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

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

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.

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

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

Dabigatran for Prevention of Stroke after Embolic Stroke of Undetermined Source.

BACKGROUND: Cryptogenic strokes constitute 20 to 30% of ischemic strokes, and most cryptogenic strokes are considered to be embolic and of undetermined source. An earlier randomized trial showed that rivaroxaban is no more effective than aspirin in preventing recurrent stroke after a presumed embolic stroke from an undetermined source. Whether dabigatran would be effective in preventing recurrent strokes after this type of stroke was unclear. METHODS: We conducted a multicenter, randomized, double-blind trial of dabigatran at a dose of 150 mg or 110 mg twice daily as compared with aspirin at a dose of 100 mg once daily in patients who had had an embolic stroke of undetermined source. The primary outcome was recurrent stroke. The primary safety outcome was major bleeding. RESULTS: A total of 5390 patients were enrolled at 564 sites and were randomly assigned to receive dabigatran (2695 patients) or aspirin (2695 patients). During a median follow-up of 19 months, recurrent strokes occurred in 177 patients (6.6%) in the dabigatran group (4.1% per year) and in 207 patients (7.7%) in the aspirin group (4.8% per year) (hazard ratio, 0.85; 95% confidence interval [CI], 0.69 to 1.03; P = 0.10). Ischemic strokes occurred in 172 patients (4.0% per year) and 203 patients (4.7% per year), respectively (hazard ratio, 0.84; 95% CI, 0.68 to 1.03). Major bleeding occurred in 77 patients (1.7% per year) in the dabigatran group and in 64 patients (1.4% per year) in the aspirin group (hazard ratio, 1.19; 95% CI, 0.85 to 1.66). Clinically relevant nonmajor bleeding occurred in 70 patients (1.6% per year) and 41 patients (0.9% per year), respectively. CONCLUSIONS: In patients with a recent history of embolic stroke of undetermined source, dabigatran was not superior to aspirin in preventing recurrent stroke. The incidence of major bleeding was not greater in the dabigatran group than in the aspirin group, but there were more clinically relevant nonmajor bleeding events in the dabigatran group. (Funded by Boehringer Ingelheim; RE-SPECT ESUS ClinicalTrials.gov number, NCT02239120.).

Dabigatran versus Warfarin for Acute Venous Thromboembolism in Elderly or Impaired Renal Function Patients: Pooled Analysis of RE-COVER and RE-COVER II.

Management of acute venous thromboembolism (VTE) with anticoagulants in elderly patients and those with chronic kidney disease poses special challenges. The RE-COVER and RE-COVER II trials showed that dabigatran 150 mg twice daily was as effective as warfarin over 6 months in preventing recurrent VTE, with a lower bleeding risk. We now assess the effects of old age and renal impairment (RI) on pooled trial outcomes in 5,107 patients: 4,504 aged <75 years and 603 aged ≥75 years. The primary efficacy outcome was symptomatic VTE/VTE-related death. Safety outcomes were centrally adjudicated major bleeding events (MBEs), MBEs or clinically relevant non-major bleeding events (MBEs/CRBEs) and any bleeds. Baseline renal function was categorized as normal, mild RI or moderate RI. A total of 3,698 had normal renal function and 1,100 and 237 had mild and moderate RI, respectively (23 patients with severe RI and 49 with missing creatinine clearance data were not included). For dabigatran, VTE/VTE-related death decreased from 3.1% (normal renal function) to 1.9% for mild RI and to 0.0% for moderate RI. For warfarin, the event rates were 2.6, 1.6 and 4.1%, respectively. Overall, major bleeding increased with increasing RI (p = 0.0037) and with age (p = 0.4350), with no apparent difference between the dabigatran and warfarin patients. Dabigatran shows better efficacy than warfarin in RI and in the elderly patients, probably because of an increase in the concentration of dabigatran. However, bleeding risk increases with both dabigatran and warfarin in the presence of RI.

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 .).

Net clinical benefit of dabigatran vs. warfarin in venous thromboembolism: analyses from RE-COVER®, RE-COVER™ II, and RE-MEDY™.

