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

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

Official Title
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The Impact Of Platelet Function Inhibition On Circulating Cancer Cells In Metastatic Breast Cancer Patients

Conditions
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Breast Neoplasms

Intervention / Treatment
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* Drug: Plavix
* Drug: Aspirin


Participation Criteria
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Eligibility Criteria
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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. Exclusion Criteria: Patients going on to surgery Patients with a serious bleeding disorder that make them inappropriate candidates for NSAID therapy Patients with history of significant bleeding related to peptic ulcer disease Patients on standing doses of NSAIDS or platelet function inhibitors Patients on standing doses of anti-coagulants

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Plavix and Aspirin<br>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. | Drug: Plavix<br> <br> * Other names: Clopidogrel Bisulfate;Drug: Aspirin<br> <br> * Other names: acetylsalicylic acid;|
| No Intervention: Observation only<br>Observation by treating physician | |

What is the study measuring?
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Primary Outcome Measures

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

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of Patients With a Given Absolute Number of Circulating Tumor Cells (Broken Into Categories) Plotted Against Time | 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 | Baseline, 2 weeks and 1 month | 
| Mean Aspirin-Mediated Platelet Inhibition vs. Time Plotted for Plavix and Aspirin and Observation Groups | 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 beads increase light transmittance which is reported in Aspirin Reaction Units (ARU). | Baseline, 2 weeks and 1 month | 
| Clopidogrel-Mediated Percent of Platelet Inhibition vs. Time Plotted for Aspirin and Plavix and Observation Groups | Mean Clopidogrel-Mediated platelet inhibition (% inhibition) vs. time for Aspirin and Plavix and Observation groups | Baseline, 2 weeks and 1 month | 
| Progression Free Survival |  | Maximum of 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Breast Cancer, Metastatic, Platelet