Refining risk stratification to improve prognosis in juvenile myelomonocytic leukemia.

Not available.

Pharmacokinetics, Safety, and Efficacy of Letermovir for Cytomegalovirus Prophylaxis in Adolescent Hematopoietic Cell Transplantation Recipients.

INTRODUCTION: Letermovir is a cytomegalovirus (CMV) terminase complex inhibitor approved for prophylaxis of CMV infection and disease in adult CMV-seropositive allogeneic hematopoietic cell transplantation (allo-HCT) recipients (R+). We report pharmacokinetics (PK), safety, and efficacy of letermovir in adolescent (12-18 years) allogeneic HCT recipients from an ongoing clinical study. METHODS: In this phase 2b, multicenter, open-label study (NCT03940586), 28 adolescents received 480 mg letermovir [240 mg with cyclosporin A (CsA)] once daily orally or intravenously. Blood was collected for intensive (n = 14) plasma concentrations of letermovir. Intensive PK data were used for dose confirmation. Target exposure range 34,400-100,000 h × ng/mL for pediatric median exposures was based on model-predicted phase 3 population PK simulations in adult HCT recipients. RESULTS: All participants were CMV-seropositive (body weight 28.7-95.0 kg). Of 12 PK-evaluable participants, 8 receiving 480 mg letermovir without CsA and 4 receiving 240 mg letermovir with CsA achieved exposures comparable to the adult exposure range. Exposure above the target but below the adult clinical program maximum was observed in 1 patient. Safety was consistent with previously described safety in adults. The proportion of participants with clinically significant CMV infection through week 24 post-HCT was comparable (24%) to that in the pivotal phase 3 study in adults (37.5%). CONCLUSIONS: Administration of adult letermovir doses in this adolescent cohort resulted in exposures within adult clinical program margins and was associated with safety and efficacy similar to adults. Results support a letermovir dose of 480 mg (240 mg with CsA) in adolescent allo-HCT recipients.

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.

COVID-19 vaccination in children and adolescents aged 5 years and older undergoing treatment for cancer and non-malignant haematological conditions: Australian and New Zealand Children's Haematology/Oncology Group consensus statement.

INTRODUCTION: The Australian Technical Advisory Group on Immunisation and New Zealand Ministry of Health recommend all children aged ≥ 5 years receive either of the two mRNA COVID-19 vaccines: Comirnaty (Pfizer), available in both Australia and New Zealand, or Spikevax (Moderna), available in Australia only. Both vaccines are efficacious and safe in the general population, including children. Children and adolescents undergoing treatment for cancer and immunosuppressive therapy for non-malignant haematological conditions are particularly vulnerable, with an increased risk of severe or fatal COVID-19. There remains a paucity of data regarding the immune response to COVID-19 vaccines in immunosuppressed paediatric populations, with data suggestive of reduced immunogenicity of the vaccine in immunocompromised adults. RECOMMENDATIONS: Considering the safety profile of mRNA COVID-19 vaccines and the increased risk of severe COVID-19 in immunocompromised children and adolescents, COVID-19 vaccination is strongly recommended for this at-risk population. We provide a number of recommendations regarding COVID-19 vaccination in this population where immunosuppressive, chemotherapeutic and/or targeted biological agents are used. These include the timing of vaccination in patients undergoing active treatment, management of specific situations where vaccination is contraindicated or recommended under special precautions, and additional vaccination recommendations for severely immunocompromised patients. Finally, we stress the importance of upcoming clinical trials to identify the safest and most efficacious vaccination regimen for this population. CHANGES IN MANAGEMENT AS A RESULT OF THIS STATEMENT: This consensus statement provides recommendations for COVID-19 vaccination in children and adolescents aged ≥ 5 years with cancer and immunocompromising non-malignant haematological conditions, based on evidence, national and international guidelines and expert opinion. ENDORSED BY: The Australian and New Zealand Children's Haematology/Oncology Group.

Evaluation of two software using Bayesian methods for monitoring exposure and dosing once-daily intravenous busulfan in paediatric patients receiving haematopoietic stem cell transplantation.

