ENNOBLE-ATE trial: an open-label, randomised, multi-centre, observational study of edoxaban for children with cardiac diseases at risk of thromboembolism

Real-world experience with edoxaban for anticoagulation in children at risk for coronary artery thrombosis

BACKGROUND

Direct oral anticoagulants have the potential to improve care in children requiring chronic anticoagulation. Edoxaban has favourable pharmacokinetics that could benefit younger patients but data on long-term safety and efficacy for specific paediatric indications are lacking.

STUDY AIMS

We present a single-centre experience using edoxaban in children who require chronic anticoagulation for large coronary artery aneurysms secondary to Kawasaki disease.

METHODS

Weight-based dosing of once-daily oral edoxaban was offered as alternative to standard anticoagulation for patients aged 1-18 years. Chart review was performed for a median follow-up period of 49 months on edoxaban. Steady-state pharmacokinetics and pharmacodynamics of edoxaban were also explored.

RESULTS

Sixteen patients on chronic therapy with edoxaban were included. No major bleeding events were reported. Two patients experienced coronary artery thrombosis after 23 and 38 months on edoxaban, 7 and 11 years after diagnosed with Kawasaki disease, respectively. This predicts 70% event-free rate at 12 years from diagnosis. Area under the curve estimates over the dosing interval of 24 hours were similar to those reported in adults.

CONCLUSIONS

Edoxaban use is feasible and well-tolerated for long-term use in paediatric population. We suggest appropriate exposure using weight-based once-daily dosing strategy that may be comparable to standard-of-care anticoagulation in prevention of coronary artery thrombosis. Larger studies are needed to evaluate long-term safety and efficacy of edoxaban in this population.

Hospital-Acquired Venous Thromboembolism and Invasive Mechanical Ventilation: A Report From the Children's Hospital Acquired Thrombosis Consortium

OBJECTIVES

To determine if the duration of invasive mechanical ventilation (IMV) was associated with hospital-acquired venous thromboembolism (HA-VTE) among critically ill children.

DESIGN

A multicenter, matched case-control study as a secondary analysis of Children's Hospital Acquired Thrombosis (CHAT) Consortium registry.

SETTING

PICUs within U.S. CHAT Consortium participating centers.

PATIENTS

Children younger than 21 years old admitted to a PICU receiving IMV for greater than or equal to 1 day duration from January 2012 to March 2022 were included for study. Cases with HA-VTE were matched 1:2 to controls without HA-VTE by patient age groups: younger than 1, 1-12, and older than 12 years.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was IMV duration in days. Descriptive data included demographics, anthropometrics, HA-VTE characteristics (i.e., type, location, and timing), central venous catheterization data, thromboprophylaxis practices, and Braden Q mobility scores. Descriptive, comparative, and associative (multivariate conditional logistic regression for HA-VTE) statistics were employed. A total of 152 cases were matched to 304 controls. Cases with HA-VTE were diagnosed at a median of 7 days (interquartile range [IQR], 3-16 d) after IMV. The HA-VTE were limb deep venous thromboses in 130 of 152 (85.5%) and frequently central venous catheterization-related (111/152, 73%). Cases with HA-VTE experienced a longer length of stay (median, 34 d [IQR, 18-62 d] vs. 11.5 d [IQR, 6-21 d]; p < 0.001) and IMV duration (median, 7 d [IQR, 4-15 d] vs. 4 d [IQR, 1-7 d]; p < 0.001) as compared with controls. In a multivariate logistic model, greater IMV duration (adjusted odds ratio, 1.09; 95% CI, 1.01-1.17; p = 0.023) was independently associated with HA-VTE.

CONCLUSIONS

Among critically ill children undergoing IMV, HA-VTE was associated with greater IMV duration. If prospectively validated, IMV duration should be included as part of prothrombotic risk stratification and future pediatric thromboprophylaxis trials.

