Phase 1 Trial of Antibody NI006 for Depletion of Cardiac Transthyretin Amyloid.

BACKGROUND: Transthyretin amyloid (ATTR) cardiomyopathy is a progressive and fatal disease caused by misfolded transthyretin. Despite advances in slowing disease progression, there is no available treatment that depletes ATTR from the heart for the amelioration of cardiac dysfunction. NI006 is a recombinant human anti-ATTR antibody that was developed for the removal of ATTR by phagocytic immune cells. METHODS: In this phase 1, double-blind trial, we randomly assigned (in a 2:1 ratio) 40 patients with wild-type or variant ATTR cardiomyopathy and chronic heart failure to receive intravenous infusions of either NI006 or placebo every 4 weeks for 4 months. Patients were sequentially enrolled in six cohorts that received ascending doses (ranging from 0.3 to 60 mg per kilogram of body weight). After four infusions, patients were enrolled in an open-label extension phase in which they received eight infusions of NI006 with stepwise increases in the dose. The safety and pharmacokinetic profiles of NI006 were assessed, and cardiac imaging studies were performed. RESULTS: The use of NI006 was associated with no apparent drug-related serious adverse events. The pharmacokinetic profile of NI006 was consistent with that of an IgG antibody, and no antidrug antibodies were detected. At doses of at least 10 mg per kilogram, cardiac tracer uptake on scintigraphy and extracellular volume on cardiac magnetic resonance imaging, both of which are imaging-based surrogate markers of cardiac amyloid load, appeared to be reduced over a period of 12 months. The median N-terminal pro-B-type natriuretic peptide and troponin T levels also seemed to be reduced. CONCLUSIONS: In this phase 1 trial of the recombinant human antibody NI006 for the treatment of patients with ATTR cardiomyopathy and heart failure, the use of NI006 was associated with no apparent drug-related serious adverse events. (Funded by Neurimmune; NI006-101 ClinicalTrials.gov number, NCT04360434.).

Edoxaban versus warfarin in patients with atrial fibrillation in relation to the risk of stroke: A secondary analysis of the ENGAGE AF-TIMI 48 study.

INTRODUCTION: The efficacy and safety of the oral factor Xa inhibitor edoxaban compared to warfarin stratified by CHA2DS2VASc scores have not been described. METHODS: The ENGAGE AF-TIMI 48 trial randomized patients with atrial fibrillation to once-daily edoxaban or warfarin. We classified patients based on CHA2DS2VASc score and compared pharmacokinetics (edoxaban concentration), pharmacodynamics (anti-factor Xa [FXa] with edoxaban, time-in-therapeutic range for warfarin), efficacy (stroke or systemic embolism [SSE]), safety (major bleeding [MB], intracranial hemorrhage), and cardiovascular mortality, for the approved edoxaban regimen vs warfarin. RESULTS: The distribution CHA2DS2VASc score were:≤3, N = 4159 (29.6%); 4, N = 4066 (28.9%); 5, N = 3165 (22.5%); and ≥6, N = 2681 (19.1%). Increasing rates of SSE (1.05 to 2.99%/year) and MB (2.27 to 4.66%/year) were observed in the warfarin arm as the CHA2DS2VASc score increased. The hazard ratios per unit increase of CHA2DS2VASc score were 1.29 (1.21-1.38) and 1.26 (1.17-1.36) for SSE, and 1.20 (1.13-1.27) and 1.19 (1.12-1.27) for MB, with warfarin and edoxaban, respectively. Time-in-therapeutic range in warfarin-treated patients was similar and high (median 68%-69%) across CHA2DS2VASc scores, whereas edoxaban trough concentration, exogenous anti-FXa activity and %inhibition of endogenous FXa were higher at increasing CHA2DS2VASc scores. Edoxaban reduced SSE, MB, intracranial hemorrhage, and cardiovascular mortality vs warfarin to a similar degree across the range of CHA2DS2VASc scores (P-int = 0.90, 0.96, 0.21, and 0.37, respectively). Because of higher event rates the number of events prevented with edoxaban tended to be greater in patients with higher CHA2DS2VASc scores. CONCLUSION: The benefit and safety of edoxaban versus warfarin is maintained across CHA2DS2VASc scores. While the relative risk reductions remain similar, edoxaban provides incrementally larger absolute reductions in outcomes over warfarin in patients with higher CHA2DS2VASc scores.

Pharmacogenetic-guided and clinical warfarin dosing algorithm assessments with bleeding outcomes risk-stratified by genetic and covariate subgroups.

