Treatment of hairy cell leukemia with cladribine (2-chlorodeoxyadenosine).

Hairy cell leukemia is a rare lymphoproliferative disorder resistant to conventional chemotherapeutic agents. Recently, the purine analogue cladribine (2-chlorodeoxyadenosine, 2-CdA) was introduced for the treatment of this disease. We report on 14 patients with hairy cell leukemia who were treated with 2-CdA at our department between 1993 and 1997. The patients received a single cycle of 2-CdA at a dose of 0.07 or 0.09 mg/kg/day by continuous infusion, over a seven-day period. Five patients were previously untreated, while the others had received prior treatment with interferon-alpha (seven patients), interferon-alpha and splenectomy (one patient) or interferon-alpha, splenectomy and pentostatin (one patient). Six patients achieved complete remission, three a good partial response and three partial remission. Two patients did not respond to treatment and one of them died from septicemia in aplasia. Relapse of the disease occurred in two patients. Side effects such as fever (WHO grade 2) and/or neutropenia (WHO grade 4) were noted in eight patients. Thus, 2-CdA is an effective treatment of hairy cell leukemia that can induce long lasting remissions in both, previously treated and untreated patients.