XALIA-LEA: An observational study of venous thromboembolism treatment with rivaroxaban and standard anticoagulation in the Asia-Pacific, Eastern Europe, the Middle East, Africa and Latin America.

INTRODUCTION: The prospective, non-interventional XALIA study investigated the safety and effectiveness of rivaroxaban and standard anticoagulation for the treatment of deep vein thrombosis (DVT). XALIA-LEA was conducted in regions not included in XALIA (Latin America, Eastern Europe, the Middle East, Africa, and the Asia-Pacific), and enrolled patients with isolated pulmonary embolism (PE). MATERIALS AND METHODS: Adult patients with acute venous thromboembolism (VTE) indicated for ≥3 months' anticoagulant treatment were eligible; treatment strategies were at the physician's discretion. Patients receiving rivaroxaban or standard anticoagulation (unfractionated or low-molecular weight heparin/fondaparinux alone or overlapping with and followed by a vitamin K antagonist [VKA]) were included in the safety analysis. "Early switchers" to rivaroxaban (i.e. after receiving heparin/fondaparinux for >2-14 days and/or a VKA for 1-14 days) were not included in the safety analysis set. RESULTS: Of the 1972 eligible patients, 1285 received rivaroxaban, 402 received standard anticoagulation, and 285 were early switchers. Most patients who received rivaroxaban were appropriately selected, received the correct dosing schedule, reported few adverse effects. Outcomes were similar to previously published results, with rivaroxaban associated with a low rate of major bleeding (1.6%), recurrent VTE (1.4%) and all-cause mortality (2.3%). Including early switchers, relatively fewer patients with index isolated PE received rivaroxaban (14.4%) versus standard anticoagulation therapy (20.9%). Some regional variations and differences in outcomes by VTE subtype were apparent with standard anticoagulation treatment. CONCLUSION: XALIA-LEA reaffirms the safety and effectiveness of rivaroxaban for VTE treatment for countries not included in XALIA.

Healthcare resource use in XALIA: A subgroup analysis of a non-interventional study of rivaroxaban versus standard anticoagulation for deep vein thrombosis.

INTRODUCTION: The non-interventional XALIA study compared the safety and effectiveness of rivaroxaban with standard anticoagulation for the treatment of venous thromboembolism in routine clinical practice. This substudy assessed the effect of treatment with rivaroxaban on healthcare resource use, hospital length of stay (LOS) and frequency of hospitalisation. METHODS: In XALIA, patients aged ≥18 years scheduled to receive ≥3 months of rivaroxaban or standard anticoagulation treatment for deep vein thrombosis (DVT) were eligible. Treatment decisions were at the physician's discretion. Healthcare resource use, including hospital admission for the index DVT and initial LOS, was documented. The main analyses in this substudy were conducted in a 1:1 propensity score-matched set (PMS) of patients, with adjustment for cancer at baseline. RESULTS: In the PMS analysis, 1124 rivaroxaban-treated patients and 1124 standard anticoagulation-treated patients were included. Baseline characteristics were similar between groups (mean age 60.8 years vs. 61.2 years, DVT only rates of 89.7% vs. 90.2% and cancer rates of 8.4% vs. 8.5%, respectively). Of these, 433/1124 (38.5%) rivaroxaban-treated patients and 438/1124 (39.0%) standard anticoagulation-treated patients were hospitalised. Index event LOS in the PMS analysis was a least-squares mean of 2.6 days shorter with rivaroxaban vs. standard anticoagulation (5.4 vs. 8.0 days; geometric means ratio = 0.67 [95% confidence interval 0.61-0.74, P < 0.001]). CONCLUSIONS: In XALIA, hospital LOS was shorter with rivaroxaban than with standard anticoagulation, consistent with the phase III study results. DVT treatment with rivaroxaban in routine clinical practice may reduce the cost per patient vs. standard anticoagulation.

Real-world vs. randomized trial outcomes in similar populations of rivaroxaban-treated patients with non-valvular atrial fibrillation in ROCKET AF and XANTUS.

