Pulmonary complications post allogeneic haematopoietic stem cell transplant in children.

Objectives: Haematopoietic stem cell transplant (HCT) is a cellular therapy that, whilst curative for a child's underlying disease, carries significant risk of mortality, including because of pulmonary complications. The aims of this study were to describe the burden of pulmonary complications post-HCT in a cohort of Australian children and identify risk factors for the development of these complications. Methods: Patients were identified from the HCT databases at two paediatric transplant centres in Australia. Medical records were reviewed, and demographics, HCT characteristics and pulmonary complications documented. Relative risk ratio was used to identify risk factors for developing pulmonary complications prior to first transplant episode, and survival analysis performed to determine hazard ratio. Results: In total, 243 children underwent transplant during the study period, and pulmonary complications occurred in 48% (117/243) of children. Infectious complications were more common (55%) than non-infective complications (18%) and 26% of patients developed both. Risk factors for the development of pulmonary complications included the following: diagnoses of MPAL (RR 2.16, P = 0.02), matched unrelated donor (RR1.34, P = 0.03), peripheral blood (RR 1.36, P = 0.028) or cord blood (RR 1.73, P = 0.012) as the stem cell source and pre-existing lung disease (RR1.72, P < 0.0001). Children with a post-HCT lung complication had a significantly increased risk of mortality compared with those who did not (HR 3.9, P < 0.0001). Conclusion: This study demonstrates pulmonary complications continue to occur frequently in children post-HCT and contribute significantly to mortality. Highlighting the need for improved strategies to identify patients at risk pre-transplant and enhanced treatments for those who develop lung disease.

Incidence of Sinusoidal Obstruction Syndrome/Veno-Occlusive Disease and Treatment with Defibrotide in Allogeneic Transplantation: A Multicenter Australasian Registry Study.

Sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is an established complication in patients undergoing allogeneic hemopoietic stem cell transplantation (HSCT). Defibrotide is an effective and safe pharmacologic option for treating diagnosed SOS/VOD. By exploring data provided to the Australasian Bone Marrow Transplant Recipient Registry (ABMTRR) by centers in Australia and New Zealand, this study aimed to describe the incidence of SOS/VOD and patterns of defibrotide use from 2016 to 2020. Patients who underwent allogeneic hemopoietic stem cell transplantation between 2016 and 2020 were identified from the ABMTRR. Data were extracted for a total of 3346 patients, 2692 from adult centers and 654 from pediatric centers, with a median follow-up of 21.5 months and 33.3 months, respectively. Descriptive statistics were used to describe the patient population, including the incidence of SOS/VOD and defibrotide use. Comparisons were made between patients without SOS/VOD and those with SOS/VOD, divided into defibrotide and no defibrotide cohorts. Associations with overall survival (OS) and day 100 survival with such variables as sex, age, disease at transplantation, stem cell source, conditioning agents, SOS/VOD diagnosis, and use of defibrotide, were determined. The reported incidence of SOS/VOD was 4.1% in adult centers and 11.5% in pediatric centers. Defibrotide was administered to 74.8% of adult patients and 97.3% of pediatric patients with SOS/VOD. Significant variability in the use, dosage, and duration of defibrotide was seen across the adult centers. The day 100 survival rate and median OS for patients managed with defibrotide was 51.8% and 103 days, respectively, for adult patients and 90.4% and not reached, respectively, for pediatric patients. In adults, older age at transplantation, an HLA-matched nonsibling relative donor, and a diagnosis of SOS/VOD treated with defibrotide were associated with reduced OS. In pediatric patients, the patient and transplantation characteristics associated with reduced OS were a diagnosis of SOS/VOD and a ≥2 HLA-mismatched related donor. A collaborative approach across Australasia to diagnosing and managing SOS/VOD, particularly with respect to consistent defibrotide use, is recommended.

Australia and New Zealand Transplant and Cellular Therapies (ANZTCT) position statement: COVID-19 management in patients with haemopoietic stem cell transplant and chimeric antigen receptor T cell.

