The role of nelarabine in the treatment of T-cell acute lymphoblastic leukemia: literature review and own experience.

AIM: The analysis of experience of nelarabine use in refractory/relapsed T-cell acute lymphoblastic leukemia (T-ALL) depending on the immunophenotype and the line of therapy. MATERIALS AND METHODS: All the patients with relapsed or refractory T-ALL aged from 0 to 18 years who received treatment with nelarabine as a part of the therapeutic element R6 were included in the study. For all patients a detailed immunological analysis of leukemia cells with discrimination of immunological variants TI, TII, TIII or TIV was performed. Patients administered with nelarabine as a first therapeutic element were referred to the first-line therapy group, other patients were referred to the second-line therapy group. Nelarabine was ad- ministered as intravenous infusion at a dose of 650 mg/m2, on days 1-5. Allogeneic hematopoietic stem cells transplantation (allo-HSCT) was considered for all patients. RESULTS: From 2009 to 2017, 54 patients with refractory/relapsed T-ALL were treated with nelarabine. Five-year event-free survival (EFS) and overall survival (OS) was 28% for all patients, cumulative risk of relapse (CIR) was 27%. EFS was significantly higher in nelarabine first-line therapy group in comparison with second-line therapy group (34±8% vs 8±8%, p=0,05). In patients after allo-HSCT EFS, OS and CIR were 51±10%, 50±10% and 39,1±9,5% accordingly. The best results were achieved in patients with TI immunophenotype. No toxicity-related mortality as well as severe neurologic complications or discontinuation of therapy associated with use of nelarabine were reported. CONCLUSION: The use of nelarabine is an effective strategy for the treatment of relapsed and refractory T-ALL. The best treatment outcomes were obtained in patients with TI immunophenotype and in the first-line therapy group. Optimal dosage regimens can be established dur- ing controlled clinical trials.

Results of the first randomized multicentre trial on childhood acute lymphoblastic leukaemia in Russia.

Until 1990, the survival of children with acute lymphoblastic leukaemia (ALL) in Russia was below 10%. To establish a protocol feasible under conditions there, ALL-MB 91 was designed to avoid prolonged bone marrow aplasia, thereby reducing needs for extensive supportive care, blood transfusions, long-lasting hospitalization and costs. High-dose therapies were avoided, anthracycline use was limited and CNS radiation therapy only foreseen in high-risk patients (about 30%). This was randomized against a modified BFM protocol. From 1995 to 2002, 834 patients of age up to 18 years were registered in 10 centres and 713 received after central randomization the allocated risk-stratified treatment. After a median follow-up of 7 years, the event-free survival (EFS) was 67+/-3% on ALL-MB 91 (N=358) vs 68+/-3% on ALL-BFM 90m (N=355). The overall survival (OS) was 71+/-3% vs 74+/-2%, respectively. Anaemia, thrombocytopenia, agranulocytosis >10 days and hospitalization (median 35 vs 68 days) were lower on ALL-MB 91 (P<0.01, N=197). While EFS and OS were similar with both protocols, ALL-MB 91 significantly incurred fewer toxicity and resource requirements and, therefore, has been increasingly used across Russia.