AIMS: Based on Phase III data, non-vitamin K antagonist oral anticoagulants are recommended for stroke prevention in patients with atrial fibrillation. To determine whether trial outcomes translate into similar event rates in unselected patients, this analysis compared outcomes from the real-world XANTUS study with those from the Phase III ROCKET AF study. METHODS AND RESULTS: Individual patient data from 4020 XANTUS patients were re-weighted to match the proportion of selected baseline characteristics in 7061 rivaroxaban-treated patients from ROCKET AF, using the matching-adjusted indirect comparison (MAIC) method. For the primary analysis, CHADS2 scores and gender were selected as relevant variables. Adjusted annualized incidence rates for XANTUS were calculated and compared with incidence rates from ROCKET AF-the ratio of these rates ('MAIC ratio') was used as a relative effect estimate. Rates of major bleeding [3.10%/year vs. 3.60%/year; MAIC ratio 0.86; 95% confidence interval (CI) 0.67-1.12] and stroke/non-central nervous system systemic embolism (1.54%/year vs. 1.70%/year; MAIC ratio 0.91; 95% CI 0.62-1.32) were similar between XANTUS and ROCKET AF. The rate of all-cause death was higher in XANTUS (3.22%/year vs. 1.87%/year; MAIC ratio 1.72; 95% CI 1.31-2.27), but the rates of vascular death were similar (1.83%/year vs. 1.53%/year; MAIC ratio 1.19; 95% CI 0.84-1.70). Sensitivity analyses weighted by different baseline characteristics supported these results. CONCLUSION: The low rates of major bleeding and stroke in XANTUS were consistent with results from ROCKET AF. All-cause death, but not vascular death, was higher in XANTUS, as expected in an unselected real-world population.

Effectiveness and safety of rivaroxaban versus warfarin in patients with provoked venous thromboembolism.

A paucity of real-world data evaluating rivaroxaban in provoked venous thromboembolism (VTE) exists. We assessed the effectiveness and safety of rivaroxaban versus warfarin in provoked VTE patients treated in routine practice. Using MarketScan claims data from 1/2012 to 12/2016, we identified adults who had ≥ 1 primary hospitalization/emergency department discharge diagnosis code for VTE (index event) and a provoking factor, received rivaroxaban or warfarin as their first outpatient oral anticoagulant within 30-days of the index event and had ≥ 12-month of insurance coverage prior the index VTE. Provoking factors included cancer, hospital admission for ≥ 3-consecutive days over the prior 3-months, major surgery, trauma or fracture within 90-days or pregnancy within 42-weeks of the index VTE. Differences in baseline covariates between cohorts were adjusted using inverse probability-of-treatment weights based on propensity-scores (residual standardized differences < 0.1 achieved for all covariates after adjustment). The incidence of the composite endpoint of recurrent VTE or major bleeding at 3- and 6-months was compared using Cox regression and reported as hazard ratios (HRs) and 95% confidence intervals (CIs). We included 4454 rivaroxaban and 13,164 warfarin users with provoked VTE. At 3- and 6-months, rivaroxaban was associated with a reduced hazard of the composite endpoint (HR 0.72, 95% CI 0.61-0.84 and HR 0.69, 95% CI 0.60-0.80) and recurrent VTE (HR 0.70, 95% CI 0.59-0.84 and HR 0.71, 95% CI 0.60-0.84) versus warfarin. Major bleeding was non-significantly reduced at 3-months (HR 0.77, 95% CI 0.57-1.06) and significantly reduced at 6-months (HR 0.68, 95% CI 0.53-0.88) with rivaroxaban. Rivaroxaban reduces recurrent VTE and major bleeding risk versus warfarin in provoked VTE patients treated in routine practice.

Effectiveness and Safety of Rivaroxaban Versus Warfarin in Frail Patients with Venous Thromboembolism.

PURPOSE: Frailty predicts poorer outcomes in patients receiving anticoagulation. We assessed the effectiveness and safety of rivaroxaban vs warfarin in frail patients experiencing venous thromboembolism. METHODS: Using US MarketScan claims data from January 2012-December 2016, we identified frail patients (using the Johns Hopkins Claims-Based Frailty Indicator score) who had ≥1 primary hospitalization/emergency department visit diagnosis codes for venous thromboembolism, received rivaroxaban or warfarin as their first outpatient oral anticoagulant within 30 days of the index event, and had ≥12 months of insurance prior to the index venous thromboembolism. Differences in baseline covariates between cohorts were adjusted using inverse probability of treatment weights based on propensity scores. The primary endpoint was the composite of recurrent venous thromboembolism or major bleeding. Patient claims were tracked for up to 12 months after the index venous thromboembolism or until endpoint occurrence oral anticoagulant discontinuation/switch, insurance disenrollment, or end of follow-up. Cox regression was used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: Of 58,089 incident venous thromboembolism patients identified, 6869 (1365 rivaroxaban and 5504 warfarin users) were classified as frail. Rivaroxaban reduced patients' hazard of the composite of recurrent venous thromboembolism or major bleeding (HR 0.75; 95% CI, 0.57-0.98) and recurrent venous thromboembolism alone (HR 0.65; 95% CI, 0.44-0.97) compared with warfarin. No significant difference in major bleeding was observed between cohorts (HR 0.88; 95% CI, 0.61-1.27). CONCLUSIONS: Frail patients experiencing a venous thromboembolism and given rivaroxaban experience less recurrent venous thromboembolism, with at least as good bleeding outcomes, as patients prescribed warfarin.

Effectiveness and safety of outpatient rivaroxaban versus warfarin for treatment of venous thromboembolism in patients with a known primary hypercoagulable state.

