 89 (81.7) | 91 (82.0) |
| Concurrent use of oral corticosteroids (prednisone equivalent ⩽10 mg/day), n (%) | 64 (58.7) | 62 (55.9) |
| Tender joint count, mean (SD) | 28.3 (12.5) | 29.6 (13.7) |
| Swollen joint count, mean (SD) | 19.9 (9.3) | 21.2 (10.1) |
| Patient's Global Assessment of Arthritis, mean (SD) | 3.3 (0.77) | 3.3 (0.75) |
| Physician's Global Assessment of Arthritis, mean (SD) | 3.6 (0.62) | 3.6 (0.67) |
| Patient’s assessment of arthritis pain (VAS), mean (SD) | 54.8 (20.8) | 58.2 (21.9) |
| HAQ-DI, mean (SD) | 1.6 (0.65) | 1.4 (0.63) |
| DAS28(ESR)3, mean (SD) | 6.3 (0.9) | 6.3 (1.1) |
| CRP (mg/litre), geometric mean (95% CI) | 11.3 (8.6 to 14.9) | 11.6 (9.1 to 14.9) |
| ESR (mm/h), geometric mean (95% CI) | 35.6 (30.9 to 41.0) | 30.9 (25.9 to 36.8) |
Patient's and Physician's Global Assessments of Arthritis were scored on a categorical scale of 1–5 where 1 = very good (asymptomatic and no limitation of normal activities) and 5 = very poor (very severe symptoms that are intolerable and inability to carry out all normal activities).
CRP, C-reactive protein; DAS28(ESR)3, disease activity score, erythrocyte sedimentation rate 3; DMARD, disease-modifying antirheumatic drug; HAQ-DI, Health Assessment Questionnaire Disability Index; mITT, modified intent to treat; RF, rheumatoid factor; VAS, visual analogue scale.