Patients with post-haemopoietic stem cell transplant or chimeric antigen receptor T -cell (CAR-T) therapy face a significant risk of morbidity and mortality from coronavirus disease 2019 because of their immunosuppressed state. As case numbers in Australia and New Zealand continue to rise, guidance on management in this high-risk population is needed. Whilst we have learned much from international colleagues who faced high infection rates early in the pandemic, guidance relevant to local health system structures, medication availability and emerging therapies is essential to equip physicians to manage our patients optimally.

Prospective longitudinal evaluation of treatment-related toxicity and health-related quality of life during the first year of treatment for pediatric acute lymphoblastic leukemia.

BACKGROUND: Pediatric acute lymphoblastic leukemia (ALL) therapy is accompanied by treatment-related toxicities (TRTs) and impaired quality of life. In Australia and New Zealand, children with ALL are treated with either Children's Oncology Group (COG) or international Berlin-Frankfurt-Munster (iBFM) Study Group-based therapy. We conducted a prospective registry study to document symptomatic TRTs (venous thrombosis, neurotoxicity, pancreatitis and bone toxicity), compare TRT outcomes to retrospective TRT data, and measure the impact of TRTs on children's general and cancer-related health-related quality of life (HRQoL) and parents' emotional well-being. METHODS: Parents of children with newly diagnosed ALL were invited to participate in the ASSET (Acute Lymphoblastic Leukaemia Subtypes and Side Effects from Treatment) study and a prospective, longitudinal HRQoL study. TRTs were reported prospectively and families completed questionnaires for general (Healthy Utility Index Mark 3) and cancer specific (Pediatric Quality of Life Inventory (PedsQL)-Cancer Module) health related quality of life as well the Emotion Thermometer to assess emotional well-being. RESULTS: Beginning in 2016, 260 pediatric patients with ALL were enrolled on the TRT registry with a median age at diagnosis of 59 months (range 1-213 months), 144 males (55.4%), majority with Pre-B cell immunophenotype, n = 226 (86.9%), 173 patients (66.5%) treated according to COG platform with relatively equal distribution across risk classification sub-groups. From 2018, 79 families participated in the HRQoL study through the first year of treatment. There were 74 TRT recorded, reflecting a 28.5% risk of developing a TRT. Individual TRT incidence was consistent with previous studies, being 7.7% for symptomatic VTE, 11.9% neurotoxicity, 5.4% bone toxicity and 5.0% pancreatitis. Children's HRQoL was significantly lower than population norms throughout the first year of treatment. An improvement in general HRQoL, measured by the HUI3, contrasted with the lack of improvement in cancer-related HRQoL measured by the PedsQL Cancer Module over the first 12 months. There were no persisting differences in the HRQoL impact of COG compared to iBFM therapy. CONCLUSIONS: It is feasible to prospectively monitor TRT incidence and longitudinal HRQoL impacts during ALL therapy. Early phases of ALL therapy, regardless of treatment platform, result in prolonged reductions in cancer-related HRQoL.

Assessing the utility of routine viral surveillance performed in children undergoing autologous stem cell transplantation at a single centre.

We assessed the utility of routine viral surveillance for cytomegalovirus, Epstein-Barr virus and human adenovirus in children <16 years, undergoing autologous stem cell transplantation (ASCT) at a single centre over a 10-year period. A total of 85 ASCT were performed in 65 patients. Routine viral surveillance resulted in a high number of tests performed (median 20 tests per ASCT), without any clinically significant viral detections. These data support the limited clinical utility of routine viral surveillance in children undergoing ASCT. Adopting a clinically driven approach for viral testing is likely to be both cost-effective and safe.

Skin Biopsy in Pediatric Oncology/Hematopoietic Stem Cell Transplantation Patients.

