A Study of Secukinumab to Evaluate Maintenance of Response in Participants With Non-radiographic Axial Spondyloarthritis Who Achieved Remission

This study will establish whether prolonged chronic dosing with secukinumab is needed in participants with Non-radiographic axial spondyloarthritis, (nr-axSpA) who have achieved remission. Remission is defined as Ankylosing Spondylitis Disease Activity Score - C-reactive protein (ASDAS-CRP) Inactive Disease (ID) response (ASDAS-CRP \< 1.3). Maintenance of remission on continued secukinumab treatment will be evaluated compared to placebo using a randomized withdrawal design. The primary outcome measure for this study is the proportion of participants remaining flare-free at Week 120.

Inclusion Criteria: * Male or non-pregnant, non-lactating female participants at least 18 years of age * Clinical diagnosis of axSpA AND according to ASAS axSpA criteria: 1. Inflammatory back pain for at least 6 months 2. Onset before 45 years of age 3. Sacroiliitis on MRI (magnetic resonance imaging) (as assessed by central reader) with ≥ 1 SpA feature OR HLA-B-27 positive with ≥2 SpA features * Objective signs of inflammation at screening, evident by either MRI with Sacroiliac Joint inflammation (as assessed by central reader) AND / OR hsCRP \> ULN (as defined by the central lab) * Active axSpA as assessed by total BASDAI ≥ 4 cm (0-10 cm) at baseline. * Spinal pain as measured by BASDAI question #2 ≥ 4 cm (0-10 cm) at baseline. * Total back pain as measured by VAS (visual analog scale) ≥ 40 mm (0-100 mm) at baseline. * Participants should have been on at least 2 different NSAIDs (non-steroidal anti-inflammatory drugs) at the highest recommended dose for at least 4 weeks in total prior to baseline with an inadequate response or failure to respond, or less if therapy had to be withdrawn due to intolerance, toxicity or contraindications. Exclusion Criteria: * Participants with radiographic evidence for sacroiliitis, grade ≥ 2 bilaterally or grade ≥ 3 unilaterally (radiological criterion according to the modified New York diagnostic criteria for AS) as assessed by central reader. * Participants taking high potency opioid analgesics (e.g., methadone, hydromorphone, morphine). * Previous exposure to secukinumab or any other biologic drug directly targeting IL-17 or IL-17 receptor or previous treatment with immunomodulatory biologic agents including those targeting TNFα (tumor necrosis factor α) (unless participants discontinued the treatment with TNFα inhibitor due to a reason other than efficacy \[primary or secondary lack of efficacy, inadequate response\] and only after appropriate wash-out period prior to baseline was observed). * History of hypersensitivity to the study drug or its excipients or to drugs of similar chemical classes. * Active ongoing inflammatory diseases other than nr-axSpA that might confound the evaluation of the benefit of secukinumab therapy, including uveitis. * Active inflammatory bowel disease. * History of ongoing, chronic or recurrent infectious disease or evidence of tuberculosis infection.