An Efficacy and Safety Study of Tocilizumab (RoActemra/Actemra) in Participants With Giant Cell Arteritis (GCA)

Inclusion Criteria

• Diagnosis of GCA classified according to age >/=50 years; history of ESR >/=50 mm/hr or history of CRP >/=2.45 mg/dL; and at least one of the following: unequivocal cranial symptoms of GCA or symptoms of polymyalgia rheumatica [PMR]; and at least one of the following: temporal artery biopsy revealing features of GCA or evidence of large-vessel vasculitis by angiography or cross-sectional imaging
• New onset (diagnosis within 6 weeks of baseline) or refractory (diagnosis greater than [>] 6 weeks before baseline and previous treatment with >/= 40 milligrams per day prednisone [or equivalent] for at least 2 consecutive weeks at any time) GCA
• Active disease (presence of clinical signs and symptoms [cranial or PMR] and ESR >/=30 mm/hour or CRP >/=1 mg/dL) within 6 weeks of baseline visit

Exclusion Criteria

• Major surgery within 8 weeks prior to screening or planned within 12 months after randomization
• Transplanted organs (except corneas with transplant performed >3 months prior to screening)
• Major ischemic event, unrelated to GCA, within 12 weeks of screening
• Prior treatment with any of the following: investigational agent within 12 weeks (or 5 half-lives of the investigational drug, whichever is longer) of screening; cell-depleting therapies including investigational agent; intravenous (IV) gamma globulin or plasmapheresis within 6 months of baseline; alkylating agents or with total lymphoid irradiation; tocilizumab; hydroxychloroquine, cyclosporine A, azathioprine, or mycophenolate mofetil within 4 weeks of baseline; etanercept within 2 weeks of baseline; infliximab, certolizumab, golimumab, abatacept, or adalimumab within 8 weeks of baseline; anakinra within 1 week of baseline; tofacitinib; cyclophosphamide within 6 months of baseline; >100 milligrams of daily IV methylprednisolone within 6 weeks of baseline
• Participants requiring systemic glucocorticoids for conditions other than GCA, which, in the opinion of the investigator, would interfere with adherence to the fixed glucocorticoid taper regimen and/or to assessment of efficacy in response to the test article
• History of severe allergic reactions to monoclonal antibodies or to prednisone
• Evidence of serious uncontrolled concomitant disease (for example, cardiovascular, respiratory, renal, endocrine, psychiatric, corneal ulcers/injuries, or gastrointestinal [GI] disease)
• Current liver disease, as determined by the investigator
• History of diverticulitis, inflammatory bowel disease, or other symptomatic GI tract condition that might predispose to bowel perforation
• Known active or history of recurrent bacterial, viral fungal, mycobacterial, or other infection
• Primary or secondary immunodeficiency
• Evidence of malignancies diagnosed within previous 5 years (except basal and squamous cell carcinoma of the skin or carcinoma in situ of the cervix uteri that have been excised and cured)
• Inadequate hematologic, renal or liver function
• Positive for hepatitis B or hepatitis C infection