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Key Points In 2008, rivaroxaban (Xarelto; Bayer HealthCare) became the first orally administered direct factor Xa inhibitor to be approved for clinical use in the prevention of venous thromboembolism (VTE) after elective hip- or knee-replacement surgery. This article reviews the rationale for its development, the chemical optimization programme that led to its synthesis, its pharmacological characterization and the completed and ongoing clinical studies that underlie its clinical promise. The scientific premise on which a direct factor Xa inhibitor might help to reduce the burden associated with thromboembolic disorders across a range of medical conditions is also presented. Successful early validation studies, conducted with naturally occurring inhibitors of factor Xa, led to the initiation in 1998 of a medicinal chemistry programme to develop oral selective synthetic factor Xa inhibitors. The article details the medicinal chemistry that culminated in the synthesis of rivaroxaban — a molecule that combines both potent, specific inhibition of factor Xa and good oral bioavailability. Rivaroxaban's preclinical profile and subsequent Phase I studies showed that it has many of the characteristics required to address unmet clinical needs: high oral bioavailability, a fast onset/offset of action, dose-dependent pharmacokinetics and pharmacodynamics, few drug–drug or drug–food interactions and, as a result of these, no requirement for routine coagulation monitoring. The extensive clinical-development programme, which will enrol over 65,000 patients, is reviewed and covers the four completed studies for VTE prevention after elective hip or knee replacement; the completed and ongoing VTE treatment studies; and the three ongoing studies for stroke prevention in patients with atrial fibrillation, prevention of recurrent events in acute coronary syndromes and VTE prevention in patients with an acute medical illness. In closing, the article provides an overview of other oral anticoagulants in development and discusses their clinical potential with a view to the impact they may have in improving outcomes for patients affected by thromboembolic disorders. The anticoagulant rivaroxaban is the first approved direct inhibitor of the serine protease factor Xa. This article presents the history of rivaroxaban's development, from its discovery to the preclinical and clinical studies, and also provides a brief overview of other oral anticoagulants in advanced clinical development. The activated serine protease factor Xa is a promising target for new anticoagulants. After studies on naturally occurring factor Xa inhibitors indicated that such agents could be effective and safe, research focused on small-molecule direct inhibitors of factor Xa that might address the major clinical need for improved oral anticoagulants. In 2008, rivaroxaban (Xarelto; Bayer HealthCare) became the first such compound to be approved for clinical use. This article presents the history of rivaroxaban's development, from the structure–activity relationship studies that led to its discovery to the preclinical and clinical studies, and also provides a brief overview of other oral anticoagulants in advanced clinical development.

Rivaroxaban is an orally administered direct inhibitor of factor Xa. As compared with enoxaparin, rivaroxaban was more effective in preventing venous thromboembolism after hip replacement, without a significant increase in major bleeding. Rivaroxaban is an orally administered direct inhibitor of factor Xa. As compared with enoxaparin, rivaroxaban was more effective in preventing venous thromboembolism after hip replacement, without a significant increase in major bleeding. Prophylactic anticoagulant therapy is standard practice after total hip or knee arthroplasty, with a minimum recommended duration of 10 days. 1 After total hip arthroplasty, extended prophylaxis for 5 weeks after surgery reduces the incidence of symptomatic and asymptomatic venous thromboembolism more effectively than does short-term prophylaxis. 2 New deep-vein thromboses have been shown to form after the discontinuation of short-term prophylaxis. 3 Several meta-analyses suggest that extended thromboprophylaxis after total hip arthroplasty leads to a reduction in symptomatic venous thromboembolic events, without increasing the risk of major bleeding. 4 – 6 These findings led to a grade 1A recommendation for extended thromboprophylaxis after total . . .

This trial compared rivaroxaban with enoxaparin for thromboprophylaxis after total knee replacement. Rivaroxaban was superior to enoxaparin in the prevention of venous thrombosis, and the two drugs had similar safety profiles. For thromboprophylaxis after total knee replacement, rivaroxaban was superior to enoxaparin in the prevention of venous thrombosis, and the two drugs had similar safety profiles. Venous thromboembolism is a major, potentially fatal complication after major orthopedic surgery such as total knee arthroplasty. 1 Anticoagulants that are currently used for thromboprophylaxis require parenteral administration or have unpredictable pharmacodynamic properties that require monitoring. 2 Several anticoagulants currently in development target individual coagulation factors, including thrombin and activated factor X (factor Xa). The efficacy of the parenterally administered indirect factor Xa inhibitor fondaparinux for thromboprophylaxis encouraged the development of direct factor Xa inhibitors. 3 Rivaroxaban (Xarelto, Bayer HealthCare) is an orally active direct factor Xa inhibitor. 4 Phase 2 studies showed that rivaroxaban was potentially safe and effective for thromboprophylaxis after major . . .

The risk of venous thromboembolism is high after total hip arthroplasty and could persist after hospital discharge. Our aim was to compare the use of rivaroxaban for extended thromboprophylaxis with short-term thromboprophylaxis with enoxaparin. 2509 patients scheduled to undergo elective total hip arthroplasty were randomly assigned, stratified according to centre, with a computer-generated randomisation code, to receive oral rivaroxaban 10 mg once daily for 31–39 days (with placebo injection for 10–14 days; n=1252), or enoxaparin 40 mg once daily subcutaneously for 10–14 days (with placebo tablet for 31–39 days; n=1257). The primary efficacy outcome was the composite of deep-vein thrombosis (symptomatic or asymptomatic detected by mandatory, bilateral venography), non-fatal pulmonary embolism, and all-cause mortality up to day 30–42. Analyses were done in the modified intention-to-treat population, which consisted of all patients who had received at least one dose of study medication, had undergone planned surgery, and had adequate assessment of thromboembolism. This study is registered at ClinicalTrials.gov, number NCT00332020. The modified intention-to-treat population for the analysis of the primary efficacy outcome consisted of 864 patients in the rivaroxaban group and 869 in the enoxaparin group. The primary outcome occurred in 17 (2·0%) patients in the rivaroxaban group, compared with 81 (9·3%) in the enoxaparin group (absolute risk reduction 7·3%, 95% CI 5·2–9·4; p<0·0001). The incidence of any on-treatment bleeding was much the same in both groups (81 [6·6%] events in 1228 patients in the rivaroxaban safety population vs 68 [5·5%] of 1229 patients in the enoxaparin safety population; p=0·25). Extended thromboprophylaxis with rivaroxaban was significantly more effective than short-term enoxaparin plus placebo for the prevention of venous thromboembolism, including symptomatic events, in patients undergoing total hip arthroplasty. Bayer HealthCare AG, Johnson & Johnson Pharmaceutical Research and Development LLC.

Limited data are available on the characteristics, clinical management, and outcomes of patients with atrial fibrillation at risk of stroke, from a worldwide perspective. The aim of this study was to describe the baseline characteristics and initial therapeutic management of patients with non-valvular atrial fibrillation across the spectrum of sites at which these patients are treated. The Global Anticoagulant Registry in the FIELD (GARFIELD) is an observational study of patients newly diagnosed with non-valvular atrial fibrillation. Enrollment into Cohort 1 (of 5) took place between December 2009 and October 2011 at 540 sites in 19 countries in Europe, Asia-Pacific, Central/South America, and Canada. Investigator sites are representative of the distribution of atrial fibrillation care settings in each country. Cohort 1 comprised 10,614 adults (≥18 years) diagnosed with non-valvular atrial fibrillation within the previous 6 weeks, with ≥1 investigator-defined stroke risk factor (not limited to those in existing risk-stratification schemes), and regardless of therapy. Data collected at baseline included demographics, medical history, care setting, nature of atrial fibrillation, and treatments initiated at diagnosis. The mean (SD) age of the population was 70.2 (11.2) years; 43.2% were women. Mean±SD CHADS2 score was 1.9±1.2, and 57.2% had a score ≥2. Mean CHA2DS2-VASc score was 3.2±1.6, and 8,957 (84.4%) had a score ≥2. Overall, 38.0% of patients with a CHADS2 score ≥2 did not receive anticoagulant therapy, whereas 42.5% of those at low risk (score 0) received anticoagulant therapy. These contemporary observational worldwide data on non-valvular atrial fibrillation, collected at the end of the vitamin K antagonist-only era, indicate that these drugs are frequently not being used according to stroke risk scores and guidelines, with overuse in patients at low risk and underuse in those at high risk of stroke. ClinicalTrials.gov TRI08888.

Prophylaxis for venous thromboembolism is recommended for at least 10 days after total knee arthroplasty; oral regimens could enable shorter hospital stays. We aimed to test the efficacy and safety of oral rivaroxaban for the prevention of venous thromboembolism after total knee arthroplasty. In a randomised, double-blind, phase III study, 3148 patients undergoing knee arthroplasty received either oral rivaroxaban 10 mg once daily, beginning 6–8 h after surgery, or subcutaneous enoxaparin 30 mg every 12 h, starting 12–24 h after surgery. Patients had mandatory bilateral venography between days 11 and 15. The primary efficacy outcome was the composite of any deep-vein thrombosis, non-fatal pulmonary embolism, or death from any cause up to day 17 after surgery. Efficacy was assessed as non-inferiority of rivaroxaban compared with enoxaparin in the per-protocol population (absolute non-inferiority limit −4%); if non-inferiority was shown, we assessed whether rivaroxaban had superior efficacy in the modified intention-to-treat population. The primary safety outcome was major bleeding. This trial is registered with ClinicalTrials.gov, number NCT00362232. The primary efficacy outcome occurred in 67 (6·9%) of 965 patients given rivaroxaban and in 97 (10·1%) of 959 given enoxaparin (absolute risk reduction 3·19%, 95% CI 0·71–5·67; p=0·0118). Ten (0·7%) of 1526 patients given rivaroxaban and four (0·3%) of 1508 given enoxaparin had major bleeding (p=0·1096). Oral rivaroxaban 10 mg once daily for 10–14 days was significantly superior to subcutaneous enoxaparin 30 mg given every 12 h for the prevention of venous thromboembolism after total knee arthroplasty. Bayer Schering Pharma AG, Johnson & Johnson Pharmaceutical Research & Development.