BACKGROUND: Safe administration of warfarin presents challenges due to a narrow therapeutic INR range and significant variability in inter-individual dose response. Bleeding secondary to warfarin use is a leading cause of hospitalization. METHODS: Five warfarin dosing algorithms were assessed for accuracy of predicted compared to the INR target dose for patients with a HAS-BLED score ≥3 participating in the ENGAGE-AF TIMI 48 trial. Three warfarin metabolism subgroups (normal, sensitive, and highly sensitive responders) were established based on genotype. Mean differences between calculated and prescribed dose were determined for each algorithm across groups. RESULTS: A total of 7036 patients were analyzed and 1846 participants with HAS-BLED ≥3 were genotyped. The mean absolute error of predicted versus INR target dose for warfarin ranged from 8.1 mg/week on the pharmacogenetic-guided International Warfarin Pharmacogenetics Consortium (IWPC) and Gage algorithms to 11.3 mg/week on fixed dose. Overestimation of INR target dose occurred in 98% of highly sensitive responders by 21 mg/week for subjects on fixed dose. Pharmacogenetic-guided IWPC saw 89% overestimation with mean difference of 8.3 mg/week for highly sensitive responders. Major or clinically relevant non-major bleeding in the first 90 days of beginning warfarin was 3.27 times more likely for highly sensitive than normal responders. CONCLUSIONS: Initial doses were higher than INR target doses in high-risk bleeding subpopulations as defined by the modified HAS-BLED and genotype sensitivity analysis when compared to established algorithms. Clinical and pharmacogenetic-guided algorithms improved dosing in highly sensitive responders with HAS-BLED ≥3 compared to fixed dosing.

Left atrial structure and function and the risk of death or heart failure in atrial fibrillation.

AIMS: The present study aimed to assess the association between left atrial (LA) structure and function and the risk for cardiovascular (CV) death or heart failure (HF) hospitalization in a population with atrial fibrillation (AF). METHODS AND RESULTS: In a prospective echocardiographic substudy of the Effective Anticoagulation with Factor Xa Next Generation in AF-Thrombolysis in Myocardial Infarction 48 (ENGAGE AF-TIMI 48) study, 971 patients underwent transthoracic echocardiography. The associations between LA structure (LA volume index [LAVi]) and function (LA emptying fraction [LAEF] and LA expansion index [LAEi]) and risk for the composite endpoint of CV death or HF hospitalization, and its components, were assessed. Over a median follow-up of 2.5 years, 142 patients (14.6%) experienced CV death or HF hospitalization. Higher LAVi and lower LAEF and LAEi were each associated with a higher unadjusted risk for the composite outcome and its components. After adjustment for clinical and echocardiographic confounders, only measures of impaired LA function were predictive of the composite outcome (hazard ratio [HR] per 1 standard deviation [SD] decrease in LAEF: 1.35; 95% confidence interval [CI] 1.09-1.67 [P = 0.005]; HR per 1 SD decrease in LAEi: 1.34; 95% CI 1.06-1.69 [P = 0.012]). These findings were similar regardless of left ventricular ejection fraction, history of HF or whether patients were in AF or sinus rhythm at the time of the echocardiographic examination. CONCLUSIONS: In patients with AF, LA dysfunction was significantly associated with an increased risk for CV death or HF hospitalization and was more predictive of these outcomes than LA size. These parameters may help to identify AF patients at greatest risk for the development of HF. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT00781391.

Comparison of Events Across Bleeding Scales in the ENGAGE AF-TIMI 48 Trial.

BACKGROUND: Numerous scales exist for the classification of major bleeding events. Limited data compare the most commonly used bleeding scales within a single at-risk cohort of patients with atrial fibrillation. Here, we analyze bleeding outcomes according to the ISTH (International Society on Thrombosis and Hemostasis), TIMI (Thrombolysis in Myocardial Infarction), GUSTO (Global Usage of Strategies to Open Occluded Arteries), and BARC (Bleeding Academic Research Consortium) bleeding scales in the ENGAGE AF (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation)-TIMI 48 trial (NCT00781391) of edoxaban versus warfarin. METHODS: A total of 21 105 patients with atrial fibrillation at risk for stroke (CHADS2 score ≥2) were enrolled in the ENGAGE AF-TIMI 48 trial comparing warfarin with a higher- (60/30 mg daily) or lower- (30/15 mg daily) dose edoxaban regimen. Median follow-up was 2.8 years. Bleeding events occurring among on-treatment patients were examined. Annualized event rates were calculated by the ISTH, TIMI, GUSTO, and BARC scales and compared across treatment arms. Cox proportional hazards for a first bleeding event of each type were calculated for higher-dose edoxaban regimen vs warfarin and lower-dose edoxaban regimen versus warfarin. RESULTS: A total of 10 311 bleeding events were reported. In a comparison of the most severe events in each scale, ISTH major bleeding was the most common (n=1289), followed by TIMI major (n=548), GUSTO severe/life-threatening (n=347), and BARC 3c+5 (n=276) bleeding. Lower bleeding risk with edoxaban compared with warfarin was seen regardless of bleeding scale (higher-dose edoxaban regimen range: hazard ratio [HR], 0.47 [95% CI, 0.35-0.62] for BARC 3c+5 versus HR, 0.80 [95% CI, 0.71-0.91] for ISTH major; lower-dose edoxaban regimen range: HR, 0.32 [95% CI, 0.23-0.45] for BARC 3c+5 versus HR, 0.47 [95% CI, 0.41-0.55] for ISTH major). Furthermore, a gradient of more pronounced risk reduction with edoxaban was observed with greater severity of first bleeding event (higher-dose edoxaban regimen: HR, 0.47 [95% CI, 0.35-0.62] for BARC 3c+5 bleeds versus HR, 0.86 [95% CI, 0.81-0.91] for any BARC bleed; lower-dose edoxaban regimen: HR, 0.32 [95% CI, 0.23-0.45] for BARC 3c+5 bleeds versus HR, 0.68 [95% CI, 0.63-0.72] for any BARC bleed). The direction of this trend was consistent for both gastrointestinal bleeding and nongastrointestinal bleeding. CONCLUSIONS: Among patients with atrial fibrillation at risk for stroke, there was a >4-fold difference in the frequency of the most severe bleeding events across commonly used bleeding scales. Furthermore, the relative safety of edoxaban compared with warfarin tended to increase with greater severity of bleeding. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00781391.

