Screening and interventional strategies for the late effects and toxicities of hematological malignancy treatments in pediatric survivors.

INTRODUCTION: Advancements in pediatric cancer treatment have increased patient survival rates; however, childhood cancer survivors may face long-term health challenges due to treatment-related effects on organs. Regular post-treatment surveillance and early intervention are crucial for improving the survivors' quality of life and long-term health outcomes. The present paper highlights the significance of late effects in childhood cancer survivors, particularly those with hematologic malignancies, stressing the importance of a vigilant follow-up approach to ensure better overall well-being. AREAS COVERED: This article provides an overview of the treatment history of childhood leukemia and lymphoma as well as outlines the emerging late effects of treatments. We discuss the various types of these complications and their corresponding risk factors. EXPERT OPINION: Standardizing survivorship care in pediatric cancer aims to improve patient well-being by optimizing their health outcomes and quality of life. This involves early identification and intervention of late effects, requiring collaboration among specialists, nurses, and advocates, and emphasizing data sharing and international cooperation.

Factors Affecting Day-to-Day Variations in Tacrolimus Concentration among Children and Young Adults Undergoing Allogeneic Hematopoietic Stem Cell Transplantation.

Tacrolimus is widely used as prophylaxis for graft-versus-host disease (GVHD) in allogeneic stem cell transplantation (allo-HSCT). It has a narrow therapeutic index range; high tacrolimus concentrations are associated with toxicity, whereas low concentrations are associated with an increased risk of GVHD. Although dose adjustments based on therapeutic drug monitoring are performed, unexpected large variations in tacrolimus concentration are sometimes encountered. The available evidence suggests that the factors affecting tacrolimus concentration are not fully understood. This study was aimed primarily at investigating the factors affecting day-to-day variations in tacrolimus concentration in children and young adults who received continuous tacrolimus infusion after allo-HSCT. The secondary objective was to identify the factors causing large variations (>20%) in tacrolimus concentrations. This retrospective cohort study comprised 123 consecutive pediatric and young adult patients (age <25 years) who received continuous i.v. tacrolimus infusion after allo-HSCT at Shinshu University Hospital, Matsumoto, Japan, between January 2009 and December 2021. To compare day-to-day variations in tacrolimus concentration without consideration of the tacrolimus dose, 2 consecutive days when the tacrolimus dose was not changed were selected from between the first post-allo-HSCT day of a tacrolimus concentration >7 ng/mL and day 28 post-allo-HSCT. Subsequently, information for the subsequent 24 hours was collected along with the tacrolimus concentrations and hematocrit values. Tacrolimus concentration was determined using whole blood samples. Tacrolimus concentrations were significantly higher in patients who received red blood cell concentrate (RCC) transfusions (P < .0001) and methotrexate (P = .0162), patients with persistent fever (P = .0056), and patients with a decline in fever (P = .0003). In contrast, tacrolimus concentrations were significantly lower in patients who received platelet concentrate (PC) transfusions (P < .0001), who redeveloped fever (P = .0261), and who had a replaced tacrolimus administration route set (P = .0008). Variations in tacrolimus concentration were significantly correlated with variations in hematocrit (r = .556; P < .0001). Body weight (P < .0001), RCC transfusion (P < .0001), methotrexate use (P = .0333), persistent fever (P = .0150), and decline in fever (P = .0073) were associated with a sharp increase in tacrolimus concentration. In contrast, body weight (P < .0001), PC transfusion (P = .0025), and replacement of the tacrolimus administration route set (P = .0025) were associated with a sharp decrease in tacrolimus concentration. RCC and PC transfusions, fever, methotrexate administration, and replacement of the tacrolimus administration route set were independent factors affecting day-to-day variations in tacrolimus concentration. In addition to these factors, low body weight was a risk factor for both sharp increases and decreases in tacrolimus concentration. These findings suggest the need for better control of tacrolimus concentration using whole blood samples.

Mutated GM-CSF-based CAR-T cells targeting CD116/CD131 complexes exhibit enhanced anti-tumor effects against acute myeloid leukaemia.

