Combined Treatment With Fresh Frozen Plasma and Rituximab (Mabthera) in Patients With Advanced Refractory Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL), an indolent disease of mature-looking B lymphocytes, is the most common leukemia in Israel and the Western world. The disease is associated with considerable morbidity and mortality, and is currently incurable. Rituximab (Mabthera) is a chimeric monoclonal antibody directed against CD20 antigen, present exclusively on B lymphocytes. Treatment with Rituximab is widely used in indolent B cell malignancies. However, the administration of Rituximab in CLL patients yields less successful results than in other indolent B cell malignancies, and even responding patients may become refractory. We hypothesized that the abnormalities in the complement system identified in CLL underlie the suboptimal response to Rituximab, since complement-dependent cell cytotoxicity is a major mechanism of Rituximab action. Following patient consent and Institutional Review Board approval, standard-dose Rituximab (375 mg/m2) will be administered, preceded by 2 units of FFP. This treatment will be repeated every 1-2 weeks for 4-6 cycles. The clinical and laboratory parameters, as well as adverse drug events, will be monitored.