Long-term follow-up of hairy cell leukemia patients treated with 2-chlorodeoxyadenosine

Background and Objectives. The management of patients with hairy cell leuke mia (HCL) has evolved significantly over the past two decades. In fact, bot h 2'-deoxycoformycin (DCF) and 2-chlorodeoxyadenosine (2-CdA) induce comple te response (CR) in the majority of the patients with HCL. However, fewer d ata exist on the long-term follow-up of patients who have undergone the cha racteristically brief exposure to 2-CdA therapy. Thus, it is important to e valuate such long-term outcome data in order to increase understanding of t he efficacy of this agent in the management of HCL. Design and Methods. We reviewed the long-term follow-up data of 23 HCL pati ents pretreated with alpha-interferon and then treated with P-CdA administe red as a single continuous IV infusion for 7 days at the dose of 0.1 mg/kg/ day in our institute between January 1991 and February 1992. Results. Of 23 patients, 19 (83%) achieved a CR and 4 (17%) a partial respo nse (PR), with an overall response rate of 100%. After a median follow-up o f 102 months (range: 96-108), there have been 9 (39%) relapses, in the PR s ubset 100% of patients relapsed within the first 45 months of follow-up. in the group of patients who obtained a CR, 26% relapsed; all these relapses occurred between 54 and 86 months. Overall, the median time to relapse was 54 months (range: 16-86). All relapsed patients were retreated with 2-CdA a t the dose of 0.15 mg/kg/day for 5 days in a 2-hour infusion, and 67% and 2 2% then obtained CR or PR, respectively. The median duration of this second response was 48 months (range: 22-80). Ail but one of these patients still maintain the second response to 2-CdA. The 9-year overall and the relapse- free survivals are 91% and 70%, respectively. Interpretation and Conclusions. In HCL patients a single dose of 2-CdA indu ces a long-term CR with a 9-year survival > 90%. Over 50% of patients appea r to be clinically cured by this procedure, but the lack of a long-term pla teau in the relapse-free survival curve means caution on this point is stil l warranted. (C) 2000, Ferrata Storti Foundation.