A Study of Tocilizumab (RoActemra/Actemra) in Patients With Ankylosing Spondylitis Who Have Had an Inadequate Response to Previous Tumor Necrosis Factor (TNF) Antagonist Therapy

Inclusion Criteria: * Adult patients ≥ 18 years of age. * Ankylosing spondylitis as defined by the modified New York criteria for ≥ 3 months prior to baseline. * Active disease at screening and baseline (Bath Ankylosing Spondylitis Disease Activity Index \[BASDAI\] ≥ 4.0, spinal pain visual analog scale \[VAS\] ≥ 40). * Inadequate response or intolerant to 1 or more previous non-steroidal anti-inflammatory drugs (NSAIDs). * Inadequate response to treatment with etanercept, infliximab, adalimumab, or golimumab because of inadequate efficacy. * Tumor necrosis factor (TNF) antagonist therapy must have been discontinued at least 8 weeks prior to baseline (etanercept 4 weeks). * Traditional disease-modifying anti-rheumatic drugs (DMARDs) must be withdrawn for at least 4 weeks prior to baseline (methotrexate, sulfasalazine, and hydroxychloroquine or chloroquine may be allowed if at stable dose for at least 4 weeks prior to baseline). * Oral corticosteroids (≥ 10 mg/day prednisone or equivalent) and NSAIDs/cyclooxygenase-2 \[COX-2\] inhibitors must be at stable dose for at least 4 weeks prior to baseline. Exclusion Criteria: * Major surgery (including joint surgery) within 8 weeks prior to screening or planned major surgery within 6 months after randomization. * Total ankylosis of spine (as determined by investigator). * Inflammatory rheumatic disease other than ankylosing spondylitis. * Active, acute uveitis at baseline. * Previous treatment with tocilizumab. * Intra-articular or tendon injections or parenteral corticosteroids within 4 weeks prior to screening. * History of severe allergic or anaphylactic reactions to humanized or murine monoclonal antibodies. * Active current or history of recurrent bacterial, viral, fungal, mycobacterial, or other infection. * History of or currently active primary or secondary immunodeficiency. * Body weight \> 150 kg.