The 62nd Annual Meeting of the Japanese Society of Pediatric Hematology/Oncology

2020 Pediatric Blood & Cancer  
He also undertook post-doctoral work at the Hematology Department, Imperial College, Hammersmith Hospital, London, UK. Professor Mohty's is also head of a translational research team (INSERM) at the Saint-Antoine Research centre in Paris and his research is focused on the pathophysiology and immunobiology of normal and pathological antigenpresenting cells, especially the impact of novel immunomodulatory agents such as proteasome inhibitors, IMiDs and hypomethylating agents. He has a special
more » ... ical focus on the development of reduced-toxicity conditioning regimens, immunotherapy and different aspects of therapy of acute leukemia and multiple myeloma. Professor Mohty is past-president of the European Society for Blood and Marrow Transplantation (EBMT), and the current chairman of the Acute Leukemia Working Party of EBMT. He is also the founder and chairman of the "International Academy for Clinical Hematology (IACH; http://clinical-hematology.org/). He serves on the board of the EBMT, and the "Intergroupe Francophone du Myelome" (IFM). Professor Mohty has published more than 700 peer-reviewed articles (https://www.ncbi.nlm.nih.gov/pubmed/?term = MOHTY+M) in the field of stem cell transplantation, leukemia and myeloma, in different hematology and immunology journals. He also serves as Editor-in-Chief of the journals Bone Marrow Transplantation and Clinical Hematology International, as Associate Editor for Leukemia, European Journal of Haematology and Blood Cancer Journal, as member of the editorial board of Haematologica, and as a regular reviewer in different immunology, hematology, and cancer journals such as the New Engl. B7H3 (CD 276) is a member of the B7 family of immune checkpoint co-inhibitory receptors playing a role in local T-cell regulation. B7H3 functions beyond immune costimulation have been identified, with recent work indicating a crucial role for B7H3 in promoting carcinogenesis and metastases. Overexpression of B7H3 protein has been S2 of S89 ABSTRACTS demonstrated in many human malignancies, and is generally considered to be a negative prognostic marker. Omburtamab (8H9) is a murine monoclonal antibody specific for B7H3. Anti-B7H3 tumor targeted radioimmunotherapy has been studied using 124I-or 131Iomburtamab administered in the cerebrospinal fluid, intraperitoneum, and intratumor cavity. To improve the dismal prognosis of primary and metastatic tumors of the central nervous system, we administered compartmental radioimmunotherapy (cRIT) using intraventricular 131I-Omburtamab (8H9) targeting B7-H3 in a phase 1/2 single-institution study, 512 injections administered to 177 patients (109 with neuroblastoma, 68 with other primary or other metastatic CNS tumors). Interim results from a first ever-multicenter, international study for children with brain and leptomeningeal metastases from neuroblastoma will also be discussed. This same agent has been used to address intraperitoneal metastases from desmoplastic round cell tumors and by convection enhanced delivery for patients with diffuse intrinsic pontine glioma. This presentation will discuss the current state of the art incorporating cRIT 131I-Omburtamab for these challenging pediatric malignan-Pediatric patients with refractory or relapsed metastatic solid tumors have a poor prognosis and additional therapeutic strategies are needed. NK cell based alloreactive anti tumor effects have already been described in patients with leukemias after HLA mismatched, haploidentical stem cell transplantation (SCT). Moreover, Haplo SCT forms a basis for further immunotherapeutic approaches posttransplant. We investigated if this concept can be transferred from leukemias to solid tumors. In a retrospective analysis, patients with refractory or relapsed metastatic ewing's sarcomas and neuroblastomas were evaluated. Additionally, a phase I/II-trial analysing subsequent immunotherapy with anti-GD2mAb (CH14.18/CHO) following was conducted. 26 patients with refractory (n = 5) or metastatic relapsed (n = 20) or locally relapsed MYCN+ (n = 1) neuroblastoma received T/B cell depleted grafts from haploidentical donors. The conditioning regimen comprised melphalan, fludarabine, thiotepa, OKT3 and short course mycophenolate mofetil posttransplant. Engraftment occurred in 96%. EFS and OS at 5 years were 19% and 23%, respectively. No transplantrelated mortality was observed, and single cause of death was progression/subsequent relapse. Median follow-up was 8.1 years. Patients in complete remission before SCT had a significantly better prognosis than those with residual tumor load (p < 0.01). Grades II / III acute GvHD were found in 31% and 12%, respectively. Chronic limited / extensive GvHD occurred in 28% and 10%. Moreover, 36 patients with ewing's sarcomas (≥ 2 bone metastases and/or bone marrow involvement at diagnosis or at relapse and/or relapse ≤ 2 years after diagnosis) received grafts from mismatched unrelated (n = 8) or from haploidentical donors (n = 28). Conditioning regimens were melphalan or busulfan based. 