Introduction.Neuroblastoma (NB) is the most common extracranial pediatric solid tumor. The high-risk group patients are characterized by adverse prognosis and require intensive complex therapy including high-dose chemotherapy (HDCT) with hematopoietic stem cell transplantation (auto-HSCT). The current study presents a single center experience of HSCT with auto-HSCT for high-risk NB performed in Raisa Gorbacheva Memorial Research Institute of Children Oncology, Hematology and Transplantation, First Pavlov State Medical University of St. Petersburg, Ministry of Health of Russia.Patients and methods.A cohort of 72 consecutive high-risk NB patients was included in the study. Among them 69 patients received Bu-Mel conditioning regimen (busulfan 16 mg/kg, melphalan 140 mg/m2 ), in 3 patients the 5D/5D regimen was used (carboplatin 1000 mg/m2 , irinotecan 150 mg/m2 , temozolomide 750 mg/m2 , etoposide 400 mg/m2 , cyclophosphamide 140 mg/kg). In most cases the autologous hematopoietic stem cells source was bone marrow (BM) (n = 59; 82 %), peripheral blood stem cells (PBSC) (n = 11; 15 %), or BM and PBSC (n = 2; 3 %). In 52/66 (79 %) patients with initial bone marrow involvement the potential transplant contamination was assessed by flow cytometry.Results.The 2-year and 5-year overall (OS) and event-free (EFS) survival was 61 % and 48 %, 41 % and 35 % accordingly. The main adverse factors for OS and EFS were age of more than 18 months at diagnosis, combined bone marrow and bones involvement, MYCN amplification, initial neuron-specific enolase level of more than 100 ng/ml, primary resistance or relapse, and metaiodobenzylguanidinepositive lesions persistence prior to or after HSCT with auto-HSCT.Conclusions.The results achieved are comparable to those described for similar cohorts. Some patient subgroups are unlikely to achieve response after HSCT with auto-HSCT. Therefore, additional stratification methods and treatment modalities are needed.Conflict of interest. The authors declare no conflict of interest.Funding. The study was performed without external funding.

Neuroblastoma (NB) is the most frequent pediatric extracranial solid tumor characterized by extreme biological heterogeneity with variable clinical course. Older age is an important risk factor. These patients may lack other common risk features but still have a chemoresistant disease with dismal prognosis. As there is currently no consensus on optimal treatment for patients with primary resistant NB, a number of clinical options is being explored including immunotherapy-based approaches. Immunotherapy with dinutuximab beta (DB) have proven its effectiveness as maintenance therapy. Allogeneic stem cell transplantation from haploidentical donor (haplo-HSCT) may be an effective consolidation in some cases. However, all forms of immunotherapy are much less effective in patients with large residual tumor. While there is no data on immune checkpoints inhibitors effectiveness in NB, some patients may benefit from this option as a part of complex immunotherapy strategy. Case presentation A 12-year old girl with gross paravertebral thoracic and abdominal tumor was diagnosed with undifferentiated neuroblastoma and bone metastases. While there was no response to several lines of chemotherapy, and only partial tumor resection was possible, the hematopoietic stem cell transplantation from haploidentical donor (haplo-HSCT) was performed as salvage therapy. Since there was only minor decrease in tumor volume with good dynamics by MIBG scan, additional post-transplant therapy was initiated. External beam radiotherapy was given for local control. The patient also received combined immunotherapy with DB and nivolumab. Currently, 3.5 years post haplo-HSCT, despite still gross residual tumor mass, it is MIBG-negative and shows signs of differentiation. Conclusion The combination of haplo-HSCT with post-transplant anti-GD2 and nivolumab may lead to a long-term response in an adolescent with primary resistant NB in spite of a large residual tumor mass.

Immune checkpoint inhibitors (ICIs) are rather efficient in classical Hodgkin's lymphoma (cHL). Pembrolizumab (pembro) is approved in children and demonstrates high response rates with acceptable toxicity. The role of nivolumab (nivo) in pediatric cHL is only to be elucidated. The aim of the presented study was to assess safety and efficiency of nivo in this age group with relapsed or refractory (R-R) cHL. Twenty-one pediatric heavily pre-treated patients 9-18 years old received nivo-based therapy. Overall response was registered in 86% (complete response-57% and partial response-29%). Three-year overall survival (OS) and progression free survival (PFS) were 95% and 29%, respectively. Only 1 clinically significant adverse effect (AE) of nivo was registered in the study (autoimmune thyroiditis). We did not observe any unacceptable toxicity of nivo.

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К л и н и ч е с к и е н а б л ю д е н и я Длительная стабилизация заболевания после аллогенной трансплантации гемопоэтических стволовых клеток у пациента с рецидивом нейробластомы. Клиническое наблюдение и обзор литературы