STrategies for Anticoagulation in Patients With thRombocytopenia and Cancer-associated Thrombosis

NCT05255003 | Recruiting Phase 4 DMC

• 1 other identifier: START Pilot
• Study Type: interventional
• Target: 50
• Locations: 1 country
• Sites: 4

Brief Summary

Patients with cancer are prone to have blood clots, which are usually treated with blood thinners. The main complication of blood thinners is bleeding. This is especially a concern when the number of platelets in the blood is lower than 50,000 per microliter. The role of platelets is to stop bleeding, so when the number of platelets is low, patients are at a higher risk of bleeding. Cancer patients are prone to have lower platelet numbers due to cancer therapies and/or cancer itself. It is not clear what the best treatment is for cancer patients who need blood thinners for a blood clot but have low platelet counts. The investigators plan to do a small study called a pilot study to help plan for a larger study in such patients. In the pilot study, investigators will include 50 patients with cancer, low platelet counts, and a blood clot diagnosed within 2 weeks. Patients will be randomly assigned to one of the two treatment strategies: the full dose of blood thinners along with platelet transfusion or a reduced dose of blood thinners without platelet transfusion. The investigators will follow all patients for 30 days. If this pilot study is successful, it will help lead to a much larger trial, which will provide important information on the best treatment strategy for these patients.

Conditions

Cancer-associated Thrombosis; Thrombocytopenia

Outcome Measures

Primary Outcomes (1)

• Feasibility - The average number of patients recruited per month

  The average number of patients recruited per month

  18 months

Secondary Outcomes (15)

• Feasibility - Proportion of eligible patients who provide consent

  18 months

• Feasibility - Reasons for non-participation in eligible patients

  18 months

• Feasibility - Number of patients who complete study procedures by adhering to protocol

  18 months

• Feasibility - Rates of withdrawal

  18 months

• Feasibility - Loss to follow-up

  18 months

Study Arms (2)

Modified dose LMWH without platelet transfusion support

EXPERIMENTAL

Patients will be given modified dose LMWH as below based on the first platelet count of the day (daily in admitted patients or at least 2 times a week in outpatients), without empiric platelet transfusion: I. Platelet count 25-50,000/µL: 50% dose LMWH II. Platelet count \< 25,000/µL: hold anticoagulation

Biological: Enoxaparin; Biological: Dalteparin; Biological: Tinzaparin

Higher dose LMWH with platelet transfusion support

ACTIVE COMPARATOR

Patients assigned to higher dose LMWH (see below) will be given transfusion for 14 days when the first platelet count of the day falls below 50,000/uL (daily inpatient or at least 2 times a week in outpatients). Post-transfusion counts will not be routinely obtained unless clinically indicated I. Platelet count 25-50,000/µL: platelet transfusion + 100% dose LMWH II. Platelet count \< 25,000/µL: platelet transfusion + 50% dose LMWH After Day 14, patients will be transitioned to modified dose LMWH as the other arm without platelet transfusion. LMWH can include enoxaparin, dalteparin, or tinzaparin, with 100% as: * Enoxaparin - 1mg/kg subcutaneously twice daily * Dalteparin - 200 IU/kg subcutaneously daily for 1 month then 150 U/kg daily * Tinzaparin - 175 units/kg subcutaneously daily

Biological: Enoxaparin; Biological: Dalteparin; Biological: Tinzaparin

Interventions

Enoxaparin BIOLOGICAL

I. Platelet count 25-50,000/µL: 0.5mg/kg subcutaneously twice daily II. Platelet count \< 25,000/µL: hold anticoagulation

Also known as: Lovenox

Higher dose LMWH with platelet transfusion support; Modified dose LMWH without platelet transfusion support

Dalteparin BIOLOGICAL

I. Platelet count 25-50,000/µL: 100 IU/kg subcutaneously daily for the first month of an acute VTE then 75 U/kg II. Platelet count \< 25,000/µL: hold anticoagulation

Also known as: Fragmin

Higher dose LMWH with platelet transfusion support; Modified dose LMWH without platelet transfusion support

Tinzaparin BIOLOGICAL

I. Platelet count 25-50,000/µL: 87.5 units/kg subcutaneously daily II. Platelet count \< 25,000/µL: hold anticoagulation

Also known as: Innohep

Higher dose LMWH with platelet transfusion support; Modified dose LMWH without platelet transfusion support

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Adult patients (age ≥ 18) with active malignancy (malignancy diagnosed or treated within the previous 6 months, or progressive/relapsed);
• Objectively confirmed VTE within last 14 days for which therapeutic anticoagulation is planned;
• Thrombocytopenia with a platelet count \< 50,000/uL from cancer therapy or malignancy itself;
• Able to provide written informed consent

You may not qualify if:

• Receipt of anticoagulant for index VTE with platelet count \< 50,000/uL for \> 72 hours;
• Superficial vein thrombosis only;
• Life expectancy \< 1 month (as judged by the treating physicians);
• Creatinine clearance \< 30 ml/min;
• Contraindication to LMWH such as a history of heparin induced thrombocytopenia;
• Thrombocytopenia from other causes, such as thrombotic microangiopathy, immune thrombocytopenia, disseminated intravascular coagulation;
• Previously documented history of refractoriness to platelet transfusion secondary to HLA antibodies;
• Refusal of blood products;
• Anticoagulation at any dose is deemed unsafe (i.e. active bleeding or bleeding disorders)

Sponsors & Collaborators

• Tzu-Fei Wang: lead

Study Sites (4)

University of Alberta

Edmonton, Alberta, Canada

WITHDRAWN

The Ottawa Hospital

Ottawa, Ontario, K1H 8L6, Canada

RECRUITING

Niagara Health - St. Catharines Site

Saint Catharines, Ontario, Canada

RECRUITING

Windsor Regional Hospital

Windsor, Ontario, N8W 1L9, Canada

RECRUITING

MeSH Terms

Conditions

Thrombocytopenia

Interventions

Enoxaparin; Dalteparin; Tinzaparin

Condition Hierarchy (Ancestors)

Blood Platelet Disorders; Hematologic Diseases; Hemic and Lymphatic Diseases; Cytopenia

Intervention Hierarchy (Ancestors)

Heparin, Low-Molecular-Weight; Heparin; Glycosaminoglycans; Polysaccharides; Carbohydrates

Study Officials

• Tzu-Fei Wang, MD

  Ottawa Hospital Research Institute

  PRINCIPAL INVESTIGATOR

• Marc Carrier, MD

  Ottawa Hospital Research Institute

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Jennifer Brinkhurst

CONTACT

+16137378899; jbrinkhurst@ohri.ca

Study Design

• Study Type: interventional
• Phase: phase 4
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR INVESTIGATOR
• PI Title: Qualified Investigator

Study Record Dates

• First Submitted: February 6, 2022
• First Posted: February 24, 2022
• Study Start: August 29, 2022
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): January 31, 2027
• Last Updated: December 17, 2025

Record last verified: 2025-12

Data Sharing

• IPD Sharing: Will not share

Locations

CA (4)