Development and validation of thromboembolism diagnostic algorithms in children with cancer from real-world data.

OBJECTIVE: To evaluate the accuracy of diagnostic algorithms developed using the International Classification of Diseases (ICD-9-CM and ICD-10-CA) diagnostic codes and physician billing codes for thromboembolism (TE) from health administrative data compared to chart review diagnoses of TE in children with cancer. METHODS: Using data linkage between the Pediatric Oncology Group of Ontario Network Information System (Ontario pediatric cancer registry) and various administrative data housed at ICES, eight algorithms were developed including a single reference to one of the billing codes, multiple references with varying time intervals, and combinations of various billing codes during primary cancer therapy for the whole cohort and, for early (<04/2002) and later (≥04/2002, solely ICD-10 codes) periods. Reference standard was chart review data from prior studies (from 1990 to 2016) among children (≤19 years) with cancer and radiologically confirmed TE. RESULTS: Records of 2056 patients diagnosed with cancer at two participating sites during study period were reviewed; 112 had radiologically confirmed TE. The algorithm with addition of anticoagulation utilization codes was the best performing algorithm (sensitivity = 0.76;specificity = 0.85). With use of ICD-10 only codes, sensitivity of the same algorithm improved to 0.84 with specificity of 0.80. CONCLUSION: This study provides a valid approach for ascertaining pediatric TE using real-world data. IMPACT: Research in pediatric thrombosis, especially cancer-related thrombosis, is limited mainly due to small-sized studies. Real-world data provide ready access to large and diverse populations. However, there are no validated algorithms for identifying thrombosis in real-world data for children. An algorithm based on combination of thrombosis and anticoagulation utilization codes had 76% sensitivity and 85% specificity to identify diagnosis of thrombosis in children in administrative data. This study provides a valid approach for ascertaining pediatric thrombosis using real-world data and offers a good avenue to advance pediatric thrombosis research.

Safety of dabigatran etexilate for the secondary prevention of venous thromboembolism in children.

This open-label, single-arm, prospective cohort trial is the first phase 3 safety study to describe outcomes in children treated with dabigatran etexilate for secondary venous thromboembolism (VTE) prevention. Eligible children aged 12 to <18 years (age stratum 1), 2 to <12 years (stratum 2), and >3 months to <2 years (stratum 3) had an objectively confirmed diagnosis of VTE treated with standard of care (SOC) for ≥3 months, or had completed dabigatran or SOC treatment in the DIVERSITY trial (NCT01895777) and had an unresolved clinical thrombosis risk factor requiring further anticoagulation. Children received dabigatran for up to 12 months, or less if the identified VTE clinical risk factor resolved. Primary end points included VTE recurrence, bleeding events, and mortality at 6 and 12 months. Overall, 203 children received dabigatran, with median exposure being 36.3 weeks (range, 0-57 weeks); 171 of 203 (84.2%) and 32 of 203 (15.8%) took capsules and pellets, respectively. Overall, 2 of 203 children (1.0%) experienced on-treatment VTE recurrence, and 3 of 203 (1.5%) experienced major bleeding events, with 2 (1.0%) reporting clinically relevant nonmajor bleeding events, and 37 (18.2%) minor bleeding events. There were no on-treatment deaths. On-treatment postthrombotic syndrome was reported for 2 of 162 children (1.2%) who had deep vein thrombosis or central-line thrombosis as their most recent VTE. Pharmacokinetic/pharmacodynamic relationships of dabigatran were similar to those in adult VTE patients. In summary, dabigatran showed a favorable safety profile for secondary VTE prevention in children aged from >3 months to <18 years with persistent VTE risk factor(s). This trial was registered at www.clinicaltrials.gov as #NCT02197416.

Safety of Venous Thromboprophylaxis With Low-molecular-weight Heparin in Children With Ulcerative Colitis.

OBJECTIVES: To evaluate for increased rectal bleeding following enoxaparin thromboprophylaxis in children hospitalized for ulcerative colitis (UC). METHODS: Retrospective cohort study (2007--2016) of 218 inpatients with active UC. Patients receiving enoxaparin were compared with a nonenoxaparin-treated patient group. Severity of UC was determined using the Pediatric Ulcerative Colitis Activity Index (PUCAI). Hemoglobin (Hb) values and packed red blood cell (pRBC) transfusions were reviewed for a 7-day period following hospital admission. A linear mixed effect model was used to compare change in Hb values between the groups. Risk of pRBC transfusion was compared using a log-rank test and Cox proportional hazard regression. A sub-analysis was also conducted restricting to patients with severe UC to provide more generalizable insight into safety profile of enoxaparin. RESULTS: Children hospitalized for UC and receiving enoxaparin were more likely to have severe disease, received infliximab therapy and be admitted after 2010. Use of enoxaparin showed there was not a difference (P = 0.60) in the fall of Hb detected among those with acute severe colitis (initial PUCAI ≥65) during the week following admission. Moreover, there was no difference in the risk of requiring a pRBC transfusion with enoxaparin use (log-rank test all patients: P = 0.80; severe UC: P = 0.88; Cox proportional hazard regression all patients: P = 0.72; severe UC: 0.85). CONCLUSIONS: There was no difference in Hb levels or need for blood transfusions in children hospitalized for severe UC (PUCAI ≥65) whether or not they received enoxaparin for thromboembolism prophylaxis.

Clinical presentation and therapeutic management of venous thrombosis in young children: a retrospective analysis.

BACKGROUND: Venous thromboembolism (VTE) in young children is not well documented. METHODS: Clinicians from 12 institutions retrospectively evaluated the presentation, therapeutic management, and outcome of VTE in children younger than 2 years seen in 2011-2016. Feasibility of recruiting these children in EINSTEIN-Jr. phase III, a randomized trial evaluating rivaroxaban versus standard anticoagulation for VTE, was assessed. RESULTS: We identified 346 children with VTE, of whom 227 (65.6%) had central venous catheter-related thrombosis (CVC-VTE), 119 (34.4%) had non-CVC-VTE, and 156 (45.1%) were younger than 1 month. Of the 309 children who received anticoagulant therapy, 86 (27.8%) had a short duration of therapy (i.e. < 6 weeks for CVC-VTE and < 3 months for non-CVC-VTE) and 17 (5.5%) had recurrent VTE during anticoagulation (n = 8, 2.6%) or shortly after its discontinuation (n = 9, 2.9%). A total of 37 (10.7%) children did not receive anticoagulant therapy and 4 (10.5%) had recurrent VTE.The average number of children aged < 0.5 years and 0.5-2 years who would have been considered for enrolment in EINSTEIN-Jr is approximately 1.0 and 0.9 per year per site, respectively. CONCLUSIONS: Young children with VTE most commonly have CVC-VTE and approximately one-tenth and one-fourth received no or only short durations of anticoagulant therapy, respectively. Recurrent VTE rates without anticoagulation, during anticoagulation or shortly after its discontinuation seem comparable to those observed in adults. Short and flexible treatment durations could potentially increase recruitment in EINSTEIN-Jr. phase III.

Pediatric Oncology Clinic Care Model: Achieving Better Continuity of Care for Patients in a Medium-sized Program.

Providing the best care in both the inpatient and outpatient settings to pediatric oncology patients is all programs goal. Using continuous improvement methodologies, we changed from a solely team-based physician care model to a hybrid model. All patients were assigned a dedicated oncologist. There would then be 2 types of weeks of outpatient clinical service. A "Doc of the Day" week where each oncologist would have a specific day in clinic when their assigned patients would be scheduled, and then a "Doc of the Week" week where one physician would cover clinic for the week. Patient satisfaction surveys done before and 14 months after changing the model of care showed that patients were very satisfied with the care they received in both models. A questionnaire to staff 14 months after changing showed that the biggest effect was increased continuity of care, followed by more efficient clinic workflow and increased consistency of care. Staff felt it provided better planning and delivery of care. A hybrid model of care with a primary physician for each patient and assigned clinic days, alternating with weeks of single physician coverage is a feasible model of care for a medium-sized pediatric oncology program.

The Spectrum of Recovery From Fracture-Induced Vertebral Deformity in Pediatric Leukemia.

Vertebral fractures (VF) are a frequent complication of acute lymphoblastic leukemia. Some children with VF undergo vertebral body reshaping to the point of complete restoration of normal vertebral dimensions. Others are left with permanent vertebral deformity if the degree of reshaping has been incomplete by the time of final adult height attainment. In this report, we describe three children with painful VF at leukemia diagnosis or during chemotherapy. Each patient highlights different clinical trajectories in their recovery from VF and underscores the need for osteoporosis intervention trials with the goal to prevent permanent vertebral deformity in selected patients.

Bone morbidity in childhood leukemia: epidemiology, mechanisms, diagnosis, and treatment.

Skeletal abnormalities are commonly seen in children and adolescents with leukemia. The spectrum ranges from mild pain to debilitating osteonecrosis (ON) and fractures. In this review, we summarize the skeletal manifestations, provide an update on therapeutic strategies for prevention and treatment, and discuss the most recent advances in musculoskeletal research. Early recognition of skeletal abnormalities and strategies to optimize bone health are essential to prevent long-term skeletal sequelae and diminished quality of life observed in children and adolescents with leukemia.

Dabigatran for Treatment and Secondary Prevention of Venous Thromboembolism in Pediatric Congenital Heart Disease.

BACKGROUND: Congenital heart disease (CHD) is common in children and associated with greater risk of thrombotic complications. Management of these complications with standard-of-care treatment is suboptimal for these children. METHODS AND RESULTS: The effectiveness and safety of dabigatran were demonstrated in pivotal pediatric studies for the treatment of acute venous thromboembolism (VTE; NCT01895777) and secondary VTE prevention (NCT02197416). We report safety and efficacy outcomes from subgroup analyses of these studies for children with CHD (diagnosed according to local practice) and those without. In NCT01895777, 17/21 (81.0%) and 16/27 (59.3%) patients with CHD (including cyanotic) treated with dabigatran and standard of care, respectively, met the primary end point (complete thrombus resolution, freedom from recurrent VTE, and freedom from VTE-related death; odds ratio [OR], 0.34 [95% CI, 0.08-1.23]). In patients without CHD, 41.0% (n=64) versus 34.9% (n=22) achieved this end point with the respective treatments (OR, 0.77 [95% CI, 0.42-1.41]). Although numerical differences were observed, no heterogeneity in treatment effect of dabigatran on the composite primary end point was detected in patients with and without CHD (interaction P =0.2674). In NCT02197416, recurrent VTE at 12 months occurred in 0/17 patients with CHD versus 3/194 (1.5%) without. No patient with CHD experienced major or clinically relevant nonmajor bleeding events. CONCLUSIONS: Data on favorable anticoagulant alternatives for the unmet needs of children with CHD are emerging, and our exploratory results suggest that dabigatran could be an appropriate treatment choice, although challenging sample size limitations in pediatric studies require cautious interpretation of findings. REGISTRATION: URL: https://www.clinicaltrials.gov; Unique identifiers: NCT01895777, NCT02197416.

Vertebral Body Reshaping after Fractures: An Important Index of Recovery in Glucocorticoid-Treated Children.

PURPOSE: In this 6-year study we identified factors associated with spontaneous vertebral body reshaping in glucocorticoid (GC)-treated children with leukemia, rheumatic disorders, and nephrotic syndrome. METHODS: Subjects were 79 children (mean age 7.4 years) who had vertebral fracture (VF) evaluation on lateral spine radiographs at least 1 year after VF detection. VF were graded using the modified Genant semiquantitative method and fracture burden for individuals was quantified using the spinal deformity index (SDI; sum of grades from T4 to L4). RESULTS: Sixty-five children (82.3%) underwent complete vertebral body reshaping (median time from VF detection to complete reshaping 1.3 years by Cox proportional hazard modeling). Of 237 VF, the majority (83.1%) ultimately reshaped, with 87.2% reshaping in the thoracic region vs 70.7% in the lumbar region (P = .004). Cox models showed that (1) every g/m2 increase in GC exposure in the first year after VF detection was associated with a 19% decline in the probability of reshaping; (2) each unit increase in the SDI at the time of VF detection was associated with a 19% decline in the probability of reshaping [hazard ratio (HR) = 0.81; 95% confidence interval (CI) = 0.71, 0.92; P = .001]; (3) each additional VF present at the time of VF detection reduced reshaping by 25% (HR = 0.75; 95% CI = 0.62, 0.90; P = .002); and (4) each higher grade of VF severity decreased reshaping by 65% (HR = 0.35; 95% CI = 0.21, 0.57; P < .001). CONCLUSION: After experiencing a VF, children with higher GC exposure, higher SDI, more severe fractures, or lumbar VF were at increased risk for persistent vertebral deformity.

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.

The prediction of lean body mass and fat mass from arm anthropometry at diagnosis in children with cancer.

Maintenance of adequate nutrition is important in the care of children with cancer. In clinical practice, determination of nutritional status can be accomplished with measurement of body composition by dual-energy x-ray absorptiometry (DXA). However, DXA is seldom available in low-income countries where most children with cancer live. This study sought to provide predictive equations for lean body mass and fat mass, measured by DXA, on the basis of simple arm anthropometry providing measures of mid-upper arm circumference and triceps skin-fold thickness in a population (N=99) of children diagnosed with cancer. Such equations were derived successfully with the inclusion of absolute body weight, the body weight Z-score, and the predicted whole-body bone mineral content on the basis of age and sex. Attempted validation in a small sample (N=7) of children who completed therapy for acute lymphoblastic leukemia revealed disparities reflective of the prevalence of obesity in such survivors. Further validation must be undertaken in large samples of children with a variety of malignant diseases to assess the robustness of the equations predictive of body composition.

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).

Do children with central venous line (CVL) dysfunction have increased risk of symptomatic thromboembolism compared to those without CVL-dysfunction, while on cancer therapy?

BACKGROUND: Thromboembolism (TE) and infection are two common complications of central venous line (CVL). Thrombotic CVL-dysfunction is a common, yet less studied, complication of CVL. Two retrospective studies have reported significant association of CVL-dysfunction and TE. Recent studies indicate association of CVL-related small clot with infection. Infection is the most common cause of non-cancer related mortality in children with cancer. We and others have shown reduced overall survival (OS) in children with cancer and CVL-dysfunction compared to those without CVL-dysfunction. Despite these observations, to date there are no prospective studies to evaluate the clinical significance of CVL-dysfunction and it's impact on the development of TE, infection, or outcome of children with cancer. STUDY DESIGN: This is a prospective, analytical cohort study conducted at five tertiary care pediatric oncology centers in Ontario. Children (≤ 18 years of age) with non-central nervous system cancers and CVL will be eligible for the study. Primary outcome measure is symptomatic TE and secondary outcomes are infection, recurrence of cancer and death due to any cause. Data will be analyzed using regression analyses. DISCUSSION: The overall objective is to delineate the relationship between CVL-dysfunction, infection and TE. The primary aim is to evaluate the role of CVL-dysfunction as a predictor of symptomatic TE in children with cancer. We hypothesize that children with CVL-dysfunction have activation of the coagulation system resulting in an increased risk of symptomatic TE. The secondary aims are to study the impact of CVL-dysfunction on the rate of infection and the survival [OS and event free survival (EFS)] of children with cancer. We postulate that patients with CVL-dysfunction have an occult CVL-related clot which acts as a microbial focus with resultant increased risk of infection. Further, CVL-dysfunction by itself or in combination with associated complications may cause therapy delays resulting in adverse outcome.This study will help to identify children at high risk for TE and infection. Based on the study results, we will design randomized controlled trials of prophylactic anticoagulant therapy to reduce the incidence of TE and infection. This in turn will help to improve the outcome in children with cancer.

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.

Dabigatran in the treatment and secondary prophylaxis of venous thromboembolism in children with thrombophilia.

