The Food and Drug Administration has approved etanercept for treating rheumatoid arthritis, another inflammatory disease. The drug works by blocking the activity of TNF-a protein made by white blood cells that is involved in the inflammatory process. Since prednisone also affects inflammatory proteins and lowers TNF production, the use of etanercept may reduce the need for prednisone in patients with Wegener's granulomatosis, and thus the risk of its side effects.