EP38 Secukinumab provides sustained improvement of enthesitis in patients with ankylosing spondylitis: pooled analysis of four pivotal Phase 3 studies

Abstract

Background: Enthesitis can be a debilitating extra‐articular spondyloarthritis manifestation that causes considerable pain and reduced quality of life. We evaluated the effect of secukinumab on axial and peripheral enthesitis in ankylosing spondylitis (AS) patients with baseline enthesitis (BLE) across all MASES sites (N=13), axial MASES sites (N=11; 13 MASES minus Achilles tendons [AT] [AxS]), peripheral sites (N=6; AT + lateral condyles of humerus/femur [PS]) and the AT (N=2) at Weeks 16 and 52. Methods: This post‐hoc analysis pooled data across four AS studies (MEASURE 1‐4) from patients originally randomised to secukinumab 150mg (approved AS dose), 300mg (MEASURE 3 only) or placebo with BLE (MASES >0). Evaluations included mean change from baseline in MASES score, complete resolution (CR; MASES=0) and improvement from baseline in MASES score ≥5 counts. Mixed‐effect model repeat measurement analysis was performed on change from baseline in MASES score and non‐responder imputation for resolution of enthesitis at Week 16; data are reported as observed at Week 52. Results: 355 (70.4%), 58 (76.3%) and 280 (72%) patients had BLE in the 150 mg, 300mg and placebo groups, respectively. Baseline characteristics were comparable across groups. At Week 16, mean change from baseline for overall MASES and at AxS was greater for secukinumab 150mg (‐2.4, ‐2.3) and 300mg (‐2.9, ‐2.9) vs placebo (‐1.9, ‐1.8; P<0.05, P<0.01). At Week 16, patients treated with secukinumab 150mg (40.8%, 42.7%) and 300mg (36.2%, 42.1%) vs placebo (28.9%, 30.1%) achieved CR of enthesitis at overall MASES and AxS. Secukinumab 150mg and 300mg were consistently associated with a higher mean change in MASES and CR of enthesitis at PS and AT vs placebo. More patients treated with secukinumab 150/300mg vs placebo achieved a higher threshold of improvement (≥5 counts) in overall MASES at Week 16. Further improvements were observed for all endpoints at Week 52 (Table 1). Conclusion: Secukinumab 150mg and 300mg were associated with a higher mean change in MASES and CR of enthesitis for overall MASES and at AxS vs placebo in AS patients at Week 16, which further improved through Week 52.