Purine Analogue-Based Chemotherapy Regimens for Patients With Previously Untreated B-Chronic Lymphocytic Leukemia

B-cell chronic lymphocytic leukemia (B-CLL) is a clonal malignancy characterized by the expansion of small B lymphocytes and accumulation of CLL cells. This disease is the most common form of leukemia in the Western hemisphere and is currently not considered to be curable using currently available therapies. Published reports have suggested that purine analogues have activity in B-CLL and superior to alkylating agents. Even though responses have been observed with purine analogues that are used as single agents, these responses were not durable. The use of combination purine analogue therapy with alkylating agents and/or monoclonal antibodies was then explored in order to take advantage of synergistic actions of these agents to improve the quality of clinical responses. Both fludarabine and pentostatin have shown improved responses when combined with alkylating agents and even higher overall and complete responses (CRs) when combined with monoclonal antibodies.