Edoxaban Versus Warfarin in Patients With Atrial Fibrillation and History of Liver Disease.

BACKGROUND: Patients with liver disease have increased risk of thrombosis and bleeding but are typically excluded from trials of direct oral anticoagulant agents. OBJECTIVES: This study evaluated the pharmacokinetics (PK), pharmacodynamics (PD), clinical efficacy and safety of edoxaban versus warfarin in patients with atrial fibrillation (AF) and history of liver disease. METHODS: ENGAGE AF-TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis In Myocardial Infarction Study 48) was a randomized, double-blind trial comparing edoxaban with warfarin in patients with AF followed for 2.8 years. History of liver disease was defined as investigator-reported liver disease or >2-fold transaminase elevation at randomization. The primary efficacy and safety endpoints of stroke or systemic embolic event (SSEE) and major bleeding were assessed stratified by history of liver disease. PK/PD assessments of edoxaban included endogenous and extrinsic factor Xa activity and edoxaban concentration. RESULTS: Among 21,105 patients, 1,083 (5.1%) had a history of liver disease; they had a higher prevalence of many comorbidities. The adjusted risks of SSEE were similar (adjusted hazard ratio [HRadj]: 0.90; 95% confidence interval [CI]: 0.67 to 1.22; p = 0.50), but major bleeding was more common in patients with liver disease (HRadj: 1.38; 95% CI: 1.10 to 1.74; p = 0.005). There were no significant differences in PK/PD assessment of edoxaban in patients with versus without liver disease. The HRs for higher-dose edoxaban versus warfarin for SSEE were 0.86 (95% CI: 0.73 to 1.01) in patients without and 1.11 (95% CI: 0.54 to 2.30) with liver disease (p for interaction [pint] = 0.47), major bleeding 0.80 (95% CI: 0.70 to 0.91) in patients without and 0.91 (95% CI: 0.56 to 1.47) with liver disease (pint = 0.63). There were no significant differences in hepatic adverse events between the 2 treatment groups. CONCLUSIONS: Among patients with AF receiving oral anticoagulation, bleeding, but not thromboembolic events, was increased in patients with liver disease. A history of liver disease did not alter the relative efficacy and safety of edoxaban compared with warfarin. Hepatic adverse events were similar between edoxaban and warfarin.

Relationship between body mass index and outcomes in patients with atrial fibrillation treated with edoxaban or warfarin in the ENGAGE AF-TIMI 48 trial.

AIMS: To investigate the relationship between body mass index (BMI) and outcomes in patients with atrial fibrillation (AF). METHODS AND RESULTS: In the ENGAGE AF-TIMI 48 trial, patients with AF were randomized to warfarin (international normalized ratio 2.0-3.0) or edoxaban. The cohort (N = 21 028) included patients across BMI categories (kg/m2): underweight (<18.5) in 0.8%, normal (18.5 to <25) in 21.4%, overweight (25 to <30) in 37.6%, moderately obese (30 to <35) in 24.8%, severely obese (35 to <40) in 10.0%, and very severely obese (≥40) in 5.5%. In an adjusted analysis, higher BMI (continuous, per 5 kg/m2 increase) was significantly and independently associated with lower risks of stroke/systemic embolic event (SEE) [hazard ratio (HR) 0.88, P = 0.0001], ischaemic stroke/SEE (HR 0.87, P < 0.0001), and death (HR 0.91, P < 0.0001), but with increased risks of major (HR 1.06, P = 0.025) and major or clinically relevant non-major bleeding (HR 1.05, P = 0.0007). There was a significant interaction between sex and increasing BMI category, with lower risk of ischaemic stroke/SEE in males and increased risk of bleeding in women. Trough edoxaban concentration and anti-Factor Xa activity were similar across BMI groups >18.5 kg/m2, while time in therapeutic range for warfarin improved significantly as BMI increased (P < 0.0001). The effects of edoxaban vs. warfarin on stroke/SEE, major bleeding, and net clinical outcome were similar across BMI groups. CONCLUSION: An increased BMI was independently associated with a lower risk of stroke/SEE, better survival, but increased risk of bleeding. The efficacy and safety profiles of edoxaban were similar across BMI categories ranging from 18.5 to >40.

Edoxaban in atrial fibrillation patients with established coronary artery disease: Insights from ENGAGE AF-TIMI 48.

BACKGROUND:: The relative efficacy and safety profile of the oral Factor Xa inhibitor edoxaban compared with warfarin in patients with atrial fibrillation and established coronary artery disease (CAD) has not been analyzed. MATERIALS AND METHODS:: In the ENGAGE AF-TIMI 48 trial, two edoxaban regimens were compared with warfarin in 21,105 patients with atrial fibrillation and CHADS2 ⩾2. We analyzed the primary trial endpoints (efficacy: stroke or systemic embolic event, safety: International Society on Thrombosis and Haemostasis major bleeding) in patients with versus without CAD, and used interaction testing to assess for treatment effect modification. RESULTS:: The 4510 patients (21.4%) with known CAD were older, more likely male, on aspirin, with lower creatinine clearance and higher CHADS2 and HAS-BLED scores ( p <0.001 for each). Treatment with the higher-dose edoxaban regimen (versus warfarin) in patients with known CAD tended to have a greater reduction in stroke/systemic embolic event compared with patients without CAD (CAD: hazard ratio 0.65 (0.46-0.92) versus no CAD: hazard ratio 0.94 (0.79-1.12), p-INT 0.062) and also in myocardial infarction (CAD: hazard ratio 0.69 (0.49-0.98) versus no CAD: hazard ratio 1.24 (0.89-1.72), p-INT 0.017), while there was a similar reduction in bleeding irrespective of CAD status (hazard ratio 0.81 and 0.80, p-INT 0.97). Presence or absence of CAD did not modify the efficacy or safety profile of the lower-dose edoxaban regimen (versus warfarin). CONCLUSION:: The reduction in ischemic events with the higher-dose edoxaban regimen versus warfarin was greater in patients with CAD, while bleeding was significantly reduced with edoxaban regardless of CAD status. The efficacy and safety profile of the lower-dose edoxaban regimen relative to warfarin was unaffected by CAD status.

Edoxaban and implantable cardiac device interventions: insights from the ENGAGE AF-TIMI 48 trial.

AIMS: Pacemaker, implantable cardioverter-defibrillator, and cardiac resynchronization therapy device implantations and generator changes are frequently performed in patients receiving direct oral anticoagulants. In an exploratory analysis, we investigated the outcome of patients undergoing such device procedures in the ENGAGE AF-TIMI 48 trial. METHODS AND RESULTS: During the trial, 1217 device procedures were performed in 1145 patients, with intervention dates available for 1203 procedures. Two hundred and twenty-five procedures (in 212 patients) were performed >30 days after study drug was stopped and are not included in the event analysis. For most interventions (n = 728, 74%), study drug was interrupted >3 days (median for the entire cohort: 5 days, interquartile range 0-11 days); 250 interventions were performed with ≤3 days study drug interruption. During the first 30 days after the procedure, six strokes/systemic embolic events (SEEs) (three each in the lower-dose edoxaban and warfarin arm) and one major bleeding event (in the lower-dose edoxaban arm) occurred; no stroke/SEEs or major bleeds occurred around the 295 device procedures in the higher-dose edoxaban arm. Two ischaemic and one major bleeding event occurred after the 288 device procedures performed with ≤3 days periprocedural interruption of study drug. CONCLUSION: In this first experience of patients undergoing device surgery with edoxaban, a low risk of ischaemic and bleeding events was observed during the first 30 days post-procedure. Our data are in line with current recommendations of no or only brief interruption of non-vitamin K antagonist oral anticoagulants prior to cardiac device surgery.

Clinical outcomes, edoxaban concentration, and anti-factor Xa activity of Asian patients with atrial fibrillation compared with non-Asians in the ENGAGE AF-TIMI 48 trial.

AIMS: Prior studies suggested that the risks of ischaemic stroke and bleeding in patients of Asian race with atrial fibrillation (AF) may be higher than that of non-Asians. In the analysis of ENGAGE AF-TIMI 48 trial, we compared clinical outcomes, edoxaban concentration, and anti-factor Xa (anti-FXa) activity, between Asian and non-Asian races. METHODS AND RESULTS: There were 2909 patients of Asian race and 18 195 non-Asian race in the ENGAGE AF-TIMI 48 trial. The risks of thromboembolism and bleeding events were compared for Asians and non-Asians treated with warfarin. The trough levels of edoxaban concentration and anti-FXa activity were also compared and correlated with the efficacy and safety of edoxaban vs. warfarin. Compared to non-Asian patients, the Asian population was on average 2 years younger and 20 kg lighter. In the warfarin group, the adjusted risk of ischaemic stroke did not differ significantly for patients of Asian and non-Asian race [adjusted hazard ratio (aHR) = 1.12, P = 0.56). Asians treated with warfarin had a higher-adjusted risk of intracranial haemorrhage (ICH: aHR 1.71, P = 0.03) compared with non-Asians. The trough edoxaban concentration and anti-FXa activity were 20-25% lower for Asians compared with non-Asians. Compared to warfarin, higher dose edoxaban significantly reduced ICH while preserving the efficacy of stroke prevention in both Asians and non-Asians. Two of three net clinical outcomes appeared to be more favourably reduced with edoxaban in Asians compared with non-Asians (Pint = 0.063 for primary, 0.037 for secondary, and 0.032 for third net clinical outcomes, respectively). CONCLUSION: Compared to warfarin, higher dose edoxaban preserved the efficacy for stroke prevention and was associated with a favourable safety profile for Asians, which may be due to the lower trough edoxaban concentration and anti-FXa activity achieved in patients of Asian race.

