Summary of efficacy outcomes at week 64 in the randomised withdrawal intent-to-treat population
| Withdrawn to placebo N=53 | IXE Q4W N=48 | IXE Q2W N=54 | Combined IXE N=102 | |||||||
| Response n (%) | Response n (%) | Difference vs placebo (95% CI) | P value vs placebo | Response n (%) | Difference vs placebo (95% CI) | P value vs placebo | Response n (%) | Difference vs placebo (95% CI) | P value vs placebo | |
| Flare-free patients* | 29 (54.7%) | 40 (83.3%) | 28.6%(11.6% to 45.7%) | 0.003 | 45 (83.3%) | 28.6% (11.9% to 45.3%) | 0.001 | 85 (83.3%) | 28.6% (13.4% to 43.8%) | <0.001 |
| Patients without clinically important worsening (ASDAS worsening ≥0.9 per ASAS definition)† | 16 (30.2%) | 35 (72.9%) | 42.7% (25.1% to 60.4%) | <0.001 | 40 (74.1%) | 43.9% (26.9% to 60.9%) | <0.001 | 75 (73.5%) | 43.3% (28.3% to 58.4%) | <0.001 |
| ASDAS | ||||||||||
| ASDAS LDA (<2.1) | 24 (45.3%) | 40 (83.3%) | 38.1% (21.0% to 55.1%) | <0.001 | 44 (81.5%) | 36.2% (19.3% to 53.1%) | <0.001 | 84 (82.4%) | 37.1% (21.8% to 52.4%) | <0.001 |
| ASDAS ID (<1.3) | 13 (24.5%) | 29 (60.4%) | 35.9% (17.8% to 53.9%) | <0.001 | 29 (53.7%) | 29.2% (11.5% to 46.8%) | 0.003 | 58 (56.9%) | 32.3% (17.3% to 47.4%) | <0.001 |
*Flare was defined as an ASDAS≥2.1 at two consecutive visits or an ASDAS>3.5 at any visit.
†Assessment of ASDAS worsening of ≥0.9 was conducted as a post hoc analysis and was not the prespecified definition of flare nor a criterion for retreatment after flare. Six patients (IXE Q4W: n=4, IXE Q2W: n=1, and withdrawn to placebo: n=1) were censored due to retreatment after meeting the prespecified definition of flare. As a result, response is slightly underestimated using non-responder imputation.
ASAS, Assessment of Spondyloarthritis International Society criteria; ASDAS, Ankylosing Spondylitis Disease Activity Score; ID, inactive disease; IXE, ixekizumab; LDA, low disease activity; Q2W, every 2 weeks; Q4W, every 4 weeks.