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.

Hematopoietic stem cell transplantation with alpha/beta T-lymphocyte depletion and short course of eculizumab in adolescents and young adults with paroxysmal nocturnal hemoglobinuria.

AIM: The main goal is to optimize hematopoietic stem cell transplantation (HSCT) approach among adolescents and young adults with paroxysmal nocturnal hemoglobinuria (PNH) by means of Graft-versus-host disease (GVHD) and post-transplant complications risk lowering. MATERIALS AND METHODS: We report our experience of HSCT from HLA-matched unrelated donors using TCR alfa/beta and CD19 depletion in 5 pts (1M/4F) with PNH, developed after successful immunosuppressive therapy (IST) of acquired aplastic anemia (AA). Median age of pts at the moment of transplantation was 17,8 years (range 14,5-22,7), median interval from IST to PNH was 4 years (5mo - 6,5 y). In all patients non-severe pancytopenia was present: granulocytes 0,8х109/l (0,8-1,8 х109/l) platelets 106 х109/l (27-143 х109/l) and Hb -78 g/l, median PNH clone size in granulocytes was 94 (range 75-99)%. One pts previously developed sinus thrombosis. Conditioning consisted of thoraco-abdominal irradiation 4-6 Gy, cyclophosphamide 100 mg/kg, fludarabine 150 mg/m2 and anti-thymocyte globulin (ATG) or alemtuzumab. Eculizumab was given from day (-7) till day (+14) (every 7 days, only 4 times). GVHD prophylaxis was tacrolimus ± methotrexate. RESULTS: Infusedgraft characteristics were: CD34+ - 8,1х106/kg, CD3TCRab·150х103/kg, CD3gd+ - 7,3х106/kg, СD19+ - 221х103/kg, NK -6,4х108/kg. Engraftment was achieved in all 5 pts with a median of 15(12-18) и 13(10-18) days for granulocytes and platelets, respectively. Skin acute GVHD grade I developed in only 1 pt, and subsided with short course of glucocorticoids. CMV reactivation occurred in 1 pt; there were no episodes of Epstein-Barr Virus (EBV) o rAdenovirus (AdV) reactivation. Full donor myeloid chimerism was established in all pts by day +30. Immune reconstitution was delayed until 6 months after transplant but no severe infections occurred. All pts are alive 1,7-5,5 years (med 4 years) after HSCT with normal hematopoiesis and immune function, full donor chimerism and no late sequelae. CONCLUSION: Transplantation of TCRalfa/beta and CD19 depleted hematopoietic cells from matched unrelated donor after immunoablative conditioning and supported with short course of eculizumab is perfectly safe and efficient technology leading to cure in young patients with PNH.

[Use of crizotinib for refractory ALK-positive lymphomas]. / Primenenie krizotiniba pri refrakternykh formakh ALK- pozitivnykh limfom.

AIM: To evaluate the safety and efficacy of crizotinib used in pediatric patients with relapsed or refractory ALK-positive anaplastic large-cell lymphoma (ALCL). SUBJECTS AND METHODS: The paper describes the experience with crizotinib used in 8 patients with refractory ALK-ALCL before and after allogeneic hematopoietic stem cell transplantation (HSCT). RESULTS: All the 8 (100%) patients treated with crizotinib were recorded to have complete responses, including complete metabolic ones (tumor disappearance as evidenced by positron emission tomography (PET)/computed tomography. CONCLUSION: Low and manageable toxicity of crizotinib and complete PET-negative responses in patients with resistant ALK lymphomas favor the need to test the drug as first-line therapy, by possibly decreasing the intensification of chemotherapy.

Tracking T-cell immune reconstitution after TCRαß/CD19-depleted hematopoietic cells transplantation in children.

αßT-cell-depleted allogeneic hematopoietic cell transplantation holds promise for the safe and accessible therapy of both malignant and non-malignant blood disorders. Here we employed molecular barcoding normalized T-cell receptor (TCR) profiling to quantitatively track T-cell immune reconstitution after TCRαß-/CD19-depleted transplantation in children. We demonstrate that seemingly early reconstitution of αßT-cell counts 2 months after transplantation is based on only several hundred rapidly expanded clones originating from non-depleted graft cells. In further months, frequency of these hyperexpanded clones declines, and after 1 year the observed T-cell counts and TCRß diversity are mostly provided by the newly produced T cells. We also demonstrate that high TCRß diversity at day 60 observed for some of the patients is determined by recipient T cells and intrathymic progenitors that survived conditioning regimen. Our results indicate that further efforts on optimization of TCRαß-/CD19-depleted transplantation protocols should be directed toward providing more efficient T-cell defense in the first months after transplantation.

[Transplantation of the bone marrow from a HLA-compatible unrelated donor after immunoablative conditioning in children with acquired aplastic anemia unresponsive to combined immunosuppressive therapy: preliminary results].

AIM: To analyze the efficiency of transplantation of the bone marrow from a HLA-compatible unrelated donor and continued immunosuppressive therapy (IST) in children with aplastic anemia (AA) unresponsive to 2 courses of IST. SUBJECTS AND METHODS: The study enrolled 14 children aged 2-16 years (median 9 years). A control group comprised 26 patients in whom IST was continued. The median interval between the diagnosis of AA and transplantation was 26 months (9-156 months). The conditioning regimen consisted of thoracoabdominal irradiation in a dose of 2 Gy, fludarabin (Flu) 100-150 mg/m2, cyclophosphamide (Cy) 100-200 mg/kg, antithymocyte globulin (ATG) in 11 patients and Flu, Cy, and ATG in 3. A graft-versus-host reaction was prevented with mycophenolate mefetil in all the patients, tacrolimus in 11, and cyclosporin A in 3. Donors were compatible for high-resolution typing of 10/10 and 9/10 alleles in 8 and 6 patients, respectively; the source of a transplant was bone marrow in 13 patients and granulocyte colony-stimulating factor-mobilized peripheral blood precursors in one case. RESULTS: Thirteen patients achieved primary engraftment after single transplantation; one patient did after repeat transplantation. Grades I to II graft-versus-host reaction (GVHR) developed in 9 patients; postengraftment life-threatening infections in 3, extensive chronic GVHR in 2, circumscribed GVHR in 7. All fourteen hemopoietic cell transplant recipients followed for a median 17.5 months (range 1-71 months) were survivors. CONCLUSION: The likelihood of good survival after unrelated transplantations in AA is much higher than that after continued IST: 100% versus 15 +/- 11%.