Successful treatment of patients with hairy cell leukemia (HCL) using a single cycle of 2-chloro-2'-deoxyadenosine...

2-Chloro-deoxyadenosine (CdA) is a new adenosine-deaminase (ADA) resistant purine analogue with high specificity for lymphoid cells. It was shown that CdA is very effective in hairy cell leukemia (HCL), refractory chronic lymphocytic leukemia and cutaneous T-cell lymphoma leading to lasting remissions in the majority of patients with HCL. We report the successful treatment of five patients with HCL at different stages of their disease using CdA, who were either previously untreated or had received interferon, splenectomy and deoxycoformycin (dCF), an ADA-inhibitor with high therapeutic efficacy in HCL. After one 7-day course of treatment, all patients reached remission. CdA was well tolerated and, only mild side effects such as skin rash, headache, fever, nausea were observed. Aplasia was pronounced in all instances with a slow recovery. The type of histomorphological procedure in preparing and evaluating bone marrow biopsies is emphasized to detect minimal residual infiltration by hairy cells.