Pentostatin in the treatment of advanced hairy cell leukemia

inhibitor of adenosine deaminase (ADA), was admin-istered in a biweekly low-dose (2 to 4 mg/m 2) intrave-nous (IV) schedule to patients with advanced hairy cell leukemia. Twenty-three patients were treated, including 12 patients previously treated by splenec-tomy and five patients treated with interferon. Twen-ty-one of 23 patients had objective responses, includ-ing 20 who achieved a complete remission (CR). Responses occurred rapidly, with an average time to CR of 5.4 months. Treatment was not continued once CR was achieved, and 15 of 20 patients remain in remission with an average duration of 12.6 months. CRs were achieved in both patients previously treated H AIRY CELL LEUKEMIA is a chronic leukemia of B lymphocyte lineage first described by Bouroncle et al in 1958. ' The clini-cal course is variable, with some patients remain-ing asymptomatic for years, while the majority of patients require treatment for symptomatic cyto-penia and/or marked splenomegaly.2 " The standard treatment for these patients was splenectomy, which improved the hematologic complications of the disease in 90 % of the patients.3'4 However, splenectomy may not pro-long survival and a significant number of patients do not respond to, or relapse after, splenectomy. 4 6 In patients who require further therapy, other modalities tried in the past include low-dose chlorambucil, intensive chemotherapy, leuka-pheresis, radiation therapy, and bone marrow transplantation. However, none of these treat-ments have made a significant impact in th