Systemic Sclerosis (also known as Scleroderma) is a chronic, autoimmune disease of the connective tissue generally classified as one of the rheumatic diseases. Systemic Sclerosis causes fibrosis (scar tissue) to be formed in the skin and internal organs. The fibrosis eventually causes the involved skin to harden, limiting mobility, and can also damage other organs. Excess Transforming Growth Factor Beta-1 (TGF-beta1) activity may result in the abnormal fibrosis characteristic of Systemic Sclerosis. An antibody against TGF-beta1 may modify pathologic processes characterized by inappropriate fibrosis. Genzyme Corporation is currently investigating a human monoclonal antibody (CAT-192) that neutralizes active TGF-beta1. This study is being conducted in the U.S. and Europe to evaluate the safety, tolerability, and pharmacokinetics of repeated treatments with CAT-192 in patients with early stage diffuse Systemic Sclerosis.