The direct oral anticoagulants, e.g., dabigatran etexilate (DE), are effective and well tolerated treatments for venous thromboembolism (VTE). Net clinical benefit (NCB) is a useful concept in weighing potential benefits against potential harm of comparator drugs. The NCB of DE vs. warfarin in VTE treatment was compared. Post-hoc analyses were performed on pooled data from the 6-month RE-COVER® and RE-COVER™ II trials, and data from the RE-MEDY™ trial (up to 36 months), to compare the NCB of DE (150 mg twice daily) and warfarin [target international normalized ratio (INR) 2.0-3.0]. Patients (≥18 years old) had symptomatic proximal deep vein thrombosis and/or pulmonary embolism. NCB was the composite of cardiovascular endpoints (non-fatal events of recurrent VTE, myocardial infarction, stroke or systemic embolism), all-cause death, and bleeding outcomes, all weighted equally. A broad definition of NCB included major bleeding events (MBE) and clinically relevant non-major bleeding events as bleeding outcomes, while a narrow definition included just MBE. The pooled dataset totalled 5107 patients from RE-COVER/RE-COVER II and 2856 patients from RE-MEDY. When NCB was narrowly defined, NCB was similar between DE and warfarin. When broadly defined, NCB was superior with DE vs. warfarin [RE-COVER/RE-COVER II, hazard ratio (HR) 0.80; 95% confidence interval (CI), 0.68-0.95 and RE-MEDY, HR 0.73; 95% CI 0.59-0.91]. These findings were unaffected by warfarin time in therapeutic range. The NCB of DE was similar or superior to warfarin, depending on the NCB definition used, regardless of the quality of INR control.

Effect of Age and Renal Function on Idarucizumab Pharmacokinetics and Idarucizumab-Mediated Reversal of Dabigatran Anticoagulant Activity in a Randomized, Double-Blind, Crossover Phase Ib Study.

BACKGROUND AND OBJECTIVES: Idarucizumab is an antibody fragment that specifically reverses dabigatran-mediated anticoagulation. Safety, pharmacokinetics and pharmacodynamics of idarucizumab were investigated in dabigatran-treated, middle-aged, elderly and renally impaired volunteers with characteristics similar to patients receiving anticoagulant therapy. METHODS: In this randomized, double-blind, crossover study, 46 subjects (12 middle-aged, 45-64 years; 16 elderly, 65-80 years; and 18 with mild or moderate renal impairment) received dabigatran etexilate (DE; 220 or 150 mg twice daily) for 4 days. Idarucizumab doses of 1, 2.5 and 5 g or 2 × 2.5 g 1 h apart, or placebo, were administered as a rapid (5 min) infusion ~2 h after DE at steady state. RESULTS: Dabigatran-prolonged diluted thrombin time, ecarin clotting time and activated partial thromboplastin time were reversed to baseline immediately after idarucizumab infusion in all groups. Reversal was sustained with doses ≥2.5 g. Idarucizumab was well tolerated under all conditions. No impact of age on idarucizumab pharmacokinetics was observed; however, subjects with mild or moderate renal impairment demonstrated increased exposure (up to 84 %), decreased clearance and prolonged (by up to 49 %) initial half-life of idarucizumab compared with healthy middle-aged subjects. CONCLUSIONS: Impaired renal function was associated with increased exposure and decreased clearance of idarucizumab. Idarucizumab resulted in immediate, complete and sustained reversal of dabigatran anticoagulant activity, and was safe and well tolerated in middle-aged, elderly and renally impaired volunteers. The results support the clinical use of a 5 g dose of idarucizumab. CLINICAL TRIAL REGISTRATION: http://www.clinicaltrials.gov . Unique identifier: NCT01955720.

Electronic health records to facilitate clinical research.

