['axial spondyloarthritis']
['khk4827', 'placebo']

        Inclusion Criteria:

          -  Subject with age at onset <45 years and continuous chronic back pain for ≥ 3 months
             fulfills the ASAS classification criteria of axial spondyloarthritis (with the
             exception of the Crohn's disease)

          -  Subject has Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) score ≥ 4 at
             screening and enrollment

          -  Subject has spinal pain score (BASDAI question #2) ≥ 4 at screening and enrollment

          -  Subject has had adequate therapy with non-steroidal anti-inflammatory drugs (oral
             NSAIDs) for back pain for at least 3 months with inadequate treatment response before
             enrollment

        Exclusion Criteria:

          -  Complete ankylosis (fusion) of the spine

          -  Subject with active ongoing inflammatory diseases other than axSpA that might confound
             the evaluation of KHK4827 therapy, including reactive arthritis, spondyloarthritis
             associated with inflammatory bowel disease, SAPHO syndrome (pustulotic
             arthro-osteitis), fibromyalgia, ankylosing spinal hyperostosis, osteitis condensans
             ilii, spondylosis deformans, or osteoarthritis sacroiliac joint disease

          -  Subject has a prior history of >1 anti-TNF therapy

          -  Subject has a history or evidence of suicidal ideation (severity of 4 or 5) or any
             suicidal behavior based on an assessment with the Columbia-Suicide Severity Rating
             Scale (C-SSRS) at enrollment

          -  Subject has a history or evidence of a psychiatric disorder, alcohol and/or substance
             abuse

          -  Subject has severe depression based on a total score of ≥ 15 on the Patient Health
             Questionnaire-8 (PHQ-8) at enrollment (note: subjects with a total score of 10 to 14
             on the PHQ-8 should be referred to a mental health care professional)
      