2y EFS was 30% for patients who achieved another CR prior to SCT. Additionally, we evaluated anti GD2 based immunotherapy posttransplant in a prospective trial. 68 patients with 1st to 5th metastatic relapse were enrolled, relapse treatment comprised induction chemotherapy and surgical intervention and local irradiation if possible. Stem cell transplantation was well tolerated without TRM, primary engraftment occurred in 64 patients (95,5%), the median time to an ANC > 0.5 × 109/l was 11 days. Induction of relevant late onset acute GvHD (during antibody treatment) was seen in two patients, one steroid-sensitive stage III GvHD of the GI-tract, one stage II GvHD of the GI-tract. Frequent side effects of antibody treatment were pain, fever, and CRP elevation; rare side effects were SIRS (n = 7) seizures (n = 3), and accommodation disturbances (n = 8). Thirteen of twenty-four patients (54,2%) who achieved CR already prior to antibody treatment, could maintain a complete remission (CR), 20/36 patients (55%) with partial remission prior to antibody treatment achieved CR or could significantly reduce their tumour load after antibody treatment. 2/8 patients (25%) with NR (stable disease/mixed resp.) responded only transiently. Overall survival at 2 and 3 years was 68,6% and 58%. Event free survival at 2 and 3 years was 51,2% and 46,9% (median follow up: 2.5 years). Thus, anti GD2 treatment significantly increased EFS and OS compared to patients who received only Haplo SCT without following immunotherapy. Conclusions: haploidentical SCT is a feasible treatment option that can induce long-term remission in some patients with tolerable side effects and may enable further posttransplant therapeutic strategies based on the donor-derived immune system. Biography: 1991 Completion of medical training at the Eberhard KarlsABSTRACTS S3 of S89 2005 PhD in cellular immunology and transplant biology 2009 associate Professor and Head of the pediatric stem cell transplantation unit. Deputy Medical Director of the department of Hematology/Oncology, University Children's Hospital Tuebingen. Member of the EBMT pediatric working party, the SIOPEN group and of several German study executive boards. The research work concerns clinical trials with graft manipulation in allogeneic stem cell transplantation and immunotherapeutic strategies against lymphatic leukemias and neuroblastoma based on donor NK cells and antibody constructs as well as antiviral therapy with antigen specific T cells. A subset of high risk pediatric acute myeloid leukemia (AML) patients may proceed to allogeneic hematopoietic stem cell transplantation (HSCT) in first complete remission (CR). Among them are patients with adverse prognosis genetic features, such as FLT3-ITD mutation, -7, and complex karyotype, as well as those with poor response to remission induction chemotherapy. Allogenic HSCT is also an important method of salvage for patients previously treated with chemotherapy only who subsequently relapse. The high risk and relapse/refractory AML patients who then relapse after allogeneic HSCT may have very poor outcome. However, a minor but significant subset of these relapsed patients may be cured by a second allogeneic HSCT. Although studies specifically pertaining to second HSCT for pediatric leukemias are few, several have reported long-term overall survival ranging from 20-40%. Important good prognostic factors that derive from these studies include younger patient age, a greater length of time between the two transplants, and the use of myeloablative conditioning prior to the second transplant. In our institution, AML patients who relapse after allogeneic HSCT are treated with salvage chemotherapy only, or salvage chemotherapy consolidated by a second HSCT. Both strategies have resulted in long-term survival in a minor group of relapsed patients. Although excellent treatment outcome has been achieved in the field of childhood acute lymphoblastic leukemia (ALL) over the past decades, allogeneic hematopoietic stem cell transplantation (HSCT) still has been an effective and curative treatment modality for relapsed or refractory cases. However, disease relapse is the major cause of treatment failure after allogeneic HSCT, and at least 30% to 