Background S‐pindolol has metabolic effects of potential benefit in cancer cachexia: reduced catabolism through nonselective β‐blockade; increased anabolism through partial β2 receptor agonism; and increased appetite and reduced fatigue through central 5‐hydroxytryptamine/serotonin receptor activity. A Phase 2a clinical trial demonstrated that S‐pindolol can reverse weight loss and improve fat‐free mass in patients with cancer‐related weight loss. A comparative phase I bioavailability study of S‐pindolol and racemic pindolol was performed to support the development of S‐pindolol in cancer cachexia. Methods This two‐part study assessed the comparative bioavailability and pharmacokinetics of single doses of S‐pindolol benzoate (ACM‐001.1) or pindolol (Part 1) and the steady‐state pharmacokinetics and pharmacodynamics of multiple doses of ACM‐001.1 and pindolol (Part 2) in healthy volunteers (NCT06028321). ACM‐001.1 5, 10 and 15 mg and pindolol 15, 20 and 30 mg were tested. In Part 1, subjects were randomised to ACM‐001.1 15 mg followed after a 48‐h washout period by pindolol 30 mg, or the reverse sequence; another group received pindolol 15 mg. Subjects in Part 2 were randomised to pindolol 20 mg twice‐daily or ACM‐001.1 5, 10 or 15 mg twice‐daily for 4 days. Bioavailability, pharmacokinetics, pharmacodynamics, potential for and extent of stereoconversion, and tolerability were assessed. Results Parts 1 and 2 included 24 and 27 healthy volunteers, respectively. ACM‐001.1 had predictable pharmacokinetics up to a dose of 15 mg twice daily, with low intersubject variability, after single and multiple doses (Tmax 1 vs. 1.5 h; Cmax 74 vs. 73.6 ng/mL; AUC(0−t) 440 vs. 414 ng·h/mL; t1/2 4.042 vs. 3.566 h). The bioavailability of S‐pindolol after equivalent doses of pindolol (20 mg) and ACM‐001.1 (10 mg) was comparable, and formal bioequivalence margins were met (90% CI for Cmax, AUC(0−t) and AUC(0–inf) within 80%–125% bioequivalence acceptance criteria). No evidence of stereoconversion of the S‐enantiomer into the R‐enantiomer, no accumulation, dose linearity and dose proportionality of S‐pindolol over a range of doses were demonstrated; we also show indirectly that there was no food effect. ACM‐001.1 was generally well tolerated, with no apparent relationship of side effects to dose, no serious adverse events, severe treatment‐emergent adverse events (TEAEs) or deaths, and similar incidences of TEAEs (fatigue, dizziness, somnolence, nausea and headache) with ACM‐001.1 10 and 15 mg and pindolol 20 mg. Conclusions Data from this bridging study of enantiomerically pure ACM‐001.1 and its parent racemic drug, pindolol, support clinical trials of ACM‐001.1 for the treatment of cancer cachexia.

Atrial fibrillation (AF) is associated with high rates of morbidity and mortality. Patients with AF carry a fivefold increased risk of stroke and the risk of death from AF-related stroke is doubled. Current management is often inadequate, leaving patients at risk for a potentially fatal or disabling event. The purpose of the GARFIELD registry is to evaluate the management and outcomes of patients with newly diagnosed non-valvular AF at risk for stroke. The GARFIELD registry is an observational, multicenter, prospective study of patients with newly diagnosed AF and one or more additional risk factors for stroke. The aim is to enroll 55,000 patients at >1,000 centers in 50 countries. Enrollment will take place in five independent, sequential, prospective cohorts. An additional retrospective validation cohort of 5,000 patients with established AF and at least one additional risk factor for stroke will be conducted in parallel with cohort one. The study started in December 2009, with a planned recruitment period of 4 years and a minimum of 2-year follow-up for each patient. The GARFIELD registry will provide valuable insights into the clinical management and related outcomes of AF patients throughout many regions of the world and across the spectrum of healthcare systems. By capturing data from unselected patients treated in everyday practice, the registry has the potential to identify best practices as well as deficiencies in available treatment options for specific patient populations and to describe how therapeutic strategies, patient care, and outcomes will evolve over time.

