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Featured researches published by At Cohen.


The New England Journal of Medicine | 2016

Andexanet Alfa for Acute Major Bleeding Associated with Factor Xa Inhibitors

Stuart J. Connolly; Truman J. Milling; John W. Eikelboom; C. Michael Gibson; John T. Curnutte; Alex Gold; Michele D. Bronson; Genmin Lu; Pamela B. Conley; Peter Verhamme; Jeannot Schmidt; Saskia Middeldorp; At Cohen; Jan Beyer-Westendorf; Pierre Albaladejo; Jose Lopez-Sendon; Shelly Goodman; Janet Leeds; Brian Wiens; Deborah M. Siegal; Elena Zotova; Brandi Meeks; Juliet Nakamya; W. Ting Lim; Mark Crowther

BACKGROUNDnAndexanet alfa (andexanet) is a recombinant modified human factor Xa decoy protein that has been shown to reverse the inhibition of factor Xa in healthy volunteers.nnnMETHODSnIn this multicenter, prospective, open-label, single-group study, we evaluated 67 patients who had acute major bleeding within 18 hours after the administration of a factor Xa inhibitor. The patients all received a bolus of andexanet followed by a 2-hour infusion of the drug. Patients were evaluated for changes in measures of anti-factor Xa activity and were assessed for clinical hemostatic efficacy during a 12-hour period. All the patients were subsequently followed for 30 days. The efficacy population of 47 patients had a baseline value for anti-factor Xa activity of at least 75 ng per milliliter (or ≥0.5 IU per milliliter for those receiving enoxaparin) and had confirmed bleeding severity at adjudication.nnnRESULTSnThe mean age of the patients was 77 years; most of the patients had substantial cardiovascular disease. Bleeding was predominantly gastrointestinal or intracranial. The mean (±SD) time from emergency department presentation to the administration of the andexanet bolus was 4.8±1.8 hours. After the bolus administration, the median anti-factor Xa activity decreased by 89% (95% confidence interval [CI], 58 to 94) from baseline among patients receiving rivaroxaban and by 93% (95% CI, 87 to 94) among patients receiving apixaban. These levels remained similar during the 2-hour infusion. Four hours after the end of the infusion, there was a relative decrease from baseline of 39% in the measure of anti-factor Xa activity among patients receiving rivaroxaban and of 30% among those receiving apixaban. Twelve hours after the andexanet infusion, clinical hemostasis was adjudicated as excellent or good in 37 of 47 patients in the efficacy analysis (79%; 95% CI, 64 to 89). Thrombotic events occurred in 12 of 67 patients (18%) during the 30-day follow-up.nnnCONCLUSIONSnOn the basis of a descriptive preliminary analysis, an initial bolus and subsequent 2-hour infusion of andexanet substantially reduced anti-factor Xa activity in patients with acute major bleeding associated with factor Xa inhibitors, with effective hemostasis occurring in 79%. (Funded by Portola Pharmaceuticals; ANNEXA-4 ClinicalTrials.gov number, NCT02329327 .).


The New England Journal of Medicine | 2017

Rivaroxaban or Aspirin for Extended Treatment of Venous Thromboembolism

Jeffrey I. Weitz; Anthonie W. A. Lensing; Martin H. Prins; Rupert Bauersachs; Jan Beyer-Westendorf; Henri Bounameaux; Timothy A. Brighton; At Cohen; Bruce L. Davidson; Hervé Decousus; Maria C.S. Freitas; Gerlind Holberg; Ajay K. Kakkar; Lloyd Haskell; Bonno van Bellen; Akos F. Pap; Scott D. Berkowitz; Peter Verhamme; Philip S. Wells; Paolo Prandoni