Physiologically-based pharmacokinetic pharmacodynamic parent-metabolite model of edoxaban to predict drug-drug-disease interactions: M4 contribution

This study aimed to develop a physiologically-based pharmacokinetic pharmacodynamic (PBPK/PD) parent-metabolite model of edoxaban, an oral anticoagulant with a narrow therapeutic index, and to predict pharmacokinetic (PK)/PD profiles and potential drug-drug-disease interactions (DDDIs) in patients with renal impairment. A whole-body PBPK model with a linear additive PD model of edoxaban and its active metabolite M4 was developed and validated in SimCYP for healthy adults with or without interacting drugs. The model was extrapolated to situations including renal impairment and drug-drug interactions (DDIs). Observed PK and PD data in adults were compared with predicted data. The effect of several model parameters on the PK/PD response of edoxaban and M4 was investigated in sensitivity analysis. The PBPK/PD model successfully predicted PK profiles of edoxaban and M4 as well as anticoagulation PD responses with or without the influence of interacting drugs. For patients with renal impairment, the PBPK model successfully predicted the fold change in each impairment group. Inhibitory DDI and renal impairment had a synergistic effect on the increased exposure of edoxaban and M4, and their downstream anticoagulation PD effect. Sensitivity analysis and DDDI simulation show that renal clearance, intestinal P-glycoprotein activity, and hepatic OATP1B1 activity are the major factors affecting edoxaban-M4 PK profiles and PD responses. Anticoagulation effect induced by M4 cannot be ignored when OATP1B1 is inhibited or downregulated. Our study provides a reasonable approach to adjust the dose of edoxaban in several complicated scenarios especially when M4 cannot be ignored due to decreased OATP1B1 activity.

50 Years of Pediatric Hemostasis: Knowledge, Diagnosis, and Treatment

Studies from the past 50 years have contributed to the expanding knowledge regarding developmental hemostasis. This is a dynamic process that begins in the fetal phase and is characterized by physiological variations in platelet counts and function, and concentrations of most coagulation factors and the native coagulation inhibitors in early life, as compared with adulthood. The developmental hemostasis studies since the 1980 to 1990s established the laboratory reference values for coagulation factors. It was only a decade or two later, that thromboelastography (TEG) or (rotational thromboelastometry [ROTEM]) as well as thrombin generation studies, provided special pediatric reference values along with the ability to evaluate clot formation and lysis. In addition, global whole blood-based clotting assays provided point of care guidance for proper transfusion support to children hospitalized in intensive care units or undergoing surgery. Although uncommon, thrombosis in children and neonates is gaining increasing recognition, typically as a secondary complication in sick children. Bleeding in children, and particularly intracerebral hemorrhage in newborns, still represent a therapeutic challenge. Notably, our review will outline the advancements in understanding developmental hemostasis and its manifestations, with respect to the pathophysiology of thrombosis and bleeding complications in young children. The changes of transfusion policy and approach to thrombophilia testing during the last decade will be mentioned. Subsequently, a brief summary of the data on anticoagulant treatments in pediatric patients will be presented. Finally, we will point out the 10 most cited articles in the field of pediatric and neonatal hemostasis.

Just DOAC: Use of direct-acting oral anticoagulants in pediatrics

PURPOSE

The aim of this article is to provide an overview of the current literature for direct-acting oral anticoagulant (DOAC) use in pediatric patients and summarize ongoing trials.

SUMMARY

In treatment of venous thromboembolism (VTE) in pediatric patients, evidence supports use of both dabigatran and rivaroxaban. Dabigatran has been shown to be noninferior to standard of care (SOC) in terms of efficacy, with similar bleeding rates. Similarly, treatment with rivaroxaban in children with acute VTE resulted in a low recurrence risk and reduced thrombotic burden, without increased risk of bleeding, compared to SOC. Treatment of pediatric cerebral venous thrombosis as well as central venous catheter-related VTE with rivaroxaban appeared to be both safe and efficacious and similar to that with SOC. Dabigatran also has a favorable safety profile for prevention of VTE, and rivaroxaban has a favorable safety profile for VTE prevention in children with congenital heart disease. Many studies with several different DOACs are ongoing to evaluate both safety and efficacy in unique patient populations, as well as VTE prevention.