35% of patients experience disease relapse. Options to treat relapse after allogeneic HSCT include the choice of no further therapy, withdrawal of immunosuppression to elicit a therapeutic graft-versus-tumor response, reinduction chemotherapy with the same or different agents, donor lymphocyte infusions and second allogeneic HSCT. (1) In general, if the patient's condition is fit, re-induction therapy followed by second allogeneic HSCT can be considered for the purpose of cure. However, the outcome of this approach in children with ALL is uncertain, with data limited to small retrospective trials conducted mostly at single institutions or at multiple institutions in the same country. To date, there has been two large multi-institutional study of second HSCT in pediatric patients with ALL. A retrospective analysis from Japan (2), which included 171 children, reported that the 2-year overall survival rate was 29%, with a cumulative incidence of relapse of 44%. In 2018, the largest retrospective study from the registry of the European Society for Blood and Marrow Transplantation's Pediatric Diseases Working Party was published (3), which included 214 patients with ALL. Overall survival was 43% at 2 years and 33% at 5 years, and leukemiafree survival was 34% at 2 years and 31% at 5 years. Relapse was also the major cause of treatment failure, which accounts for 47% at 5 years. The common factors reported to correlate with survival outcomes include disease status at the time of second HSCT and interval between transplantations.(2-4) Notably, chronic graft-versus-host disease before second HSCT was shown to be associated with better outcomes.(3) The use of the same donor did not affect the prognosis. Given that many novel targeted and immunotherapies have been under development, it is important to identify specific patient subpopulations that may benefit from a second HSCT compared with those better suited to new approaches. Consequently, we should identify prognostic factors that are useful for establishing a standard treatment strategy in this population. In this presentation, we will review the recent progress in second HSCT in pediatric ALL. Moreover, the experience with second HSCT for children and adolescents with ALL in Republic of Korea will be shared. References : (1) Thakar MS, Forman SJ. ASH evidence-based guidelines: is there a role for second allogeneic transplant after relapse? Hematology Am Soc Hematol Educ Program. 2009;414-418. (2) Kato M, Horikoshi Y, Okamoto Y, et al. Second allogeneic hematopoietic SCT for relapsed ALL in children. Bone Marrow Transplant. 2012;47:1307-1311. (3) Yaniv I, Krauss AC, Beohou E, et al. Second Hematopoietic Stem Cell Transplantation for Post-Transplantation Relapsed Acute Leukemia in Children: A Retrospective EBMT-PDWP Study. Biol Blood Marrow Transplant 24 (2018) 1629-1642 (4) Menon NN, Jenkins LM, Cui H, et al. Factors associated with improved outcomes after second allogeneic hematopoietic cell transplantation for relapsed pediatric leukemia. Ann Hematol. 2016;95:637-644. S4 of S89 ABSTRACTS In the past, the second stem cell transplantation (SCT) was the only possible treatment for relapse after SCT for children with acute lymphoblastic leukemia (ALL). We performed a retrospective analysis of 171 pediatric ALL patients who underwent a second allogeneic SCT for ALL that relapsed after SCT between 1983 and 2009. The 2-year overall survival (OS) was 29 ± 4%, the cumulative incidence of relapse was 44 ± 4%, and the non-relapse mortality rate was 19 ± 4%. Younger age (<9 years), later relapse (>180 days after the first SCT), complete remission (CR) at the time of the second SCT, and myeloablative conditioning were found to be associated with more prolonged survival. Multivariate analysis showed that younger age and later recurrence were associated with better outcomes. Furthermore, the risk of transplantation is significant when patients are forced to undergo transplantation in the non-CR. Next, we examined the outcomes associated with SCT in 325 patients with non-CR ALL who underwent SCT between 2001 and 2015. The 3-year OS was 22% (95% confidence interval, 18-27%). Low-performance scores, presence of >25% myeloblasts, T-cell phenotype, poor risk or normal cytogenetics, and history of SCT were predictors of poor prognosis. With recent developments in immunotherapy, the position of SCT has changed to some extent. Immunotherapy is expected to increase the probability of achieving CR; we would expect to see improved outcomes for second SCT. On the other hand, the SCT outcomes for patients not rescued by immunotherapy will be even more severe. Allogeneic hematopoietic cell transplantation (HCT) is