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Background The COMPASS (Cardiovascular Outcomes for People Using Anticoagulation Strategies) trial showed that rivaroxaban plus aspirin reduced major adverse cardiovascular events (MACE) in patients with chronic coronary artery disease (CAD) and/or peripheral artery disease (PAD). We explored whether CHA2DS2-VASc or CHADS2 scores, well-validated tools for assessing risk of thromboembolic events in atrial fibrillation, can identify vascular patients at highest risk of recurrent events who may derive greatest benefits of treatment. Methods Predictive accuracies of the CHA2DS2-VASc and CHADS2 scores for MACE, were assessed in this analysis of the COMPASS trial. Kaplan-Meier estimates of cumulative risk were used to compare the effects of rivaroxaban plus aspirin (n = 9152) with aspirin alone (n = 9126) according to risk scores. Results High CHA2DS2-VASc (6-9) or CHADS2 (3-6) scores were associated with over three times greater absolute risk of MACE compared with CHA2DS2-VASc score of 1-2 or CHADS2 score of 0. The effects of rivaroxaban plus aspirin compared with aspirin alone were consistent across CHA2DS2-VASc and CHADS2 score categories for MACE, bleeding and net clinical benefit, with greatest reduction in MACE observed in patients treated for 30 months with highest CHADS2 score (3-6) (hazard ratio = 0.67, 95% CI: 0.53-0.86, p = 0.0012, 25 events per 1000 patients prevented). Conclusion The CHA2DS2-VASc and CHADS2 scores can be used in patients with chronic CAD and/or PAD to identify patients who are at highest risk of MACE. Those identified at highest risk by CHADS2 scores had greatest benefit from dual pathway inhibition with rivaroxaban plus aspirin. Clinical Trial Registration: NCT01776424.

BACKGROUND: Recently, the randomized EINSTEIN-Jr study showed similar efficacy and safety for rivaroxaban and standard anticoagulation for treatment of pediatric venous thromboembolism (VTE). The rivaroxaban dosing strategy was established based on phase 1 and 2 data in children and through pharmacokinetic (PK) modeling. METHODS: Rivaroxaban treatment with tablets or the newly developed granules-for-oral suspension formulation was bodyweight-adjusted and administered once-daily, twice-daily, or thrice-daily for children with bodyweights of ≥30, ≥12 to <30, and <12 kg, respectively. Previously, these regimens were confirmed for children weighing ≥20 kg but only predicted in those <20 kg. Based on sparse blood sampling, the daily area under the plasma concentration-time curve [AUC(0-24)ss ] and trough [Ctrough,ss ] and maximum [Cmax,ss ] steady-state plasma concentrations were derived using population PK modeling. Exposure-response graphs were generated to evaluate the potential relationship of individual PK parameters with recurrent VTE, repeat imaging outcomes, and bleeding or adverse events. A taste-and-texture questionnaire was collected for suspension-recipients. RESULTS: Of the 335 children (aged 0-17 years) allocated to rivaroxaban, 316 (94.3%) were evaluable for PK analyses. Rivaroxaban exposures were within the adult exposure range. No clustering was observed for any of the PK parameters with efficacy, bleeding, or adverse event outcomes. Results were similar for the tablet and suspension formulation. Acceptability and palatability of the suspension were favorable. DISCUSSION: Based on this analysis and the recently documented similar efficacy and safety of rivaroxaban compared with standard anticoagulation, we conclude that bodyweight-adjusted pediatric rivaroxaban regimens with either tablets or suspension are validated and provide for appropriate treatment of children with VTE.

Anticoagulant treatment of pediatric central venous catheter-related venous thromboembolism (CVC-VTE) has not been specifically evaluated. In EINSTEIN-Jr, 500 children with any VTE received rivaroxaban or standard anticoagulants. A predefined analysis of the CVC-VTE cohort was performed. Children with CVC-VTE (age, birth to 17 years) were administered rivaroxaban or standard anticoagulants during the 1-month (children <2 years) or 3-month (all other children) study period. Predefined outcomes were recurrent VTE, change in thrombotic burden on repeat imaging, and bleeding. Predictors for continuation of anticoagulant therapy beyond the study period were evaluated. One hundred twenty-six children with symptomatic (n = 76, 60%) or asymptomatic (n = 50, 40%) CVC-VTE received either rivaroxaban (n = 90) or standard anticoagulants (n = 36). There was no recurrent VTE (0%; 95% confidence interval [CI], 0.0%-2.8%). Three children had the principal safety outcome: none had major bleeding and 3 children had clinically relevant nonmajor bleeding (2.4%; 95% CI, 0.7%-6.5%), all in the rivaroxaban arm. Complete or partial vein recanalization occurred in 57 (55%) and 38 (37%) of 103 evaluable children, respectively. Results were similar for symptomatic and asymptomatic CVC-VTE. Continuation of anticoagulant therapy beyond the study period occurred in 61 (48%) of children and was associated with residual VTE but only in children <2 years (odds ratio [OR], 20.9; P = .003) and continued CVC use (OR, 6.7; P = .002). Anticoagulant therapy appeared safe and efficacious and was associated with reduced clot burden in most children with symptomatic or asymptomatic CVC-VTE. Residual VTE and continued CVC use were associated with extended anticoagulation. This trial was registered at www.clinicaltrials.gov as #NCT02234843.