INTRODUCTION: Screening for primary hypercoagulable states (PHSs) in venous thromboembolism (VTE) patients was not mandated in the EINSTEIN trials; and therefore, few patients with a known PHS were available for analysis. We sought to assess the effectiveness and safety of rivaroxaban versus warfarin for treatment of VTE in patients with a known PHS. METHODS: Using MarketScan claims data from 1/2012-9/2015, we identified adults with a primary diagnosis of VTE during a hospitalization/emergency department visit (the index event), with ≥180-days of continuous insurance coverage prior to the index event, a documented diagnosis for a PHS and newly-initiated as an outpatient on rivaroxaban or warfarin within 30-days of the index VTE. Rivaroxaban and warfarin users were 1:1 propensity-score matched. Balance between cohorts was evaluated by inspecting standardized differences for baseline covariates (<0.1 considered well-balanced). Patients were followed up to 12-months from the index event or until occurrence of an endpoint, switch/discontinuation of index oral anticoagulation or insurance disenrollment. Rates of recurrent VTE and major bleeding were compared using Cox regression and reported as hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: We matched 403 rivaroxaban and 403 warfarin patients with VTE and a known PHS. All baseline covariates had a standardized difference < 0.1. Rivaroxaban use was associated with a non-significant reduction in recurrent VTE (HR = 0.70, 95%CI = 0.33-1.49) and major bleeding (HR = 0.55, 95%CI = 0.16-1.86) versus warfarin. CONCLUSIONS: In routine practice, the effectiveness and safety of rivaroxaban versus warfarin in VTE patients with a known PHS appears to be similar to that observed in the EINSTEIN trial program.

A post-marketing assessment of major bleeding in total hip and total knee replacement surgery patients receiving rivaroxaban.

BACKGROUND: Rivaroxaban is a novel oral anticoagulant indicated for prophylaxis against deep vein thrombosis and pulmonary embolism in patients undergoing total hip replacement (THR) or total knee replacement (TKR) surgery. OBJECTIVE: To evaluate major bleeding (MB) in THR/TKR patients receiving post-operative rivaroxaban. METHODS: Electronic medical records of nearly 10 million US Department of Defense (DoD) beneficiaries were queried from 1 January 2013 through 30 June 2015. Using the validated Cunningham case-finding algorithm, post-surgical MB events in rivaroxaban users were identified and analyzed. The incidence of MB was determined, and descriptive statistics were used to compare patient characteristics and other covariates in those with and without MB. Two additional methods were used to explore and identify bleeding cases that were not considered MB events per the study case-finding algorithm. RESULTS: A total of 12,429 patients received THR and/or TKR surgery, and were post-operatively prescribed rivaroxaban. Nine patients had MB, yielding an incidence proportion of 0.07% (95% CI 0.02-0.13). The alternative case-finding methods found bleeding incidences of 0.46% and 0.21%, though it is not clear whether these are clinical MB cases, since the alternative methods were not validated. CONCLUSIONS: The incidence of MB in this retrospective analysis is lower than that observed in the clinical trials of rivaroxaban. Whether this is due to lower real-world MB rates or challenges with case-finding algorithms is unclear.

Effectiveness and safety of rivaroxaban versus warfarin for treatment and prevention of recurrence of venous thromboembolism.

The efficacy and safety or rivaroxaban versus enoxaparin/vitamin K antagonist for treatment and prevention recurrence of venous thromboembolism (VTE) was demonstrated in the randomised EINSTEIN trials. We assessed the effectiveness and safety of rivaroxaban versus warfarin in VTE patients managed in routine practice. Using US MarketScan claims from 1/2012-6/2015, we included adults with a primary diagnosis of deep vein thrombosis (DVT) or pulmonary embolism (PE) during a hospitalisation/emergency department visit, newly-initiated on rivaroxaban or warfarin within 30-days after the VTE and with ≥180-days of continuous medical/prescription benefits prior to the VTE (baseline). Patients with a claim for anticoagulation at baseline were excluded. Recurrent VTE, major bleeding, intracranial haemorrhage (ICH) and gastrointestinal bleeding (GIB) were assessed. Differences in baseline characteristics between cohorts were adjusted for using inverse probability of treatment weights based on propensity-scores. Patients had a maximum of 12-months period of follow-up post-VTE or until endpoint occurrence, switch/discontinuation of index anticoagulation, insurance disenrollment or end-of-follow-up. Cox regression was performed and reported as hazard ratios (HRs) with 95 % confidence intervals (CIs). In total, 13,609 rivaroxaban and 32,244 warfarin users experiencing VTE were included. Rivaroxaban was associated with an 19 % (95 %CI=10-27 %) reduction in recurrent VTE and a 21 % (95 %CI=4-35 %) reduction in major bleeding hazard versus warfarin. Rivaroxaban was also associated with significantly decreased hazards of ICH (HR=0.40) and GIB (HR=0.72). Rivaroxaban appears to reduce patients' hazard of both recurrent VTE and major bleeding in routine practice. These results appear consistent with EINSTEIN and post-marketing registry studies.

Analysis of patients with deep vein thrombosis switched from standard therapy to rivaroxaban in the non-interventional XALIA study.

INTRODUCTION: XALIA assessed the safety and effectiveness of rivaroxaban for deep vein thrombosis (DVT) treatment in routine clinical practice. This substudy describes the clinical characteristics and outcomes of 'early switchers' - patients who received heparin or fondaparinux for >2-14days and/or a vitamin K antagonist (VKA) for 1-14days before switching to rivaroxaban. MATERIALS AND METHODS: Patients with DVT (latterly with concomitant pulmonary embolism) received rivaroxaban or standard anticoagulation (initial treatment with heparin or fondaparinux, usually overlapping with and followed by a VKA). Patients administered rivaroxaban alone, or heparin or fondaparinux for ≤48h pre-enrollment were included in the rivaroxaban cohort. Therapy type, dose, and duration were at the physician's discretion. Primary outcomes were major bleeding, recurrent venous thromboembolism (VTE), and all-cause mortality. RESULTS: In 368 early switchers, recurrence or bleeding risk factors were more prevalent versus the rivaroxaban cohort, including creatinine clearance<50mL/min (6.5% vs. 3.9%), previous major bleeding (4.6% vs. 1.4%), active cancer (8.2% vs. 5.6%), and concomitant pulmonary embolism (20.9% vs. 8.4%). Crude incidence rates were numerically higher versus the rivaroxaban cohort for major bleeding (1.4% vs. 0.7%), recurrent VTE (2.2% vs. 1.4%), and all-cause mortality (0.8% vs. 0.5%). CONCLUSIONS: Patients who switched to rivaroxaban early in the treatment process had a higher frequency of risk factors for bleeding and recurrent VTE than patients treated with rivaroxaban; reflected by the higher risk of adverse events in that group during follow-up.

Impact of Switching From a Vitamin K Antagonist to Rivaroxaban on Satisfaction With Anticoagulation Therapy: The XANTUS-ACTS Substudy.

BACKGROUND: The efficacy, safety, and ease of use of rivaroxaban may reduce anticoagulation-treatment burden and improve nonvalvular atrial fibrillation (NVAF) patient satisfaction compared with vitamin K antagonists (VKAs). HYPOTHESIS: Transitioning from a VKA to rivaroxaban improves treatment satisfaction in routine practice. METHODS: Xarelto for Prevention of Stroke in Patients With Atrial Fibrillation (XANTUS) is a prospective, noninterventional study in patients with NVAF prescribed rivaroxaban for prevention of stroke in routine practice. Patients receiving a VKA 4 weeks prior to the initial XANTUS study visit and switched to rivaroxaban were asked to complete the Anti-Clot Treatment Scale (ACTS). Changes from the initial visit to the first follow-up visit at ∼ 3 months (corresponding to a comparison of rivaroxaban vs prior VKA) for ACTS burden and benefit scores were calculated using and reported as least squared mean differences (LSMDs) with 95% confidence intervals (CIs). RESULTS: The study included 1291 NVAF patients with prior VKA treatment. The mean baseline ACTS burden and benefit scores were 50.51 ± 8.42 and 10.30 ± 2.70, respectively. After ∼ 3 months of rivaroxaban treatment, LSMDs were 4.38 points (95% CI: 2.53-6.22, P < 0.0001) for the burden and 1.01 points (95% CI: 0.27-1.75, P = 0.0075) for the benefit score. Fifty-four percent and 48% of patients reported experiencing at least a minimally important clinical difference in burden and benefit scores, respectively. CONCLUSIONS: Within this XANTUS cohort, switching from a VKA to rivaroxaban yielded statistically and clinically significant improvements in ACT burden and benefit scores.

Bivariate evaluation of thromboembolism and bleeding in clinical trials of anticoagulants in patients with atrial fibrillation.