AIM: To assess the ability of model-based personalised dosing tools to estimate busulfan exposure (i) in comparison to clinically used intensive sampling exposure estimation procedure, (ii) using limited sampling strategies and (iii) to predict changes in busulfan clearance during busulfan treatment. METHODS: Data on intravenous busulfan dosing for patients with 4 consecutive days were entered into Bayesian forecasting software, InsightRX and NextDose. Prediction of busulfan cumulative exposure was compared to current clinical practice estimation, aiming for pre-defined individualised target of cumulative exposure. Estimation performance was tested given several limited sampling strategies. RESULTS: Thirty-two paediatric patients (0.2-16.5 years) provided a total of 103 daily exposure measurements estimated using 7 samples taken per day (full sampling), with 19 patients having sampling following all doses administered. Both software tools utilising Bayesian methods provided acceptable relative bias and precision of cumulative exposure estimations under the tested sampling scenarios. Relative bias ranged from median RE of 0.1-14.6% using InsightRX and from 3.4-7.8% using NextDose. Precision ranged from median RMSE of 0.19-0.32 mg·h·L-1 for InsightRX and 0.08-0.1 mg·h·L-1 for NextDose. A median reduction in busulfan clearance from day 1 to day 4 was observed in the clinical data (-10.9%), when using InsightRX (-18.6%) and with NextDose (-14.7%). CONCLUSION: Bayesian methods were shown to have relatively low bias and precisely estimate busulfan exposure using intensive sampling and several limited sampling strategies, which provides evidence for prospective studies to evaluate these tools in clinical practice. A trend to overestimation of exposure using Bayesian methods was observed compared to clinical practice. Reduction of busulfan clearance from day 1 to 4 of once daily dosing was confirmed and should be considered when adjusting doses.

Multisystem inflammation and susceptibility to viral infections in human ZNFX1 deficiency.

BACKGROUND: Recognition of viral nucleic acids is one of the primary triggers for a type I interferon-mediated antiviral immune response. Inborn errors of type I interferon immunity can be associated with increased inflammation and/or increased susceptibility to viral infections as a result of dysbalanced interferon production. NFX1-type zinc finger-containing 1 (ZNFX1) is an interferon-stimulated double-stranded RNA sensor that restricts the replication of RNA viruses in mice. The role of ZNFX1 in the human immune response is not known. OBJECTIVE: We studied 15 patients from 8 families with an autosomal recessive immunodeficiency characterized by severe infections by both RNA and DNA viruses and virally triggered inflammatory episodes with hemophagocytic lymphohistiocytosis-like disease, early-onset seizures, and renal and lung disease. METHODS: Whole exome sequencing was performed on 13 patients from 8 families. We investigated the transcriptome, posttranscriptional regulation of interferon-stimulated genes (ISGs) and predisposition to viral infections in primary cells from patients and controls stimulated with synthetic double-stranded nucleic acids. RESULTS: Deleterious homozygous and compound heterozygous ZNFX1 variants were identified in all 13 patients. Stimulation of patient-derived primary cells with synthetic double-stranded nucleic acids was associated with a deregulated pattern of expression of ISGs and alterations in the half-life of the mRNA of ISGs and also associated with poorer clearance of viral infections by monocytes. CONCLUSION: ZNFX1 is an important regulator of the response to double-stranded nucleic acids stimuli following viral infections. ZNFX1 deficiency predisposes to severe viral infections and a multisystem inflammatory disease.

Review of the Pharmacokinetics and Pharmacodynamics of Intravenous Busulfan in Paediatric Patients.

We aimed to review the pharmacokinetics (PK) of intravenous busulfan in paediatric patients, identify covariate factors influencing exposure, investigate evidence of changes in PK behaviour over time, and correlate exposure with efficacy and toxicity outcomes. A literature review was undertaken of original research published between 2007 and 2019, investigating the PK and pharmacodynamics (PD) of intravenous busulfan in patients ≤ 18 years of age. The review identified 41 publications characterising the PK, and 45 publications describing the PD, of busulfan. Median typical clearance (CL) was 0.22 L/h/kg and median typical volume of distribution was 0.69 L/kg. Patient weight, age, glutathione-S-transferase A1 (GSTA1) genotype and busulfan dosing day/time were the most commonly identified factors affecting CL. Of nine studies investigating changes in CL, seven reported reduced CL over the 4-day course of treatment. Exposure monitoring methods and therapeutic targets were heterogeneous across studies. Relationships between busulfan exposure and patient outcomes were observed in five studies. One study observed a cumulative area under the concentration-time curve over all days of treatment of between 78 and 101 mg/L·h, and two studies observed an average concentration at first dose of < 600 ng/mL improved overall survival, transplant-related mortality, or relapse. One study observed increased sinusoidal obstructive syndrome with maximum busulfan concentration > 1.88 ng/mL. Patient weight, age and GSTA1 genotype are important covariates to consider when individualising busulfan therapy. Reduced busulfan CL over time may need to be accounted for, particularly in patients not receiving phenytoin co-therapy. Standardised monitoring of busulfan exposure over the entire course of treatment and further investigation of the role of busulfan metabolites and pharmacogenomics is warranted.

