Conditions: Metastatic Breast Cancer
Keywords: Breast cancer Her-2/neu Granulocyte Colony Stimulating Factor Trastuzumab Vinorelbine Antibody-dependent cellular cytotoxicity Effector cells
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 23
Healthy volunteers: no

Brief summary:
Trastuzumab or Herceptin is an antibody directed against Her-2. Her-2 is a growth factor receptor which is present on the tumors of 25% of patients with breast cancer. The addition of trastuzumab to chemotherapy has been shown in a randomized clinical trial to increase the response rate to chemotherapy, the duration of response to chemotherapy, and to improve the duration of survival of patients with metastatic breast cancer. The anticancer mechanism of action of trastuzumab is unknown, but it is possible that trastuzumab acts by promoting antibody-dependent cell mediated cytotoxicity (ADCC), or direct killing of cancer cells by immune cells, triggered by antibodies bound to the surface of the cancer cell. G-CSF is a drug which is a growth factor for certain types of immune cells. G-CSF has two favorable effects on ADCC. G-CSF increases the pool of circulating cancer-killing immune cells, and G-CSF increases the strength of binding of cancer-killing immune cells to a specific part of the antibody. Therefore, priming with G-CSF significantly increases the efficiency of ADCC, and four days of treatment with G-CSF has been shown to optimize ADCC in some studies. Recent data from the investigators' laboratory indicates that chemotherapy can augment ADCC directed against tumor cells.

The investigators' hypothesis is that pre-treatment with the drug G-CSF would increase the effectiveness of chemotherapy given with trastuzumab.

Detailed description:
This is a randomized phase II study comparing trastuzumab with G-CSF against trastuzumab with placebo during the first two weeks of therapy.

Twenty five patients with metastatic breast cancer will be randomized to receive weekly trastuzumab plus either G-CSF or placebo by subcutaneous (SQ) injection daily for five days weekly for two weeks. Subsequently, all patients will receive an additional 12 weeks of weekly trastuzumab, G-CSF by SQ injection daily for five days weekly for 12 weeks, and vinorelbine once weekly at a dose of 25 mg/m2 weeks 3, 4, 6, 7, 9, 10, 12, 13. Baseline evaluation will include a history and physical exam, comprehensive metabolic panel (CMP), complete blood count (CBC), serum pregnancy test, computerized tomography (CT) scan for disease measurements, and a Multiple Uptake Gated Acquisition (MUGA) scan. The CT scan and MUGA will be repeated upon completion of the study treatment. Blood will be drawn pre-trastuzumab, 2 hours post-trastuzumab, and 48 hours post-trastuzumab on weeks 1, 2, 3, 4, and 12 to measure whole blood ADCC activity. Two additional assays for whole blood ADCC activity will be drawn at baseline pre-treatment, and following completion of protocol treatment. These assays will measure chromium release from a Her-2 positive target cell exposed to the patient's effector cells. Measurement of soluble Her-2 in patient serum will also be measured at each ADCC time point.

Arms:
arm 1: Subjects will receive ten doses of G-CSF at a dose of 5 mcgm/kg daily Monday through Friday for the first two weeks of the trial. All patients will also receive trastuzumab at 4 mg/kg week 1, and 2 mg/kg week 2 during the first two weeks of the trial. All patients will then receive 12 weeks of trastuzumab at 2 mg/kg IV weeks 3 through 14, vinorelbine at 25 mg/m2 IV weekly weeks 3,4,6,7,9,10,12,13 and G-CSF at 5 mcgm/kg SQ daily Monday through Friday weeks 3-14. arm 2: Subjects will receive ten doses of a placebo injection SQ daily Monday through Friday for the first two weeks of the trial. All patients will also receive trastuzumab at 4 mg/kg week 1, and 2 mg/kg week 2 during the first two weeks of the trial. All patients will then receive 12 weeks of trastuzumab at 2 mg/kg weeks 3-14, vinorelbine at 25 mg/m2 IV weekly weeks 3,4,6,7,9,10,12,13, and G-CSF at 5 mcgm/kg SQ daily Monday through Fridays weeks 3-14.

Interventions: intervention 1: G-CSF intervention 2: trastuzumab intervention 3: vinorelbine intervention 4: G-CSF intervention 5: saline placebo
Intervention descriptions: intervention 1: 5 mcgm/kg daily Monday through Friday weeks 3-14 intervention 2: 4 mcgm/kg intravenously (IV) over 90 minutes week 1, then 2 mg/kg IV over 30 minutes weeks 2-14 intervention 3: 25 mg/m2 over 6 minutes IV weekly, weeks 3, 4, 6, 7, 9, 10, 12, 13 intervention 4: 5 mcgm/kg SQ daily for ten days, Monday through Friday of the first two weeks of the study intervention 5: Saline will be given SQ daily for ten days, Monday through Friday of the first two weeks of the study

Protocol document: