Dabigatran Reversal With Idarucizumab in Patients Requiring Urgent Surgery: A Subanalysis of the RE-VERSE AD Study.

OBJECTIVE: To further examine anticoagulation reversal and clinical outcomes in dabigatran treated patients requiring urgent surgery or procedural interventions. BACKGROUND: Idarucizumab, a humanized monoclonal antibody fragment, reverses dabigatran anticoagulation. METHODS: Data from surgical and procedural patients in RE-VERSE AD, a multicenter, open-label, single-arm, prospective cohort of dabigatran reversal were evaluated. A total of 202 patients in this group received 5 g of idarucizumab before surgery or procedures. RESULTS: The interventions included 49 abdominal, 45 orthopedic, 34 vascular, 8 neurologic, and 4 genitourinary surgical procedures, or 29 catheter-based cases, 20 cases for drainage, and 8 diagnostic procedures. Five patients did not undergo their intended intervention after receiving idarucizumab. Complete reversal of the dabigatran anticoagulant effect occurred within minutes in almost all patients, with normal hemostasis in more than 91% of patients. The median time from the first vial of idarucizumab to surgery or procedures was less than 2 hours in all groups except neurosurgery, where it was 3.3 hours. Fresh frozen plasma and packed red cells were the most frequently transfused blood products. Postreversal thromboembolic events occurred in 10 (5%) patients at 30 days, 5 of whom had restarted anticoagulation before the event. Overall 30-day mortality was 12.6%. There were no serious adverse safety signals due to idarucizumab dosing. CONCLUSIONS: Idarucizumab facilitates management of patients requiring urgent procedures by providing rapid dabigatran reversal, and is the only agent of its class studied in surgical patients.

Idarucizumab for Dabigatran Reversal - Full Cohort Analysis.

BACKGROUND: Idarucizumab, a monoclonal antibody fragment, was developed to reverse the anticoagulant effect of dabigatran. METHODS: We performed a multicenter, prospective, open-label study to determine whether 5 g of intravenous idarucizumab would be able to reverse the anticoagulant effect of dabigatran in patients who had uncontrolled bleeding (group A) or were about to undergo an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the diluted thrombin time or ecarin clotting time. Secondary end points included the restoration of hemostasis and safety measures. RESULTS: A total of 503 patients were enrolled: 301 in group A, and 202 in group B. The median maximum percentage reversal of dabigatran was 100% (95% confidence interval, 100 to 100), on the basis of either the diluted thrombin time or the ecarin clotting time. In group A, 137 patients (45.5%) presented with gastrointestinal bleeding and 98 (32.6%) presented with intracranial hemorrhage; among the patients who could be assessed, the median time to the cessation of bleeding was 2.5 hours. In group B, the median time to the initiation of the intended procedure was 1.6 hours; periprocedural hemostasis was assessed as normal in 93.4% of the patients, mildly abnormal in 5.1%, and moderately abnormal in 1.5%. At 90 days, thrombotic events had occurred in 6.3% of the patients in group A and in 7.4% in group B, and the mortality rate was 18.8% and 18.9%, respectively. There were no serious adverse safety signals. CONCLUSIONS: In emergency situations, idarucizumab rapidly, durably, and safely reversed the anticoagulant effect of dabigatran. (Funded by Boehringer Ingelheim; RE-VERSE AD ClinicalTrials.gov number, NCT02104947 .).

Idarucizumab for Dabigatran Reversal.

BACKGROUND: Specific reversal agents for non-vitamin K antagonist oral anticoagulants are lacking. Idarucizumab, an antibody fragment, was developed to reverse the anticoagulant effects of dabigatran. METHODS: We undertook this prospective cohort study to determine the safety of 5 g of intravenous idarucizumab and its capacity to reverse the anticoagulant effects of dabigatran in patients who had serious bleeding (group A) or required an urgent procedure (group B). The primary end point was the maximum percentage reversal of the anticoagulant effect of dabigatran within 4 hours after the administration of idarucizumab, on the basis of the determination at a central laboratory of the dilute thrombin time or ecarin clotting time. A key secondary end point was the restoration of hemostasis. RESULTS: This interim analysis included 90 patients who received idarucizumab (51 patients in group A and 39 in group B). Among 68 patients with an elevated dilute thrombin time and 81 with an elevated ecarin clotting time at baseline, the median maximum percentage reversal was 100% (95% confidence interval, 100 to 100). Idarucizumab normalized the test results in 88 to 98% of the patients, an effect that was evident within minutes. Concentrations of unbound dabigatran remained below 20 ng per milliliter at 24 hours in 79% of the patients. Among 35 patients in group A who could be assessed, hemostasis, as determined by local investigators, was restored at a median of 11.4 hours. Among 36 patients in group B who underwent a procedure, normal intraoperative hemostasis was reported in 33, and mildly or moderately abnormal hemostasis was reported in 2 patients and 1 patient, respectively. One thrombotic event occurred within 72 hours after idarucizumab administration in a patient in whom anticoagulants had not been reinitiated. CONCLUSIONS: Idarucizumab completely reversed the anticoagulant effect of dabigatran within minutes. (Funded by Boehringer Ingelheim; RE-VERSE AD ClinicalTrials.gov number, NCT02104947.).