Performance of the ABC Scores for Assessing the Risk of Stroke or Systemic Embolism and Bleeding in Patients With Atrial Fibrillation in ENGAGE AF-TIMI 48.

BACKGROUND: The ABC (age, biomarker, clinical history)-stroke and ABC-bleeding risk scores incorporate clinical variables and cardiovascular biomarkers to estimate risk of stroke or systemic embolic events and bleeding, respectively, in patients with atrial fibrillation. These scores have been proposed for routine clinical use, but their performance in external cohorts remains uncertain. METHODS: ENGAGE AF-TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction 48) was a multinational randomized trial of the oral factor Xa inhibitor edoxaban in patients with atrial fibrillation and a CHADS2 score ≥2. We performed a nested prospective biomarker study in 8705 patients, analyzing baseline high-sensitivity troponin T (hsTnT), NT-proBNP (N-terminal B-type natriuretic peptide), and growth differentiation factor-15 (GDF-15), as well as in serial samples after 12 months. The ABC-stroke (age, prior stroke/transient ischemic attack, hsTnT, NT-proBNP) and ABC-bleeding (age, prior bleeding, hemoglobin, hsTnT, and GDF-15) scores were tested. Hazard ratios were adjusted for estimated glomerular filtration rate and the components of the CHA2DS2-VASc and HAS-BLED scores, respectively. Discrimination and reclassification were compared with these established scores. RESULTS: Median baseline hsTnT, NT-proBNP, and GDF-15 levels were 13.7 ng/L (25th-75th percentiles, 9.6-20.4 ng/L), 811 pg/mL (386-1436 pg/mL), and 1661 pg/mL (1179-2427 pg/mL), respectively. Elevated hsTnT, NT-proBNP, and GDF-15 were independently associated with higher rates of stroke or systemic embolic events, and elevated hsTnT and GDF-15 were independently associated with higher rates of major bleeding ( P<0.001 for each). The ABC-stroke and ABC-bleeding scores were well calibrated and yielded higher c indexes than the CHA2DS2-VASc score for stroke or systemic embolic events (0.67 [95% CI, 0.65-0.70] versus 0.59 [95% CI, 0.57-0.62]; P<0.001) and HAS-BLED score for major bleeding (0.69 [95% CI, 0.66-0.71] versus 0.62 [95% CI, 0.60-0.64]; P<0.001), respectively. The ABC-stroke and ABC-bleeding scores stratified patients within CHA2DS2-VASc and HAS-BLED risk categories ( P<0.001 for both). Patients with ABC-bleeding scores predicting a high 1-year risk of bleeding (>2%) derived greater benefit from treatment with edoxaban compared with warfarin. CONCLUSIONS: The ABC-stroke and ABC-bleeding scores evaluated in this anticoagulated clinical trial cohort were well calibrated and outperformed the CHA2DS2-VASc and HAS-BLED scores, respectively. These scores may help identify patients most likely to derive a benefit from treatment with non-vitamin K antagonist oral anticoagulants. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00781391.

Reproducibility of thrombus volume quantification in multicenter computed tomography pulmonary angiography studies.

AIM: To evaluate reproducibility of pulmonary embolism (PE) clot volume quantification using computed tomography pulmonary angiogram (CTPA) in a multicenter setting. METHODS: This study was performed using anonymized data in conformance with HIPAA and IRB Regulations (March 2015-November 2016). Anonymized CTPA data was acquired from 23 scanners from 18 imaging centers using each site's standard PE protocol. Two independent analysts measured PE volumes using a semi-automated region-growing algorithm on an FDA-approved image analysis platform. Total thrombus volume (TTV) was calculated per patient as the primary endpoint. Secondary endpoints were individual thrombus volume (ITV), Qanadli score and modified Qanadli score per patient. Inter- and intra-observer reproducibility were assessed using intra-class correlation coefficient (ICC) and Bland-Altman analysis. RESULTS: Analyst 1 found 72 emboli in the 23 patients with a mean number of emboli of 3.13 per patient with a range of 0-11 emboli per patient. The clot volumes ranged from 0.0041 - 47.34 cm3 (mean +/- SD, 5.93 +/- 10.15cm3). On the second read, analyst 1 found the same number and distribution of emboli with a range of volumes for read 2 from 0.0041 - 45.52 cm3 (mean +/- SD, 5.42 +/- 9.53cm3). Analyst 2 found 73 emboli in the 23 patients with a mean number of emboli of 3.17 per patient with a range of 0-11 emboli per patient. The clot volumes ranged from 0.00459-46.29 cm3 (mean +/- SD, 5.91 +/- 10.06 cm3). Inter- and intra-observer variability measurements indicated excellent reproducibility of the semi-automated method for quantifying PE volume burden. ICC for all endpoints was greater than 0.95 for inter- and intra-observer analysis. Bland-Altman analysis indicated no significant biases. CONCLUSION: Semi-automated region growing algorithm for quantifying PE is reproducible using data from multiple scanners and is a suitable method for image analysis in multicenter clinical trials.

