Reductions in Bone Mineral Density Are Apparent Early in Children With Prevalent Osteonecrosis Lesions Following Leukemia Therapy.

Osteonecrosis (ON) is a serious complication of childhood acute lymphoblastic leukemia. We determined the prevalence of osteonecrotic lesions in our patient population by a one-time multisite magnetic resonance imaging (MRI) more than 1 year following leukemia therapy. MRI findings were evaluated in relationship to clinical factors (including longitudinal changes in bone mineral density [BMD]). Eighty-six children enrolled in the Steroid Associated Osteoporosis in the Pediatric Population (STOPP) study were evaluated for ON at 3.1 ± 1.3 years following therapy. Thirty children had a total of 150 confirmed ON lesions (35%). Lumbar spine (LS) BMD Z-scores (mean ± SD) were low at diagnosis and similar between patients with and without ON (-1.09 ± 1.53 versus -1.27 ± 1.25, p = 0.549). LS BMD Z-scores declined from baseline to 12 months in children with ON (-0.31 ± 1.02) but not in those without (0.13 ± 0.82, p = 0.035); the hip BMD Z-scores from baseline to 24 months declined in both groups, but to a greater extent in those with ON (-1.77 ± 1.22) compared to those without (-1.03 ± 1.07, p = 0.045). At the time of the MRI, mean total hip and total body (TB) BMD Z-scores were lower in children with ON (hip -0.98 ± 0.95 versus -0.28 ± 1.06, p = 0.010; TB -1.36 ± 1.10 versus -0.48 ± 1.50, p = 0.018). Pain occurred in 11/30 (37%) with ON versus 20/56 (36%) without, p = 0.841. In multivariable models, older age at diagnosis (odds ratio [OR] 1.57; 95% confidence interval [CI], 1.15-2.13; p = 0.004), and hip BMD Z-score at MRI (OR 2.23; 95% CI, 1.02-4.87; p = 0.046) were independently associated with ON. Overall, one-third of children demonstrated ON after leukemia therapy. Those with ON had greater reductions in spine and hip BMD Z-scores in the first 1 and 2 years of therapy, respectively. Older age and lower hip BMD Z-scores at MRI were significantly associated with prevalent, off-therapy ON. These data assist in identifying children at risk of ON. © 2023 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Anticoagulant Effects of Dabigatran in Paediatric Patients Compared with Adults: Combined Data from Three Paediatric Clinical Trials.

BACKGROUND: Physiological age-related changes in the haemostatic and coagulation systems result in differing anticoagulant assay responses to standard anticoagulants. Therefore, we investigated the response of anticoagulant assays to dabigatran etexilate (DE) in children compared with adults. OBJECTIVE: This article assesses the relationship between plasma dabigatran concentration and coagulation assay results across age groups in children and adults. PATIENTS AND METHODS: Data from three clinical trials in which children received DE following standard of care for venous thromboembolism were compared with data from adult clinical trials. The effects of dabigatran concentration on diluted thrombin time (dTT), ecarin clotting time (ECT) and activated partial thromboplastin time (aPTT) were analysed graphically and with modelling. RESULTS: The concentration-dTT relationships were consistent in children across all ages and adults in the graphical analysis. For ECT and aPTT, relationships based on ratios over baseline were similar across all ages; absolute clotting times showed that the same exposure resulted in longer clotting times in some of the children aged < 1 year versus adults. Modelling showed concentration-clotting time relationships for all three assays were largely comparable between adults and children, except in those aged < 2 months, in whom there was a slight upward shift in ECT and aPTT relative to adults. CONCLUSION: Results suggest that developmental haemostatic changes will have little impact on response to DE. However, further paediatric clinical trials assessing the relationship between coagulation assay responses and clinical outcomes will be needed to confirm this finding.

Design and rationale for the DIVERSITY study: An open-label, randomized study of dabigatran etexilate for pediatric venous thromboembolism.

BACKGROUND: The current standard of care (SOC) for pediatric venous thromboembolism (VTE) comprises unfractionated heparin (UFH), or low-molecular-weight heparin (LMWH) followed by LMWH or vitamin K antagonists, all of which have limitations. Dabigatran etexilate (DE) has demonstrated efficacy and safety for adult VTE and has the potential to overcome some of the limitations of the current SOC. Pediatric trials are needed to establish dosing in children and to confirm that results obtained in adults are applicable in the pediatric setting. OBJECTIVES: To describe the design and rationale of a planned phase IIb/III trial that will evaluate a proposed dosing algorithm for DE and assess the safety and efficacy of DE versus SOC for pediatric VTE treatment. PATIENTS/METHODS: An open-label, randomized, parallel-group noninferiority study will be conducted in approximately 180 patients aged 0 to <18 years with VTE, who have received initial UFH or LMWH treatment and who are expected to require ≥3 months of anticoagulation therapy. Patients will receive DE or SOC for 3 months. DE will be administered twice daily as capsules, pellets, or an oral liquid formulation according to patient age. Initial doses will be calculated using a proposed dosing algorithm. RESULTS: There will be two coprimary endpoints: a composite efficacy endpoint comprising the proportion of patients with complete thrombus resolution, freedom from recurrent VTE and VTE-related mortality, and a safety endpoint: freedom from major bleeding events. CONCLUSION: Findings will provide valuable information regarding the efficacy and safety of DE for the treatment of pediatric VTE. ClinicalTrials.gov registration number: NCT01895777.

Phase 3, single-arm, multicenter study of dabigatran etexilate for secondary prevention of venous thromboembolism in children: Rationale and design.

BACKGROUND: Anticoagulant therapy for venous thromboembolism (VTE) in children is largely based on treatment recommendations for adults. However, differences in both physiology (ie, renal maturation and drug excretion) and developmental hemostasis must be considered when treating children, as such differences could affect dose appropriateness, safety and efficacy. OBJECTIVES: To address these concerns, a study was designed to evaluate the safety of dabigatran etexilate in children requiring secondary thrombus prevention in whom an initial VTE was associated with an identified risk factor that persisted after the acute VTE treatment period. We report herein the rationale and design of the study. PATIENTS/METHODS: This phase 3, open-label, single-arm, multicenter, multinational, prospective cohort study will be conducted in ≥100 children aged 0 to <18 years at ~100 specialist sites worldwide. Children will be treated with dabigatran etexilate for 12 months, or for a shorter duration if their identified VTE risk factor resolves, as per current American College of Chest Physicians recommendations. A nomogram will be used to determine starting doses for each patient. RESULTS: The primary outcomes of the study will be VTE recurrence, bleeding events, overall mortality, and VTE-related mortality. Secondary outcomes will include occurrence of post-thrombotic syndrome, the pharmacokinetics of dabigatran, and the need for dose adjustments during treatment. Data on adverse events during the study will also be collected. CONCLUSION: This study will evaluate the safety of dabigatran etexilate for the secondary prevention of VTE in children, in addition to providing further data to guide pediatric dosing with dabigatran.

Pharmacokinetics, Pharmacodynamics, Safety and Tolerability of Dabigatran Etexilate Oral Liquid Formulation in Infants with Venous Thromboembolism.

Venous thromboembolism (VTE) is more frequent in infants than in older children. Treatment guidelines in children are adapted from adult VTE data, but do not currently include direct oral anticoagulant use. Dabigatran etexilate (DE) use in the paediatric population with VTE therefore requires verification. We investigated the pharmacokinetic/pharmacodynamic (PK/PD) relationship, safety and tolerability of DE oral liquid formulation (OLF) in infants with VTE (aged < 12 months) who had completed standard anticoagulant treatment in an open-label, phase IIa study. Patients received a single-dose of DE OLF (based on an age- and weight-adjusted nomogram) yielding an exposure comparable to 150 mg in adults. The PK end point was plasma concentration of total dabigatran; PD end points included activated partial thromboplastin time (aPTT), ecarin clotting time (ECT) and diluted thrombin time (dTT). Safety end points included incidence of all bleeding and other adverse events (AEs). Ten patients were screened; eight entered the study (age range, 41-169 days). The geometric mean (gMean) total dabigatran plasma concentrations 2 hours post-dose (around peak concentrations) were 120 ng/mL with a geometric coefficient of variation (gCV) of 62.1%. The gMean at 12 hours post-dosing was 60.4 ng/mL (gCV 30%). PK/PD relationship was linear for ECT and dTT (R2 = 0.858 and 0.920, respectively), while total dabigatran concentration and aPTT showed a non-linear correlation. There were no deaths, treatment discontinuations or treatment-related AEs. In conclusion, DE was well tolerated without any treatment-related AEs in infants. The observed PK/PD relationships were comparable with the established profile in older patients with VTE.

Safety, tolerability and clinical pharmacology of dabigatran etexilate in adolescents. An open-label phase IIa study.

Venous thromboembolism (VTE) incidence is increasing among children owing to many factors, including improved diagnosis of VTE. There is a need for alternative treatment options. Our objective was to investigate the safety, pharmacokinetics (PK) and pharmacodynamics (PD) of dabigatran etexilate in adolescents with VTE. Adolescents aged 12 to <18 years (n = 9) who successfully completed planned treatment for primary VTE were administered dabigatran etexilate twice daily for three days; initially 1.71 (± 10 %) mg/kg (80 % of a 150 mg/70 kg twice daily adult dose), followed by 2.14 (± 10 %) mg/kg (target adult dose adjusted for patient's weight), if there were no safety concerns. No bleeding events, deaths or drug-related serious adverse events (AEs) were reported; three treatment-emergent AEs, all gastrointestinal-related, occurred in two patients. In these adolescent patients with normal renal function, presumed steady-state trough plasma concentrations of dabigatran were low (geometric mean dose-normalised total dabigatran plasma concentration: 0.493 ng/ml/mg at 72 hours). Total dabigatran concentrations were well predicted by the RE-LY® population PK model (94 % of trough concentrations were within the 80 % prediction interval). The relationship between total dabigatran plasma concentration, diluted thrombin time and ecarin clotting time (ECT) was linear; the relationship with activated partial thromboplastin time (aPTT) was non-linear. Adult population PK/PD models predicted the adolescent concentration-ECT and -aPTT relationships well. In conclusion, dabigatran etexilate was generally well tolerated, except for occurrence of dyspepsia in two patients, over the three-day treatment period. The dabigatran PK/PD relationship observed in adolescent patients was similar to that in adult patients.

Establishing physician to patient ratios and predicting workforce needs for Canadian pediatric hematology-oncology programs.

BACKGROUND: A Human Resources (HR) Committee of C17, the national network of Canadian academic pediatric hematology/oncology programs, obtained comprehensive data enabling analysis and planning for the physician workforce. This study establishes physician to patient ratios and predicts workforce needs for Canadian pediatric hematology/oncology programs. PROCEDURES: Over a 10-year period, six surveys were sent to the 17 pediatric tertiary care centers treating children with cancer and blood disorders. Data were obtained on physician demographics, full time equivalent (FTE) positions, and time spent in clinical, research, education, and administrative activities. Survey results were debated at the C17 national meetings to obtain consensus on workload ratios. RESULTS: Since 1999, the pediatric hematologist/oncologist workforce has increased from 71 FTE (43 oncology, 20 hematology, 8 BMT) to 109.5 FTE positions (69.7 oncology, 29.4 hematology, and 10.4 BMT). The median age of pediatric hematologists/oncologists increased from 46 years to 52 years and the male to female ratio changed from 1.8:1 to 0.9:1. The 2011 job profile showed the median time spent on activities was 60% clinical, 15% education, 15% research, and 10% administration. After assessing workload, models of care, and optimal physician FTE per program, the C17 HR Committee recommended a ratio of one oncologist per 15 newly diagnosed patients with malignancy and a ratio of one BMT physician per 15 transplants. For every 2.5 oncologists, a 1.0 hematologist is the minimum required. CONCLUSION: Physician staffing ratios for pediatric hematology/oncology programs have been established and should be adopted across Canadian academic institutions as a standard.

Corticosteroids, behavior, and quality of life in children treated for acute lymphoblastic leukemia; a multicentered trial.

The aim of this study was to investigate the effects of high-dose corticosteroids on behavior and quality of life of children with acute lymphoblastic leukemia (ALL) in maintenance therapy. Forty-three families (patient and/or parent) completed the Child Behavior Checklist (CBCL), the Pediatric Quality of Life Inventory (PedsQL) Cancer module questionnaires, a checklist of common complaints, and a descriptive intervention data questionnaire, on and off steroids, each child serving as his/her own control. Children 5 years and younger had higher CBCL scores in the somatic complaints, affective problems, internalizing, externalizing, and total problem scales, when comparing "on-steroid" to "off-steroid" periods (P<0.01). Children 6 years and above had higher CBCL scores in the externalizing, aggressive, and oppositional defiant problem scales on steroids compared with off steroids (P<0.05). Older children had larger changes on dexamethasone, compared with prednisone (P<0.05). On the PedsQL questionnaire, parents reported more pain and hurt (P<0.001), nausea (P=0.042), and procedural anxiety (P=0.013) when children were on steroids compared with off steroids. Corticosteroid treatment during ALL maintenance therapy is associated with behavior and emotional disturbances and adversely affects quality of life. Dexamethasone is associated with more significant behavioral changes in older children.

Skin erosion over totally implanted vascular access devices in children.

Erosion of the skin over a totally implanted vascular access device (TIVAD) is a rare event that may lead to life-threatening sequelae. From 1994 to 2007, we reviewed the medical records and central line database of 960 central line insertions for the complication of skin erosion over the TIVAD. Outcome measures included age, gender, and nutritional status, number of days until complication, insertion site, and attending surgeon. A total of 540 of the 960 central lines were TIVAD. Skin erosion occurred in 9 patients for an incidence of 1.67%. Average age at insertion was 51 months (range 25-116.5 months). The average catheter duration use in days was 335 with a range of 39-1575 days. Malnutrition defined as BMI <5% or a decrease in BMI percentiles occurred in 2 and 4 patients, respectively, and contributed to the thinning of the subcutaneous fat. Skin erosion over TIVAD is a rare complication. Most cases can be prevented by inserting the device in a subfacial location in the very young child or in the child with expected weight loss. Furthermore, the device should be placed at a fair distance from the skin incision to prevent early skin erosion through the wound.

Bilateral adrenal neuroblastoma: stage V disease.

Neuroblastoma frequently arises from the adrenal gland and has rarely been reported to arise synchronously in both adrenal glands. The majority of reports of bilateral adrenal neuroblastoma are in children under the age of 1 year. We present a case of bilateral adrenal neuroblastoma in an 8-year-old child. This is the first report of bilateral disease in a child over the age of 1 year with stage IV neuroblastoma.

Cognitive changes in children treated for acute lymphoblastic leukemia with chemotherapy only according to the Pediatric Oncology Group 9605 protocol.