Comparison of Dabigatran and Warfarin in Patients With Atrial Fibrillation and Valvular Heart Disease: The RE-LY Trial (Randomized Evaluation of Long-Term Anticoagulant Therapy).

BACKGROUND: The RE-LY trial (Randomized Evaluation of Long-Term Anticoagulant Therapy) compared dabigatran 150 and 110 mg twice daily with warfarin in 18 113 patients with atrial fibrillation. Those with prosthetic heart valves, significant mitral stenosis, and valvular heart disease (VHD) requiring intervention were excluded. Others with VHD were included. METHODS: This is a post hoc analysis of the RE-LY trial. RESULTS: There were 3950 patients with any VHD: 3101 had mitral regurgitation, 1179 with tricuspid regurgitation, 817 had aortic regurgitation, 471 with aortic stenosis, and 193 with mild mitral stenosis. At baseline, patients with any VHD had more heart failure, coronary disease, renal impairment, and persistent atrial fibrillation. Patients with any VHD had higher rates of major bleeds (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.16-1.5) but similar stroke or systemic embolism event rates (HR, 1.09; 95% CI, 0.88-1.33). For patients receiving dabigatran 110 mg, major bleed rates were lower than for patients taking warfarin (HR, 0.73; 95% CI, 0.56-0.95 with VHD; HR, 0.84; 95% CI, 0.71-0.99 without VHD), and major bleed rates for dabigatran 150 mg were similar to those for warfarin in patients with VHD (HR, 0.82; 95% CI, 0.64-1.06) or without VHD (HR, 0.98; 95% CI, 0.83-1.15). For dabigatran 150 mg, stroke/systemic embolic event rates were lower compared with warfarin in those with VHD (HR, 0.59; 95% CI, 0.37-0.93) and those without VHD (HR, 0.67; 95% CI, 0.52-0.86), and stroke/systemic embolic event rates were similar for warfarin and dabigatran 110 mg regardless of the presence of VHD (HR, 0.97; 95% CI, 0.65-1.45; and HR, 0.88; 95% CI, 0.70-1.10). Intracranial bleeds and death rates for dabigatran 150 and 110 mg were lower compared with warfarin independently of the presence of VHD. CONCLUSIONS: The presence of any VHD did not influence the comparison of dabigatran with warfarin. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00262600.

Growth-differentiation factor 15 and risk of major bleeding in atrial fibrillation: Insights from the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial.

OBJECTIVE: To evaluate and validate the prognostic value of growth-differentiation factor 15 (GDF-15) beyond clinical characteristics and other biomarkers concerning bleeding and stroke outcomes in patients with atrial fibrillation in the RE-LY trial. METHODS: GDF-15 was measured in samples collected at randomization in 8,474 patients with a median follow-up time of 1.9 years. Patients were stratified based on predefined GDF-15 cutoffs: group 1, <1,200 ng/L (the 90th percentile in healthy individuals); group 2, 1,200-1,800; and group 3, >1,800 ng/L (high-risk individuals). Efficacy and safety outcomes were compared across groups of GDF-15 in Cox models adjusted for baseline characteristics, cardiac (N-terminal pro-b-type natriuretic peptide, high-sensitive troponin T), inflammatory (interleukin 6, C-reactive protein) and coagulation (D-dimer) biomarkers, and randomized treatment. RESULTS: GDF-15 concentrations were <1,200 ng/L in 2,647 (31.2%), between 1,200 and 1,800 ng/L in 2,704 (31.9%), and >1,800 ng/L in 3,123 (36.9%) participants, respectively. Annual rates of stroke, major bleeding, and mortality increased with higher GDF-15 levels. The prognostic value of GDF-15 was independent of clinical characteristics for these outcomes. In models also adjusted for biomarkers, GDF-15 remained significantly associated with major bleeding (hazard ratio [95% CI] group 3 vs group 1 1.76 [1.28-2.42], P < .0005) and all-cause mortality (hazard ratio 1.72 [1.30-2.29], P < .0005). GDF-15 improved the c index of both the HAS-BLED (0.62-0.69) and ORBIT (0.68-0.71) bleeding risk scores. CONCLUSIONS: In patients with atrial fibrillation, GDF-15 is an independent risk indicator for major bleeding and all-cause mortality, but not for stroke. Therefore, GDF-15 seems useful as a specific marker of bleeding in patients with AF on oral anticoagulant treatment.

Evaluation of the immunogenicity of the dabigatran reversal agent idarucizumab during Phase I studies.

AIMS: Idarucizumab, a humanized monoclonal anti-dabigatran antibody fragment, is effective in emergency reversal of dabigatran anticoagulation. Pre-existing and treatment-emergent anti-idarucizumab antibodies (antidrug antibodies; ADA) may affect the safety and efficacy of idarucizumab. This analysis characterized the pre-existing and treatment-emergent ADA and assessed their impact on the pharmacokinetics and pharmacodynamics (PK/PD) of idarucizumab. METHODS: Data were pooled from three Phase I, randomized, double-blind idarucizumab studies in healthy Caucasian subjects; elderly, renally impaired subjects; and healthy Japanese subjects. In plasma sampled before and after idarucizumab dosing, ADA were detected and titrated using a validated electrochemiluminescence method. ADA epitope specificities were examined using idarucizumab and two structurally related molecules. Idarucizumab PK/PD data were compared for subjects with and without pre-existing ADA. RESULTS: Pre-existing ADA were found in 33 out of 283 individuals (11.7%), seven of whom had intermittent ADA. Titres of pre-existing and treatment-emergent ADA were low, estimated equivalent to <0.3% of circulating idarucizumab after a 5 g dose. Pre-existing ADA had no impact on dose-normalized idarucizumab maximum plasma levels and exposure and, although data were limited, no impact on the reversal of dabigatran-induced anticoagulation by idarucizumab. Treatment-emergent ADA were detected in 20 individuals (19 out of 224 treated [8.5%]; 1 out of 59 received placebo [1.7%]) and were transient in ten. The majority had specificity primarily toward the C-terminus of idarucizumab. There were no adverse events indicative of immunogenic reactions. CONCLUSION: Pre-existing and treatment-emergent ADA were present at extremely low levels relative to the idarucizumab dosage under evaluation. The PK/PD of idarucizumab appeared to be unaffected by the presence of pre-existing ADA.

Long-term evaluation of dabigatran 150 vs. 110 mg twice a day in patients with non-valvular atrial fibrillation.

AIMS: The Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial allowed patients who completed the trial receiving their assigned dabigatran 150 mg (D150) or 110 mg (D110) twice a day to continue into the Long-term Multicenter Extension of Dabigatran Treatment in Patients with Atrial Fibrillation (RELY-ABLE) trial. This permitted assessment of outcomes over a median of 4.6 and a maximum of 6.7 years, respectively. METHODS AND RESULTS: The analysed population included only those patients who completed RE-LY on dabigatran and continued into RELY-ABLE without interruption of assigned dabigatran. Cumulative risk was expressed as Kaplan-Meier plots. Outcomes were compared using Cox proportional hazard modelling. Stroke or systemic embolization rates were 1.25 and 1.54% per year (D150 and D110, respectively); hazard ratio (HR) 0.81 [95% confidence interval (CI): 0.68-0.96] (P = 0.02). Ischaemic stroke was 1.03 (D150) and 1.29%/year (D110); HR 0.79 (95% CI: 0.66-0.95) (P = 0.01). Haemorrhagic stroke rates were 0.11 (D150) and 0.13%/year (D110); HR 0.91 (95% CI: 0.51-1.62) (P = 0.75). Rates of major haemorrhage were 3.34 (D150) and 2.76%/year (D110); HR 1.22 (95% CI: 1.08-1.37) (P = 0.0008). Intracranial haemorrhage rates were 0.32 (D150) and 0.23%/year (D110); HR 1.37 (95% CI: 0.93-2.01) (P = 0.11). Mortality was 3.43 (D150) and 3.55%/year (D110); HR 0.97 (95% CI: 0.87-1.08) (P = 0.54). CONCLUSION: Annualized rates of all outcomes were constant with better efficacy of D150, less major bleeding with D110, and low intracerebral haemorrhage rates for both doses. There were no additional safety concerns. This is the longest continuous randomized experience of a novel anticoagulant.

Idarucizumab, a specific reversal agent for dabigatran: mode of action, pharmacokinetics and pharmacodynamics, and safety and efficacy in phase 1 subjects.

The direct oral anticoagulants (DOACs) provide a number of clinical advantages over vitamin K antagonists for the treatment of thromboembolism, including improved efficacy and safety, as well as no need for regular monitoring of anticoagulant effect. However, as with all anticoagulants, bleeding complications may occur, and anticoagulant reversal may be required in specific clinical situations, such as in patients experiencing spontaneous or traumatic bleeds, or in anticoagulated patients requiring emergency surgery or other invasive procedures. Therefore, several reversal agents for the DOACs are in development. This includes the specific reversal agent idarucizumab, which has been approved by the U.S. Food and Drug Administration and the European Medicines Agency for use in patients treated with dabigatran when urgent reversal of its anticoagulant effects is needed. Idarucizumab is a humanized monoclonal antibody fragment that binds with high affinity to free and thrombin-bound dabigatran, resulting in an almost irreversibly bound idarucizumab-dabigatran complex and thereby neutralizing dabigatran's anticoagulant activity. The reversal of the anticoagulant effects of dabigatran by idarucizumab has been demonstrated in animal bleeding models, in healthy volunteers with a range of ages and renal function, and in anticoagulated patients. In the phase 1 trials, at doses of 2 g or greater, idarucizumab resulted in immediate and complete reversal of the dabigatran anticoagulant effects and was well tolerated. In the absence of dabigatran, idarucizumab showed no effect on coagulation parameters or thrombin formation. These findings provide initial evidence that idarucizumab could provide a safe and effective means of reversing anticoagulant activity in patients treated with dabigatran in need of emergency surgery or in emergency bleeding situations.

Efficacy and safety of dabigatran compared with warfarin in relation to baseline renal function in patients with atrial fibrillation: a RE-LY (Randomized Evaluation of Long-term Anticoagulation Therapy) trial analysis.

BACKGROUND: Renal impairment increases the risk of stroke and bleeding in patients with atrial fibrillation. In the Randomized Evaluation of Long-Term Anticoagulant Therapy (RELY) trial, dabigatran, with ≈80% renal elimination, displayed superiority over warfarin for prevention of stroke and systemic embolism in the 150-mg dose and significantly less major bleeding in the 110-mg dose in 18 113 patients with nonvalvular atrial fibrillation. This prespecified study investigated these outcomes in relation to renal function. METHODS AND RESULTS: Glomerular filtration rate was estimated with the Cockcroft-Gault, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), and Modification of Diet in Renal Disease (MDRD) equations in all randomized patients with available creatinine at baseline (n=17 951), and cystatin C-based glomerular filtration rate was estimated in a subpopulation with measurements available (n=6190). A glomerular filtration rate ≥80, 50 to <80, and <50 mL/min was estimated in 32.6%, 47.6%, and 19.8% and in 21.6%, 59.6%, and 18.8% of patients based on Cockcroft-Gault and CKD-EPI, respectively. Rates of stroke or systemic embolism, major bleeding, and all-cause mortality increased as renal function decreased. The rates of stroke or systemic embolism were lower with dabigatran 150 mg and similar with 110 mg twice daily compared with warfarin, without significant heterogeneity in subgroups defined by renal function (interaction P>0.1 for all). For the outcome of major bleeding, there were significant interactions between treatment and renal function according to CKD-EPI and MDRD equations, respectively (P<0.05). The relative reduction in major bleeding with either dabigatran dose compared with warfarin was greater in patients with glomerular filtration rate ≥80 mL/min. CONCLUSIONS: The efficacy of both dosages of dabigatran was consistent with the overall trial irrespective of renal function. However, with the CKD-EPI and MDRD equations, both dabigatran dosages displayed significantly lower rates of major bleeding in patients with glomerular filtration rate ≥80 mL/min. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00262600.

Variations in cause and management of atrial fibrillation in a prospective registry of 15,400 emergency department patients in 46 countries: the RE-LY Atrial Fibrillation Registry.

BACKGROUND: Atrial fibrillation (AF) is the most common sustained arrhythmia; however, little is known about patients in a primary care setting from high-, middle-, and low-income countries. METHODS AND RESULTS: This prospective registry enrolled patients presenting to an emergency department with AF at 164 sites in 46 countries representing all inhabited continents. Patient characteristics were compared among 9 major geographic regions. Between September 2008 and April 2011, 15,400 patients were enrolled. The average age was 65.9, standard deviation 14.8 years, ranging from 57.2, standard deviation 18.8 years in Africa, to 70.1, standard deviation 13.4 years in North America, P<0.001. Hypertension was globally the most common risk factor for AF, ranging in prevalence from 41.6% in India to 80.7% in Eastern Europe, P<0.001. Rheumatic heart disease was present in only 2.2% of North American patients, in comparison with 21.5% in Africa and 31.5% in India, P<0.001. The use of oral anticoagulation among patients with a CHADS2 score of ≥2 was greatest in North America (65.7%) but was only 11.2% in China, P<0.001. The mean time in the therapeutic range was 62.4% in Western Europe, 50.9% in North America, but only between 32% and 40% in India, China, Southeast Asia, and Africa, P<0.001. CONCLUSIONS: There is a large global variation in age, risk factors, concomitant diseases, and treatment of AF among regions. Improving outcomes globally requires an understanding of this variation and the conduct of research focused on AF associated with different underlying conditions and treatment of AF and predisposing conditions in different socioeconomic settings.

