ORAL CLADRIBINE AS PRIMARY THERAPY FOR PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC-LEUKEMIA

Purpose: Purine analogs have wide potential indications in the treatme nt of hematologic malignancies, but intravenous administration has bee n required, We previously established that the oral bioavailability of cladribine is 50%. Our aim was to evaluate the efficacy and toxicity of oral cladribine to previously untreated patients with chronic lymph ocytic leukemia (CLL). Patients and Methods: Sixty-three patients with symptomatic but previously untreated CLL received cladribine solution 10 mg/m(2)/d orally for 5 consecutive days in monthly courses. Result s: Complete remission (CR) was achieved in 24 patients (38%), and 23 p atients (37%) had a partial response (PR), Most patients, including th ose in whom there was no remission (NR) achieved normal blood lymphocy te counts. Failure to meet response criteria was mostly due to thrombo cytopenia. The median response duration was not reached at 2 years. Th e median survival time among 13 deceased patients was 322 days, wherea s the median observation time of surviving patients is 760 days. The o verall survival rate at 2 years is 82%, Response rate was associated w ith clinical stage. Grade III to IV infectious toxicity occurred in on e third of patients. Conclusion: Orally administered cladribine is an effective and feasible therapy for CLL, and produces durable remission s in three quarters of the patients, However, significant toxicity may occur and further studies are required to assess long-term effects an d quality-of-life aspects.