still the attractive strategy for children with high risk acute myeloid leukemia (AML), such as those with unfavorable cytogenetic or molecular aberrations, primary induction failures, relapse, and positivity of minimal residual disease. However, relapse remains a major cause of treatment failure following HCT. Second HCT is a potentially curative option for children with relapsed AML following HCT. In 2016, Dr. Taga from pediatric AML working group of Japan Society for Hematopoietic Cell Transplantation (JSHCT) reported the clinical outcomes of 46 children who underwent second HCT in second complete remission, using the database provided by the JSHCT. The median duration from the first to second HCT was 20 months, and the source of the second HCT was related bone marrow (BM) in 22, related peripheral blood in 6, unrelated BM in 14, and unrelated cord blood in 4 patients. Twenty-five children eventually died of the following causes: progressive disease in 14 and transplantrelated toxicities in 9. The probability of overall survival at 5 years was 41.7%. Multivariate analysis identified that an interval of less than 24 months between the first and second HCT was a significant poor prognostic factor. They concluded that children with AML who experience a relapse after HCT in first remission have a good chance of survival with a second HCT if a second remission is achieved. Whether patients who have relapsed after HCT and are not in remission will benefit from a second HCT is an issue for further study. Background: The prognosis of children with AML has improved owing to hematopoietic cell transplantation (HCT) as a second line therapy and improvements in supportive care following anthracycline-and cytarabine-based chemotherapy; however, the outcome of children with relapsed AML still remain unsatisfactory prognosis. Patients and methods: In order to identify the prognostic factors and improve their prognoses, we conducted a retrospective analysis of the JPLSG AML-05R study using a questionnaire and analyzed 111 patients who relapsed after treatment with the AML-05 protocol. Furthermore, ten genetic alterations were investigated using the available 93 samples. Results: The 5-year OS rate was 36.1%. The major determinant of survival was the duration from diagnosis to relapse. The mean duration was shorter in the non-surviving group (10.1 ± 4.1 months) than in the surviving group (16.3 ± 8.3 months) (p < 0.01). Moreover, achieving a second complete remission (CR2) prior to HCT was associated with a good prognosis (p < 0.01). ECM-or FLAG-based regimens were therefore recommended for reinduction therapy. Genetic analysis also revealed the prognostic significance of FLT3-ITD (p = 0.04) and CBF-AML [t(8;21) and inv(16)] (p < 0.01). Conclusions: Achieving CR2 prior to HCT is important to improve the prognosis with relapsed pediatric AML. Recent molecular target therapy, such as FLT3 inhibitors, may help to improve the patient prognoses. Larger prospective investigations are necessary to establish individualized treatment strategies in patients with relapsed childhood AML. Japan Neuroblastoma (NB) is the second most common solid tumors in children and survival rate of NB patients with high-risk tumor still needs to be improved. Cancer-related gene panel test is one of the useful methods for tumor diagnosis and therapeutic drug selection and its clinical application has been rapidly spreading mainly for adult cancer. However, the system has not yet been well established for pediatric tumors including NB. Therefore, we modified the clinically used NCC-Oncopanel to develop "NCC-Oncopanel-Ped" customized for pediatric cancer. It can survey mutations in 211 genes (including ATRX) and 9 known gene fusions frequently found in pediatric tumors. By using this panel, we conducted sequencing of 49 NB tumors obtained from the JCCG-JNBSG clinical study for high-risk NB (JN-H-11) with Illumina NextSeq sequencer. At least one mutation was detected in 45 tumors. ATRX deletion was successfully identified in one tumor from a male patient. Four tumors had copy number alterations in cell cycle-related genes (amplifications of CDK4, MDM2 and CCND1 or homozygous deletion in CDKN2A/2B). Hotspot mutations such as ALK-R1275Q, FGFR1-N546K, MYCN-P44L and HRAS-G12S were also found. Thus, this panel analysis will provide beneficial information for considering subsequent therapeutic strategies for high risk NBs by showing targetable gene mutations, mutation frequencies and copy number alterations. MYCN oncogene is involved in the development of various malignant tumors such as neuroblastoma, glioblastoma, and small cell lung cancer. TP53 mutation is one of the most common