Monoclonal antibodies in the treatment of chronic lymphocytic leukemia

Traditional therapy for chronic lymphocytic leukemia (CLL) has consisted of alkylating agents, purine analogs, or a combination of these drugs. These agents are effective at producing remissions but are not curative. Thus, new drugs are still needed to improve the outcome of patients with CLL. The introduction of monoclonal antibodies, such as rituximab and alemtuzumab, provides a novel therapeutic modality. Rituximab is an active agent in CLL. Standard doses of rituximab result in higher response rates in previously untreated than in relapsed patients but low complete response (CR) rates. Rituximab is most effective in combination with chemotherapy, especially fludarabine-based regimens in the first-line and salvage setting. Rituximab is also useful in the treatment of complications of CLL, such as pure red cell aplasia, autoimmune thrombocytopenia, and autoimmune hemolytic anemia. Alemtuzumab has impressive activity in patients with refractory CLL and may play an important role in the consolidation treatment of CLL. Alemtuzumab is most efficacious at clearing disease in the peripheral blood and bone marrow. Bulky lymphadenopathy is less sensitive to therapy. Because of the significant lymphopenia associated with alemtuzumab, antibacterial and antiviral prophylaxis should always be used.