Clinical trials of antithrombotic therapy require a cohesive assessment of benefit and risk. A new graphical method to represent the bivariate relation of benefit and risk in trials of antithrombotic drugs is described and illustrated using published data from the four major registration clinical trials of non-vitamin K oral anticoagulants (NOACs) totalling 71,683 patients for prevention of thromboembolic events (TE) in patients with atrial fibrillation (RE-LY, ROCKET AF, ARISTOTLE, and ENGAGE-AF TIMI48). A curve representing a null hypothesis defines a region of benefit on a two-dimensional plane. Trial results are summarised by a rectangle defined by standard 95 % confidence intervals (CI) for thrombosis and bleeding risks. Benefit is judged by whether the confidence rectangle contains the null curve. The treatment effect is measured by the distance from the null curve to the opposing corners of the confidence rectangle (termed "corner distance (CD)"). Across trials NOACs reduced the absolute risk of TE compared to warfarin by 0.30 % (95 % CI: -0.56 % to -0.05 %) and reduced major bleeding by 0.88 % (95 % CI: -1.26 % to -0.51 %). Bivariate evaluation showed NOAC superiority to warfarin overall and elucidated dose differences; low dose edoxaban increased bivariate TE-bleeding risk 0.08 % (CD = -0.85 % to 0.78 %), whereas high dose edoxaban reduced risk 1.41 % (CD = -2.07 % to -0.70 %). In conclusion, bivariate evaluation facilitates visual assessment of the safety-efficacy profile of antithrombotic drugs. Its application to trials in atrial fibrillation found NOACs superior to warfarin without substantial differences between agents.

Safety and effectiveness of oral rivaroxaban versus standard anticoagulation for the treatment of symptomatic deep-vein thrombosis (XALIA): an international, prospective, non-interventional study.

BACKGROUND: The efficacy and safety of the anticoagulant rivaroxaban for the treatment and secondary prevention of deep-vein thrombosis and pulmonary embolism has been shown in phase 3 trials. However, data about rivaroxaban use in routine clinical practice are needed. METHODS: XA inhibition with rivaroxaban for Long-term and Initial Anticoagulation in venous thromboembolism (XALIA) was a multicentre, international, prospective, non-interventional study of patients with deep-vein thrombosis, done in hospitals and community care centres in 21 countries. The study investigated the safety and effectiveness of rivaroxaban compared with standard anticoagulation therapy (initial treatment with unfractionated heparin, low-molecular-weight heparin, or fondaparinux, usually overlapping with and followed by a vitamin K antagonist) for at least 3 months. Eligible patients were adults (aged ≥18 years) with an objectively confirmed diagnosis of deep-vein thrombosis, and an indication to receive anticoagulation treatment for at least 3 months. Following approval of rivaroxaban for the pulmonary embolism indication, patients with deep-vein thrombosis and concomitant pulmonary embolism were also eligible; however, those with isolated pulmonary embolism were not included. Type, dose, and duration of therapy for each patient were at the physician's discretion. The primary effectiveness and safety outcomes were major bleeding, recurrent venous thromboembolism, and all-cause mortality. Propensity score-adjusted analyses were done to account for potential imbalances between groups. This study is registered with ClinicalTrials.gov, number NCT01619007. FINDINGS: Between June 26, 2012, and March 31, 2014, 5142 patients were enrolled. The safety population (all patients who received at least one dose of the anticoagulant of interest) comprised 2619 patients in the rivaroxaban group and 2149 in the standard anticoagulant therapy group. Patients in the rivaroxaban group were younger and fewer had active cancer or concomitant pulmonary embolism than those in the standard anticoagulation group. In the propensity score-adjusted population, the frequency of major bleeding was 0·8% (19/2505) in the rivaroxaban group and 2·1% (43/2010) in the standard anticoagulation group, with a propensity score-adjusted hazard ratio (HR) of 0·77 (95% CI 0·40-1·50); p=0·44. The frequency of recurrent venous thromboembolism was 1·4% (36/2505) in the rivaroxaban group and 2·3% (47/2010) in the standard anticoagulation group (propensity score-adjusted HR 0·91 [95% CI 0·54-1·54], p=0·72). The all-cause mortality frequency was 0·4% (11/2505) in the rivaroxaban group and 3·4% (69/2010) in the standard anticoagulation group (propensity score-adjusted HR 0·51 [95% CI 0·24-1·07], p=0·074). The incidence of treatment-emergent adverse events in the safety population was similar between the two groups (944 [36·0%] of 2619 in the rivaroxaban group vs 805 [37·5%] of 2149 in the standard anticoagulation group). INTERPRETATION: In routine clinical practice, rivaroxaban-treated patients had a lower risk profile at baseline than those treated with standard anticoagulation. Propensity score-adjusted results confirm that rivaroxaban is a safe and effective alternative to standard anticoagulation therapy in a broad range of patients. Rates of major bleeding and recurrent venous thromboembolism were low in rivaroxaban-treated patients and consistent with phase 3 findings. FUNDING: Bayer HealthCare Pharmaceuticals and Janssen Research & Development, LLC.

XANTUS: a real-world, prospective, observational study of patients treated with rivaroxaban for stroke prevention in atrial fibrillation.

