Efficacy of fludarabine, a new adenine nucleoside analogue, in patients with prolymphocytic leukemia and the prolymphocytoid variant of chronic lymphocytic leukemia.

PURPOSE: To describe the results of fludarabine therapy in patients with prolymphocytic leukemia (PLL) and the prolymphocytoid variant of chronic lymphocytic leukemia (CLL-Pro). PATIENTS AND METHODS: Seventeen patients with a diagnosis of PLL or CLL-Pro received fludarabine 30 mg/m2 over 30 minutes daily for 5 days every 4 weeks alone (12 patients), or with prednisone (five patients). Previously defined criteria for response were used. Differences in response rates according to various characteristics were evaluated by chi-square test. RESULTS: Three patients (18%) achieved complete remission, and three (18%) had a partial remission, for an overall response rate of 35%. Responses were durable and occurred in all involved organ sites. Lower response rates were observed in patients with anemia, thrombocytopenia, advanced Rai stages, and primary resistance to prior therapy. Toxicities were minimal except for febrile episodes associated with therapy. CONCLUSION: Fludarabine has shown encouraging results in these patients and deserves further investigation in combination with other active agents, and in the setting of front-line therapy.