Electronic health records (EHRs) provide opportunities to enhance patient care, embed performance measures in clinical practice, and facilitate clinical research. Concerns have been raised about the increasing recruitment challenges in trials, burdensome and obtrusive data collection, and uncertain generalizability of the results. Leveraging electronic health records to counterbalance these trends is an area of intense interest. The initial applications of electronic health records, as the primary data source is envisioned for observational studies, embedded pragmatic or post-marketing registry-based randomized studies, or comparative effectiveness studies. Advancing this approach to randomized clinical trials, electronic health records may potentially be used to assess study feasibility, to facilitate patient recruitment, and streamline data collection at baseline and follow-up. Ensuring data security and privacy, overcoming the challenges associated with linking diverse systems and maintaining infrastructure for repeat use of high quality data, are some of the challenges associated with using electronic health records in clinical research. Collaboration between academia, industry, regulatory bodies, policy makers, patients, and electronic health record vendors is critical for the greater use of electronic health records in clinical research. This manuscript identifies the key steps required to advance the role of electronic health records in cardiovascular clinical research.

Design and Rationale of the RE-DUAL PCI Trial: A Prospective, Randomized, Phase 3b Study Comparing the Safety and Efficacy of Dual Antithrombotic Therapy With Dabigatran Etexilate Versus Warfarin Triple Therapy in Patients With Nonvalvular Atrial Fibrillation Who Have Undergone Percutaneous Coronary Intervention With Stenting.

Antithrombotic management of patients with atrial fibrillation (AF) undergoing coronary stenting is complicated by the need for anticoagulant therapy for stroke prevention and dual antiplatelet therapy for prevention of stent thrombosis and coronary events. Triple antithrombotic therapy, typically comprising warfarin, aspirin, and clopidogrel, is associated with a high risk of bleeding. A modest-sized trial of oral anticoagulation with warfarin and clopidogrel without aspirin showed improvements in both bleeding and thrombotic events compared with triple therapy, but large trials are lacking. The RE-DUAL PCI trial (NCT 02164864) is a phase 3b, a strategy of prospective, randomized, open-label, blinded-endpoint trial. The main objective is to evaluate dual antithrombotic therapy with dabigatran etexilate (110 or 150 mg twice daily) and a P2Y12 inhibtor (either clopidogrel or ticagrelor) compared with triple antithrombotic therapy with warfarin, a P2Y12 inhibtor (either clopidogrel or ticagrelor, and low-dose aspirin (for 1 or 3 months, depending on stent type) in nonvalvular AF patients who have undergone percutaneous coronary intervention with stenting. The primary endpoint is time to first International Society of Thrombosis and Hemostasis major bleeding event or clinically relevant nonmajor bleeding event. Secondary endpoints are the composite of all cause death or thrombotic events (myocardial infarction, or stroke/systemic embolism) and unplanned revascularization; death or thrombotic events; individual outcome events; death, myocardial infarction, or stroke; and unplanned revascularization. A hierarchical procedure for multiple testing will be used. The plan is to randomize ∼ 2500 patients at approximately 550 centers worldwide to try to identify new treatment strategies for this patient population.

Bleeding events with dabigatran or warfarin in patients with venous thromboembolism.

Dabigatran was as effective as warfarin for the acute treatment of venous thromboembolism in the RE-COVER and RE-COVER II trials. We compared the incidence of bleeding with dabigatran versus warfarin in pooled data from these studies. The localisation, bleeding severity, and the impact of key factors on the incidence of bleeding, were compared between the dabigatran and warfarin treatment group. Altogether, 2553 patients received dabigatran and 2554 warfarin, each for a mean of 164 days. The incidence of any bleeding event was significantly lower with dabigatran (hazard ratio [HR] 0.70; 95% confidence interval [CI], 0.61-0.79), as was the incidence of the composite of MBEs and clinically relevant non-major bleeding events (HR 0.62; 95% CI, 0.50-0.76). The incidence of major bleeding events (MBEs) was also significantly lower with dabigatran in the double-dummy phase (HR, 0.60; 95%CI, 0.36-0.99) but not statistically different between the two treatment arms when the entire treatment period is considered (HR 0.73 95% CI, 0.48-1.11). Increasing age, reduced renal function, Asian ethnicity, and concomitant antiplatelet therapy were associated with higher bleeding rates in both treatment groups. The reduction in bleeding with dabigatran compared to warfarin was consistent among the subgroups and with a similar pattern for intracranial, and urogenital major bleeding. In conclusion, treatment of venous thromboembolism with dabigatran is associated with a lower risk of bleeding compared to warfarin. This reduction did not differ with respect to the location of bleeding or among predefined subgroups.