ABSTRACT: The aim of this study was to review the dermatopathological findings in skin biopsy specimens from pediatric oncology and hematopoietic stem cell transplantation patients over a 20-year period. Three hundred fifty-two skin biopsies from 240 patients were reviewed, and the findings were grouped into 6 categories: index neoplasms, nonindex neoplasms, infections, graft-versus-host disease, other treatment complications, and others. Among the index neoplasms identified on skin biopsy, the most common conditions were Langerhans cell histiocytosis (14 patients) and melanoma (7 patients), with other hematological malignancies and an array of soft-tissue tumors accounting for the bulk of the remainder. Neoplastic conditions common in general dermatopathological practice such as basal cell carcinoma and squamous cell carcinoma were uncommon, each being identified in only 1 patient younger than the age of 18, although basal cell carcinomas developing subsequently in young adult life were identified in 7 patients. Infections were common, with infectious agents or viral cytopathic effects (not including human papillomavirus) identified in 34 biopsies. A significant proportion (74%) represented invasive fungal infections, which are of very significant clinical importance. Biopsies performed for a clinical suspicion of graft-versus-host seldom showed histological features to suggest an alternative diagnosis, with only a single case suggesting a diagnosis of toxic erythema of chemotherapy identified.

Population pharmacokinetic model for once-daily intravenous busulfan in pediatric subjects describing time-associated clearance.

This study aimed to characterize the population pharmacokinetics (PK) of busulfan focusing on how busulfan clearance (CL) changes over time during once-daily administration and assess different methods for measuring busulfan exposure and the ability to achieve target cumulative exposure under different dosing adjustment scenarios in pediatric stem cell transplantation recipients. Daily serial blood sampling was performed and concentration-time data were analyzed using a nonlinear mixed-effects approach. The developed PK model was used to assess achievement of target exposure under six dose-adjustment scenarios based on simulations performed in RStudio (RxODE package)®. A total of 2491 busulfan plasma concentration-time measurements were collected from 95 patients characterizing 379 dosing days. A two-compartment model with time-associated CL best described the data with a typical CL of 14.5 L/h for an adult male with 62 kg normal fat mass (NFM; equivalent to 70 kg total body weight), typical volume of distribution central compartment (V1) of 40.6 L/59 kg NFM (equivalent to 70 kg total body weight), and typical volume of distribution peripheral compartment of 3.57 L/62 kg NFM. Model interindividual variability in CL and V1 was 14.7% and 34.9%, respectively, and interoccasional variability in CL was 6.6%. Patient size described by NFM, a maturation component, and time since start of treatment significantly influenced CL. Simulations demonstrated that using model-based exposure estimates with each dose, and either a proportional dose-adjustment calculation or model-based calculated individual CL estimates to support dose adjustments, increased proportion of subjects attaining cumulative exposure within 5% of target compared with using noncompartmental analysis (100% vs. 0%). A time-associated reduction in CL during once-daily busulfan treatment was described.

Outcomes of pediatric patients with therapy-related myeloid neoplasms.

Long-term outcomes after allogeneic hematopoietic cell transplantation (HCT) for therapy-related myeloid neoplasms (tMNs) are dismal. There are few multicenter studies defining prognostic factors in pediatric patients with tMNs. We have accumulated the largest cohort of pediatric patients who have undergone HCT for a tMN to perform a multivariate analysis defining factors predictive of long-term survival. Sixty-eight percent of the 401 patients underwent HCT using a myeloablative conditioning (MAC) regimen, but there were no statistically significant differences in the overall survival (OS), event-free survival (EFS), or cumulative incidence of relapse and non-relapse mortality based on the conditioning intensity. Among the recipients of MAC regimens, 38.4% of deaths were from treatment-related causes, especially acute graft versus host disease (GVHD) and end-organ failure, as compared to only 20.9% of deaths in the reduced-intensity conditioning (RIC) cohort. Exposure to total body irradiation (TBI) during conditioning and experiencing grade III/IV acute GVHD was associated with worse OS. In addition, a diagnosis of therapy-related myelodysplastic syndrome and having a structurally complex karyotype at tMN diagnosis were associated with worse EFS. Reduced-toxicity (but not reduced-intensity) regimens might help to decrease relapse while limiting mortality associated with TBI-based HCT conditioning in pediatric patients with tMNs.

Subcutaneous panniculitis-like T-cell lymphoma in a 14-year-old female homozygous for HAVCR2 mutation.