Interleukin-6 and C-reactive protein and risk for death and cardiovascular events in patients with atrial fibrillation.

BACKGROUND: Inflammation has been associated with cardiovascular disease and the burden of atrial fibrillation (AF). In this study we evaluate inflammatory biomarkers and future cardiovascular events in AF patients in the RE-LY study. METHODS: Interleukin-6 (IL-6), C-reactive protein (CRP) (n = 6,187), and fibrinogen (n = 4,893) were analyzed at randomization; outcomes were evaluated by Cox models and C-statistics. RESULTS: Adjusted for clinical risk factors IL-6 was independently associated with stroke or systemic embolism (P = .0041), major bleedings (P = .0001), vascular death (P < .0001), and a composite thromboembolic outcome (ischemic stroke, systemic embolism, myocardial infarction, pulmonary embolism and vascular death) (P < .0001). CRP was independently related to myocardial infarction (P = .0047), vascular death (P = .0004), and the composite thromboembolic outcome (P = .0001). When further adjusted for cardiac (troponin and N-terminal fragment B-type natriuretic peptide [NT-proBNP]) and renal (cystatin-C) biomarkers on top of clinical risk factors IL-6 remained significantly related to vascular death (P < .0001), major bleeding (P < .0170) and the composite thromboembolic outcome (P < .0001), and CRP to myocardial infarction (.0104). Fibrinogen was not associated with any outcome. C-index for stroke or systemic embolism increased from 0.615 to 0.642 (P = .0017) when adding IL-6 to the clinically used CHA2DS2-VASc risk score with net reclassification improvement of 28%. CONCLUSION: In patients with AF, IL-6 is related to higher risk of stroke and major bleeding, and both markers are related to higher risk of vascular death and the composite of thromboembolic events independent of clinical risk factors. Adjustment for cardiovascular biomarkers attenuated the prognostic value, although IL-6 remained related to mortality, the composite of thromboembolic events, and major bleeding, and CRP to myocardial infarction.

Novel oral anticoagulants and reversal agents: Considerations for clinical development.

This white paper provides a summary of presentations and discussions that were held at an Anticoagulant-Induced Bleeding and Reversal Agents Think Tank co-sponsored by the Cardiac Safety Research Consortium and the US Food and Drug Administration (FDA) at the FDA's White Oak Headquarters on April 22, 2014. Attention focused on a development pathway for reversal agents for the novel oral anticoagulants (NOACs). This is important because anticoagulation is still widely underused for stroke prevention in patients with atrial fibrillation. Undertreatment persists, although NOACs, in general, overcome some of the difficulties associated with anticoagulation provided by vitamin K antagonists. One reason for the lack of a wider uptake is the absence of NOAC reversal agents. As there are neither widely accepted academic and industry standards nor a definitive regulatory policy on the development of such reversal agents, this meeting provided a forum for leaders in the fields of cardiovascular clinical trials and cardiovascular safety to discuss the issues and develop recommendations. Attendees included representatives from pharmaceutical companies; regulatory agencies; end point adjudication specialist groups; contract research organizations; and active, academically based physicians. There was wide and solid consensus that NOACs overall offer improvements in convenience, efficacy, and safety compared with warfarin, even without reversal agents. Still, it was broadly accepted that it would be helpful to have reversal agents available for clinicians to use. Because it is not feasible to do definitive outcomes studies demonstrating a reversal agent's clinical benefits, it was felt that these agents could be approved for use in life-threatening bleeding situations if the molecules were well characterized preclinically, their pharmacodynamic and pharmacokinetic profiles were well understood, and showed no harmful adverse events in early human testing. There was also consensus that after such approval, efforts should be made to augment the available clinical information until such time as there is a body of evidence to demonstrate real-world clinical outcomes with the reversal agents. No recommendations were made for more generalized use of these agents in the setting of non-life-threatening situations. This article reflects the views of the authors and should not be construed to represent FDA's views or policies.

Efficacy and Safety of Dabigatran Etexilate vs. Warfarin in Asian RE-LY Patients According to Baseline Renal Function or CHADS2 Score.