In the phase 2b/3 DIVERSITY trial, 3 months treatment with dabigatran was noninferior to standard of care (SOC) for acute venous thromboembolism (VTE) in children. In a single-arm, phase 3, secondary VTE prevention study, up to 12 months dabigatran use was associated with favorable safety. Dabigatran is approved by the European Medicines Agency and US Food and Drug Administration for pediatric indications. We assessed primary composite efficacy (complete thrombus resolution and freedom from VTE recurrence/VTE-related death) in subgroups with thrombophilia vs those with negative/unknown thrombophilia status in the DIVERSITY trial and safety in both studies. Thrombophilia types were similar between the DIVERSITY trial (total population) and secondary prevention studies: factor V Leiden, 42% vs 33%; prothrombin mutation (G20210A), 19% vs 17%; antithrombin deficiency, 15% vs 20%; protein C/S deficiency, 23% vs 25%; and antiphospholipid antibodies, 18% vs 20% of patients, respectively. In DIVERSITY, 36% and 22% of thrombophilia subgroup patients treated with dabigatran and SOC, respectively, met the primary end point (Mantel-Haenszel-weighted rate difference, -0.135; 95% confidence interval, -0.36 to 0.08; noninferiority P = .0014); comparable to the total DIVERSITY trial population (46% vs 42%) showing dabigatran noninferiority to SOC. Within this subgroup, numerically fewer patients experienced VTE recurrence or progression of index thrombus in the dabigatran treatment group vs SOC. In the secondary prevention study, VTE recurrence at 12 months occurred in 2.8% of patients with thrombophilia vs 0% with negative/unknown thrombophilia. Safety profiles were consistent with those reported previously. Although they should be interpreted with caution, these exploratory findings suggest dabigatran could be an appropriate long-term anticoagulant for children with thrombophilia. These trials were registered at www.clinicaltrials.gov as #NCT01895777 and #NCT02197416.

Anticoagulant Effects of Dabigatran on Coagulation Laboratory Parameters in Pediatric Patients: Combined Data from Five Pediatric Clinical Trials.

BACKGROUND: Dabigatran etexilate, a direct oral thrombin inhibitor, is approved to treat venous thromboembolism (VTE) in both adults and children. OBJECTIVES: This population analysis characterized relationships between dabigatran total plasma concentrations and coagulation laboratory parameters (activated partial thromboplastin time [aPTT]; diluted thrombin time [dTT]; ecarin clotting time [ECT]). METHODS: Data from three phase 2a and one single-arm and one randomized, comparative phase 2b/3 pediatric studies (measurements: aPTT 2,925 [N = 358]; dTT 2,348 [N = 324]; ECT 2,929 [N = 357]) were compared with adult data (5,740 aPTT, 3,472 dTT, 3,817 ECT measurements; N = 1,978). Population models were fitted using nonlinear mixed-effects modeling. Covariates (e.g., sex, age) were assessed on baseline and drug-effect parameters, using a stepwise covariate model-building procedure. RESULTS: Overall, relationships between dabigatran, aPTT, dTT, and ECT were similar in children and adults. For children aged <6 months, a higher proportion of baseline samples were outside or close to the upper aPTT and ECT adult ranges. No age-related differences were detected for dTT. With increasing dabigatran concentration, aPTT rose nonlinearly (half the maximum effect at 368 ng/mL dabigatran) while dTT and ECT increased linearly (0.37 and 0.73% change per ng/mL dabigatran, respectively). Mean baseline aPTT (45 vs. 36 seconds) and ECT (40 vs. 36 seconds) were slightly increased for those aged <6 months versus older children. CONCLUSION: The similar relationships of laboratory parameters observed across pediatric age groups suggests that developmental changes in the hemostatic system may have little effect on response to dabigatran.

Nutritional status at diagnosis in children with cancer. 2. An assessment by arm anthropometry.