AIMS: Although non-vitamin K antagonist oral anticoagulants are recommended for stroke prevention in patients with non-valvular atrial fibrillation (NVAF) based on clinical trial results, there is a need for safety and efficacy data from unselected patients in everyday clinical practice. XANTUS investigated the safety and efficacy of the Factor Xa inhibitor rivaroxaban in routine clinical use in the NVAF setting. METHODS AND RESULTS: Consecutive consenting patients with NVAF newly started on rivaroxaban were eligible and were followed up at ∼3-month intervals for 1 year, or for at least 30 days after permanent discontinuation. All adverse events (AEs) were recorded as AEs or serious AEs; major outcomes (including major bleeding, symptomatic thromboembolic events [stroke, systemic embolism, transient ischaemic attack, and myocardial infarction], and all-cause death) were centrally adjudicated. There were 6784 patients treated with rivaroxaban at 311 centres in Europe, Israel, and Canada. Mean patient age was 71.5 years (range 19-99), 41% were female, and 9.4% had documented severe or moderate renal impairment (creatinine clearance <50 mL/min). The mean CHADS2 and CHA2DS2-VASc scores were 2.0 and 3.4, respectively; 859 (12.7%) patients had a CHA2DS2-VASc score of 0 or 1. The mean treatment duration was 329 days. Treatment-emergent major bleeding occurred in 128 patients (2.1 events per 100 patient-years), 118 (1.9 events per 100 patient-years) died, and 43 (0.7 events per 100 patient-years) suffered a stroke. CONCLUSION: XANTUS is the first international, prospective, observational study to describe the use of rivaroxaban in a broad NVAF patient population. Rates of stroke and major bleeding were low in patients receiving rivaroxaban in routine clinical practice. TRIAL REGISTRATION NUMBER: Clinicaltrials.gov: NCT01606995.

Rivaroxaban compared with standard thromboprophylaxis after major orthopaedic surgery: co-medication interactions.

AIM: The aim of the present study was to analyse concomitant drug use and its association with outcome in patients (N = 17 701) receiving rivaroxaban or standard of care (SOC) for the prevention of venous thromboembolism after major orthopaedic surgery in the non-interventional, phase IV XAMOS (Xarelto® in the prophylaxis of post-surgical venous thromboembolism after elective major orthopaedic surgery of hip or knee) study. METHODS: Concomitant drug use was at the discretion of the treating physician. Prespecified co-medications of interest were cytochrome P450 (CYP) 3A4/P-glycoprotein inhibitors/inducers, platelet aggregation inhibitors (PAIs) and nonsteroidal anti-inflammatory drugs (NSAIDs). Crude event incidences were compared between rivaroxaban and SOC groups. RESULTS: CYP3A4/P-glycoprotein inhibitor/inducer use was infrequent, in contrast to PAI (~7%) and NSAID (~52%) use. Rivaroxaban was associated with a lower incidence of overall symptomatic thromboembolic events compared with SOC, regardless of co-medication use. In both treatment groups, PAI users, with higher age and prevalence of cardiovascular co-morbidities, had similar higher (>7-fold) incidences of symptomatic arterial but not venous thromboembolic events compared with non-users. NSAID use had no influence on thromboembolic events. However, odds ratios (ORs) for major bleeding events (European Medicines Agency definition) were higher in NSAID users compared with non-users in rivaroxaban [OR = 1.50; 95% confidence interval (CI) 1.06, 2.13] and SOC (OR = 1.70; CI 1.16, 2.49) groups. In PAI users, ORs for major bleeding events were no different from those of non-users in both the rivaroxaban (OR = 1.49; CI 0.84, 2.65) and SOC (OR = 1.46; CI 0.82, 2.62) groups. CONCLUSIONS: Use of NSAIDs in XAMOS was frequent and associated with a higher frequency of bleeding events in patients receiving rivaroxaban or SOC, although the benefit-risk profile of rivaroxaban compared with SOC was maintained.

Trends in Prescribing Oral Anticoagulants in Canada, 2008-2014.

PURPOSE: The non-vitamin K antagonist oral anticoagulants (NOACs), dabigatran, rivaroxaban, and apixaban, provide several advantages over vitamin K antagonists, such as warfarin. Little is known about the trends of prescribing OACs in Canada. In this study we analyzed changes in prescription volumes for OAC drugs since the introduction of the NOACs in Canada overall, by province and by physician specialty. METHODS: Canadian prescription volumes for warfarin, dabigatran, rivaroxaban, and apixaban from January 2008 to June 2014 were obtained from the Canadian Compuscript Audit of IMS Health Canada Inc and were analyzed by physician specialty at the national and provincial levels. Total prescriptions by indication were calculated based on data from the Canadian Disease and Therapeutic Index for all OAC indications and for each commonly prescribed dose of dabigatran (75, 110, and 150 mg), rivaroxaban (10, 15, and 20 mg), and apixaban (2.5 and 5 mg). FINDINGS: The overall number of OAC prescriptions in Canada has increased annually since 2008. With the availability of the NOACs, the proportion of total OAC prescriptions attributable to warfarin has steadily decreased, from 99% in 2010 to 67% by June 2014, and the absolute number of warfarin prescriptions has been decreasing since February 2011. The greatest decline in proportionate warfarin prescriptions was in Ontario. In general, the increase of NOAC prescriptions coincided with the introduction of provinces' reimbursement of NOAC prescription costs. The proportion of total OAC prescriptions represented by the NOACs varied by specialty, with the greatest proportionate prescribing found among orthopedic surgeons, cardiologists, and neurologists. IMPLICATIONS: Since their approval, the NOACs have represented a growing share of total OAC prescriptions in Canada. This trend is expected to continue because the NOACs are given preference over warfarin in guidelines on stroke prevention in patients with atrial fibrillation, because of growing physician experience, and due to the emergence of potential new indications. An understanding of the current prescribing patterns will help to encourage knowledge translation and possibly influence policy/reimbursement strategies.

