Antithrombotic Therapy to Ameliorate Complications of COVID-19 (ATTACC)

Summary

Endothelial injury as a consequence of SARS-CoV-2 infection leads to a dysregulated host inflammatory response and activation of coagulation pathways. Macro- and micro-vascular thrombosis may contribute to morbidity, organ failure, and death. Therapeutic anticoagulation with heparin may improve clinical outcomes in patients with COVID-19 through anti-thrombotic, anti-inflammatory, and anti-viral activities of heparins. This pragmatic, Bayesian adaptive randomized controlled trial will determine whether therapeutic anticoagulation with heparin (subcutaneous low molecular weight heparin or intravenous unfractionated heparin) versus usual care reduces the need for intubation or death in hospitalized patients with COVID-19. The trial uses an adaptive design which was chosen to overcome limitations in available data to inform a priori estimation of event rates and possible effect sizes. The adaptive design also includes response-adaptive randomization based on baseline D-dimer level, probing for differential efficacy across subgroups defined based on initial D-dimer level. This Bayesian adaptive randomized trial will stop at a conclusion 1) when the posterior probability that the proportional odds ratio is greater than 1.0 reaches 99% (definition of benefit); 2) when the posterior probability that the proportional odds ratio is greater than 1.2 is less than 10% (definition of futility) or; 3) when the posterior probability that the proportional odds ratio is less than 1.0 is greater than 90% (definition of harm). The trial will enroll a maximum of 3,000 patients, although in many simulations the trial may require fewer patients. The trial is strategically aligned with the international REMAP-CAP/COVID platform trial to accelerate evidence generation.

Conditions

• COVID-19
• Pneumonia

Interventions

DRUG

Heparin

Low molecular weight heparin (LMWH) Preferred therapeutic anticoagulant is enoxaparin. Generally regimens: 1.5 mg/kg subcutaneous once daily or 1 mg/kg subcutaneous twice daily. Alternatively, other subcutaneous LMWH used, including tinzaparin (175 anti-Xa IU/kg subcutaneous once daily) or dalteparin (200 IU/kg subcutaneous once daily or 100 IU/kg subcutaneous twice a day). Unfractionated heparin (UFH) Commenced, administered, and monitored according to local hospital policy, and guidelines that are used for the treatment of venous thromboembolism (i.e. not for acute coronary syndrome). Intravenous infusion of UFH is according to total body weight and pragmatically adjusted according to local institutional policy to achieve an activated partial thromboplastin time (aPTT) of 1.5-2.5x the reference value. If UFH is used, the availability of a local hospital policy that has specifies an aPTT target in this range or an anti-Xa value is a requirement.

Sponsors & Collaborators

• University Health Network, Toronto

  collaborator OTHER

• University of Manitoba

  lead OTHER

Principal Investigators

• Patrick R. Lawler, MD, MPH · Peter Munk Cardiac Centre/University Health Network

• Ewan C. Goligher, MD, PhD · University Health Network, Toronto

• Ryan Zarychanski, MD, MSc · University of Manitoba

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2020-05-20

Primary Completion

2021-05-17

Completion

2021-05-17

FDA Drug

Yes

Countries

• United States
• Brazil
• Canada
• Mexico

Study Locations