CONCLUSION

The literature regarding pediatric VTE treatment and prophylaxis is growing, but the need for evidence-based pediatric guidelines remains. Additional long-term, postauthorization studies are warranted to further elucidate safety and efficacy in clinical scenarios excluded in clinical trials. Additional data on safety, efficacy, and dosing strategies for reversal agents are also necessary, especially as the use of DOACs becomes more common in the pediatric population.

Edoxaban for Thromboembolism Prevention in Pediatric Patients With Cardiac Disease

BACKGROUND

Standard of care (SOC) anticoagulation for thromboembolism (TE) prevention in children with cardiac disease includes low molecular weight heparins or vitamin K antagonists. Limited data exists for alternate use of direct oral anticoagulants in children.

OBJECTIVES

The investigators aimed to obtain safety and efficacy data for edoxaban in children.

METHODS

We performed a phase 3, multinational, prospective, randomized, open-label, blinded-endpoint trial in patients <18 years of age with cardiac disease (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots (Thrombotic Events) in Children at Risk Because of Cardiac Disease] trial). Patients were randomized 2:1 to age- and weight-based oral edoxaban once daily vs SOC for 3 months (main study period), stratified by cardiac diagnosis. Both groups could continue in an open-label edoxaban extension arm through 1 year. The primary endpoint was adjudicated clinically relevant bleeding (CRB). The main secondary endpoint was symptomatic TE or asymptomatic intracardiac thrombosis.

RESULTS

The modified intention-to-treat cohort included 167 children. One patient per group experienced a nonmajor CRB in the main period. Treatment-emergent adverse events occurred in 46.8% (51 of 109) with edoxaban and 41.4% (24 of 58) with SOC. One SOC patient experienced 2 TE events (DVT with PE). Among 147 children in the extension, 1 CRB event (0.7%) and 4 TEs occurred (2.8%; 2 strokes and 2 of 33 Kawasaki disease patients with coronary artery thromboses and/or myocardial infarctions).

CONCLUSIONS

Edoxaban is a potential alternative mode of thromboprophylaxis in children with cardiac disease showing low rates of CRB and TEs with advantages of once daily dosing and infrequent monitoring requirement. (ENNOBLE-ATE [Edoxaban for Prevention of Blood Vessels Being Blocked by Clots] (Thrombotic Events) in Children at Risk Because of Cardiac Disease trial; NCT03395639).

Mechanical Ventilation and Hospital-Acquired Venous Thromboembolism Among Critically Ill Children

OBJECTIVES

To estimate the occurrence of, and evaluate associations between, hospital-acquired venous thromboembolism (HA-VTE) and invasive mechanical ventilation (MV) among children hospitalized in the PICU.

METHODS

We performed a multicenter, retrospective cohort study comparing HA-VTE frequencies among subjects <18 years of age hospitalized in the PICU from January 2018 through December 2019 among 47 participating centers, via the Pediatric Health Information Systems registry. We excluded perinatal encounters, those with VTE present at admission, and those with observational status. The primary outcome was the proportion of HA-VTE events before hospital discharge, including extremity deep venous thrombosis, pulmonary embolism, and organ-specific deep venous thrombosis. The HA-VTE frequencies were compared using χ2 tests. The association between HA-VTE and MV was investigated via multivariable logistic regression, adjusting for previously described VTE risk factors.

RESULTS

Of the 205 231 PICU encounters identified for study, 70 829 (34.5%) underwent MV. The occurrence of HA-VTE was 2.2% and was greater among children who received, versus did not receive, MV (4.4% versus 1.1%, P < .001). Multivariable logistic regression revealed significant association between MV and HA-VTE (odds ratio 2.51, 95% confidence interval 2.33-2.69; P < .001).

CONCLUSIONS

In this multicenter, retrospective, registry-based cohort study, HA-VTE were diagnosed in 2.2% of critically-ill children, and after adjustment for central venous catheterization, MV independently increased the risk of HA-VTE 2.5-fold. These findings warrant prospective validation to inform the design of future risk-stratified clinical trials of thromboprophylaxis in critically-ill children.