XANTUS: rationale and design of a noninterventional study of rivaroxaban for the prevention of stroke in patients with atrial fibrillation.

Atrial fibrillation (AF) is associated with a fivefold increase in the risk of stroke. The Phase III ROCKET AF (Rivaroxaban Once-Daily Oral Direct Factor Xa Inhibition Compared with Vitamin K Antagonism for Prevention of Stroke and Embolism Trial in Atrial Fibrillation) trial showed that rivaroxaban, an oral, direct Factor Xa inhibitor, was noninferior to warfarin for the reduction of stroke or systemic embolism in patients with AF. Compared with warfarin, rivaroxaban significantly reduced rates of intracranial and fatal hemorrhages, although not rates of bleeding overall. XANTUS (Xarelto(®) for Prevention of Stroke in Patients with Atrial Fibrillation) is a prospective, international, observational, postauthorization, noninterventional study designed to collect safety and efficacy data on the use of rivaroxaban for stroke prevention in AF in routine clinical practice. The key goal is to determine whether the safety profile of rivaroxaban established in ROCKET AF is also observed in routine clinical practice. XANTUS is designed as a single-arm cohort study to minimize selection bias, and will enroll approximately 6,000 patients (mostly from Europe) with nonvalvular AF prescribed rivaroxaban, irrespective of their level of stroke risk. Overall duration of follow-up will be 1 year; the first patient was enrolled in June 2012. Similar studies (XANTUS-EL [Xarelto(®) for Prevention of Stroke in Patients with Nonvalvular Atrial Fibrillation, Eastern Europe, Middle East, Africa and Latin America] and XANAP [Xarelto(®) for Prevention of Stroke in Patients with Atrial Fibrillation in Asia-Pacific]) are ongoing in Latin America and Asia-Pacific. Data from these studies will supplement those from ROCKET AF and provide practical information concerning the use of rivaroxaban for stroke prevention in AF.

Oral anticoagulant use in addition to antiplatelet therapy for secondary prevention in acute coronary syndrome: current perspectives.

Patients with acute coronary syndrome (ACS) are typically managed with long-term dual antiplatelet therapy of acetylsalicylic acid plus a P2Y12 platelet receptor antagonist; however, although effective, the risk of another vascular event within 12 months remains at approximately 10%. Considerable efforts have been made to find improved therapeutic approaches to secondary prevention in ACS. The ATLAS ACS 2-TIMI 51 trial demonstrated that rivaroxaban (2.5 mg twice daily) significantly reduced recurrent vascular events, increased the risk of major bleeding but not the risk of fatal bleeding, and resulted in reduced rates of death from cardiovascular causes. These results formed the basis for approval in Europe of rivaroxaban (2.5 mg twice daily) in conjunction with standard antiplatelet therapy for the secondary prevention of ACS.

Benefit-risk assessment of rivaroxaban versus enoxaparin for the prevention of venous thromboembolism after total hip or knee arthroplasty.

