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Aim. To evaluate the efficiency of the original ALL-MB-2002 protocol within the multicenter study of treatment of acute lymphoblastic leukemia (ALL) in children. Subjects and methods. A total of 1873 primary patients with ALL aged 1 to 18 years, of whom 1544 patients were enrolled in this study, were notified at 36 clinics of Russia and Belarus from April 15, 2002, to January 1, 2008. Results. With the median observation of 4.12 years, 7-year event-free survival (EFS) was 73±13%; overall survival (OS) 78±2%; relapse-free survival 82±1%. The rates of EFS and OS were equal and amounted to 76±2 and 80±2% in the standard-risk group (SRG) and intermediate-risk group (ImRG), respectively. In the high-risk group (HRG) patients, EFS and OS were as high as 30±6 and 37±6%, respectively. The frequency of relapses with central nervous system lesion was as much as 4.7% in all the patients, 6-year cumulative risk for isolated neurorecurrences being 2.5% in the SRG patients. Adolescents, patients with the baseline leukocytosis (more than 100109/l), and those with a splenic size of over 4 cm or more from the costal arch margin had substantially worse survival rates. A poor early response to therapy (on induction days 8 and 15) was also associated with its lower efficiency. Conclusion. Despite a considerable rise in the number of centers and a slight increase in the intensity of therapy, the results of the new ALL-MB-2002 protocol are as minimum equivalents obtained in the use of the previous ALL-MB-91 protocol. A significant improvement in the overall results of therapy and a reduction in the cumulative risk for isolated neurorecurrences were noted in the ImRG patients.

The paper presents the results of a multicenter randomized study of two-dose COLI-ASP regimens in therapy of consolidation of standard risk-group (SRG) children and adolescents with acute lymphoblastic leukemia (ALL) treated by the ALL-MB-2002 protocol. The principal aim of the study was to elucidate whether the dose of COLI-ASP might be reduced without losing the efficiency of therapy. The analysis covered primary ALL patients notified at 36 clinics of Russia and Belarus, enrolled for the study in the period of May 1, 2002, to October 10, 2006. Out of 819 patients to be examined, 414 received COLI-ASP in a dose of 10,000 U/m2 (a control group), and 405 children took it in a dose of 5,000 U/m2 (a study group). No statistically significant differences were found between the patients in gender, age, baseline leukocytosis, and spleen size. The study showed no statistically and clinically significant differences in event-free, overall, and relapse-free survival (EFS, OS, and RFS, respectively) and relapse rates with the use of two-dose COLI-ASP regimens. However, in the control group, the death rate in remission was twice greater than that in the study group (p = 0.02). Detailed analysis of the outcomes of therapy in some subgroups revealed no differences between the control and study groups. The Cox multiple regression analysis has indicated that the factors influencing EFS and RFS are the baseline sizes of the spleen, baseline leukocytosis, age, and a response to treatment in the period of induction, rather than the dose of E. coli asparaginase. The authors have also found that among the SRG patients, there is a subgroup of patients without risk factors, in whom the reduction in the COLI-ASP dose may substantially increase survival rates, by lowering toxicity and mortality in remission.

The results of two consecutive multicenter clinical trials enrolled 241 patient with childhood mature B-cells non-Hodgkin lymphomas/leukemia are presented. Patients received treatment according B-NHL 2004mab protocol (n = 83) and B-NHL 2010M (n = 158) with combined immunochemotherapy (ICT) in Russian and Belarus pediatric clinics from 2004 to 2015 years. Primary patients with different mature B-NHL (Burkitt lymphoma/leukemia, diffuse large B-cell lymphoma and primary mediastinal B-cell lymphoma (DLBCL and PMBCL)) aged from 2 to 18 years are included in the studies.Protocol B-NHL 2004mab for treatment of children and adolescents with B-NHL/B-AL, stage III and IV, includes a combination of chemotherapy (PCT) and rituximab – an antibody against the B-cells receptor CD20. PCT courses similar to those in the B-NHL BFM90 protocol (group III) with the exception of methotrexate dose in induction courses, reduced to 1 g/m2 /24 h in order to reduce toxicity. Rituximab (Mabthera, 375 mg/m2 /h) used for the first time in the treatment of children and adolescents with B-NHL. Of the 83 patients included, clinical remission was achieved in 77 (92.8 %). With a median follow time of 51.6 months, remission continued in 23 (85.2 %) patients with B-AL, in 32 (88.9 %) patients with LB and 19 (95.0 %) patients – with DLBCL. With median follow time of 65.2 months, event-free and overall survival was 84 ± 6 and 82 ± 8 %, respectively.Based on previous experience in order to further optimize B-NHL treatment, new protocol B-NHL 2010M with effect-adapted therapy and improvement of stratification risk group criteria was proposed. Overall survival in patients of 1st and 2nd risk groups with full implementation of diagnosis and treatment is approaching 100 %. In interim analysis of 3rd risk group patients, pOS was 88 ± 3 %. The incidence of induction death (infections, metabolic complications) remains within 2.7 % (n = 4); refractory cases (n = 2; 1.3 %) and relapses (n = 4; 2.7 %) developed after 2–4 months of remission, were observed only in patients with Burkitt lymphoma/leukemia. In this cases 2nd line therapy and auto-HSCT is not allowed to achieve remission. All PMBCL and DLBCL patients were achieved remission, but in 50 % of cases only after second line, radio- and cell therapy.The authors conclude that a combined immunochemotherapy of B-NHL in children and adolescents, including the target drug (rituximab) and 5-day courses of cytostatic therapy, highly effective, despite a reduce induction intensity. Therapy for the analyzed protocol requires qualitative dynamic efficacy monitoring and timely correction of therapy. In order to solve a refractory problem and further reduce the toxicity, necessary to continue research using fundamental discoveries in recent years.