The purpose of this study was to examine cognitive functioning and neuroimaging in children with leukemia treated with the Pediatric Oncology Group 9605 protocol at the Children's Hospital of Eastern Ontario. Mean age at diagnosis was 4.88 +/- 2.54 years. The mean (n = 24) Wechsler Verbal and Performance IQ fell in the low-average range (87.33 +/- 15.69 and 84.83 +/- 19.11, respectively). Mean (n = 20) Verbal and Visual Memory Indexes of 82.95 +/- 15.46 and 88.30+/- 10.80, respectively, were obtained. The proportion of scores on measures of intelligence and memory falling > 1 SD below the normative mean was substantially higher than expected. Paired t-test suggested that Wechsler Verbal IQ and memory remained stable, whereas Wechsler Performance IQ declined significantly. The results of growth curve analyses replicated these findings and suggested a significant adverse effect of cumulative dosage of intrathecal methotrexate on estimated Wechsler Performance IQ. Although only two children experienced seizures, 78% of the group showed leukoencephalopathy on at least one magnetic resonance image. Reliance on seizures as a predictor of leukoencephalopathy might underestimate the incidence of neurotoxicity.

Hypomagnesemia associated with chemotherapy in patients treated for acute lymphoblastic leukemia: possible mechanisms.

Body weight, height and lumbar spine bone mineral density (BMD) were measured in 40 children (27 male, 13 female, aged 0.3-17.0 years) with acute lymphoblastic leukemia (ALL) at diagnosis and 6 months after initiation of chemotherapy, and in 40 age- and sex-matched local healthy children. Serum and urinary biochemical indices of mineral metabolism were measured in the children with ALL at both time points. From diagnosis to 6 months, a reduction in the fractional excretion of magnesium was found. Serum osteocalcin was low at diagnosis and increased during chemotherapy, whereas 24-h urinary type I collagen cross-linked N-telopeptide was unchanged. The Z-scores for lumbar spine BMD increased and were correlated with the serum osteocalcin at 6 months. The change in serum magnesium was correlated negatively with the change in lumbar spine BMD, and with the lumbar spine BMD Z-score at 6 months. After initiation of treatment for ALL, rapid recovery in bone formation, which results in the movement of extracellular magnesium into the skeleton through bone formation, may be an important contributor to hypomagnesemia.

Maintenance of ankle range of motion in children treated for acute lymphoblastic leukemia.

PURPOSE: This study documented ankle dorsiflexion range of motion (DF-ROM) in children during treatment for leukemia and studied the effects of preventative education and individualized intervention as a standard of care. METHODS: Active and passive DF-ROM were measured throughout a two-year treatment period and one year after treatment in 40 subjects. Children without health problems and historical controls who had not received therapeutic input were used for comparison. RESULTS: Active DF-ROM showed an average tendency to decline significantly during treatment, whereas passive DF-ROM did not. Both increased significantly following the end of treatment. There were substantial individual differences around these patterns of average change. Gender (female) was a predictor of negative change in DF-ROM during treatment. Average DF-ROM one year after treatment was significantly greater than for the historical controls and not significantly different from the healthy controls. None of the children required surgical intervention, in contrast to the historical controls. CONCLUSIONS: Education and intervention appears to have improved DF-ROM outcome in children treated for leukemia.

Brain metastases in Wilms' tumor: case report and literature review.

A 2-year-old girl who had a stage 2, favorable-histology Wilms tumor diagnosed when she was age 10 months presented with multiple brain metastases at second recurrence. She had been treated with combined radiotherapy, surgery, and chemotherapy; at 2 months after treatment, recurrent disease developed in the central nervous system and she died. Brain metastases are rare in the natural history of Wilms tumor. Although it does not appear that cerebral metastases are a barrier to tumor eradication and long-term survival if treated with combined modality therapy, treatment should be individualized.

The diagnosis and treatment of von Willebrand disease in children.

von Willebrand disease is the most common bleeding disorder seen in children and it affects approximately 1% of the population. Because the bleeding symptoms in von Willebrand disease are generally mild, the diagnosis is often delayed. Prompt diagnosis and management can help to avoid potentially life-threatening bleeding events and unnecessary exposure to blood products. In this review, the various types of von Willebrand disease are outlined, the difficulties in diagnosis are discussed and the therapeutic approach to this common disorder is described.