Improving clinical trials for cardiovascular diseases: a position paper from the Cardiovascular Round Table of the European Society of Cardiology.

AIMS: Cardiovascular disease is the most common cause of mortality and morbidity in the world, but the pharmaceutical industry's willingness to invest in this field has declined because of the many challenges involved with bringing new cardiovascular drugs to market, including late-stage failures, escalating regulatory requirements, bureaucracy of the clinical trial business enterprise, and limited patient access after approval. This contrasts with the remaining burden of cardiovascular disease in Europe and in the world. Thus, clinical cardiovascular research needs to adapt to address the impact of these challenges in order to ensure development of new cardiovascular medicines. METHODS AND RESULTS: The present paper is the outcome of a two-day workshop held by the Cardiovascular Round Table of the European Society of Cardiology. We propose strategies to improve development of effective new cardiovascular therapies. These can include (i) the use of biomarkers to describe patients who will benefit from new therapies more precisely, achieving better human target validation; (ii) targeted, mechanism-based approaches to drug development for defined populations; (iii) the use of information technology to simplify data collection and follow-up in clinical trials; (iv) streamlining adverse event collection and reducing monitoring; (v) extended patent protection or limited rapid approval of new agents to motivate investment in early phase development; and (vi) collecting data needed for health technology assessment continuously throughout the drug development process (before and after approval) to minimize delays in patient access. Collaboration across industry, academia, regulators, and payers will be necessary to enact change and to unlock the existing potential for cardiovascular clinical drug development. CONCLUSIONS: A coordinated effort involving academia, regulators, industry, and payors will help to foster better and more effective conduct of clinical cardiovascular trials, supporting earlier availability of innovative therapies and better management of cardiovascular diseases.

Oral dabigatran etexilate versus enoxaparin for venous thromboembolism prevention after total hip arthroplasty: pooled analysis of two phase 3 randomized trials.

BACKGROUND: Two phase 3 trials compared 28-35 days of treatment with oral dabigatran 220 mg or 150 mg (RE-NOVATE) or 220 mg (RE-NOVATE II) once daily with subcutaneous enoxaparin 40 mg once daily for prevention of venous thromboembolism (VTE) after elective total hip arthroplasty. METHODS: This prespecified pooled analysis compared the outcomes for the dabigatran 220 mg dose with enoxaparin, which included 4,374 patients. Total VTE (venographic and symptomatic) plus all-cause mortality (primary efficacy), major VTE (proximal deep vein thrombosis [DVT] or non-fatal pulmonary embolism) plus VTE-related death, and bleeding events were evaluated. Efficacy analysis was based on the modified intention-to-treat (ITT) population and safety analysis was based on all treated patients. The common risk difference (RD) for dabigatran versus enoxaparin was estimated using a fixed effects model. RESULTS: Total VTE and all-cause mortality occurred in 6.8 % (114/1,672) and 7.7 % (129/1,682) (RD:-0.8 %, 95 % confidence interval [CI] -2.6 to 0.9) for dabigatran and enoxaparin, respectively. Major VTE plus VTE-related mortality occurred in 2.7 % (46/1,714) and 4.0 % (69/1,711) (RD: -1.4 %, 95 % CI -2.6 to -0.2) of patients receiving dabigatran 220 mg and enoxaparin, respectively. Major bleeding occurred in 1.7 % (37/2,156) and 1.3 % (27/2,157) (RD: 0.5 %, 95 % CI -0.2 to 1.2), for dabigatran and enoxaparin respectively. CONCLUSIONS: Extended prophylaxis with oral dabigatran 220 mg once daily was as effective as enoxaparin 40 mg once daily in reducing the risk of total VTE and all-cause mortality after total hip arthroplasty, with a similar bleeding profile. The clinically relevant outcome of major VTE and VTE-related death was significantly reduced with dabigatran versus enoxaparin. TRIAL REGISTRATION: NCT00657150 and NCT00168818.

Clinical imaging in anti-atherosclerosis drug development.