BACKGROUND Although many patients with venous thromboembolism require extended treatment, it is uncertain whether it is better to use full‐ or lower‐intensity anticoagulation therapy or aspirin. METHODS In this randomized, double‐blind, phase 3 study, we assigned 3396 patients with venous thromboembolism to receive either once‐daily rivaroxaban (at doses of 20 mg or 10 mg) or 100 mg of aspirin. All the study patients had completed 6 to 12 months of anticoagulation therapy and were in equipoise regarding the need for continued anticoagulation. Study drugs were administered for up to 12 months. The primary efficacy outcome was symptomatic recurrent fatal or nonfatal venous thromboembolism, and the principal safety outcome was major bleeding. RESULTS A total of 3365 patients were included in the intention‐to‐treat analyses (median treatment duration, 351 days). The primary efficacy outcome occurred in 17 of 1107 patients (1.5%) receiving 20 mg of rivaroxaban and in 13 of 1127 patients (1.2%) receiving 10 mg of rivaroxaban, as compared with 50 of 1131 patients (4.4%) receiving aspirin (hazard ratio for 20 mg of rivaroxaban vs. aspirin, 0.34; 95% confidence interval [CI], 0.20 to 0.59; hazard ratio for 10 mg of rivaroxaban vs. aspirin, 0.26; 95% CI, 0.14 to 0.47; P<0.001 for both comparisons). Rates of major bleeding were 0.5% in the group receiving 20 mg of rivaroxaban, 0.4% in the group receiving 10 mg of rivaroxaban, and 0.3% in the aspirin group; the rates of clinically relevant nonmajor bleeding were 2.7%, 2.0%, and 1.8%, respectively. The incidence of adverse events was similar in all three groups. CONCLUSIONS Among patients with venous thromboembolism in equipoise for continued anticoagulation, the risk of a recurrent event was significantly lower with rivaroxaban at either a treatment dose (20 mg) or a prophylactic dose (10 mg) than with aspirin, without a significant increase in bleeding rates. (Funded by Bayer Pharmaceuticals; EINSTEIN CHOICE ClinicalTrials.gov number, NCT02064439.)


Blood | 2016

Recurrent venous thromboembolism and abnormal uterine bleeding with anticoagulant and hormone therapy use

Ida Martinelli; Anthonie W. A. Lensing; Saskia Middeldorp; Marcel Levi; Jan Beyer-Westendorf; Bonno van Bellen; Henri Bounameaux; Timothy A. Brighton; At Cohen; Mila Trajanovic; Martin Gebel; Phuong Lam; Philip S. Wells; Martin H. Prins

Women receiving vitamin K antagonists (VKAs) require adequate contraception because of the potential for fetal complications. It is unknown whether the use of hormonal therapy, especially those containing estrogens, is associated with recurrent venous thromboembolism (VTE) during anticoagulation. Despite the absence of data, World Health Organization guidelines state that use of estrogen-containing contraceptives confers an unacceptable health risk during established anticoagulation for VTE. We compared the incidences of recurrent VTE and abnormal uterine bleeding with and without concomitant hormonal therapy in women aged <60 years who were receiving anticoagulation with rivaroxaban or enoxaparin/VKA for confirmed VTE. Incidence densities in percentage per year were computed for the on and off estrogen-containing or progestin-only therapy periods. Cox regression models were fitted, with hormonal therapy (on vs off) as a time-dependent variable to derive the hazard ratio (HR) for the effects on recurrent VTE and abnormal uterine bleeding. In total, 1888 women were included. VTE incidence densities on and off hormonal therapy were 3.7%/year and 4.7%/year (adjusted HR, 0.56; 95% confidence interval [CI], 0.23-1.39), respectively, and were 3.7%/year and 3.8%/year, respectively, for estrogen-containing and progestin-only therapy. The adjusted HR for all abnormal uterine bleeding (on vs off hormonal therapy) was 1.02 (95% CI, 0.66-1.57). Abnormal uterine bleeding occurred more frequently with rivaroxaban than with enoxaparin/VKA (HR, 2.13; 95% CI, 1.57-2.89). Hormonal therapy was not associated with an increased risk of recurrent VTE in women receiving therapeutic anticoagulation. The observed increased risk of abnormal uterine bleeding with rivaroxaban needs further exploration.