Hemostatic and Thrombotic Considerations in the Diagnosis and Management of Childhood Arterial Ischemic Stroke: A Narrative Review

Although rare in children, arterial ischemic stroke (AIS) is associated with increased mortality and neurological morbidity. The incidence of AIS after the neonatal period is approximately 1-2/100,000/year, with an estimated mortality of 3-7%. A significant proportion of children surviving AIS experience life-long neurological deficits including hemiparesis, epilepsy, and cognitive delays. The low incidence of childhood AIS coupled with atypical clinical-presentation and lack of awareness contribute to delay in diagnosis and consequently, the early initiation of treatment. While randomized-clinical trials have demonstrated the efficacy and safety of reperfusion therapies including thrombolysis and endovascular thrombectomy in appropriately-selected adult patients, similar data for children are unavailable. Consequently, clinical decisions surrounding reperfusion therapy in childhood AIS are either extrapolated from adult data or based on local experience. The etiology of childhood AIS is multifactorial, often occurring in the setting of both acquired and congenital risk-factors including thrombophilia. While multiple studies have investigated the association of thrombophilia with incident childhood AIS, its impact on stroke recurrence and therefore duration and intensity of antithrombotic therapy is less clear. Despite these limitations, a significant progress has been made over the last decade in the management of childhood AIS. This progress can be attributed to international consortiums, and in selected cohorts to federally-funded clinical trials. In this narrative review, the authors have systematically appraised the literature and summarize the hemostatic and thrombotic considerations in the diagnosis and management of childhood AIS focusing on the evidence supporting reperfusion therapies, relevance of thrombophilia testing, and duration and drug choices for secondary-prophylaxis.

Practical Considerations for Use of Direct Oral Anticoagulants in Children

Direct oral anticoagulants (DOACs) provide an attractive alternative for the management and prevention of thrombosis in pediatric patients. With multiple ongoing and published pediatric trials and recent regulatory approval of dabigatran and rivaroxaban, the landscape of pediatric anticoagulation is rapidly changing. However, as pediatricians gain experience with these drugs, it is important to be mindful of pediatric-specific considerations that may limit the use of DOACs in certain children and adolescents. While there is increasing adult data and experience, there is a paucity of real-world evidence to guide the use of these drugs in children who would not have met clinical trial inclusion criteria. In this mini review, we summarize pediatric specific data, areas for future research, and practical considerations for the use of DOACs in children and adolescents.

A systematic review of the evidence supporting post-operative antithrombotic use following cardiopulmonary bypass in children with CHD

OBJECTIVES

To determine the optimal antithrombotic agent choice, timing of initiation, dosing and duration of therapy for paediatric patients undergoing cardiac surgery with cardiopulmonary bypass.

METHODS

We used PubMed and EMBASE to systematically review the existing literature of clinical trials involving antithrombotics following cardiac surgery from 2000 to 2020 in children 0-18 years. Studies were assessed by two reviewers to ensure they met eligibility criteria.

RESULTS

We identified 10 studies in 1929 children across three medications classes: vitamin K antagonists, cyclooxygenase inhibitors and indirect thrombin inhibitors. Four studies were retrospective, five were prospective observational cohorts (one of which used historical controls) and one was a prospective, randomised, placebo-controlled, double-blind trial. All included were single-centre studies. Eight studies used surrogate biomarkers and two used clinical endpoints as the primary endpoint. There was substantive variability in response to antithrombotics in the immediate post-operative period. Studies of warfarin and aspirin showed that laboratory monitoring levels were frequently out of therapeutic range (variably defined), and findings were mixed on the association of these derangements with bleeding or thrombotic events. Heparin was found to be safe at low doses, but breakthrough thromboembolic events were common.

CONCLUSION

There are few paediatric prospective randomised clinical trials evaluating antithrombotic therapeutics post-cardiac surgery; most studies have been observational and seldom employed clinical endpoints. Standardised, validated endpoints and pragmatic trial designs may allow investigators to determine the optimal drug, timing of initiation, dosing and duration to improve outcomes by limiting post-operative morbidity and mortality related to bleeding or thrombotic events.