Assessment of nutritional status in children with cancer is important but measures based on weight can be problematic at diagnosis, especially in those with advanced disease. Likewise, dual energy x-ray absorptiometry may be confounded by other radiological procedures and is not commonly available in low-income countries where most children with cancer live. Arm anthropometry is not subject to these constraints. In a study sample of 99 Canadian patients with cancer at diagnosis, mid-upper arm circumference correlated well with lean body mass as measured by dual energy x-ray absorptiometry but triceps skin fold thickness was a poor predictor of fat mass. Arm anthropometry can be a useful tool for the measurement of nutritional status in children with cancer. However, further studies, particularly in low-income countries and in children with solid tumors at diagnosis, are required to determine the full extent of its utility.

Pharmacokinetic modeling and simulation support for age- and weight-adjusted dosing of dabigatran etexilate in children with venous thromboembolism.

BACKGROUND: Dabigatran etexilate (DE), a direct oral thrombin inhibitor, has been evaluated in children with venous thromboembolism (VTE) using oral solution, pellets, or capsules. OBJECTIVES: This study evaluated DE pharmacokinetics (PK) in children with VTE and the appropriateness of a DE pediatric age- and weight-based dosing algorithm. PATIENTS/METHODS: A population PK model was fitted to data from four single-arm and one randomized, comparative pediatric VTE studies (358 children aged birth to <18 years; 2748 PK observations) and one healthy-adult study (32 males aged <40 years; 1523 PK observations) using nonlinear mixed-effects modeling. A stepwise, covariate, model-building procedure evaluated the influence of covariates (e.g., age, body weight, body surface area [BSA]-normalized renal function, and sex). The final model was used to evaluate the pediatric dosing algorithm, with simulations comparing pediatric trough exposure with reference exposure defined for the pediatric studies. RESULTS: The population PK of dabigatran was adequately described by a two-compartment model with first-order elimination and absorption. Age, weight, BSA-normalized renal function, and sex were statistically significant covariates (all P < .05). Apparent clearance increased with age (independently of body weight), diminished with decreasing BSA-normalized renal function, and was lower in females than males. All disposition parameters increased with body weight escalation (allometric scaling). Simulations confirmed that for all DE formulations, the final pediatric dosing algorithms achieved reference exposure without dose adjustment. CONCLUSIONS: Using a population PK model of DE for children with VTE, simulations showed that the final dosing algorithms were appropriate for all DE formulations; no dose titration was needed.

Dabigatran etexilate for the treatment of acute venous thromboembolism in children (DIVERSITY): a randomised, controlled, open-label, phase 2b/3, non-inferiority trial.