The development of novel drugs for the treatment of atherosclerosis faces many challenges, particularly caused by the need for large and costly outcome trials. When predictive biochemical biomarkers are not available, clinical imaging data can serve as intermediate Phase II endpoints to demonstrate mechanistic and anti-atherosclerotic activity of new compounds. These data can support risk mitigation before continuing development in large Phase III outcome trials. Imaging techniques such as magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound [intima-media thickness (IMT) and intravascular ultrasound (IVUS)] can provide detailed information on vascular plaque volume and morphology, whereas functional changes can potentially be captured by positron emission tomography (PET) techniques in the vessel wall. We will review the application and operational aspects of clinical imaging methods and endpoints used in interventional atherosclerosis trials.

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.).

Safety, tolerability, and efficacy of idarucizumab for the reversal of the anticoagulant effect of dabigatran in healthy male volunteers: a randomised, placebo-controlled, double-blind phase 1 trial.

BACKGROUND: Idarucizumab is a monoclonal antibody fragment that binds dabigatran with high affinity in a 1:1 molar ratio. We investigated the safety, tolerability, and efficacy of increasing doses of idarucizumab for the reversal of anticoagulant effects of dabigatran in a two-part phase 1 study (rising-dose assessment and dose-finding, proof-of-concept investigation). Here we present the results of the proof-of-concept part of the study. METHODS: In this randomised, placebo-controlled, double-blind, proof-of-concept phase 1 study, we enrolled healthy volunteers (aged 18-45 years) with a body-mass index of 18·5-29·9 kg/m(2) into one of four dose groups at SGS Life Sciences Clinical Research Services, Belgium. Participants were randomly assigned within groups in a 3:1 ratio to idarucizumab or placebo using a pseudorandom number generator and a supplied seed number. Participants and care providers were masked to treatment assignment. All participants received oral dabigatran etexilate 220 mg twice daily for 3 days and a final dose on day 4. Idarucizumab (1 g, 2 g, or 4 g 5-min infusion, or 5 g plus 2·5 g in two 5-min infusions given 1 h apart) was administered about 2 h after the final dabigatran etexilate dose. The primary endpoint was incidence of drug-related adverse events, analysed in all randomly assigned participants who received at least one dose of dabigatran etexilate. Reversal of diluted thrombin time (dTT), ecarin clotting time (ECT), activated partial thromboplastin time (aPTT), and thrombin time (TT) were secondary endpoints assessed by measuring the area under the effect curve from 2 h to 12 h (AUEC2-12) after dabigatran etexilate ingestion on days 3 and 4. This trial is registered with ClinicalTrials.gov, number NCT01688830. FINDINGS: Between Feb 23, and Nov 29, 2013, 47 men completed this part of the study. 12 were enrolled into each of the 1 g, 2 g, or 5 g plus 2·5 g idarucizumab groups (nine to idarucizumab and three to placebo in each group), and 11 were enrolled into the 4 g idarucizumab group (eight to idarucizumab and three to placebo). Drug-related adverse events were all of mild intensity and reported in seven participants: one in the 1 g idarucizumab group (infusion site erythema and hot flushes), one in the 5 g plus 2·5 g idarucizumab group (epistaxis); one receiving placebo (infusion site haematoma), and four during dabigatran etexilate pretreatment (three haematuria and one epistaxis). Idarucizumab immediately and completely reversed dabigatran-induced anticoagulation in a dose-dependent manner; the mean ratio of day 4 AUEC2-12 to day 3 AUEC2-12 for dTT was 1·01 with placebo, 0·26 with 1 g idarucizumab (74% reduction), 0·06 with 2 g idarucizumab (94% reduction), 0·02 with 4 g idarucizumab (98% reduction), and 0·01 with 5 g plus 2·5 g idarucizumab (99% reduction). No serious or severe adverse events were reported, no adverse event led to discontinuation of treatment, and no clinically relevant difference in incidence of adverse events was noted between treatment groups. INTERPRETATION: These phase 1 results show that idarucizumab was associated with immediate, complete, and sustained reversal of dabigatran-induced anticoagulation in healthy men, and was well tolerated with no unexpected or clinically relevant safety concerns, supporting further testing. Further clinical studies are in progress. FUNDING: Boehringer Ingelheim Pharma GmbH & Co KG.