BACKGROUND: In Asian patients in RE-LY, dabigatran etexilate (DE) was as effective as warfarin, with a significantly lower bleeding risk. We evaluated the relationship between baseline renal function or CHADS2 score and efficacy or safety outcomes in these patients. METHODS AND RESULTS: Asian patients (n=2,782) were categorized according to baseline renal function or CHADS2 score, and efficacy and safety outcomes were analyzed for DE (110 mg and 150 mg b.i.d.) vs. warfarin. There was an increase in the rates of stroke/systemic embolism and major bleeding with worsening renal function and CHADS2 score. For stroke/systemic embolism (primary efficacy endpoint), there was no treatment interaction for dabigatran at either 110 or 150 mg b.i.d. compared with warfarin related to patients' baseline renal function (Pinteraction=0.56 for DE 110 mg and 0.62 for DE 150 mg vs. warfarin) or CHADS2 score (Pinteraction=0.68 for DE 110 mg and 0.31 for DE 150 mg vs. warfarin). For major bleeding, there was no treatment interaction by creatinine clearance category observed for either dose (Pinteraction=0.60 and 0.62 for DE 110 mg and DE 150 mg, respectively). Baseline CHADS2 score had no significant effect on bleeding event rates with DE vs. warfarin. CONCLUSIONS: Bleeding and stroke rates in Asian patients varied according to renal function and CHADS2 score, but the relative benefits of DE over warfarin were preserved when analyzed by subcategories.

Concomitant use of antiplatelet therapy with dabigatran or warfarin in the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial.

BACKGROUND: The Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) trial showed that dabigatran etexilate 150 mg BID was superior and dabigatran etexilate 110 mg BID was noninferior to warfarin in preventing stroke and systemic embolism in patients with atrial fibrillation. In this subgroup analysis, we assess the efficacy and safety of dabigatran in patients who did and did not receive concomitant antiplatelets. METHODS AND RESULTS: All comparisons used a Cox proportional hazards model with adjustments made for risk factors for bleeding. A time-dependent analysis was performed when comparing patients with concomitant antiplatelets with those without. Of 18 113 patients, 6952 (38.4%) received concomitant aspirin or clopidogrel at some time during the study. Dabigatran etexilate 110 mg BID was noninferior to warfarin in reducing stroke and systemic embolism, whether patients received antiplatelets (hazard ratio [HR], 0.93; 95% confidence interval [95% CI], 0.70-1.25) or not (HR, 0.87; 95% CI, 0.66-1.15; interaction P=0.738). There were fewer major bleeds than warfarin in both subgroups (HR, 0.82; 95% CI, 0.67-1.00 for patients who used antiplatelets; HR, 0.79; 95% CI, 0.64-0.96 for patients who did not; interaction P=0.794). Dabigatran etexilate 150 mg BID reduced the primary outcome of stroke and systemic embolism in comparison with warfarin. This effect seemed attenuated among patients who used antiplatelets (HR, 0.80; 95% CI, 0.59-1.08) in comparison with those who did not (HR, 0.52; 95% CI, 0.38-0.72; P for interaction=0.058). Major bleeding was similar to warfarin regardless of antiplatelet use (HR, 0.93; 95% CI, 0.76-1.12 for patients who used antiplatelets; HR, 0.94; 95% CI, 0.78-1.15 for patients who did not; P for interaction=0.875). In the time-dependent analysis, concomitant use of a single antiplatelet seemed to increase the risk of major bleeding (HR, 1.60; 95% CI, 1.42-1.82). Dual antiplatelet seemed to increased this even more (HR, 2.31; 95% CI, 1.79-2.98). The absolute risks were lowest on dabigatran etexilate 110 mg BID in comparison with dabigatran etexilate 150 mg BID or warfarin. CONCLUSIONS: Concomitant antiplatelet drugs appeared to increase the risk for major bleeding in RE-LY without affecting the advantages of dabigatran over warfarin. Choosing between dabigatran etexilate 110 mg BID and dabigatran etexilate 150 mg BID requires a careful assessment of characteristics that influence the balance between benefit and harm. CLINICAL TRIAL REGISTRATION: URL: http://clinicaltrials.gov. Unique identifier: NCT00262600.

The Long-Term Multicenter Observational Study of Dabigatran Treatment in Patients With Atrial Fibrillation (RELY-ABLE) Study.

