Long-term effects of interleukin-17A inhibition with secukinumab in active ankylosing spondylitis

Secukinumab, a fully human anti-IL-17A monoclonal antibody, provided rapid and sustained improvements in signs and symptoms of ankylosing spondylitis (AS) over 2 years in the Phase 3 MEASURE 1 trial. Here, we report efficacy and safety after 3 years of treatment. Methods AS subjects completing 2 years of treatment every 4 weeks with subcutaneous secukinumab 150 or 75 mg (following intravenous loading or initial placebo treatment to 16/24 weeks) entered a separate 3-year extension study (NCT01863732). Assessments included ASAS20/40, ASAS5/6, BASDAI, BASDAI 50, BASFI, BASMI, SF-36 physical component summary, ASAS partial remission and ASDAS-CRP. Results were also analysed by prior anti-TNF treatment status. Results Among 290 subjects completing the core trial, 274 entered the extension study, with 260 subjects (94.9%) completing 156 weeks of treatment. ASAS20/40 response (observed) was 80.2%/61.6% in the IV→150 mg group and 75.5%/50.0% in the IV→75 mg group after 156 weeks. Sustained improvements were also seen in BASDAI, BASFI, BASMI and across all other endpoints regardless of previous exposure to anti-TNF agents. Mean secukinumab exposure was 964.3 days (137.8 weeks). Discontinuation rates were low, and secukinumab had a favourable safety profile, consistent with previous reports. Exposure-adjusted incidence rates for serious infections, Candida infections, Crohn's disease, ulcerative colitis, malignant/unspecified tumours, and adjudicated major adverse cardiac events were 1.1, 0.4, 0.5, 0.1, 0.5 and 0.7 per 100 subject-years, respectively. Conclusion Secukinumab provided sustained efficacy in signs, symptoms and physical function in subjects with AS over 3 years. No new safety signals were observed.