genetic abnormalities in tumors. In this study, we attempted artificial tumorigenesis in normal cells by high expression of MYCN in the background of TP53 mutation. We successfully induced the cranial-and trunk-neural crest cells (NCCs) from iPS cells (iPSCs). Cranial NCCs differentiate into bone, cartilage and trunk NCCs differentiate into sympathetic ganglia, melanocytes. Therefore, we used the NCCs to induce the above-mentioned tumors. We prepared wild-type (WT) iPSC, Li-Fraumeni (Li-F) syndrome patient (TP53 gene mutated)-derived iPSC, and differentiated them into cranial NCCs in vitro. MYCN was introduced into the NCCs by lentivirus. By soft agar colony formation, transformed (TF) clones were obtained from mock-, MYCN-overexpressed (OE)-Li-F, and MYCN-OE WT NCCs. The TF clones were analyzed by microarray. The result of pathway analysis shows that DNA damage response/ apoptosis were downregulated and DNA modification/ telomere maintenance were upregulated after transformation. We injected the TF clones into periadrenal adipose tissue of SCID-Beige mice and a white tumor mass was found in MYCN-OE-Li-F NCCs. HE staining showed pathological features of chondroblastic osteosarcoma (COS). MYCN-OE COS in this study is seemed to be dependent on the cranial NCC background. It is suggested that phenotype of tumors would be determined by adequate differentiation processes during the tumorigenesis. Introduction: Blood transfusion is an essential supportive therapy for pediatric patients with hematological and oncological disease; however, allergic transfusion reaction (ATR) and febrile nonhemolytic transfusion reaction (FNHTR) can occur frequently. Single-nucleotide polymorphisms (SNPs) are known to be associated with the onset of various diseases and adverse events caused by medical treatments. If SNPs' association with ATR or FNHTR is identified, safer transfusion medicine can be provided. Materials and Methods: In this study, we analyzed the association between the onset of ATRs or FNHTRs and 22 allergic sensitizationrelated SNPs. A total of 219 children with hematological and oncological disease who received transfusions of platelets and/or red cell concentrates were included. Results: Of these 219 patients, 105 developed ATRs and/or FNHTRs at least once; there were 71 cases of ATRs only, 19 cases of FNHTRs only, and 15 cases of both. Patients who developed ATRs exhibited significant frequency of a risk allele (T) in the SNP rs6473223 (odds S6 of S89 ABSTRACTS ratio [OR], 2.281; 95% confidence interval [CI], 1.018-5.111; P = .044). Patients who had developed FNHTRs exhibited significant frequency of a risk allele (G) in the SNP rs10893845 (OR, 3.767; 95% CI, 1.701-8.339; P = .001). Conclusion: Recipient's allergic constitution would be a risk factor for developing ATRs and FNHTRs. Analysis of SNPs could help predict which patients are likely to develop these transfusion-related reactions and may help clarify the pathogenic mechanism underlying ATRs and FNHTRs. Introduction: Tumor burden significantly affects the efficacy and toxicity of Chimeric Antigen Receptor T (CAR-T) therapy. Therefore, an optimal tumor reduction strategy is required to improve clinical outcomes. Our report focuses on the management of B-ALL candidate patients before CAR-T cell infusion. Case 1: A 13-year-old (y/o) female with first relapse was refractory to many agents, including a bortezomib-based pre-apheresis regimen and post-apheresis PSL, Ara-C, and Flu/CPA. Her treatment course was complicated by bacteremia and pneumonia. Case 2: A 24 y/o female with second relapse received pre-apheresis PSL and FLA (Flu/Ara-C) and post-apheresis FLA and PSL, which reduced blasts. During treatment, she contracted pneumonia and invasive fungal infection. Case 3: An 11y/o female with fourth relapse after second allo-HSCT had no blasts in the peripheral blood and underwent apheresis without any treatment. Post-apheresis PSL and FLA brought morphological remission but caused pneumonia and bacteremia, requiring chemotherapy discontinuation. Case 4: A 17 y/o female with third relapse after second allo-HSCT also developed extramedullary disease. Her leukemia was resistant to pre-apheresis PSL, VCR/PSL/L-Asp, and CPA but partially responded to Ara-C. She was transferred to another institution for apheresis. Discussion: Pre-and post-apheresis treatments do not necessarily need to aim for remission. Appropriate intensity of individualized regimens should be used instead for disease management while maintaining bone marrow function to avoid life-threatening infections. Between 2004 and 2019, 49 patients received re-carbon ion radiotherapy (re-CIRT) for sarcomas. At the times of initial