BACKGROUND: During follow-up of between 1 and 3 years in the Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) trial, 2 doses of dabigatran etexilate were shown to be effective and safe for the prevention of stroke or systemic embolism in patients with atrial fibrillation. There is a need for longer-term follow-up of patients on dabigatran and for further data comparing the 2 dabigatran doses. METHODS AND RESULTS: Patients randomly assigned to dabigatran in RE-LY were eligible for the Long-term Multicenter Extension of Dabigatran Treatment in Patients with Atrial Fibrillation (RELY-ABLE) trial if they had not permanently discontinued study medication at the time of their final RE-LY study visit. Enrolled patients continued to receive the double-blind dabigatran dose received in RE-LY, for up to 28 months of follow up after RE-LY (median follow-up, 2.3 years). There were 5851 patients enrolled, representing 48% of patients originally randomly assigned to receive dabigatran in RE-LY and 86% of RELY-ABLE-eligible patients. Rates of stroke or systemic embolism were 1.46% and 1.60%/y on dabigatran 150 and 110 mg twice daily, respectively (hazard ratio, 0.91; 95% confidence interval, 0.69-1.20). Rates of major hemorrhage were 3.74% and 2.99%/y on dabigatran 150 and 110 mg (hazard ratio, 1.26; 95% confidence interval, 1.04-1.53). Rates of death were 3.02% and 3.10%/y (hazard ratio, 0.97; 95% confidence interval, 0.80-1.19). Rates of hemorrhagic stroke were 0.13% and 0.14%/y. CONCLUSIONS: During 2.3 years of continued treatment with dabigatran after RE-LY, there was a higher rate of major bleeding with dabigatran 150 mg twice daily in comparison with 110 mg, and similar rates of stroke and death.

Cardiac biomarkers are associated with an increased risk of stroke and death in patients with atrial fibrillation: a Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) substudy.

BACKGROUND: Cardiac biomarkers are strong predictors of adverse outcomes in several patient populations. We evaluated the prevalence of elevated troponin I and N-terminal pro-B-type natriuretic peptide (NT-proBNP) and their association to cardiovascular events in atrial fibrillation (AF) patients in the Randomized Evaluation of Long-Term Anticoagulation Therapy (RE-LY) trial. METHODS AND RESULTS: Biomarkers at randomization were analyzed in 6189 patients. Outcomes were evaluated by Cox proportional hazards models adjusting for established cardiovascular risk factors and the CHADS(2) and CHA(2)DS(2)-VASc risk scores. Patients were stratified based on troponin I concentrations: <0.010 µg/L, n=2663; 0.010 to 0.019 µg/L, n=2006; 0.020 to 0.039 µg/L, n=1023; ≥0.040 µg/L, n=497; and on NT-proBNP concentration quartiles: <387; 387 to 800; 801 to 1402; >1402 ng/L. Rates of stroke were independently related to levels of troponin I with 2.09%/year in the highest and 0.84%/year in the lowest troponin I group (hazard ratio [HR], 1.99 [95% CI, 1.17-3.39]; P=0.0040), and to NT-proBNP with 2.30%/year versus 0.92% in the highest versus lowest NT-proBNP quartile groups, (HR, 2.40 [95% CI, 1.41-4.07]; P=0.0014). Vascular mortality was also independently related to biomarker levels with 6.56%/year in the highest and 1.04%/year the lowest troponin I group (HR, 4.38 [95% CI, 3.05-6.29]; P<0.0001), and 5.00%/year in the highest and 0.61%/year in the lowest NT-proBNP quartile groups (HR, 6.73 [3.95-11.49]; P<0.0001). Biomarkers increased the C-statistic from 0.68 to 0.72, P<0.0001, for a composite of thromboembolic events. CONCLUSIONS: Elevations of troponin I and NT-proBNP are common in patients with AF and independently related to increased risks of stroke and mortality. Cardiac biomarkers seem useful for improving risk prediction in AF beyond currently used clinical variables.

Variation in warfarin dose adjustment practice is responsible for differences in the quality of anticoagulation control between centers and countries: an analysis of patients receiving warfarin in the randomized evaluation of long-term anticoagulation therapy (RE-LY) trial.

BACKGROUND: The outcome of atrial fibrillation patients on warfarin partially depends on maintaining adequate time in therapeutic International Normalized Ratio range (TTR). Large differences in TTR have been reported between centers and countries. The association between warfarin dosing practice, TTR, and clinical outcomes was evaluated in Randomized Evaluation of Long-term Anticoagulation Therapy (RE-LY) trial patients receiving warfarin. METHODS AND RESULTS: RE-LY provided an algorithm for warfarin dosing, recommending no change for in-range, and 10% to 15% weekly dose changes for out-of-range International Normalized Ratio values. We determined whether dose adjustments were consistent with algorithm recommendations but could not verify whether providers used the algorithm. Using multilevel regression models to adjust for patient, center, and country characteristics, we assessed whether algorithm-consistent warfarin dosing could predict patient TTR and the composite outcome of stroke, systemic embolism, or major hemorrhage. We included 6022 nonvalvular atrial fibrillation patients from 912 centers in 44 countries. We found a strong association between the proportion of algorithm-consistent warfarin doses and mean country TTR (R(2)=0.65). The degree of algorithm-consistency accounted for 87% of the between-center and 55% of the between-country TTR variation. Each 10% increase in center algorithm-consistent dosing independently predicted a 6.12% increase in TTR (95% confidence interval, 5.65-6.59) and an 8% decrease in rate of the composite clinical outcome (hazard ratio, 0.92; 95% confidence interval, 0.85-1.00). CONCLUSIONS: Adherence, intentional or not, to a simple warfarin dosing algorithm predicts improved TTR and accounts for considerable TTR variation between centers and countries. Systems facilitating algorithm-based warfarin dosing could optimize anticoagulation quality and improve clinical outcomes in atrial fibrillation on a global scale. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00262600.

