Table 2.

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	Withdrawn to placebo N=53	IXE Q4W N=48			IXE Q2W N=54			Combined IXE N=102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 Six patients (IXE Q4W: n=4, IXE Q2W: n=1, and withdrawn to placebo: n=1) were censored due to retreatment after meeting the prespecified definition of flare.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.