NCT05848713 · University of Manitoba
AntiThrombotic Therapy to Ameliorate Clinical Complications in Community Acquired Pneumonia
(ATTACC-CAP)
What this study is about
This is an international, where both patients and doctors know the treatment given, stratified randomly assigned controlled trial with Bayesian adaptive stopping rules to compare the effects of therapeutic-dose heparin vs. usual care pharmacological thromboprophylaxis on outcomes in patients admitted to hospital with community acquired pneumonia (CAP).
View original scientific description
This is an international, open-label, stratified randomized controlled trial with Bayesian adaptive stopping rules to compare the effects of therapeutic-dose heparin vs. usual care pharmacological thromboprophylaxis on outcomes in patients admitted to hospital with community acquired pneumonia (CAP).
Interventions
DRUG
Heparin
Preference is for LMWH given ease of administration and possibility of a more favorable safety profile, if no contraindication is present. Enoxaparin, dalteparin, or tinzaparin are acceptable LMWHs to be used for patients in the investigational arm and dose should be based on measured or estimated weight of the patient. Alternatively, intravenous UFH may be used and may be preferred in the presence of significant renal compromise. Intravenous UFH is typically dosed 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, or a corresponding UFH anti-Xa level. If UFH is used, the availability of a local site policy that specifies an aPTT target in this range or a corresponding anti-Xa value is a requirement.
Primary outcome measures
Ordinal endpoint reflecting survival
Time frame: 30 days
Survival to hospital discharge without ICU-level organ support. Organ support is defined as receipt of high flow nasal oxygen, invasive or non-invasive mechanical ventilation, vasopressor/inotropic therapy, or extracorporeal life support (ECLS) within an ICU. This outcome reflects disease progression to ICU-level organ failure or the worst possible outcome (death). It was chosen because of its importance to patients, clinicians, and other stakeholders. Given the limited number of ICU beds, reducing the burden of critical illness has important health system capacity implications.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Patients ≥18 years of age
- Admitted to hospital for a suspected or confirmed diagnosis of CAP defined by:
- Radiographic evidence of new or worsening infiltrate
- One or more of the following signs and/or symptoms of lower respiratory tract infection i. New or increased cough or sputum production ii. Fever of \> 37.8C or temperature \< 36C iii. WBC \> 11 x 109/L or \< 4 x 109/L c. The primary diagnosis is believed to be CAP as per the attending physician
- Requires supplemental oxygen to treat hypoxemia (or requires an increased level of supplemental oxygen if on chronic oxygen therapy)
- Hospital admission anticipated to last ≥72 hours from randomization
Exclusion criteria
- Suspected or confirmed active COVID-19 infection
- Hospital admission for \>72 hours prior to randomization
- Patients receiving non-invasive or invasive ventilation, vasopressors, or extracorporeal life support (ECLS) within an ICU at the time of enrollment
- Requirement for chronic mechanical ventilation via tracheostomy prior to hospitalization
- Patients for whom the intent is to not use pharmacologic thromboprophylaxis
- Patients with an independent indication for therapeutic-dose anticoagulation
- Patients with a contraindication to therapeutic-dose anticoagulation, including:
- Non-traumatic bleeding that requires medical evaluation or hospitalization within 30 days prior to CAP hospital admission
- History of an inherited or acquired bleeding disorder
- Cerebral aneurysm or mass lesions of the central nervous system
- Ischemic stroke within 3 months of hospital admission
- Gastrointestinal bleeding within 3 months of hospital admission
- Platelet count \<50 x109/L OR INR \>2.0 OR hemoglobin \<80 g/L at the time of screening
- Other physician-perceived contraindications to therapeutic anticoagulation
- History of heparin induced thrombocytopenia (HIT) or other heparin allergy
- Current or recent (within 7 days of screening) use of dual anti-platelet inhibitors (For example; Aspirin + one of the following; clopidogrel, ticagrelor, prasugrel)
- Patients in whom imminent death is anticipated
- Anticipated transfer to another hospital that is not a study site within 72 hours of randomization
- Enrollment in other interventional trials related to anticoagulation or antiplatelet therapy during current hospitalization
Where
- Chicago, Illinois
- Jefferson, Louisiana
- Portland, Maine
- Dearborn, Michigan
- Camden, New Jersey
- Milwaukee, Wisconsin
Collaborators
Canadian Institutes of Health Research (CIHR), Research Manitoba, Ozmosis Research Inc., Canadian Venous Thromboembolism Clinical Trials and Outcomes Research (CanVECTOR) Network, Canadian Critical Care Trials Group, AVANTI, Aurora Clinical Research
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Sep 30, 2026 · Source of record for eligibility and locations