Efficacy and Safety of Edoxaban in Patients With Active Malignancy and Atrial Fibrillation: Analysis of the ENGAGE AF - TIMI 48 Trial.

Background Anticoagulation in patients with malignancy and atrial fibrillation is challenging because of enhanced risks for thrombosis and bleeding and the frequent need for invasive procedures. Data on direct oral antagonists in such patients are sparse. Methods and Results The ENGAGE AF - TIMI 48 (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction Study 48) trial randomized 21 105 patients with atrial fibrillation to edoxaban or warfarin. Patients with malignancy, defined as a postrandomization new diagnosis or recurrence of remote cancer, were followed up over a median of 2.8 years. Adjusted Cox proportional hazard models were used to evaluate the safety and efficacy of edoxaban versus warfarin. Over a median of 495 days (interquartile range, 230-771 days), 1153 patients (5.5%) were diagnosed with new or recurrent malignancy, most commonly involving the gastrointestinal tract (20.6%), prostate (13.6%), and lung (11.1%). Malignancy was associated with increased risk of death (adjusted hazard ratio [HR], 3.12; 95% confidence interval [CI], 2.78-3.50) and major bleeding (adjusted HR, 2.45; 95% CI, 2.07-2.89), but not stroke/systemic embolism (adjusted HR, 1.08; 95% CI, 0.83-1.42). Relative outcomes with higher-dose edoxaban versus warfarin were consistent regardless of malignancy status for stroke/systemic embolism ( HR , 0.60 [95% CI, 0.31-1.15] for malignancy versus HR , 0.89 [95% CI, 0.76-1.05] for no malignancy; interaction P=0.25) and major bleeding ( HR , 0.98 [95% CI, 0.69-1.40] for malignancy versus HR , 0.79 [95% CI, 0.69-1.05] for no malignancy; interaction P=0.31). There was, however, a significant treatment interaction for the composite ischemic end point (ischemic stroke/systemic embolism/myocardial infarction), with greater efficacy of higher-dose edoxaban versus warfarin in patients with malignancy ( HR , 0.54; 95% CI, 0.31-0.93) compared with no malignancy ( HR , 1.02; 95% CI, 0.88-1.18; interaction P=0.026). Conclusions In patients with atrial fibrillation who develop malignancy, the efficacy and safety profile of edoxaban relative to warfarin is preserved, and it may represent a more practical alternative.

Clinical Impact of Bleeding in Cancer-Associated Venous Thromboembolism: Results from the Hokusai VTE Cancer Study.

In the Hokusai VTE Cancer study, edoxaban was non-inferior to dalteparin for the composite outcome of recurrent venous thromboembolism (VTE) and major bleeding in 1,050 patients with cancer-associated VTE. The absolute rate of recurrent VTE was 3.4% lower with edoxaban, whereas the absolute rate of major bleeding was 2.9% higher. The present analysis focuses on the sites, clinical presentation, course and outcome of bleeding events, and the associated tumour types. Major bleeds and their severity (categories 1-4) were blindly adjudicated by a committee using a priori defined criteria, and data were analysed in the safety population. Major bleeding occurred in 32 of 522 patients given edoxaban (median treatment duration, 211 days) and in 16 of 524 patients treated with dalteparin (median treatment duration, 184 days); no patients had more than one major bleed. There were no fatal bleeds with edoxaban, and two with dalteparin. Severe bleeding at presentation (category 3 or 4) occurred in 10 (1.9%) and 11 (2.1%) patients in the edoxaban and dalteparin groups, respectively. The excess of major bleeding with edoxaban was confined to patients with gastrointestinal cancer. However, severe major bleeding at presentation (category 3 or 4) in this sub-group occurred in 5 of 165 (3.0%) and in 3 of 140 (2.1%) patients given edoxaban or dalteparin, respectively.In conclusion, this analysis suggests that while oral edoxaban is an appropriate alternative to subcutaneous dalteparin for treatment of cancer-associated VTE, the use of edoxaban in patients with gastrointestinal cancer requires careful benefit-risk weighting.

Linking Endogenous Factor Xa Activity, a Biologically Relevant Pharmacodynamic Marker, to Edoxaban Plasma Concentrations and Clinical Outcomes in the ENGAGE AF-TIMI 48 Trial.

