Table 1 Patients' baseline characteristics.

Mean (SD, range) age (years)	40 (9.2, 24–59)
Mean (SD, range) disease duration (years)	14 (10.2, 1–39)
Sex, male:female (n)	14:6
HLA‐B27 positivity (%)	85
Mean (SD, range) BASDAI at screening	5.6 (1.2, 4–9.3)
CRP >10 mg/l at screening (%)	40
Peripheral arthritis at screening (n)	7
Enthesitis at screening (Berlin scale) (n)	8
IBD (history and at screening) (n)	0
Psoriasis (history and at screening) (n)	4
History of anterior uveitis (n)	3
Concomitant treatment at screening
NSAIDs (n)	20
Glucocorticoids (n)	4
Previous DMARDs (n)	6

BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C reactive protein (normal value <5 mg/l); DMARDs, disease‐modifying antirheumatic drugs; HLA, human leucocyte antigen; IBD, inflammatory bowel disease; NSAIDs, non‐steroidal anti‐inflammatory drugs.