Cladribine treatment in two-hour intravenous infusion for previously-treated low grade B-cell lymphoma: a pilot study

Cladribine is approved to be used in 24-hour continuous infusion for the treatment of low-grade lymphoma by the Ministry of Health, Labor and Welfare in Japan. Pharmacokinetic studies showed that the antitumor activity of cladribine by 2-hour infusion should be comparable to that given by continuous infusion. The safety and anti-tumor activity of short infusion of cladribine was shown in hairy cell leukemia, chronic lymphocytic leukemia and low-grade non-Hodgkin's lymphoma in Europe. We therefore underwent a pilot study to confirm the safety and efficacy of cladribine given by 2-hour infusion for Japanese patients with relapsed or refractory indolent B-cell lymphoma. Cladribine at a dose of 0.09 mg/kg was administered in 2-hour intravenous infusion for 5 consecutive days. The treatment was repeated at a 28-day interval for at least 2 cycles, and its efficacy and toxicity were investigated. Fourteen patients were entered into this study. Eight patients (57%) responded to cladribine, including 2 (14%) complete response (CR) and 6 (43%) partial response (PR). The median duration of response was 20+ and 21+ months for CR, and 12 months ranging from 3 to 34 months for PR, respectively. Grade 3 or 4 neutropenia and lymphocytopenia occurred in 43% and 71% of patients, respectively, but there was no febrile neutropenia or opportunistic infection associated with cladribine treatment. No other adverse events greater than grade 3 were encountered. The tumor response and degree of toxicity were comparable with those observed in cladribine treatment given by continuous infusion at a same dose. Cladribine can be administered in 2-hour infusion in an outpatient clinic and is therefore quite convenient for patients.