OBJECTIVES: As the prognosis of relapsed/refractory (R/R) acute myeloid leukaemia (AML) remains poor, novel treatment strategies are urgently needed. Clinical trials have shown that chimeric antigen receptor (CAR)-T cells for AML are more challenging than those targeting CD19 in B-cell malignancies. We recently developed piggyBac-modified ligand-based CAR-T cells that target CD116/CD131 complexes, also known as the GM-CSF receptor (GMR), for the treatment of juvenile myelomonocytic leukaemia. This study therefore aimed to develop a novel therapeutic method for R/R AML using GMR CAR-T cells. METHODS: To further improve the efficacy of the original GMR CAR-T cells, we have developed novel GMR CAR vectors incorporating a mutated GM-CSF for the antigen-binding domain and G4S spacer. All GMR CAR-T cells were generated using a piggyBac-based gene transfer system. The anti-tumor effect of GMR CAR-T cells was tested in mouse AML xenograft models. RESULTS: Nearly 80% of the AML cells predominant in myelomonocytic leukaemia were found to express CD116. GMR CAR-T cells exhibited potent cytotoxic activities against CD116+ AML cells in vitro. Furthermore, GMR CAR-T cells incorporating a G4S spacer significantly improved long-term in vitro and in vivo anti-tumor effects. By employing a mutated GM-CSF at residue 21 (E21K), the anti-tumor effects of GMR CAR-T cells were also improved especially in long-term in vitro settings. Although GMR CAR-T cells exerted cytotoxic effects on normal monocytes, their lethality on normal neutrophils, T cells, B cells and NK cells was minimal. CONCLUSIONS: GMR CAR-T cell therapy represents a promising strategy for CD116+ R/R AML.

Heterozygous missense variant in TRPC6 in a boy with rapidly progressive infantile nephrotic syndrome associated with diffuse mesangial sclerosis.

Transient receptor potential channel C6 encoded by TRPC6 is involved in slit diaphragm formation in podocytes, and abnormalities of the TRPC6 protein cause various glomerular diseases. The first identified pathogenic variant of TRPC6 was found to cause steroid-resistant nephrotic syndrome that typically developed in adulthood and then slowly led to end-stage renal disease, along with a renal pathology of focal segmental glomerulosclerosis. Here, we report a patient with rapidly progressing infantile nephrotic syndrome and a heterozygous missense TRPC6 variant. The patient, a 2-year-old Japanese boy, developed steroid-resistant nephrotic syndrome at age 11 months. His renal function deteriorated rapidly, and peritoneal dialysis was introduced at age 1 year and 6 months. His renal pathology, obtained at age 1 year and 1 month, was consistent with diffuse mesangial sclerosis (DMS). Clinical exome analysis and custom panel analysis for hereditary renal diseases revealed a reported heterozygous missense variant in TRPC6 (NM_004621.5:c.523C > T:p.Arg175Trp). This is the first report of a patient with a TRPC6-related renal disorder associated with DMS.

Autologous non-human primate model for safety assessment of piggyBac transposon-mediated chimeric antigen receptor T cells on granulocyte-macrophage colony-stimulating factor receptor.

OBJECTIVES: Chimeric antigen receptor (CAR)-T cell therapy redirected to specific antigens on tumor cells is a promising immunotherapy strategy for various cancers. Most target antigens are also expressed on normal tissues at varying levels, and therefore, a considerable challenge in the field is determining safety profiles, including life-threatening off-tumor and off-target toxicities. The granulocyte-macrophage colony-stimulating factor receptor (hGMR) is a promising target for CAR T-cell therapy for a subset of acute myelocytic leukaemia, although it is also expressed on normal cells including monocytes, macrophages, CD34-positive haematopoietic cells and vascular endothelial cells. hGMR and other immune-related proteins are highly conserved between humans and cynomolgus macaques (Macaca fascicularis). Therefore, in this study, we engineered cynomolgus T cells to express CAR molecules redirected to hGMR by piggyBac (PB) transposon-based gene transfer and adoptively transferred autologous hGMR-CAR T cells into cynomolgus macaques. METHODS: We established PB-mediated human GMR (hGMR)-specific CAR T cells using cynomolgus peripheral blood mononuclear cells and transferred them into autologous individuals, and evaluated the potential toxicity related to hGMR-CAR T cells. RESULTS: hGMR-CAR T cells did not exert overt organ toxicities such as bone marrow suppression, monocytopenia and vasculitis, although they recognised and killed cynomolgus monocytes and macrophages in vitro. CONCLUSION: Although our model did not simulate a tumor-bearing model, it supports the safety of hGMR-CAR T cells and demonstrates the usefulness of a non-human primate model to evaluate the safety of T-cell products by assessing off-tumor/off-target toxicity before clinical trials.

Myelodysplastic syndrome in an infant with constitutional pure duplication 1q41-qter.

We report on a Japanese female infant as the fourth patient with the constitutional pure duplication 1q41-qter confirmed by chromosomal microarray and as the first who developed myelodysplastic syndrome (MDS) among those with the constitutional 1q duplication. Common clinical features of the constitutional pure duplication 1q41-qter include developmental delay, craniofacial characteristics, foot malformation, hypertrichosis, and respiratory insufficiency. The association between MDS and the duplication of the genes in the 1q41-qter region remains unknown.