A Study of the Effects of Inhibiting Platelet Function on Circulating Cancer Cells in Breast Cancer Patients

Phase 2

Terminated

Brief Summary: The purpose of this study is to determine the effects of Plavix and aspirin in women with metastatic breast cancer.

Recruitment & Eligibility

Inclusion Criteria

Women with metastatic breast cancer who are completing planned course of chemotherapy with planned treatment break
On stable hormone therapy for at least 2 months are also eligible for the study
Estimated survival of at least 3 months
No platelet inhibitor therapy within 1 month of study entry
Platelets ≥ 100,000
Coagulation screening tests within normal range (INR between 0.81 and 1.20)
Normal kidney and liver function as defined by:
- Aspartate aminotransferase(AST)/serum glutamic oxaloacetic transaminase (SGOT))/alanine aminotransferase(ALT) ≤ 2 x Institutional Normal
- Creatinine ≤ 2 x Institutional Normal
Able to provide signed, informed consent.

Arm && Interventions

Group	Intervention	Description
Plavix and Aspirin	Plavix	Patients will receive a 300 mg loading dose of Plavix on day 1, followed by 75 mg/day, and aspirin 81 mg per day starting day 1. Treatment will be continued until the treating physician elects to resume systemic therapy for the treatment of breast cancer or until unacceptable toxicity is observed. A pill diary will be collected monthly to monitor patients' compliance with the medication regimen.
Plavix and Aspirin	Aspirin	Patients will receive a 300 mg loading dose of Plavix on day 1, followed by 75 mg/day, and aspirin 81 mg per day starting day 1. Treatment will be continued until the treating physician elects to resume systemic therapy for the treatment of breast cancer or until unacceptable toxicity is observed. A pill diary will be collected monthly to monitor patients' compliance with the medication regimen.

Primary Outcome Measures

Name	Time	Method
Platelet Inhibition of Circulating Tumor Cells (CTCs) Measured by the Number of Patients With Detectable CTCs	Week 4	Measured by number of patients who have detectable circulating tumor cells
Safety and Tolerability of Aspirin and Plavix Measured by the Number of Patients Who Discontinue the Study Drug	Maximum of 6 months	Measured by number of patients who discontinue administration of study drug because of toxicity and the incidence categorized by type.

Secondary Outcome Measures

Name	Time	Method
Percentage of Patients With a Given Absolute Number of Circulating Tumor Cells (Broken Into Categories) Plotted Against Time	Baseline, 2 weeks and 1 month	Percent of patients with a given number/range of CTCs ( 0, 1-5 \>+ 5) vs. time baseline 2-weeks and 1 month for plavix \& Aspirin arm and observation only
Mean Aspirin-Mediated Platelet Inhibition vs. Time Plotted for Plavix and Aspirin and Observation Groups	Baseline, 2 weeks and 1 month	Mean platelet inhibition vs. time plotted for Plavix \& Aspirin Arm and Observation group. Citrated whole blood is added to a test carriage containing fibrinogen-coated beads and a platelet activator (arachidonic acid to synthesize thromboxane A2). Using a turbidimetric-based optical detection system, aggregation of activated platelets to fibrinogen-coated b...
Clopidogrel-Mediated Percent of Platelet Inhibition vs. Time Plotted for Aspirin and Plavix and Observation Groups	Baseline, 2 weeks and 1 month	Mean Clopidogrel-Mediated platelet inhibition (% inhibition) vs. time for Aspirin and Plavix and Observation groups
Progression Free Survival	Maximum of 6 months

Locations (1): Washington University School of Medicine
🇺🇸
St. Louis, Missouri, United States