A Study to Evaluate the Efficacy and Safety of Bimekizumab in Subjects With Active Ankylosing Spondylitis

Inclusion Criteria: * Male or female patients at least 18 years of age * Subject has ankylosing spondylitis (AS) as per the Modified New York (mNY) criteria with documented radiologic evidence, and at least 3 months of symptoms with age at symptom onset less than 45 years * Subjects has moderate-to-severe active disease defined by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) \>=4 AND spinal pain \>=4 on a 0 to 10 Numeric Rating Scale * Subjects had to have either failed to respond to 2 different nonsteroidal anti-inflammatory drugs (NSAIDs) given at the maximum tolerated dose for a total of 4 weeks or have a history of intolerance to or a contraindication to NSAID therapy * Patients who have taken a tumor necrosis factor alpha (TNFα) inhibitor must have experienced an inadequate response or intolerance to treatment given at an approved dose for at least 12 weeks * Patients currently taking NSAIDs, cyclooxygenase 2 (COX-2) inhibitors, analgesics, corticosteroids, methotrexate (MTX), leflunomide (LEF), sulfasalazine (SSZ), hydroxychloroquine (HCQ) AND/OR apremilast can be allowed if they fulfill specific requirements prior to study entry Exclusion Criteria: * Total ankylosis of the spine * Treatment with more than 1 TNFα inhibitor and/or more than 2 additional non-TNFα biological response modifiers, or any interleukin (IL)-17 biological response modifier at any time are excluded * Active infection or history of recent serious infections * Viral hepatitis B or …