ObjectivesThis study evaluated the comparative effectiveness of vitamin K antagonists (VKAs), direct thrombin inhibitors (DTIs) and factor Xa inhibitors (FXaI) in patients with atrial fibrillation (AF) at risk of stroke in everyday practice.MethodsData from patients with AF and Congestive heart failure, Hypertension, Age 75 years, Diabetes mellitus, prior Stroke, TIA, or thromboembolism, Vascular disease, Age 65-74 years, Sex category (CHA2DS2-VASc) score ≥2 (excluding gender) in the Global Anticoagulant Registry in the FIELD–Atrial Fibrillation registry were analysed using an improved method of propensity weighting, overlap weights and Cox proportional hazards models.ResultsAll-cause mortality, non-haemorrhagic stroke/systemic embolism (SE) and major bleeding over 2 years were compared in 25 551 patients, 7162 (28.0%) not treated with oral anticoagulant (OAC) and 18 389 (72.0%) treated with OAC (FXaI (41.8%), DTI (11.4%) and VKA (46.8%)). OAC treatment compared with no OAC treatment was associated with decreased risk of all-cause mortality (HR 0.82 (95% CI 0.74 to 0.91)) and non-haemorrhagic stroke/SE (HR 0.71 (95% CI 0.57 to 0.88)) but increased risk of major bleeding (HR 1.46 (95% CI 1.15 to 1.86)). Non-vitamin K antagonist oral anticoagulant (NOAC) use compared with no OAC treatment was associated with lower risks of all-cause mortality and non-haemorrhagic stroke/SE (HR 0.67 (95% CI 0.59 to 0.77)) and 0.65 (95% CI 0.50 to 0.86)) respectively, with no increase in major bleeding (HR 1.10 (95% CI 0.82 to 1.47)). NOAC use compared with VKA use was associated with lower risk of all-cause mortality and major bleeding (rates/100 patient-years 3.6 (95% CI 3.3 to 3.9) vs 4.8 (95% CI 4.5 to 5.2) and 1.0 (95% CI 0.9 to 1.1) vs 1.4 (95% CI 1.2 to 1.6); HR 0.79 (95% CI 0.70 to 0.89) and 0.77 (95% CI 0.61 to 0.98) respectively), with similar risk of non-haemorrhagic stroke/SE (rates/100 patient-years 0.8 (95% CI 0.7 to 0.9) versus 1.0 (95% CI 0.8 to 1.1); HR 0.96 (95% CI 0.73 to 1.25).ConclusionImportant benefits in terms of mortality and major bleeding were observed with NOAC versus VKA with no difference among NOAC subtypes.Trial registration number NCT01090362.

ObjectiveIn patients with newly diagnosed atrial fibrillation (AF), do baseline risk factors and stroke prevention strategies account for the geographically diverse outcomes.DesignGlobal Anticoagulant Registry in the FIELD-Atrial Fibrillation is a prospective multinational non-interventional registry of patients with newly diagnosed AF (n=52 018 patients).SettingInvestigator sites (n=1317) were representative of the care settings/locations in each of the 35 participating countries. Treatment decisions were all determined by the local responsible clinicians.ParticipantsThe patients (18 years and over) with newly diagnosed AF had at least 1 investigator-determined stroke risk factor and patients were not required to meet specific thresholds of risk score for anticoagulant treatment.Main outcomes and measuresObserved 1-year event rates and risk-standardised rates were derived.ResultsRates of death, non-haemorrhagic stroke/systemic embolism and major bleeding varied more than three-to-four fold across countries even after adjustment for baseline factors and antithrombotic treatments. Rates of anticoagulation and antithrombotic treatment varied widely. Patients from countries with the highest rates of cardiovascular mortality and stroke were among the least likely to receive oral anticoagulants. Beyond anticoagulant treatment, variations in the treatment of comorbidities and lifestyle factors may have contributed to the variations in outcomes. Countries with the lowest healthcare Access and Quality indices (India, Ukraine, Argentina, Brazil) had the highest risk-standardised mortality.ConclusionThe variability in outcomes across countries for patients with newly diagnosed AF is not accounted for by baseline characteristics and antithrombotic treatments. Residual mortality rates were correlated with Healthcare Access and Quality indices. The findings suggest the management of patients with AF needs to not only address guideline indicated and sustained anticoagulation, but also the treatment of comorbidities and lifestyle factors.Trial registration numberNCT01090362.