Long-term follow-up of front-line treatment of hairy cell leukemia with 2-chlorodeoxyadenosine.

Background And Objectives: Although remission of hairy cell leukemia (HCL) after treatment with 2-chlorodeoxyadenosine (2-CdA) appears to be long lasting, few reports currently provide results from follow-up exceeding 5 years.

Design And Methods: We reviewed our HCL patients treated with front-line 2-CdA (by 2-hour infusion) either for 5 consecutive days at 0.14 mg/kg/day (daily subset, n=21) or once a week at 0.14 mg/kg for 5 cycles (weekly subset, n=16).

Results: Of the 37 eligible patients, 30 (81%) achieved complete response (CR) and 7 (19%) partial response (PR) (overall response rate, 100%); identical response rates were recorded in the daily and weekly subsets. After a median follow-up of 122 months (range, 54-156), the overall relapse rate was 27% (8/30): 24% (4/17) had relapsed in the subset treated daily whereas 30% (4/13) had done so in the subset treated weekly (p=ns). The projected 13-year overall and the relapse-free survivals are 96% and 52%, respectively. In terms of hematologic toxicity, the weekly 2-CdA schedule was associated with significantly fewer cases of grade 3-4 neutropenia.

Interpretation And Conclusions: In HCL patients, a single dose of 2-CdA induces a long-term CR. Over 90% of patients are alive 13 years later and over 50% of patients appear to be clinically cured by this treatment. The weekly schedule seems to be a safer option for neutropenic HCL patients, while apparently providing equivalent results in terms of response rates and long-term outcome.