Objective: Secukinumab, a fully human monoclonal antibody that neutralizes interleukin-17A, improved the signs and symptoms of ankylosing spondylitis (AS) in three Phase 3 global studies (MEASURE 1, 2, and 3). Here, we describe the efficacy and safety results through Week 24 of a study of secukinumab in Japanese patients with active AS. Methods: In this multicenter, open-label, single arm, 52-week study, 30 AS patients self-administered secukinumab 150 mg subcutaneously at baseline, Weeks 1, 2, 3, and 4, and every 4 weeks thereafter. The primary efficacy endpoint was ASAS 20 response at Week 16. Overall safety and tolerability were assessed beyond Week 24 up to the data reporting cutoff date. Results: The ASAS 20 response rate was 70% (21/30) at Week 16, which was sustained to Week 24. Secukinumab was effective in various clinical outcomes including patient's global assessment of disease activity, spinal pain, nocturnal pain, physical function, spinal mobility, and CRP level. Comparable ASAS 20 and 40 responses were observed regardless of previous anti-TNF therapy. Secukinumab was well-tolerated with a safety profile consistent with previous reports. Conclusion: Secukinumab 150 mg provided sustained improvement in the signs and symptoms of Japanese AS patients through 24 weeks, with no new or unexpected safety signals.