BMJ | 2016

Testosterone treatment and risk of venous thromboembolism: population based case-control study

Carlos Martinez; Samy Suissa; Stephan Rietbrock; Anja Katholing; Ben Freedman; At Cohen; David J. Handelsman

Objective To determine the risk of venous thromboembolism associated with use of testosterone treatment in men, focusing particularly on the timing of the risk. Design Population based case-control study Setting 370 general practices in UK primary care with linked hospital discharge diagnoses and in-hospital procedures and information on all cause mortality. Participants 19u2009215 patients with confirmed venous thromboembolism (comprising deep venous thrombosis and pulmonary embolism) and 909u2009530 age matched controls from source population including more than 2.22 million men between January 2001 and May 2013. Exposure of interest Three mutually exclusive testosterone exposure groups were identified: current treatment, recent (but not current) treatment, and no treatment in the previous two years. Current treatment was subdivided into duration of more or less than six months. Main outcome measure Rate ratios of venous thromboembolism in association with current testosterone treatment compared with no treatment were estimated using conditional logistic regression and adjusted for comorbidities and all matching factors. Results The adjusted rate ratio of venous thromboembolism was 1.25 (95% confidence interval 0.94 to 1.66) for current versus no testosterone treatment. In the first six months of testosterone treatment, the rate ratio of venous thromboembolism was 1.63 (1.12 to 2.37), corresponding to 10.0 (1.9 to 21.6) additional venous thromboembolisms above the base rate of 15.8 per 10u2009000 person years. The rate ratio after more than six months’ treatment was 1.00 (0.68 to 1.47), and after treatment cessation it was 0.68 (0.43 to 1.07). Increased rate ratios within the first six months of treatment were observed in all strata: the rate ratio was 1.52 (0.94 to 2.46) for patients with pathological hypogonadism and 1.88 (1.02 to 3.45) for those without it, and 1.41 (0.82 to 2.41) for those with a known risk factor for venous thromboembolism and 1.91 (1.13 to 3.23) for those without one. Conclusions Starting testosterone treatment was associated with an increased risk of venous thromboembolism, which peaked within six months and declined thereafter.


Thrombosis Research | 2015

The use of aspirin for primary and secondary prevention in venous thromboembolism and other cardiovascular disorders

At Cohen; S. Imfeld; J. Markham; S. Granziera

Cardiovascular disease (CVD) includes a number of conditions such as myocardial infarction, coronary heart disease, stroke, and venous thromboembolism. CVD is a leading health problem worldwide and a major cause of mortality, morbidity, and disability; it is also associated with high healthcare costs. The incidence of CVD is predicted to increase in the forthcoming years, and thus it is crucial that physicians are aware of the benefits and limitations of the available therapies to ensure patients receive optimized treatment. Current clinical practice guidelines provide recommendations on the use of anticoagulants and antiplatelets for both the prevention and treatment of CVD. Aspirin is the most studied antiplatelet agent in this context. The benefits of aspirin are well documented and supported by data from robust clinical trials for CVD conditions, such as acute coronary syndrome and stroke prevention in patients with atrial fibrillation. However, the clinical benefits of aspirin are less clear for other conditions, namely for primary prevention of venous thromboembolism after major orthopaedic surgery, particularly in comparison with newer drugs such as the direct oral anticoagulants. This article provides an outline of the current guidelines and a critical assessment of the efficacy and safety data supporting the recommendations for the use of aspirin in the treatment and prevention of venous thromboembolism and other cardiovascular disorders.


Advances in Therapy | 2014

Phase III Trials of New Oral Anticoagulants in the Acute Treatment and Secondary Prevention of VTE: Comparison and Critique of Study Methodology and Results

At Cohen; Stephan Imfeld; Thomas Rider

The traditional treatment of venous thromboembolism (VTE) has been use of heparin and vitamin K antagonists (VKA), and although shown to be effective, they have numerous limitations. New oral anticoagulants (NOACs) including direct thrombin (factor IIa) inhibitors (dabigatran) and selective factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) have emerged as promising alternatives with the potential to overcome the limitations of traditional treatments. Clinical trials have been performed with a view to making significant changes to the acute, long-term and extended treatment of VTE. Data are now available on the efficacy and safety, including bleeding rates, of the NOACs in comparison with VKA in the acute treatment and secondary prevention of VTE as well as in comparison with placebo extended VTE treatment. This review compares and contrasts the design and results of the Phase III trials of NOACs in VTE and discusses the implications of the NOACs in terms of treatment strategies in VTE patients.