Anticoagulant treatment of pediatric cerebral venous thrombosis has not been evaluated in randomized trials. We evaluated the safety and efficacy of rivaroxaban and standard anticoagulants in the predefined subgroup of children with cerebral venous thrombosis (CVT) who participated in the EINSTEIN-Jr trial. Children with CVT were randomized (2:1), after initial heparinization, to treatment with rivaroxaban or standard anticoagulants (continued on heparin or switched to vitamin K antagonist). The main treatment period was 3 months. The primary efficacy outcome, symptomatic recurrent venous thromboembolism (VTE), and principal safety outcome, major or clinically relevant nonmajor bleeding,were centrally evaluated by blinded investigators. Sinus recanalization on repeat brain imaging was a secondary outcome. Statistical analyses were exploratory. In total, 114 children with confirmed CVT were randomized. All children completed the follow-up. None of the 73 rivaroxaban recipients and 1 (2.4%; CVT) of the 41 standard anticoagulant recipients had symptomatic, recurrent VTE after 3 months (absolute difference, 2.4%; 95% confidence interval [CI], -2.6% to 13.5%). Clinically relevant bleeding occurred in 5 (6.8%; all nonmajor and noncerebral) rivaroxaban recipients and in 1 (2.5%; major [subdural] bleeding) standard anticoagulant recipient (absolute difference, 4.4%; 95% CI, -6.7% to 13.4%). Complete or partial sinus recanalization occurred in 18 (25%) and 39 (53%) rivaroxaban recipients and in 6 (15%) and 24 (59%) standard anticoagulant recipients, respectively. In summary, in this substudy of a randomized trial with a limited sample size, children with CVT treated with rivaroxaban or standard anticoagulation had a low risk of recurrent VTE and clinically relevant bleeding. This trial was registered at clinicaltrials.gov as #NCT02234843.

BACKGROUND: Venous thromboembolism (VTE) is a relatively rare condition in childhood with treatment mainly based on extrapolation from studies in adults. Therefore, clinical trials of anticoagulation in children require novel approaches to deal with numerous challenges. The EINSTEIN-Jr program identified pediatric rivaroxaban regimens commencing with in vitro dose finding studies followed by evaluation of children of different ages through phase I and II studies using extensive modeling to determine bodyweight-related doses. Use of this approach resulted in drug exposure similar to that observed in young adults treated with rivaroxaban 20 mg once-daily. METHODS: EINSTEIN-Jr phase III is a randomized, open-label, study comparing the efficacy and safety of rivaroxaban 20 mg-equivalent dose regimens with those of standard anticoagulation for the treatment of any types of acute VTE in children aged 0-18 years.A total of approximately 500 children are expected to be included during the 4-year study window. Flexibility of treatment duration is allowed with study treatment to be given for 3 months with the option to continue treatment in 3-month increments, up to a total of 12 months. However, based on most common current practice, children younger than 2 years with catheter-related thrombosis will have a main treatment period of 1 month with the option to prolong treatment in 1-month increments, up to a total of 3 months. CONCLUSIONS: EINSTEIN-Jr will compare previously established 20 mg-equivalent rivaroxaban dosing regimens with standard anticoagulation for the treatment of VTE in children. Demonstration of similarity of disease, as well as equivalent rivaroxaban exposure and exposure-response will enable extrapolation of efficacy from adult trials, which is critical given the challenges of enrollment in pediatric anticoagulation trials. TRIAL REGISTRATION: Clinicaltrials.gov NCT02234843, registered on 9 September 2014.

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.

BACKGROUND: Atrial fibrillation is associated with higher mortality. Identification of causes of death and contemporary risk factors for all-cause mortality may guide interventions. METHODS AND RESULTS: In the Rivaroxaban Once Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation (ROCKET AF) study, patients with nonvalvular atrial fibrillation were randomized to rivaroxaban or dose-adjusted warfarin. Cox proportional hazards regression with backward elimination identified factors at randomization that were independently associated with all-cause mortality in the 14 171 participants in the intention-to-treat population. The median age was 73 years, and the mean CHADS2 score was 3.5. Over 1.9 years of median follow-up, 1214 (8.6%) patients died. Kaplan-Meier mortality rates were 4.2% at 1 year and 8.9% at 2 years. The majority of classified deaths (1081) were cardiovascular (72%), whereas only 6% were nonhemorrhagic stroke or systemic embolism. No significant difference in all-cause mortality was observed between the rivaroxaban and warfarin arms (P=0.15). Heart failure (hazard ratio 1.51, 95% CI 1.33-1.70, P<0.0001) and age ≥75 years (hazard ratio 1.69, 95% CI 1.51-1.90, P<0.0001) were associated with higher all-cause mortality. Multiple additional characteristics were independently associated with higher mortality, with decreasing creatinine clearance, chronic obstructive pulmonary disease, male sex, peripheral vascular disease, and diabetes being among the most strongly associated (model C-index 0.677). CONCLUSIONS: In a large population of patients anticoagulated for nonvalvular atrial fibrillation, ≈7 in 10 deaths were cardiovascular, whereas <1 in 10 deaths were caused by nonhemorrhagic stroke or systemic embolism. Optimal prevention and treatment of heart failure, renal impairment, chronic obstructive pulmonary disease, and diabetes may improve survival. CLINICAL TRIAL REGIST