Dabigatran versus warfarin: effects on ischemic and hemorrhagic strokes and bleeding in Asians and non-Asians with atrial fibrillation.

BACKGROUND AND PURPOSE: Intracranial hemorrhage rates are higher in Asians than non-Asians, especially in patients receiving warfarin. This randomized evaluation of long-term anticoagulation therapy subgroup analysis assessed dabigatran etexilate (DE) and warfarin effects on stroke and bleeding rates in patients from Asian and non-Asian countries. METHODS: There were 2782 patients (15%) from 10 Asian countries and 15 331 patients from 34 non-Asian countries. A Cox regression model, with terms for treatment, region, and their interaction was used. RESULTS: Rates of stroke or systemic embolism in Asians were 3.06% per year on warfarin, 2.50% per year on DE 110 mg BID (DE 110), and 1.39% per year on DE 150 mg BID (DE 150); in non-Asians, the rates were 1.48%, 1.37%, and 1.06% per year with no significant treatment-by-region interactions. Hemorrhagic stroke on warfarin occurred more often in Asians than non-Asians (hazard ratio [HR], 2.4; 95% confidence interval [CI], 1.3-4.7; P=0.007), with significant reductions for DE compared with warfarin in both Asian (DE 110 versus warfarin HR, 0.15; 95% CI, 0.03-0.66 and DE 150 versus warfarin HR, 0.22; 95% CI, 0.06-0.77) and non-Asian (DE 110 versus warfarin HR, 0.37; 95% CI, 0.19-0.72 and DE 150 versus warfarin HR, 0.28; 95% CI, 0.13-0.58) patients. Major bleeding rates in Asians were significantly lower on DE (both doses) than warfarin (warfarin 3.82% per year, DE 110 2.22% per year, and DE 150 2.17% per year). CONCLUSIONS: Hemorrhagic stroke rates were higher on warfarin in Asians versus non-Asians, despite similar blood pressure, younger age, and lower international normalized ratio values. Hemorrhagic strokes were significantly reduced by DE in both Asians and non-Asians. DE benefits were consistent across Asian and non-Asian subgroups. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT00262600.

Analysis of upper gastrointestinal adverse events among patients given dabigatran in the RE-LY trial.

BACKGROUND & AIMS: Dabigatran is an oral and direct inhibitor of thrombin. In a study of patients with atrial fibrillation (the RE-LY trial), twice as many subjects given dabigatran reported dyspepsia-like symptoms compared with those given warfarin (controls). We analyzed data from this trial to quantify upper gastrointestinal nonbleeding adverse events (NB-UGI AEs). METHODS: We analyzed the AE database from the RE-LY trial (18,113 subjects) and assigned NB-UGI AEs to 4 groups: those associated with gastroesophageal reflux (GERD), upper abdominal pain and dyspepsia, dysmotility, or gastroduodenal injury. We analyzed frequency, timing, and severity, and clinical variables associated with NB-UGI AEs. RESULTS: NB-UGI AEs occurred in 16.9% of subjects given dabigatran and in 9.4% of controls (relative risk [RR], 1.81; 95% confidence interval [CI], 1.66%-1.97%; P < .001). Rates of AEs were not associated with the dose of dabigatran. Among subjects with any UGI symptom who were given dabigatran (n = 2045), symptoms were rated as mild in 46.3%, moderate in 44.8%, and severe in 8.9%; these values were similar to those of controls. GERD-associated NB-UGI AEs were most frequent among the 4 groups (compared with controls, RR, 3.71; 95% CI, 2.98%-4.62%; P < .001). Four percent of subjects stopped taking dabigatran because of NB-UGI AEs (most within 3 months of starting therapy), compared with 1.7% of controls (RR, 2.34; 95% CI, 1.90%-2.88%; P < .001). NB-UGI AEs slightly increased risk of major GI bleeding among subjects given dabigatran and controls (6.8% vs 2.3%, P < .001). CONCLUSIONS: Among patients given dabigatran for atrial fibrillation, NB-UGI AEs are generally mild or moderate; 4% stopped taking the drug over a median of 21.7 months. The greatest increase was in GERD-type NB-UGI AEs. These observations should guide management and prevention strategies.