| Baseline* characteristic | All patients enrolled in OLE | All patients completing OLE |
| n = 257 | n = 126 | |
| Age, mean (SD) years | 41.6 (10.2) | 43.0 (9.6) |
| Sex, no. (%) | ||
| Female | 64 (24.9) | 35 (27.8) |
| Male | 193 (75.1) | 91 (72.2) |
| Ethnicity, no. (%) | ||
| Caucasian, no. (%) | 239 (93.0) | 118 (93.7) |
| Hispanic, no. (%) | 9 (3.5) | 4 (3.2) |
| Asian, no. (%) | 5 (1.9) | 2 (1.6) |
| Native American, no. (%) | 3 (1.2) | 2 (1.6) |
| Other, no. (%) | 1 (0.4) | 0 (0.0) |
| Duration of AS, mean (SD) years | 10.7 (8.6) | 10.7 (8.3) |
| Prior DMARDs used, no. (%) | 106 (41.2) | 58 (46.0) |
| DMARDs use at baseline, no. (%) | 81 (31.5) | 45 (35.7) |
| Methotrexate | 29 (11.3) | 19 (15.1) |
| Sulfasalazine | 56 (21.8) | 19 (15.1) |
| Hydroxychloroquine | 4 (1.6) | 1 (0.8) |
*Baseline from randomised controlled trial.
AS, ankylosing spondylitis; DMARD, disease-modifying anti-rheumatic drugs; OLE, open-label extension.