Development and Validation of a High Pressure Liquid Chromatography-UV Method for the Determination of Treosulfan and Its Epoxy Metabolites in Human Plasma and Its Application in Pharmacokinetic Studies.

Treosulfan (l-threitol-1,4-di-methanesulfonate) is a prodrug of a bifunctional alkylating agent that is being used increasingly in pediatric bone marrow transplantation regimens. The activation pathway is a complex reaction, which consists of two consecutive reactions leading to epoxybutane derivatives which are responsible for DNA alkylation. A simple, sensitive high performance liquid chromatography method for the determination of the sum of treosulfan and its epoxy metabolites by UV detection after derivatization with sodium diethyldithiocarbamate in human plasma was developed and validated. Plasma samples containing treosulfan and epoxy metabolites were converted into thiocarbamate derivative with 10% sodium diethyldithiocarbamate. Dinitrobiphenyl was used as an internal standard. The analysis was carried out using a reversed phase C18 column with a mobile phase consisting of methanol-water (65:35, v/v) at a flow rate of 1 mL/min. The eluent was monitored at 254 nm. The standard calibration curve was established between 2.5 and 50 µg/mL, with a correlation coefficient of 0.9987. Intra- and interday precision and accuracy of the method was <8% and met the analytical criteria. Pharmacokinetic parameters were determined in six children who received intravenous treosulfan (dose range 12-24 g/m(2)) in combination with fludarabine prior to blood or marrow transplantation.

Survival from haematological malignancy in childhood, adolescence and young adulthood in Australia: is the age-related gap narrowing?

OBJECTIVES: To examine 5-year survival from haematological malignancies in children, adolescents and young adults in Australia and determine if there has been any improvement in survival for the older age groups compared with children (the age-related "survival gap"). DESIGN, SETTING AND PARTICIPANTS: Population-based study of all Australian children (aged 0-14 years), adolescents (15-19 years) and young adults (20-29 years) diagnosed with acute lymphoblastic leukaemia (ALL), acute myeloid leukaemia (AML), Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) between 1982 and 2004, with follow-up to 2006. MAIN OUTCOME MEASURES: 5-year survival from ALL, AML, HL and NHL analysed for four periods of diagnosis (1982-1989, 1990-1994, 1995-1999 and 2000-2004). RESULTS: During 1982-2004, 13 015 people aged < or = 29 years were diagnosed with primary leukaemia or lymphoma in Australia. For those with ALL, 5-year survival for adolescents improved from 40% (1982-1989) to 74% (2000-2004); the improvement for young adults was smaller (31% to 47%), and both these groups still had lower survival than children, whose 5-year survival improved from 74% to 88%. There was a larger narrowing of the gap for AML: for cases diagnosed in 2000-2004, 5-year survival was similar for young adults (63%), adolescents (74%) and children (69%). For lymphoma cases diagnosed in 2000-2004, 5-year survival in all age groups was greater than 95% for HL and greater than 81% for NHL, although children fared better than adolescents and young adults. CONCLUSIONS: These Australian population-based data confirm an improvement in survival from haematological malignancies across all three age groups, but an age-related survival gap remains for adolescents and young adults compared with children, especially for young adults with ALL. Greater participation of adolescents and young adults in clinical trials and more detailed data collection are needed to provide evidence about optimal treatment regimens in these age groups.

Quality of life and recovery after graft-versus-host disease.

