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Comparação do risco de sangramento entre rivaroxabana e apixabana em pacientes com fibrilação atrial (COBRRA-AF)

30 de setembro de 2026 atualizado por: Ottawa Hospital Research Institute

Atrial Fibrillation (AF) affects 200,000 Canadians and increases risk of stroke, morbidity and mortality. Having a stroke can affect a patient's ability to speak, eat, walk, work, care for themselves, and interact with others. Not only can it ruin one's life, but it can also be fatal. A stroke occurs when blood flow to the brain is blocked by a clot, depriving brain cells of oxygen. In people with atrial fibrillation, blood flow is sluggish in the top chambers of the heart, and blood clots can form there. When a piece of a clot breaks off, it can travel to the brain and cause a stroke. That's where blood thinners come in. Blood thinners, or anticoagulants, decrease the chances of blood clots forming in the heart, reducing the risk of stroke. Studies show that blood thinners are highly effective at reducing the risk of stroke by up to 95%.

The conventional blood thinner is warfarin, taken by mouth. Warfarin requires regular blood tests to make sure a patient getting the correct dose. The patient also may have to avoid certain foods since the medication can interact with them. Newer blood thinners, known as direct-oral anticoagulants (DOACs) are available, which do not require regular blood tests and do not interact with foods. Two of the new blood thinners are called rivaroxaban and apixaban. Like warfarin, they can be taken by mouth, and studies have shown them to be as effective as warfarin.

Both rivaroxaban and apixaban have been approved for stroke prevention in AF by Health Canada. However, there have been no direct head-to-head comparisons of these two anticoagulants, meaning comparative safety data is not available. Increasing use of DOACs for stroke prevention in AF and patient values around bleeding highlight the need for a comparison trial to ensure patients receive the anticoagulant with the greatest balance of benefit to potential harm.

The trial is to assess bleeding rates and superiority of using apixaban versus rivaroxaban in patients with non-valvular atrial fibrillation.

Visão geral do estudo

Status

Recrutamento

Condições

Intervenção / Tratamento

Descrição detalhada

Atrial Fibrillation (AF) affects 200,000 Canadians and increases risk of stroke, morbidity and mortality. Oral anticoagulants such as Vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs) are highly effective at reducing the risk of stroke by up to 95%. Randomized controlled trials (RCTs) have compared apixaban and rivaroxaban (both DOACs) to VKAs for stroke prevention in AF, and are approved for this use by Health Canada. However, there have been no direct head-to-head comparisons of these two anticoagulants, meaning comparative safety data is not available. Increasing use of DOACs for stroke prevention in AF, patient values around bleeding, and litigation highlight the need for a comparison trial to ensure patients receive the anticoagulant with the greatest balance of benefit to potential harm.

The objective of this RCT is to compare the safety of the first 12 months of apixaban twice daily to rivaroxaban once daily in patients with non-valvular AF (NVAF). Patients will be monitored for the primary outcome of clinically relevant bleeding (CRB; a composite of major bleeding (MB) and clinically relevant non-major bleeding (CRNMB) events during follow-up. This trial will directly inform clinical practice and the choice of first-line therapy.

Tipo de estudo

Intervencional

Inscrição (Estimado)

3018

Estágio

  • Fase 4

Contactos e Locais

Esta seção fornece os detalhes de contato para aqueles que conduzem o estudo e informações sobre onde este estudo está sendo realizado.

Contato de estudo

  • Nome: Lana Castellucci, MD
  • Número de telefone: 75481 613-737-8899
  • E-mail: lcastellucci@toh.ca

Estude backup de contato

Locais de estudo

  • Canadá
    • British Columbia
      • Victoria, British Columbia, Canadá, V8Z 0B9
        • Retirado
        • Victoria Cardiac Arrhythmia Trials
    • Nova Scotia
      • Halifax, Nova Scotia, Canadá
        • Recrutamento
        • QEII Health Science Centre
        • Investigador principal:
          • Ratika Parkash, MD
        • Contato:
    • Ontario
      • Kingston, Ontario, Canadá
      • Ottawa, Ontario, Canadá, K1H 8L6
        • Recrutamento
        • The Ottawa Hospital - General Campus
        • Investigador principal:
          • Lana Castellucci, MD
        • Contato:
          • Daniel Warner
          • Número de telefone: 79590 613-737-8899
          • E-mail: dawarner@ohri.ca
        • Contato:
      • Ottawa, Ontario, Canadá
        • Recrutamento
        • University Ottawa Heart Institute
        • Contato:
        • Contato:
        • Investigador principal:
          • Daniel Ramirez, MD
    • Quebec