PURPOSE: Venous thromboembolism is a common complication after major orthopedic surgery. When prescribing anticoagulant prophylaxis, clinicians weigh the benefits of thromboprophylaxis against bleeding risk and other adverse events. Previous benefit-risk analyses of the REgulation of Coagulation in ORthopaedic surgery to prevent Deep vein thrombosis and pulmonary embolism (RECORD) randomized clinical studies of rivaroxaban versus enoxaparin after total hip (THA) or knee (TKA) arthroplasty generally used pooled THA and TKA results, counted fatal bleeding as both an efficacy and a safety event, and included the active and placebo-controlled portions of RECORD2, which might confound benefit-risk assessments. We conducted a post hoc analysis without these constraints to assess benefit-risk for rivaroxaban versus enoxaparin in the RECORD studies. PATIENTS AND METHODS: Data from the safety population of the two THA and two TKA studies were pooled separately. The primary analysis compared the temporal course of event rates and rate differences between rivaroxaban and enoxaparin prophylaxis for symptomatic venous thromboembolism plus all-cause mortality (efficacy events) versus nonfatal major bleeding (safety events). Additionally, these rates were used to derive measures of net clinical benefit, number needed to treat (NNT), and number needed to harm (NNH) for these two end points. RESULTS: After THA or TKA, and compared with enoxaparin, rivaroxaban therapy resulted in more efficacy events prevented than safety events caused, with benefits exceeding harms early and throughout treatment and follow-up. Relative to enoxaparin, rivaroxaban treatment prevented six efficacy events per harm event caused for THA, with NNT =262/NNH =1,711. For TKA, rivaroxaban treatment prevented four to five efficacy events per harm event caused, with NNT =102/NNH =442. Sensitivity analysis that included surgical-site bleeding resulted in NNH =345 for THA and NNH =208 for TKA. CONCLUSION: In the RECORD studies, considering death, symptomatic venous thromboembolism, and major bleeding, rivaroxaban resulted in greater benefits than harms compared with enoxaparin. When incorporating surgical-site bleeding, rivaroxaban also results in greater benefit than harm for TKA and is balanced with enoxaparin for THA.

A non-interventional comparison of rivaroxaban with standard of care for thromboprophylaxis after major orthopaedic surgery in 17,701 patients with propensity score adjustment.

Rivaroxaban demonstrated superior efficacy and a similar safety profile to enoxaparin for the prevention of venous thromboembolism in the phase III RECORD programme in patients undergoing elective hip or knee replacement surgery. The XAMOS study investigated adverse events, including bleeding and thromboembolic events, in patients receiving rivaroxaban for thromboprophylaxis in routine clinical practice. XAMOS was a non-interventional, open-label cohort study in patients undergoing major orthopaedic surgery of the hip or knee (predominantly elective arthroplasty), in which rivaroxaban was compared with other pharmacological thromboprophylaxis. All adverse events were documented, including symptomatic thromboembolic and bleeding events. Crude and adjusted incidences based on propensity score subclasses were calculated and compared between the rivaroxaban and standard-of-care groups. A total of 17,701 patients were enrolled from 252 centres in 37 countries. Crude incidences of symptomatic thromboembolic events three months after surgery in the safety population were 0.89% in the rivaroxaban group (n=8,778) and 1.35% in the standard-of-care group (n=8,635; odds ratio [OR] 0.65; 95% confidence interval [CI] 0.49-0.87), and 0.91% and 1.31% (weighted) in the propensity score-adjusted analysis (OR 0.69; 95% CI 0.56-0.85), respectively. Treatment-emergent major bleeding events (as defined in the RECORD studies) occurred in 0.40% and 0.34% of patients in the rivaroxaban and standard-of-care groups in the safety population (OR 1.19; 95% CI 0.73-1.95), and in 0.44% versus 0.33% (weighted) in the propensity score-adjusted analysis (OR 1.35; 95% CI 0.94-1.93), respectively.This study in unselected patients confirmed the favourable benefit-risk profile of rivaroxaban seen in the RECORD programme.

Venous thromboembolism management: where do novel anticoagulants fit?

OBJECTIVE: To review novel oral anticoagulant (NOAC) trials in the treatment of venous thromboembolism (VTE) and the possible use of risk-stratification tools to guide their use in practice. SCOPE: MEDLINE and Cochrane databases were searched to identify relevant journal articles published from January 1982 to February 2013. Additional references were obtained from articles extracted during the database search. FINDINGS: NOACs have been developed to optimize VTE management and overcome the limitations of heparin and vitamin K antagonists (VKA). The AMPLIFY and EINSTEIN trials of apixaban and rivaroxaban, respectively, investigated single-drug management of VTE, whereas the edoxaban Hokusai-VTE trial and dabigatran RE-COVER and RE-COVER II trials investigated the use of NOACs with a heparin lead-in. The AMPLIFY and Hokusai-VTE trials are ongoing but the EINSTEIN and RE-COVER trials have demonstrated that rivaroxaban and dabigatran, respectively, are non-inferior to parenteral anticoagulants and warfarin in the management of VTE. Differences in study design complicate the application of study results to clinical practice. There are multiple validated DVT protocols that effectively and safely treat patients in outpatient settings. The pulmonary embolism (PE) severity index (PESI), simplified PESI (sPESI), and other prognostic tools have been used to risk stratify patients with PE by estimating mortality risk to guide outpatient eligibility. CONCLUSIONS: NOACs provide physicians with new therapeutic options in the management of VTE. While heparin and VKAs compose the current standard treatment for VTE, their use will likely disappear as physicians grow comfortable with the adoption of NOACs. As studies have not clearly defined the efficacy of these agents in certain patient populations, further data in special patient populations and risk stratification through the use of VTE severity scores could potentially be adapted to guide anticoagulant management and outpatient treatment eligibility.