BACKGROUND: We previously reported exogenous antifactor Xa (FXa) activity as a pharmacokinetic surrogate marker for edoxaban plasma concentrations. Inhibition of endogenous FXa activity is a more biologically relevant pharmacodynamic measure of edoxaban activity. Here we describe the value of endogenous FXa activity as a pharmacodynamic marker linking edoxaban concentrations and clinical outcomes in the ENGAGE AF-TIMI 48 trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis in Myocardial Infarction Study 48). METHODS: In ENGAGE AF-TIMI 48, edoxaban was administered in higher dose (60/30 mg QD) and lower dose (30/15 mg QD) regimens. Both regimens incorporated a 50% dose reduction in patients with characteristics known to increase edoxaban concentration. Pharmacokinetic-pharmacodynamic modeling was performed in a subgroup of 3029 patients who had samples collected for endogenous FXa activity (measured using an assay after endogenous FX was activated with Russell viper venom). RESULTS: Endogenous FXa activity decreased with increasing edoxaban concentrations of ≤440 ng/mL, indicating that inhibition of endogenous FXa activity is saturated above this concentration threshold. Baseline endogenous FXa activity averaged 92.1±20.9% (relative to normal control samples) and was lower with older age, with lower body weight, and in male patients. Model-predicted 24-hour average percentages of inhibition of endogenous FXa activity were 35.8±5.18, 29.1±3.92, 21.9±3.80, and 16.4±2.70 for the higher dose edoxaban regimen 60 mg, dose-reduced higher dose edoxaban regimen 30 mg, lower dose edoxaban regimen 30 mg, and dose-reduced lower dose edoxaban regimen 15 mg groups, respectively. A greater average percentage of inhibition of endogenous FXa activity was associated with a lower incidence of ischemic stroke or systemic embolism and a higher risk of major bleeding ( P<0.001). In a typical subject, the predicted risks for the 10th and 90th percentiles of inhibition of endogenous FXa activity were 1.04% and 0.57% for incidence of ischemic stroke or systemic embolism and 1.35% and 2.33% for major bleeding, respectively. CONCLUSIONS: The extent of inhibition of endogenous FXa activity is influenced by edoxaban dosing and clinical characteristics, and it is associated with both antithrombotic benefit and risk of bleeding. This approach of linking endogenous FXa activity to clinical outcomes may be used to guide dose selection in future clinical trials, monitor patients in certain clinical scenarios, or refine the doses of oral FXa inhibitors in patients who require precise anticoagulation therapy. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov . Unique identifier: NCT00781391.

Gastrointestinal Bleeding With Edoxaban Versus Warfarin: Results From the ENGAGE AF-TIMI 48 Trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis In Myocardial Infarction).

BACKGROUND: The ENGAGE AF-TIMI 48 trial (Effective Anticoagulation With Factor Xa Next Generation in Atrial Fibrillation-Thrombolysis In Myocardial Infarction) compared higher-dose edoxaban regimen (HD-ER) and lower-dose edoxaban regimen with well-managed warfarin in 21 105 patients with atrial fibrillation. The risk factors and clinical impact of gastrointestinal bleeding (GIB) in this trial have not been described in detail. METHODS AND RESULTS: This analysis was undertaken to identify risk factors for major GIB (MGIB) and compare the severity and outcomes of GIB with edoxaban and warfarin. During 2.8 years mean follow-up, there were 579 MGIB (1.22% per year), of which 63 were life-threatening or fatal (0.13% per year). Male sex, increased age, prior GIB, concomitant aspirin, lower baseline hemoglobin, renal dysfunction, and higher HAS-BLED and CHADS2 scores were independently associated with the risk of MGIB. Whereas the annual rate of MGIB was higher with HD-ER than with warfarin (1.53% and 1.25%, respectively; hazard ratio, 1.23; 95% confidence interval, 1.02-1.48; P=0.033), the annual rates of life-threatening or fatal GIB were similar (0.15% and 0.18%, respectively). Several indicators of more severe GIB, including hemodynamic instability, hospitalization, ≥ 4 U transfusion, and hemoglobin loss ≥5 g/dL, were similar with HD-ER and warfarin, whereas surgery required to manage bleeding was less frequent with HD-ER. Lower-dose edoxaban regimen, which achieved 50% lower trough edoxaban levels, was associated with significantly less MGIB than warfarin. CONCLUSIONS: MGIB occurred more frequently with HD-ER than warfarin. The rates of life-threatening or fatal GIB were low and similar with both HD-ER and warfarin. Clinical outcomes were generally favorable. The correlation between dose, trough edoxaban level, and the risk of GIB risk suggests GIB is exposure-related. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT00781391.

Peri-operative Adverse Outcomes in Patients with Atrial Fibrillation Taking Warfarin or Edoxaban: Analysis of the ENGAGE AF-TIMI 48 Trial.