Critérios de participação

Os pesquisadores procuram pessoas que se encaixem em uma determinada descrição, chamada de critérios de elegibilidade. Alguns exemplos desses critérios são a condição geral de saúde de uma pessoa ou tratamentos anteriores.

Critérios de elegibilidade

Idades elegíveis para estudo

18 anos e mais velhos (Adulto, Adulto mais velho)

Aceita Voluntários Saudáveis

Não

Gêneros Elegíveis para o Estudo

Tudo

Descrição

Inclusion Criteria:

  • Age ≥ 18 years old
  • Confirmed new diagnosis of AF on ECG with an indication to start anticoagulation according to Canadian Cardiovascular Society guidelines

Exclusion Criteria:

  • Creatinine clearance =<15 ml/min calculated using the Cockcroft-Gault formula

  • Any contraindication for anticoagulation with apixaban or rivaroxaban as determined by the treating physician such as, but not limited to:

    • active bleeding
    • history of mechanical valve
    • other indication for anticoagulation (e.g. mechanical valves, venous thrombosis)
    • dual antiplatelet agent use
    • known liver disease with coagulopathy
    • use of contraindicated medications (strong inducers/inhibitors of CYP 3A4/5, P-glycoprotein)
    • pregnancy or breastfeeding

Plano de estudo

Esta seção fornece detalhes do plano de estudo, incluindo como o estudo é projetado e o que o estudo está medindo.

Como o estudo é projetado?

Detalhes do projeto

  • Finalidade Principal: Tratamento
  • Alocação: Randomizado
  • Modelo Intervencional: Atribuição Paralela
  • Mascaramento: Solteiro

Armas e Intervenções

Grupo de Participantes / Braço
Intervenção / Tratamento
Comparador Ativo: Apixaban group

5 mg PO, twice daily for 12 months of treatment. A dose reduction* to 2.5 mg twice daily will apply if patients meet 2 of 3 following criteria: age > 80 years; weight < 60 kg; creatinine >133 micromol/L.

*Patients with AF who are receiving DOAC should have their renal function assessed at baseline and at least annually
Medicamento: Apixaban

Refer to Apixaban group

Outros nomes:
  • Eliquis
Comparador Ativo: Rivaroxaban Group

20 mg PO, once daily for 12 months of treatment. A dose reduction* to 15 mg daily will apply to patients with creatinine clearance <50 ml/min.

*Patients with AF who are receiving DOAC should have their renal function assessed at baseline and at least annually
Medicamento: Rivaroxaban

Refer to Rivaroxaban group

Outros nomes:
  • Xarelto

O que o estudo está medindo?

Medidas de resultados primários

Medida de resultado
Descrição da medida
Prazo
The rate of adjudicated clinically relevant bleeding (CRB) events
Prazo: For the duration of the study: 12 months

CRB events are defined as the composite of major bleeding (MB) events and clinically relevant non-major bleeding (CRNMB) events
For the duration of the study: 12 months

Medidas de resultados secundários

Medida de resultado
Descrição da medida
Prazo
Adjudicated Major Bleeding events
Prazo: For the duration of the study: 12 months

Major Bleeding includes clinically overt bleeding and is associated with:

  • Fatal bleeding, and/or
  • Symptomatic bleeding in a critical area or organ, such as intracranial, intraspinal, intraocular, retroperitoneal, intra-articular or pericardial, or intramuscular with compartment syndrome, and/or
  • A fall in hemoglobin of ≥20 g/L, or
  • Leading to transfusion of ≥2 units of whole blood or red cells.
For the duration of the study: 12 months
Adjudicated Clinically Relevant Non-Major Bleeding events
Prazo: For the duration of the study: 12 months

Clinically relevant non-major bleeding will be defined as:

• Any sign or symptom of hemorrhage (e.g., more bleeding than would be expected for a clinical circumstance, including bleeding found by imaging alone) that does not fit the criteria for the ISTH definition of major bleeding but does meet at least one of the following criteria:

  • Requiring medical intervention by a healthcare professional
  • Leading to hospitalization or increased level of care
  • Prompting a face to face (i.e., not just a telephone or electronic communication) evaluation
For the duration of the study: 12 months
Adjudicated stroke/TIA events
Prazo: For the duration of the study: 12 months

Stroke is defined as non-traumatic focal neurologic deficit lasting ≥ 24 hours and confirmed on cerebral imaging (computed tomography or magnetic resonance imaging).