Thrombosis and Haemostasis | 2016

Clinical impact and course of major bleeding with edoxaban versus vitamin K antagonists

Marjolein P. A. Brekelmans; Suzanne M. Bleker; Rupert Bauersachs; Z. Boda; Harry R. Buller; Youngsook Choi; Alexander Gallus; Michael A. Grosso; Saskia Middeldorp; Doyeun Oh; Gary E. Raskob; Lee Schwocho; At Cohen

Edoxaban is a once-daily direct oral anticoagulant (DOAC). The Hokusai-VTE study revealed that, after initial treatment with heparin, edoxaban was non-inferior to and safer than vitamin K antagonists (VKA) in the prevention of recurrent deep-vein thrombosis and pulmonary embolism. This is the first report on the clinical relevance and management of bleeding events with edoxaban. All major bleeding events were classified blindly by three study-independent adjudicators. Pre-defined criteria were used to classify severity of clinical presentation and, separately, the clinical course and outcome into four categories. Major bleeding occurred in 56 patients treated with edoxaban and 65 patients treated with VKA. The severest categories (3 or 4) of the clinical presentation were assigned to 46u2009% of the major bleeding episodes in edoxaban recipients versus 58u2009% of the major bleeds in VKA recipients (odds ratio [OR] 0.62, 95u2009% confidence interval [CI] 0.30-1.27, p = 0.19). Clinical course was classified as severe (category 3 or 4) in 23u2009% of the edoxaban and 29u2009% of the VKA associated bleeds (OR 0.73, 95u2009% CI 0.32-1.66, p = 0.46). In conclusion, edoxaban associated major bleeding events have a comparable clinical presentation and course to major bleeds with VKA in patients treated for venous thromboembolism in the Hokusai-VTE study. These results may assure physicians that it is safe to prescribe this medication. If a major bleeding during edoxaban treatment occurs, its clinical presentation and clinical course are not worse than in VKA-treated patients.


Thrombosis and Haemostasis | 2018

Apixaban versus Dalteparin for the Treatment of Acute Venous Thromboembolism in Patients with Cancer: The Caravaggio Study

Cecilia Becattini; Rupert Bauersachs; Benjamin Brenner; Mauro Campanini; At Cohen; Jean M. Connors; A. Fontanella; Gualberto Gussoni; Menno V. Huisman; Catherine Lambert; Guy Meyer; Andrés C Muñoz; Joaquim Abreu de Sousa; Adam Torbicki; Melina Verso; Giorgio Vescovo; Giancarlo Agnelli

International and national guidelines recommend low-molecular-weight heparin for the treatment of venous thromboembolism (VTE) in patients with cancer. The aim of the Caravaggio study is to assess whether oral apixaban is non-inferior to subcutaneous dalteparin for the treatment of acute proximal deep vein thrombosis and/or pulmonary embolism in patients with cancer. The study is an investigator-initiated, multi-national, prospective, randomized, open-label with blind end-point evaluation (PROBE), non-inferiority clinical trial (NCT03045406). Consecutive patients are randomized to receive oral apixaban or subcutaneous dalteparin for 6 months. Apixaban is given at a dose of 10u2009mg twice daily for the first 7 days and then 5u2009mg twice daily; dalteparin is given at a dose of 200 IU/kg for the first month and then 150 IU/kg once daily. The primary outcome of the study is objectively confirmed recurrent VTE as assessed by a central independent adjudication committee unaware of study treatment allocation. The primary safety outcome is major bleeding defined according to the guidelines of the International Society of Thrombosis and Haemostasis. Assuming a 6-month incidence of the primary outcome of 7% with dalteparin and an upper limit of the two-sided 95% confidence interval of the hazard ratio below the pre-specified margin of 2.00, 1,168 patients will be randomized considering an up to 20% loss in total patient-years (βu2009=u200980%; α one-sidedu2009=u20090.025). The Caravaggio study has the potential, along with other recently performed or on-going studies, to make less cumbersome the management of VTE in patients with cancer by replacing parenteral with oral anticoagulation.