BACKGROUND: Peri-operative management of anticoagulated patients with atrial fibrillation (AF) is challenging. To gain information on the peri-operative management of edoxaban, we compared outcomes in patients on warfarin or edoxaban enrolled in ENGAGE AF-TIMI 48 who underwent a surgery or invasive procedure. METHODS: Data from patients undergoing their first surgery/procedure were analysed and results compared by anticoagulant (warfarin vs. higher- or lower-dose edoxaban regimen [HDER and LDER, respectively]). Patients were classified by procedural management: anticoagulant interrupted (last dose 4-10 days pre-procedure) or anticoagulant continued (last dose ≤ 3 days pre-procedure). Stroke/systemic embolism (SSE), major bleeding (MB), MB or clinically relevant non-MB (CRNMB) and death were assessed from 7 days pre- until 30 days post-procedure. The chi-square test was used to compare outcomes across treatment groups. RESULTS: A total of 7,193 patients (34%) underwent surgery/procedure: 3,116 had anticoagulant interrupted, 4,077 had anticoagulant continued. Among patients on warfarin, HDER and LDER who had anticoagulant interrupted, rates of SSE were 0.6, 0.5 and 0.9% (p = 0.53), rates of MB were 1.0, 1.2 and 1.1% (p = 0.94) and rates of MB or CRNMB were 3.9, 4.2 and 3.6% (p = 0.78); among patients on warfarin, HDER and LDER who had anticoagulant continued, rates of SSE were 1.1, 0.7 and 0.9% (p = 0.51), rates of MB were 3.6, 2.6 and 2.4% (p = 0.13) and rates of MB or CRNMB were 8.5, 7.9 and 6.6% (p = 0.17). CONCLUSION: In patients requiring surgery/procedure in ENGAGE AF-TIMI 48, peri-operative rates of SSE, MB and death were not significantly different in patients who received edoxaban or warfarin.

Clinical events after interruption of anticoagulation in patients with atrial fibrillation: An analysis from the ENGAGE AF-TIMI 48 trial.

BACKGROUND: Patients with atrial fibrillation (AF) who interrupt anticoagulation are at high risk of thromboembolism and death. METHODS AND RESULTS: Patients enrolled in the ENGAGE AF-TIMI 48 trial (randomized comparison of edoxaban vs. warfarin) who interrupted study anticoagulant for >3 days were identified. Clinical events (ischemic stroke/systemic embolism, major cardiac and cerebrovascular events [MACCE]) were analyzed from day 4 after interruption until day 34 or study drug resumption. During 2.8 years median follow-up, 13,311 (63%) patients interrupted study drug for >3 days. After excluding those who received open-label anticoagulation during the at-risk window, the population for analysis included 9148 patients. The rates of ischemic stroke/systemic embolism and MACCE post interruption were substantially greater than in patients who never interrupted (15.42 vs. 0.26 and 60.82 vs. 0.36 per 100 patient-years, respectively, padj < .001). Patients who interrupted study drug for an adverse event (44.1% of the cohort), compared to those who interrupted for other reasons, had an increased risk of MACCE (HRadj 2.75; 95% CI 2.02-3.74, p < .0001), but similar rates of ischemic stroke/systemic embolism. Rates of clinical events after interruption of warfarin and edoxaban were similar. CONCLUSION: Interruption of study drug was frequent in patients with AF and was associated with a substantial risk of major cardiac and cerebrovascular events over the ensuing 30 days. This risk was particularly high in patients who interrupted as a result of an adverse event; these patients deserve close monitoring and resumption of anticoagulation as soon as it is safe to do so.

Direct Oral Anticoagulants for Pulmonary Embolism: Importance of Anatomical Extent.

Pulmonary embolism (PE) studies used direct oral anticoagulants (DOACs) with or without initial heparin. We aimed to (1) evaluate if PE patients benefit from initial heparin; (2) describe patient characteristics in the DOAC studies; and (3) investigate whether the anatomical extent of PE correlates with N-terminal pro-brain natriuretic peptide (NT-proBNP) levels, cause of PE, and recurrence rate. Our methods were (1) an indirect meta-analysis comparing the recurrence risk in DOAC-treated patients with or without initial heparin to those patients given heparin/vitamin K antagonist (VKA). (2) To compare the PE studies, information was extracted on baseline characteristics including anatomical extent. (3) The Hokusai-VTE study was used to correlate anatomical extent of PE with NT-proBNP levels, causes of PE, and recurrent venous thromboembolism (VTE). The meta-analysis included 11,539 PE patients. The relative risk of recurrent VTE with DOACs versus heparin/VKAs was 0.8 (95% confidence interval [CI]: 0.6-1.1) with heparin lead-in and 1.1 (95% CI: 0.8-1.5) without heparin. In the DOAC studies, the proportion of patients with extensive PE varied from 24 to 47%. In Hokusai-VTE, NT-proBNP was elevated in 4% of patients with limited and in over 60% of patients with extensive disease. Cause of PE and anatomical extent were not related. Recurrence rates increased from 1.6% with limited to 3.2% with extensive disease in heparin/edoxaban-treated patients, and from 2.4 to 3.9% in heparin/warfarin recipients. In conclusion, indirect evidence suggests a heparin lead-in before DOACs may be advantageous in PE. Anatomical extent was related to elevated NT-proBNP and outcome, but not to PE cause.