ABY-035-204 is a double-blind, randomized, parallel-group, placebo-controlled study.~The primary objective is to estimate the relationship between different dose regimens of ABY-035 and clinical response as assessed by Assessment of Spondyloarthritis International Society 40 (ASAS40) response at Week 16 in subjects with active AS.~The study will include the following 3 periods:~Screening Period: Up to 35 days prior to baseline randomization.~Treatment Period 1: Day 0-Week 16 Eligible subjects will be randomized 1:1:1:1 to receive 1 of 4 treatments (ABY-035 80 mg Q2W, ABY-035 160 mg Q4W, ABY-035 40 mg Q2W, or placebo), and will remain on their allowable background medication.~Randomization will be stratified by region (North Eastern Asia and North America) and previous tumor necrosis factor alpha (TNFα) inhibitor exposure (TNFα inhibitor treated or TNFα inhibitor naïve). Maximum 30% of subjects will be TNFα inhibitor-treated subjects to ensure a representative population for the assessment of efficacy and safety.~Treatment Period 1 ends at Week 16 after all trial assessments have been done and Treatment Period 2 starts at Week 16 with the IMP injection.~Treatment Period 2 (Extension Period): Week 16-Week 52 Subjects will continue their original treatment of Treatment Period 1 in a double-blinded manner.~Subjects who couldn't achieve an ASAS20 response from baseline are defined as non-responders and eligible for rescue treatment after Week 16 (Visit 9).
ABY-035-204 is a clinical study to assess the efficacy of IL-17 blocker ABY-035 in ankylosing spondylitis(AS). The primary objective is to estimate the relationship between different dose regimens of ABY-035 and clinical response as assessed by Assessment of Spondyloarthritis International Society 40 (ASAS40) response at Week 16 in subjects with active AS.