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare cytotoxic T-cell lymphoma preferentially involving subcutis. A link between patients with SPTCL and HAVCR2 mutations has recently been discovered. We present a 14-year-old girl of Chinese heritage who was diagnosed with SPTCL in the context of homozygous HAVCR2 status for c.245A>G p. (Tyr82Cys) and achieved complete remission after treatment with cyclosporin and steroids. Dermatologists should be aware of the diagnostic, management and familial genetic counselling utility of HAVCR2 for investigating and managing patients with SPTCL.

Immune function in childhood cancer survivors: a Children's Oncology Group review.

Childhood cancer and its treatment often impact the haematopoietic and lymphatic systems, with immunological consequences. Immunological assessments are not routinely included in surveillance guidelines for most survivors of childhood cancer, although a robust body of literature describes immunological outcomes, testing recommendations, and revaccination guidelines after allogeneic haematopoietic cell transplantation. Survivorship care providers might not fully consider the impaired recovery of a child's immune system after cancer treatment if the child has not undergone haematopoietic cell transplantation. We did a scoping review to collate the existing literature describing immune function after childhood cancer therapy, including both standard-dose chemotherapy and high-dose chemotherapy with haematopoietic cell rescue. This Review aims to summarise: the principles of immunology and testing of immune function; the body of literature describing immunological outcomes after childhood cancer therapy, with an emphasis on the risk of infection, when is testing indicated, and preventive strategies; and knowledge gaps and opportunities for future research.

Diagnosis and management of severe combined immunodeficiency in Australia and New Zealand.

This consensus document outlines the recommendations from the Australasian Society of Clinical Immunology and Allergy Transplantation and Primary Immunodeficiency group for the diagnosis and management of patients with severe combined immunodeficiency. It also provides a proposed framework for the early investigation, management and supportive care prior to haematopoietic stem cell transplantation.

Optimized peripheral blood progenitor cell mobilization for autologous hematopoietic cell transplantation in children with high-risk and refractory malignancies.

BACKGROUND: Autologous hematopoietic stem cell transplantation (aHSCT) using hematopoietic progenitor cells (HPCs) has become an important therapeutic modality for patients with high-risk malignancies. Current literature on standardized method for HPC apheresis in children is sparse and failure rate reported as high as 30%. PATIENTS/METHODS: A retrospective study of 125 pediatric patients with high-risk malignancies undergoing aHSCT in Western Australia between 1997 and 2016 was conducted. RESULTS: Mobilization was achieved by means of chemotherapy and granulocyte colony-stimulating factor (G-CSF). Patients underwent apheresis the day after CD34+ counts reached ≥20/µL and an additional dose of G-CSF. Peripheral arterial and intravenous lines were inserted in pediatric intensive care unit under local anesthetic and/or sedation, omitting the need for general anesthesia as well as facilitating an uninterrupted apheresis flow. Larger apheresis total blood volumes were processed in patients weighing ≤20 kg. The minimal dose of ≥2 × 106 CD34+ cells/kg was successfully collected in 98.4% of all patients. The optimal dose of 3-5 × 106 CD34+ cells/kg was collected in 96% of patients scheduled for a single aHSCT, 87.5% for tandem, and 100% for triple aHSCT. All HPC collections were completed in one apheresis session. Mobilization after ≤3 chemotherapy cycles and cycles including cyclophosphamide resulted in a significantly higher yield of CD34+ cells. CONCLUSION: Our approach to HPC mobilization by means of chemotherapy and single myeloid growth factor combined with optimal collection timing facilitated by continuous apheresis flow resulted in highly effective HPC harvest in children and adolescents with high-risk cancers.

Secondary acute myeloid leukemia after etoposide therapy for haemophagocytic lymphohistiocytosis.

Haemophagocytic lymphohistiocytosis (HLH) is an uncommon disease with a high fatality rate. Etoposide is an important component of current HLH treatment regimes. Two patients with HLH developed etoposide-related secondary acute myeloid leukemia (sAML) following therapy for HLH. Etoposide, an epipodophyllotoxin, is a topoisomerase II inhibitor that interacts with DNA to potentiate leukaemogenesis. The risk of developing sAML is estimated to be between 1% and 5%, 2-20 years after exposure to etoposide but may also be related to cumulative drug doses, treatment schedules, host factors and co-administration of other antineoplastic agents.