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

Antithrombotic Therapy to Ameliorate Complications of COVID-19 (ATTACC), in Collaboration With Accelerating COVID-19 Therapeutic Interventions and Vaccines (ACTIV-4)

Status
Completed
Phases
Phase 2Phase 3
Study type
Interventional
Source
ClinicalTrials.gov
Registry ID
NCT04372589
Acronym
ATTACC
Enrollment
1200
Registered
2020-05-04
Start date
2020-05-20
Completion date
2021-05-17
Last updated
2021-07-27

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19, Pneumonia

Brief 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.

Detailed description

This is a prospective, open-label, multicentre, Bayesian adaptive randomized clinical trial to establish whether therapeutic-dose parenteral anticoagulation improves outcomes for patients hospitalized with COVID-19 (e.g., reduces intubation or mortality). Participants will be randomized either to the investigational arm (therapeutic anticoagulation with heparin for 14 days or until recovery \[defined as hospital discharge or liberation from supplemental oxygen if initially required\], whichever comes first), or to the control arm (usual care, including thromboprophylactic dose anticoagulation according to local practice).

Interventions

DRUGHeparin

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

University Health Network, Toronto
CollaboratorOTHER
University of Manitoba
Lead SponsorOTHER

Study design

Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE

Intervention model description

Pragmatic, Bayesian adaptive randomized controlled trial

Eligibility

Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
No

Inclusion criteria

1\. Patients ≥18 years of age providing (possibly through a substitute decision maker) informed consent who require hospitalization anticipated to last ≥72 hours, for microbiologically-confirmed COVID-19, enrolled \< 72 hours of hospital admission or of COVID-19 confirmation • If the patient is already hospitalized and the COVID-19 diagnosis is due to an outbreak or an incidental finding, then enrollment can occur within 72 hours of a clinical syndrome attributable to COVID-19 that requires continued hospitalization (e.g. new or worsening oxygen requirements or acute kidney injury) which is further anticipated to extend the hospital admission by an additional 72 hours from randomization.

Exclusion criteria

1. Patients admitted to an ICU AND receiving organ support (i.e. high flow nasal oxygen, receiving non-invasive or invasive mechanical ventilation, or are requiring vasopressor/inotrope) 2. Patients for whom the intent is to not use pharmacologic thromboprophylaxis 3. Active bleeding 4. Risk factors for bleeding, including: 1. intracranial surgery or stroke within 3 months; 2. history of intracerebral arteriovenous malformation; 3. cerebral aneurysm or mass lesions of the central nervous system; 4. intracranial malignancy 5. history of intracranial bleeding 6. history of bleeding diatheses (e.g., hemophilia) 7. history of gastrointestinal bleeding within previous 3 months 8. thrombolysis within the previous 7 days 9. presence of an epidural or spinal catheter 10. recent major surgery \<14 days 11. uncontrolled hypertension (sBP \>200 mmHg, dBP \>120 mmHg) 12. other physician-perceived contraindications to anticoagulation 5. Platelet count \<50 x10\^9/L, INR \>2.0, or baseline aPTT \>50 (if available per SOC testing) 6. Hemoglobin \<80 g/L (to minimize the likelihood of requiring red blood cell transfusion if potential bleeding were to occur) 7. Acute or subacute bacterial endocarditis 8. History of heparin induced thrombocytopenia (HIT) or other heparin allergy including hypersensitivity 9. Current use of dual antiplatelet therapy 10. Patients with an independent indication for therapeutic anticoagulation 11. Patients in whom imminent demise is anticipated and there is no commitment to active ongoing intervention 12. Anticipated transfer to another hospital that is not a study site within 72 hours 13. Enrollment in other trials related to anticoagulation or antiplatelet therapy

Design outcomes

Primary

MeasureTime frameDescription
Mortality and days free of organ support21 daysThe primary endpoint in the trial is days alive and free of organ support at day 21. This endpoint is defined as the number of days that a patient is alive and free of organ support through the first 21 days after trial entry. Organ support is defined as receipt of invasive or non-invasive mechanical ventilation, high flow nasal oxygen (\>30 L/min), vasopressor therapy, or ECMO support. Death at any time (including beyond 21 days) during the index hospital stay is assigned the worst possible score of -1.

Secondary

MeasureTime frameDescription
Intubation and mortality30 daysOrdered categorical endpoint with three possible outcomes based on the worst status of each patient through day 30 following randomization: no invasive mechanical ventilation, invasive mechanical ventilation, or death.
All-cause mortality28 days and 90 days
Intubation30 daysInvasive mechanical ventilation.
Hospital-free days28 daysDays alive outside of the hospital through 28 days following randomization.
Ventilator-free days28 daysDays alive not on a ventilator assessed at 28 days following randomization.
Myocardial infarction28 days and 90 days
Ischaemic stroke28 days and 90 days
Venous thromboembolism28 days and 90 daysSymptomatic proximal venous thromboembolism (DVT or PE).
Vasopressor-free days28 daysDays alive not on a vasopressor assessed at 28 days following randomization.
Arterial and venous thrombotic conditions28 days and 90 daysA composite endpoint of death, deep vein thrombosis, pulmonary embolism, systemic arterial thromboembolism, myocardial infarction, or ischemic stroke collected during hospitalization or at 28 days and 90 days after enrollment (whichever is earlier).
Hospital re-admission28 daysHospital re-admission within 28 days.
Acute kidney injuryDuration of studyAs defined by KDIGO criteria.
Systemic arterial thrombosis or embolism28 days and 90 days
ECMO supportDuration of studyUse of extracorporeal membrane oxygenation (ECMO) support.
Mechanical circuit thrombosisDuration of studyDialysis or ECMO.
WHO ordinal scale28 daysPeak scale over 28 days, scale at 14 days, and proportion with improvement by at least 2 categories compared to enrollment, at 28 days.
Major bleedingIntervention period (maximum 14 days)As defined by the International Society on Thrombosis and Haemostasis (ISTH).
Heparin-induced thrombocytopenia (HIT)Intervention period (maximum 14 days)Laboratory-confirmed.
Renal replacement free days28 daysDays alive not on renal replacement assessed at 28 days following randomization.

Countries

Brazil, Canada, Mexico, United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 18, 2026