Background: Hairy cell leukaemia is a chronic B-cell disorder that follows an indolent course. Cladribine has in the last decade emerged as the drug of choice for treating hairy cell leukaemia.
Material: We report on the long-term follow-up of 26 patients treated from January 1992 to June 1993 with cladribine administered subcutaneously.
Results: 25 patients were evaluable for response. 21 patients (84%) achieved complete remission, three patients (12%) achieved partial remission, and one patient had no response. At a median follow-up of 6.8 years, 24 patients (92%) were still alive. One patient died from infections four months after treatment, while the other patient died from a malignant melanoma 4.4 years after treatment. Relapse assessed by flow cytometry was diagnosed in 95% of the patients. 38% of those in complete and 67% of those in partial remission were treated by a second course of cladribine during the follow-up. Retreatment led to normalisation of peripheral blood count in all patients.
Interpretation: Cladribine is not a curative treatment in hairy cell leukaemia, but it induces long lasting remission.