treatment and re-CIRT, median ages were 22.5 (5-35) and 28 (14-40) year-old. The initial local treatments were surgery in 23, CIRT in 24 and XRT in 1 patient. The major histology was osteosarcoma in 13 and Ewing in 6 patients. In six chondrosarcoma cases, 4 had hereditary multiple exostoses. Prior radiotherapy was CIRT in 40 and XRT in 9 patients. The median period to re-CIRT after initial RT was 32 (1.6-151) months. The total irradiation dose of 70.4 Gy (RBE) in 16 fractions in CIRT group was applied to most of the cases. In XRT the total irradiation dose was ranging from 30-60 Gy in 10-30 Fractions. Infield recurrence was observed in 22, marginal field recurrence in 23 and recurrence on carbon ion beam paths in 4 patients. The re-irradiated doses were 57.6-64.8 Gy (RBE) in 12 fractions, 64-70.4 Gy (RBE) in 16 fractions, 45-56 Gy (RBE) in 8 fractions. One-year overall survival (OS) and 3-year OS rates were 75%, 43%, respectively. Distant metastases were observed in 34 patients before and/or after re-CIRT. Survival rate after re-CIRT was significantly better in patients without metastases. The median survival period in patients with metastases was 19 months, while 43 months in those without metastases. More than grade 3 adverse events like nerve injury and bone fracture were observed in 7 patients. Re-CIRT was safe and would be useful for selected patients controlling metastases. Wilms tumor 1 (WT1) was considered as a high-priority antigen target for cancer immunotherapy because of its high immunogenicity and oncogenicity, as well as its expression in the majority of pediatric hematologic malignancies and solid tumors. We reported previously on a pediatric patient with relapsed diffuse midline glioma, whose H3.3K27M mutation was demonstrated by immunohistochemistry. He exhibited an encouraging clinical evolution during WT1 peptide vaccination as manifested by stable disease, improved clinical manifestations, steroid dose reductions, a WT1-specific immune response, and a good safety profile. In pediatric refractory patients with leukemia, we performed a phase II clinical study of immunotherapy targeting the WT1 protein. We were able to show that WT1 vaccination was safe and could induce WT1-specific immune response. Therefore, this immunotherapy is a potentially promising therapeutic modality for the refractory pediatric cancer. We created a novel oral cancer vaccine using a recombinant Bifidobacterium longum displaying WT1 protein. Oral administrations of B. longum significantly inhibited WT1-expressing tumor growth and protracted survival in mice. B. longum displaying WT1 protein substantially induced tumor infiltration ABSTRACTS S7 of S89 of CD4 + T and CD8 + T cells, and WT1 specific immune response including WT1 specific T cells and elevation of WT1 specific IgG in peripheral blood. We have clarified the mechanism of efficacy of this oral vaccine. This oral vaccine is expected to be effective without severe adverse event and pain for pediatric patients. Adoptive T cell therapy for solid tumor is challenging. For highly malignant metastatic cancers in children, only anti-GD2 antibody has proven efficacy, and now the standard of care for high risk neuroblastoma. GD2, a disganglioside, is a tumor associated antigen abundant on neuroblastoma, retinoblastoma, osteosarcoma, other pediatric sarcomas and melanoma. It is unique because of its restricted expression among normal tissues, its homogeneity between tumors and within tumors, and its infrequent antigen loss. 1986 was when the first phase I trial of first-in-human anti-GD2 monoclonal antibody (mAb) 3F8, a murine IgG3 mAb, began. Since then anti GD2 immunotherapy has evolved from murine, to chimeric mAb and now to humanized mAb. Since IgG antibodies kill tumors through their binding to Fc-receptors, T cells have no FcRs and hence under-utilized. Retargeting T cells using bispecific BsAbs is a logical next step. Anti GD2 Naxitamab-BsAb using the IgG(L)-scFv format, where the anti-CD3 huOKT3 scFv is linked to the carboxyl end of the Naxitamab light chain has shown promising antitumor effect against GD2(+) tumors in preclinical studies. The Phase I trial of T cells armed with chemically conjugated Naxitamab x OKT3 (BiAb) was safe with suggestions of clinical activity. We investigated the use of recombinant BsAb for ex vivo arming of activated polyclonal T cells for infusional cytotherapy and showed its safety and efficacy in preclinical models. This strategy may provide a novel approach by combining T cells with antibodies against GD2(+) tumors in pediatrics and in adults. Even though clinical trials of chimeric antigen receptor (CAR)-T cell therapy in targeting solid tumors have