Safety Study of Rituximab (Rituxan®) in Chronic Urticaria

Rituximab (Rituxan®) is a recombinant chimeric monoclonal antibody that binds to a molecule (CD20) that is present on the surface of B lymphocytes. The product is approved for the treatment of non-Hodgkin's lymphoma and has been investigated for the treatment of a number of autoimmune diseases including rheumatoid arthritis (Edwards 2004) and lupus (Looney 2004, Leandro 2002). As in most rheumatoid arthritis studies, the medication will be administered in this study as a series of two intravenous infusions given 2 weeks apart. Many cases of chronic urticaria (hives) are though to be driven by an autoimmune mechanism (Kaplan 2002, Grattan 2002). It is our hypothesis that by interfering with the autoimmune process, potentially by decreasing the levels of autoantibodies or by interfering with other mechanisms that cause basophil and mast cell activation, improvments in signs and symptoms will be seen. Given the effectiveness demonstrated for Rituximab in other autoimmune conditions, we will conduct a pilot open label investigation of 15 patients with chronic urticaria to determine the safety and effectiveness of Rituximab in this disease. All patients will receive the medication; there will be no placebo group in this study. Rituximab is not currently indicated for the treatment of this condition however. We will evaluate the safety of the Rituximab in 15 patients with urticaria as well as studies of antibody levels and cellular function. We will also evaluate clinical outcomes such as itch score, sleep disturbance, and quality of life. After receivng the Rituximab treatment, we will begin to taper antihistamines and other medications used to control urticaria symptoms.