Study Evaluating Rapid Infusion Rituximab in Patients With Autoimmune Diseases

Background Rituximab is a human/murine monoclonal antibody targeted at the CD20 antigen (cluster of differentiation antigen 20) on B-lymphocytes. The CD20 antigen is expressed in over 90% of B-cell non-Hodgkin's lymphomas. B cells are also believed to play a role in the pathogenesis of other oncologic and non-oncologic disorders. Targeting B cells appears to have a role in decreasing autoimmune and inflammatory processes, as well as antibody production in many autoimmune diseases. Rituximab is approved for the treatment of non-Hodgkin's lymphoma (NHL), chronic lymphocytic leukemia (CLL), rheumatoid arthritis (RA) in combination with methotrexate, wegener's granulomatosis, and microscopic polyangiitis in combination with glucocorticoids. Although rituximab is not approved for multiple sclerosis, myasthenia gravis, or other autoimmune diseases, it is commonly used later in the treatment course for patients that are not responding to other treatment options. Rituximab's main limitation is the occurrence of infusion-related reactions (IRR). These reactions can include fever, chills, rash, respiratory compromise, and a variety of other symptoms, including death. The incidence of IRR is known to vary depending on the rituximab indication. The incidence of IRR with the first infusion of rituximab is approximately 77% with NHL, 27% with RA, and 12% with wegener's granulomatosis and microscopic polyangiitis. The incidence of IRR decreases with subsequent infusions of rituximab to approximately 5-10%. According to the National Cancer Institute, there are 5 grades of IRR. In general, grade 1 reactions are classified as asymptomatic or only mild symptoms that do not require intervention. Grade 2 reactions are classified as moderate with minimal, local, or noninvasive interventions required. Grade 3 reactions are classified as severe and medically significant, but not immediately life-threatening. These reactions require hospitalization or prolongation of a current hospitalization. Grade 4 reactions are classified as life-threatening with urgent interventions required. Grade 5 reactions are classified as death related to an adverse drug event. The incidence of IRR is a chief concern for patients, nurses, and other healthcare providers.

The package labeling recommends the administration of a standard infusion of rituximab for all patients initiating rituximab therapy to minimize IRR. If this infusion is tolerated then subsequent infusions may be titrated up to a faster rate to decrease infusion time. Based on the manufacturer's package insert, rituximab is infused at a rate of 50 mg/hr and can be increased every 30 minutes by 50 mg/hr (maximum rate of 400 mg/hr). If a grade 3 or 4 IRR does not occur, subsequent infusions are given at a rate of 100 mg/hr and can be increased every 30 minutes by 100 mg/hr (maximum rate of 400 mg/hr). The average infusion time is estimated to be 4-6 hours for the first infusion, and 3-4 hours for subsequent infusions. Rituximab is typically given in cycles and the timing will vary depending on the indication.