not achieved comparative responses with hematological malignancies, recent trials are underway to overcome the limited effects of CAR-T therapy for solid tumors. Identifying and overcoming the mechanisms associated with dysfunction of CAR-T cells is important to increase the efficacy. Early T-cell exhaustion is a one of the key causes for the impairment of the quality and the function of CAR-T cells, which is demonstrated by low proliferative and cytokine-producing capacities, high population of effector T cell phenotype, and high expression of inhibitory receptors such as PD-1. Here, we have developed piggyBac transposon (PB)mediated CAR-T cells in targeting HER2-, GD2-, and EPHB4-expressing solid tumors. Our PB-CAR-T cells demonstrated memory-rich phenotype with reduced early T-cell exhaustion, leading to strong and sustained tumor control in vitro and in vivo. Our fast, low-cost, and simple manufacturing process has the potential of versatility for producing various CAR-T cells, enrichment of the CAR-T cells with the memory phenotype related to stable anti-tumor efficacy and scalability of CAR-T cell production for use in clinical settings. Pediatric patients with refractory or relapsed metastatic solid tumors have a poor prognosis and additional therapeutic strategies are needed. NK cell based alloreactive anti tumor effects have already been described in patients with leukemias after HLA mismatched, haploidentical stem cell transplantation (SCT). Moreover, Haplo SCT forms a basis for further immunotherapeutic approaches posttransplant. We investigated if this concept can be transferred from leukemias to solid tumors. In a retrospective analysis, patients with refractory or relapsed metastatic ewingt's sarcomas and neuroblastomas were evaluated. Additionally, a phase I/II-trial analysing subsequent immunotherapy with anti-GD2mAb (CH14.18/CHO) following was conducted. 26 patients with refractory (n = 5) or metastatic relapsed (n = 20) or locally relapsed MYCN+ (n = 1) neuroblastoma received T/B cell depleted grafts from haploidentical donors. The conditioning regimen comprised melphalan, fludarabine, thiotepa, OKT3 and short course mycophenolate mofetil posttransplant. Engraftment occurred in 96%. EFS and OS at 5 years were 19% and 23%, respectively. No transplantrelated mortality was observed, and single cause of death was progression/subsequent relapse. Median follow-up was 8.1 years. Patients in complete remission before SCT had a significantly better prognosis than those with residual tumor load (p < 0.01). Grades II / III acute GvHD were found in 31% and 12%, respectively. Chronic limited / extensive GvHD occurred in 28% and 10%. Moreover, 36 patients with ewingt's sarcomas (≥ 2 bone metastases and/or bone marrow involvement at diagnosis or at relapse and/or relapse ≤ 2 years after diagnosis) received grafts from mismatched unrelated (n = 8) or from haploidentical donors (n = 28). Conditioning regimens were melphalan or busulfan based. 2y EFS was 30% for patients who achieved another CR prior to SCT. Additionally, we evaluated anti GD2 based immunotherapy posttransplant in a prospective trial. 68 patients with 1st to 5th metastatic relapse were enrolled, relapse treatment comprised induction chemotherapy and surgical intervention and local S8 of S89 ABSTRACTS irradiation if possible. Stem cell transplantation was well tolerated without TRM, primary engraftment occurred in 64 patients (95,5%), the median time to an ANC > 0.5 × 109/l was 11 days. Induction of relevant late onset acute GvHD (during antibody treatment) was seen in two patients, one steroid-sensitive stage III GvHD of the GI-tract, one stage II GvHD of the GI-tract. Frequent side effects of antibody treatment were pain, fever, and CRP elevation; rare side effects were SIRS (n = 7) seizures (n = 3), and accommodation disturbances (n = 8). Thirteen of twenty-four patients (54,2%) who achieved CR already prior to antibody treatment, could maintain a complete remission (CR), 20/36 patients (55%) with partial remission prior to antibody treatment achieved CR or could significantly reduce their tumour load after antibody treatment. 