BACKGROUND: Dabigatran etexilate is a direct oral anticoagulant with potential to overcome the limitations of standard of care in children with venous thromboembolism. The aims of this clinical trial were to study the appropriateness of a paediatric dabigatran dosing algorithm, and the efficacy and safety of dabigatran dosed according to that algorithm versus standard of care in treating children with venous thromboembolism. METHODS: DIVERSITY is a randomised, controlled, open-label, parallel-group, phase 2b/3 non-inferiority trial done in 65 centres in 26 countries. Standard of care (low-molecular-weight heparins, unfractionated heparin, vitamin K antagonists or fondaparinux) was compared with a paediatric oral dabigatran dosing regimen (an age-adjusted and weight-adjusted nomogram) in children younger than 18 years with acute venous thromboembolism initially treated (5-21 days) with parenteral anticoagulation, requiring anticoagulation therapy for at least 3 months. Patients were randomised 1:2 (standard of care:dabigatran) and stratified by age (12 to <18 years, 2 to <12 years, and birth to <2 years) via interactive response technology. The primary composite efficacy endpoint (intention-to-treat analysis) was the proportion of children with complete thrombus resolution, and freedom from recurrent venous thromboembolism and venous thromboembolism-related death. A non-inferiority margin of absolute differences of 20% was used. Secondary endpoints included safety (determined by major bleeding events [time-to-event analysis on the treated set]), and pharmacokinetic-pharmacodynamic relationships (descriptive analyses). This trial is registered with ClinicalTrials.gov, NCT01895777 and is completed. FINDINGS: 328 children were enrolled between Feb 18, 2014, and Nov 14, 2019. 267 were randomly assigned (90 [34%] to standard of care and 177 [66%] to dabigatran) and included in the analyses. Median exposure to standard of care was 85·0 days (IQR 80·0-90·0) and to dabigatran was 84·5 days (78·0-89·0). Similar proportions of children treated with standard of care and dabigatran met the composite efficacy endpoint (38 [42%] of 90 vs 81 [46%] of 177; Mantel-Haenszel weighted difference, -0·04; 90% CI -0·14 to 0·07; p<0·0001 for non-inferiority). On-treatment bleeding events were reported in 22 (24%) of 90 children receiving standard of care and 38 (22%) of 176 children receiving dabigatran (hazard ratio [HR] 1·15, 95% CI 0·68 to 1·94; p=0·61); major bleeding events were similar between the groups (two [2%] of 90 and four [2%] of 176; HR 0·94, 95% CI 0·17 to 5·16; p=0·95). Pharmacokinetic-pharmacodynamic curves showed a linear relationship between total dabigatran plasma concentration and diluted thrombin time and ecarin clotting time, and a non-linear relationship with activated partial thromboplastin time; curves were similar to those for adults. Serious adverse events were reported for 18 (20%) of 90 children receiving standard of care and 22 (13%) of 176 children receiving dabigatran. The most common severe adverse events were vascular disorders (standard of care three [3%] of 90, dabigatran two [1%] of 176), and gastrointestinal disorders (standard of care two [2%] of 90 and dabigatran five [3%] of 176). One on-treatment death occurred in the standard of care group (retroperitoneal bleeding, not considered treatment related by the study investigators). INTERPRETATION: An age-adjusted and weight-adjusted dabigatran dosing algorithm was appropriate in children aged birth to less than 18 years with venous thromboembolism. Dabigatran was non-inferior to standard of care in terms of efficacy, with similar pharmacokinetic-pharmacodynamic relationships as those seen in adults, and might be a suitable alternative to standard of care. FUNDING: Boehringer Ingelheim.

A Validated Risk Prediction Model for Bone Fragility in Children With Acute Lymphoblastic Leukemia.

Although bone fragility may already be present at diagnosis of pediatric acute lymphoblastic leukemia (ALL), routine performance of dual-energy X-ray absorptiometry (DXA) in every child is not universally feasible. The aim of this study was to develop and validate a risk prediction model for low lumbar spine bone mineral density (LS BMD Z-score ≤ -2.0) at diagnosis, as an important indicator for fracture risk and further treatment-related BMD aggravation. Children with ALL (4-18 years), treated according to the Dutch Childhood Oncology Group protocol (DCOG-ALL9; model development; n = 249) and children from the Canadian Steroid-Associated Osteoporosis in the Pediatric Population cohort (STOPP; validation; n = 99) were included in this study. Multivariable logistic regression analyses were used to develop the prediction model and to confirm the association of low LS BMD at diagnosis with symptomatic fractures during and shortly after cessation of ALL treatment. The area under the receiver operating characteristic curve (AUC) was used to assess model performance. The prediction model for low LS BMD at diagnosis using weight (ß = -0.70) and age (ß = -0.10) at diagnosis revealed an AUC of 0.71 (95% CI, 0.63-0.78) in DCOG-ALL9 and 0.74 (95% CI, 0.63-0.84) in STOPP, and resulted in correct identification of 71% of the patients with low LS BMD. We confirmed that low LS BMD at diagnosis is associated with LS BMD at treatment cessation (OR 5.9; 95% CI, 3.2-10.9) and with symptomatic fractures (OR 1.7; 95% CI, 1.3-2.4) that occurred between diagnosis and 12 months following treatment cessation. In meta-analysis, LS BMD at diagnosis (OR 1.6; 95% CI, 1.1-2.4) and the 6-month cumulative glucocorticoid dose (OR 1.9; 95% CI, 1.1-3.2) were associated with fractures that occurred in the first year of treatment. In summary, a prediction model for identifying pediatric ALL patients with low LS BMD at diagnosis, as an important indicator for bone fragility, was successfully developed and validated. This can facilitate identification of future bone fragility in individual pediatric ALL patients. © 2021 American Society for Bone and Mineral Research (ASBMR).