Transient ischemic attack (TIA) is defined as a temporary loss of blood flow to a part of the brain with focal neurologic deficit lasting < 24 hours without imaging evidence of acute infarction.

Strokes are to be classified as ischemic, hemorrhagic stroke, or uncertain. Hemorrhagic strokes are considered and will be reported as both bleeding events as well as stroke endpoints. The location of the bleeding can be determined from the diagnostic imaging reports.
For the duration of the study: 12 months
All-cause mortality
Prazo: For the duration of the study: 12 months

Using a binary outcome of an event or no event (Individual rates of death, all causes).
For the duration of the study: 12 months
Medication adherence
Prazo: For the duration of the study: 12 months

Reported as the number of patients self-reporting "all assigned medications were taken" "missing at least one dose of study medication", or "not able to take all of the study medications" out of the total number of medication compliance assessments done respectively
For the duration of the study: 12 months
Incremental cost-effectiveness ratio
Prazo: For the duration of the study: 12 months

We will model the prognosis of a cohort of patients receiving rivaroxaban versus apixaban. The results will be presented as incremental cost per QALY gained, incremental costs per one clinically relevant bleeding cases prevented, and incremental cost per one life year saved.
For the duration of the study: 12 months

Colaboradores e Investigadores

É aqui que você encontrará pessoas e organizações envolvidas com este estudo.

Patrocinador

Ottawa Hospital Research Institute

Colaboradores

Canadian Institutes of Health Research (CIHR)
Canadian Venous Thromboembolism Clinical Trials and Outcomes Research (CanVECTOR) Network

Investigadores

  • Investigador principal: Lana Castellucci, MD, FRCPC, Ottawa Hospital Research Institute

Datas de registro do estudo

Essas datas acompanham o progresso do registro do estudo e os envios de resumo dos resultados para ClinicalTrials.gov. Os registros do estudo e os resultados relatados são revisados ​​pela National Library of Medicine (NLM) para garantir que atendam aos padrões específicos de controle de qualidade antes de serem publicados no site público.

Datas Principais do Estudo

Início do estudo (Real)

6 de julho de 2021

Conclusão Primária (Estimado)

31 de dezembro de 2027

Conclusão do estudo (Estimado)

31 de dezembro de 2027

Datas de inscrição no estudo

Enviado pela primeira vez

19 de novembro de 2020

Enviado pela primeira vez que atendeu aos critérios de CQ

19 de novembro de 2020

Primeira postagem (Real)

24 de novembro de 2020

Atualizações de registro de estudo

Última Atualização Postada (Real)

1 de outubro de 2026

Última atualização enviada que atendeu aos critérios de controle de qualidade

30 de setembro de 2026

Última verificação

1 de setembro de 2026

Mais Informações

Termos relacionados a este estudo

Palavras-chave

Termos MeSH relevantes adicionais

Outros números de identificação do estudo

  • COBRRA-AF

Plano para dados de participantes individuais (IPD)

Planeja compartilhar dados de participantes individuais (IPD)?

NÃO

Informações sobre medicamentos e dispositivos, documentos de estudo

Estuda um medicamento regulamentado pela FDA dos EUA

Não

Estuda um produto de dispositivo regulamentado pela FDA dos EUA

Não

Essas informações foram obtidas diretamente do site clinicaltrials.gov sem nenhuma alteração. Se você tiver alguma solicitação para alterar, remover ou atualizar os detalhes do seu estudo, entre em contato com register@clinicaltrials.gov. Assim que uma alteração for implementada em clinicaltrials.gov, ela também será atualizada automaticamente em nosso site .

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