2/8 patients (25%) with NR (stable disease/mixed resp.) responded only transiently. Overall survival at 2 and 3 years was 68,6% and 58%. Event free survival at 2 and 3 years was 51,2% and 46,9% (median follow up: 2.5 years). Thus, anti GD2 treatment significantly increased EFS and OS compared to patients who received only Haplo SCT without following immunotherapy. Conclusions: haploidentical SCT is a feasible treatment option that can induce long-term remission in some patients with tolerable side effects and may enable further posttransplant therapeutic strategies based on the donor-derived immune system. It is now well established that the transcriptional regulator Bcl11b specifies T cell fate. To explore the mechanism how distally located BCL11b enhancers, while separated by vast genomic distances, selectively target their cognate promoters, we have examined the nuclear architecture of a super-enhancer that regulates the expression of Bcl11b. During T cell commitment, the super-enhancer is repositioned from the lamina to the nuclear interior. In the search for candidate factors that repositioned the Bcl11b control region, we identified long non-coding RNA ThymoD (thymocyte differentiation factor). ThymoD expression pattern in T cell progenitors immediately precedes that of Bcl11b. A stoppage of ThymoD transcription in mice displayed a block in T cell development and rapidly developed T-cell malignancies. We found that ThymoD transcription acted in cis to promote demethylation at CTCF bound sites and activated cohesin-dependent looping to reposition the Bcl11b enhancer from the lamina to the nuclear interior and to juxtapose the Bcl11b enhancer and promoter into a single-loop domain. These large-scale changes in nuclear architecture were associated with the deposition of activating epigenetic marks across the loop domain, plausibly facilitating phase separation. These data indicate non-coding transcription orchestrates chromatin folding and compartmentalization to direct with high precision enhancer-promoter communication. At last, we introduce the differentially regulated topologically associated domains (TADs) in human ThymoD-BCL11b locus between ETP-ALL and T-cell ALL. MicroRNAs (miRNAs) are non-coding RNAs that co-regulate the expression of multiple genes via mRNA transcript degradation or translation inhibition. Expression profiling of miRNA was shown to be associated with progression and response to therapy, suggesting their Cancer metabolism is characterized by not only commonly known aerobic glycolysis but also specific features of cellular origin. However, it is unclear how the lineage identity influences the metabolic phenotype in cancer cells. Here we show that lysine-specific demethylase-1 (LSD1) directs the hematopoietic lineage-specific metabolic program in acute myeloid leukemia (AML). The loss of LSD1 reduced activities of heme synthesis as well as glycolysis in erythroid leukemia cells. Unexpectedly, LSD1 stabilized the erythroid transcription factor GATA1 that directly activated the enhancers of heme synthesis and glycolysis genes. In contrast, LSD1 repressed the enhancer ABSTRACTS S9 of S89 of the granulo-monocytic transcription factor C/EBPα via the H3K4 demethylation, whereas C/EBPα in turn inhibited the expression of GATA1-target genes. Further, transcriptome analyses showed that expression balances among LSD1, GATA1, CEBPA and metabolic genes were widely conserved in AML cell lines and clinical samples. Our findings uncover that LSD1 controls these lineage-specific transcription factors to define metabolic properties in AML. ABSTRACTS S11 of S89 high school education, respectively; adult medical care was often associated with admission to high school. There is plenty of experience in the department suggesting that high school education is not continued. Educational support is crucial for hemato-oncologic patients in senior high school who require long-term hospitalization. In 2017, Hiroshima University Hospital joined the Board of Education in Hiroshima City/Prefecture to provide teaching services for inpatients who are senior high-school students. Remote lessons using information and communication technology (ICT) have been applied to patients since 2018. Four patients have already received remote lessons, and five patients are currently in preparation. A humanoid robot termed "Ori-Hime" or a tablet computer has been used for virtual lessons to connect the patient to their class at school. Medical student volunteers at Hiroshima University also directly help patients with learning. Remote lessons were effective for the continuity of learning and for communication with patients' classmates and teachers, which led to effective preparation for academic life after they were discharged. Three of four patients were promoted to the next grade as a result of the acquisition of required credits in school. Thus, the expansion of ICT-based remote learning is useful for students who require long-term hospitalization. The establishment of an educational system that fosters collaboration among the hospital, regional senior high school, and Board of Education in each prefecture is necessary.
doi:10.1002/pbc.28797 pmid:33205885 fatcat:m5jeoj3l7fdbtjikanrxidv5gm