A Study of ARRY-371797 in Patients With Active Ankylosing Spondylitis

Key Inclusion Criteria: * Diagnosis of ankylosing spondylitis according to the Modified New York Criteria (1984). * Inadequate response to at least 2 weeks of continuous treatment with NSAIDs, or unable to receive ≥ 2 full weeks of continuous treatment with NSAIDs because of intolerance. * If previously treated with a biological agent, patient must not have failed due to lack of efficacy, and must have completed an appropriate washout period prior to first dose of study drug. * Patients may continue on specified stable background therapies for ankylosing spondylitis (doses should be stable for at least 4 weeks prior to the first dose of study drug). * Additional criteria exist. Key Exclusion Criteria: * Diagnosis of any other active or uncontrolled inflammatory or non-inflammatory articular disease that may interfere with disease activity assessments. * Previously treated with intravenous immunoglobulins within 6 months prior to first dose of study drug. * Patients requiring prohibited concomitant medications including moderate or strong CYP3A inhibitors, CYP3A inducers and Biologic Response Modifiers (BRMs) while on study. * Trauma or other major surgeries within 8 weeks prior to first dose of study drug. * Specific abnormal laboratory values or electrocardiogram abnormalities. * Known positive serology for human immunodeficiency virus (HIV), hepatitis C, and/or hepatitis B. * Additional criteria exist.