Acute and chronic graft versus host disease (GVHD) has a significant impact on short- and long-term morbidity as well as mortality in patients undergoing hematopoietic-cell transplantation (HCT). As a result of the physical as well as emotional aspects of the transplant process and development of GVHD, quality of life (QOL) in transplant survivors can be adversely affected. The strongest association between reduced QOL and impaired functional status following HCT is the presence of chronic GVHD. Chronic GHVD can have a negative impact on an individual's general health and mental health, and can lead to the development of functional impairments and activity limitations. In HCT survivors without chronic GVHD, self-reported QOL tends to be very similar to that in comparison groups by 1-2 years after HCT. In addition, in individuals who have been successfully treated for chronic GVHD, QOL and overall health status are not different from those with no history of chronic GVHD. These findings suggest that effective new therapies for chronic GVHD are essential, as are standardized tools for the assessment of QOL and functional outcomes in HCT survivors with chronic GVHD in order to gain a better understanding of the overall impact of the condition, as well as the effectiveness of new treatments.

The management and outcome of chronic graft-versus-host disease.

Chronic graft-versus-host disease (cGVHD) is a common complication following allogeneic haematopoietic cell transplantation (HCT). It is the leading cause of non-relapse mortality in transplant survivors and has a significant impact upon their functional status and quality of life. Despite significant advances being made in the field of HCT over the past 25 years, there has been little change in the incidence, morbidity and mortality of cGVHD. This is partly because of a lack of understanding about the pathogenesis of the disorder but also because a lack of well validated grading systems and outcome measures has hindered clinical research. Strategies for prophylaxis have largely been unsuccessful and may compromise the graft-versus-leukaemia (GVL) effect. Standard primary treatment remains a combination of corticosteroids and calcineurin inhibitors. There is no standard therapy for those who fail to respond to corticosteroids. Many agents have been studied but there is an urgent need for systematic research to compare the efficacy of different approaches. Infection is the leading cause of death among patients with cGVHD so antimicrobial prophylaxis is mandatory. A multidisciplinary approach to the care of patients with cGVHD is essential to adequately address its effects on both physical and psychological functioning.

Impact of chronic graft-versus-host disease on the health status of hematopoietic cell transplantation survivors: a report from the Bone Marrow Transplant Survivor Study.

The aim of this study was to understand the impact of chronic graft-versus-host disease (cGVHD) on the overall health status of hematopoietic cell transplantation (HCT) survivors. Subjects included 584 individuals who had undergone allogeneic HCT between 1976 and 1999, survived 2 or more years, and completed a 255-item health questionnaire. Global assessment of health status was facilitated by measurement of 6 health status domains: general health, mental health, functional impairment, activity limitation, pain, and anxiety/fear. Information regarding diagnosis of cGVHD was abstracted from medical records, and presence of active cGVHD in the preceding 12 months was self-reported. The incidence of cGVHD in participants was 54%, of whom 46% reported active cGVHD. In multivariable analyses, subjects with active cGVHD were more likely to report adverse general health, mental health, functional impairments, activity limitation, and pain than were those with no history of cGVHD. However, health status did not differ between those with resolved cGVHD and those who never had cGVHD. We conclude that active cGVHD has a significant impact on many aspects of the overall health status of HCT survivors and that, most importantly, those successfully treated for cGVHD do not appear to have long-term impairments.

First report of donor cell-derived acute leukemia as a complication of umbilical cord blood transplantation.

Donor cell leukemia is a rare complication after allogeneic hematopoietic stem cell transplantation. A 12-month-old boy underwent unrelated donor umbilical cord blood transplant (UCBT) for refractory Langerhan's cell histiocytosis. Forty months after transplantation, he developed acute myeloid leukemia. Cytogenetic and molecular analysis confirmed donor cell origin. The Cord Blood Bank (CBB) contacted the donor's family and established that the child, now 7 years old, was healthy. This represents the first reported case of donor cell leukemia following UCBT. This case illustrates that donor cell leukemia is a rare but real event after UCBT as with other stem cell sources and highlights the need for CBBs to maintain linkage data between donors and recipients.

Anaplastic large cell lymphoma of the pancreas: a pediatric case and literature review.

A 13-year-old boy presented with acute abdominal pain and later became jaundiced. Medical imaging subsequently demonstrated a 7 x 8 cm pancreatic mass. Examination of a biopsy specimen obtained by open laparotomy revealed malignant lymphoma. Histology, immunohistochemistry, and cytogenetics confirmed the diagnosis of ALK1-positive anaplastic large cell lymphoma. He was treated with multiagent chemotherapy and remains in complete remission 12 months off treatment. This is the first case of primary pancreatic ALK1-positive anaplastic large cell lymphoma described in a child and shows that aggressive surgical resection of pancreatic tumors is not always necessary to achieve a cure.