• The proportion of relapse-free subjects through Week 54
• The time to first relapse
• The levels of biochemical markers of inflammation and disease activity (eg, ESR, C-reactive protein [CRP], interleukin [IL]-6)
• The cumulative dose of prednisone (or prednisone equivalent)

The purpose of this study is to evaluate the safety and efficacy (effectiveness) of Infliximab (Remicade) in patients with Giant Cell Arteritis. Infliximab (Remicade) targets specific proteins in the body's immune system to help control the development of inflammation to help reduce painful disease.

The purpose of this study is to see if infliximab is safe and effective in treating GCA. Currently, the only treatment for GCA is prednisone. GCA is a long lasting inflammatory disease. The cause is unknown. It may affect all the arteries, but it focuses on the big vessels such as those around the heart, the vessels in the neck and head, and their major branches. It can lead to vision loss, blindness, stroke, stenosis (narrowing of blood vessels) and aneurysms (a weakening in the lining of the blood vessel wall, which may eventually lead to rupture of the blood vessel). The damage to the arteries is caused by an immune response. A naturally occurring substance in the immune system called "tumor necrosis factor alpha" (TNFa) plays a significant role in this immune response against the blood vessels. This response is thought to cause the long-lasting inflammation (irritation and swelling of the vessels). By blocking the effect of TNFa we think that we may reduce the signs and symptoms associated with GCA. This trial will study patients who are stable on prednisone treatment by evaluating whether infliximab can control their symptoms as the dose of prednisone is reduced. Patients will receive infusions of either 5mg/kg of inflixmab or placebo at weeks 0, 2, 6, 14, 22, 30, 38, and 46. Safety evaluations will be performed at specified intervals throughout the study and will consist of laboratory tests, vital signs (such as blood pressure), physical examinations and the occurrence and severity of adverse events as well as other study specific procedures.

Patients will receive receive infusions of either 5mg/kg inflixmab or placebo infusions at weeks 0, 2, 6, 14, 22, 30, 38, and 46.

Inclusion Criteria:

• Patients who have a diagnosis of Giant Cell Arteritis (GCA)
• Patients who have a diagnosis of GCA of ≤ 4 weeks' duration
• Patients who are receiving ≥ 40 mg/day of prednisone/prednisolone      

Exclusion Criteria:

• Patients must not have a prior diagnosis of GCA > 4 weeks
• Patients must not have failed to respond to glucocorticosteroid therapy within 5 days of initiation of therapy.      

• The Cleveland Clinic
• International Network for the Study of Systematic Vasculitides