Thrombosis Research | 2018

Pulmonary embolism in Europe - Burden of illness in relationship to healthcare resource utilization and return to work

Stefan N. Willich; L Chuang; Ben van Hout; Pd Gumbs; David F. Jimenez; S Kroep; Rupert Bauersachs; Manuel Monreal; Giancarlo Agnelli; At Cohen

OBJECTIVESnPulmonary embolism (PE) is associated with a substantial economic burden. However evidence from patients in Europe is scarce. The aim of this study was to report the impacts of PE on healthcare resource utilization (HCRU) and return to work using the PREFER in VTE registry.nnnMETHODSnThe PREFER in VTE registry was a prospective, observational, multicenter study in seven European countries, aiming to provide data concerning treatment patterns, HCRU, mortality, quality of life and work-loss. Patients with a first-time or recurrent PE were included and followed up at 1, 3, 6 and 12u202fmonths. Treatment patterns, re-hospitalization rates, length of hospital stays (LOS), and ambulatory/office visits, as well as proportion of patients returning to work, were assessed. Subgroups by country and with/without active cancer were examined separately. Zero-inflated negative binomial and Cox regression were applied to investigate the relationship between baseline characteristics and LOS and return to work, respectively.nnnRESULTSnAmongst 1399 patients with PE, 53.2% were male and the average age was 62.3u202f±u202f17.1u202fyears old. Overall, patients were treated with combinations of heparin, vitamin K antagonists (VKA) and the non-VKA oral anticoagulants (NOACs) (50.0% treated with the combination of heparin with VKA). Patients with active cancer were primarily treated with heparin (84.9%). NOACs were used more frequently in DACH (Germany, Austria and Switzerland) and France (55.2% and 32.6%) compared to Italy and Spain (4.5% and 6.1%). The VTE-related re-hospitalization rate within 12u202fmonths and the average LOS varied substantially between countries, from 26.2% in UK to 12.3% in France, and from 12.9u202fdays in Italy to 3.9u202fdays in France. PE patients were often co-managed by general practitioners in France and DACH (>84%), and less frequently in other countries (<47%). The regression results confirmed the country variation of HCRU. Of the employed patients (nu202f=u202f385), 60% returned to work at 1u202fmonth but 27.8% had not after one year. PE patients with DVT were more likely to return to work. Active cancer was a significant predictor for not returning to work, as well as smoking history.nnnCONCLUSIONSnMedical treatment of PE differed between patients with active cancer and patients without active cancer. VTE-related resource utilization differed markedly between countries. While the reported not return to work was high for patients with PE, this may at least in part reflect the presence of co-morbidities such as cancer.


Thrombosis Research | 2015

Treating pulmonary embolism in Pacific Asia with direct oral anticoagulants

At Cohen; Sinnadurai Jeyaindran; Jae Yeol Kim; Kihyuk Park; Suree Sompradeekul; Karmel L. Tambunan; Huyen Tran; I-Chen Tsai; Christopher Ward; Raymond Chi-Wing Wong

Pulmonary embolism (PE) is the principal preventable cause of in-hospital deaths. Prevalence of PE in Asians is uncertain but undoubtedly underestimated. Asians and Caucasians have similar non-genetic risk factors for PE, and there is mounting evidence that PE affects Asians much more commonly than previously supposed; incidence, especially among high-risk patients, may approach that in Caucasians. Furthermore, PE incidence in Asia is increasing, due to both increased ascertainment, and also population ageing and growing numbers of patients with predisposing risk factors. Despite being warranted, thromboprophylaxis for high-risk patients is not routine in Pacific Asian countries/regions. There also appears to be scope to implement venous thromboembolism (VTE) management guidelines more assiduously. Anticoagulants, primarily heparins and warfarin, have been the mainstays of VTE management for years; however, these agents have limitations that complicate routine use. The complexity of current guidelines has been another barrier to applying evidence-based recommendations in everyday practice. Updated management approaches have considerable potential to improve outcomes. New oral anticoagulants that are easier to administer, require no, or much less, monitoring or dose-adjustment and have a favourable risk/benefit profile compared with conventional modalities, may offer an alternative with the potential to simplify VTE management. However, more information is required on practical management and the occurrence and treatment of bleeding complications. Increasing recognition of the burden of PE and new therapeutic modalities are altering the VTE management landscape in Pacific Asia. Consequently, there is a need to further raise awareness and bridge gaps between the latest evidence and clinical practice.

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Manuel Monreal

Washington University in St. Louis

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B van Hout

University of Sheffield

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David F. Jimenez

University of Texas Health Science Center at San Antonio

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Peter Verhamme

Katholieke Universiteit Leuven

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