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.
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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
DOUBLE
Enrollment
23
5 mcgm/kg daily Monday through Friday weeks 3-14
4 mcgm/kg intravenously (IV) over 90 minutes week 1, then 2 mg/kg IV over 30 minutes weeks 2-14
25 mg/m2 over 6 minutes IV weekly, weeks 3, 4, 6, 7, 9, 10, 12, 13
5 mcgm/kg SQ daily for ten days, Monday through Friday of the first two weeks of the study
Saline will be given SQ daily for ten days, Monday through Friday of the first two weeks of the study
Antibody Dependent Cell-mediated Cytotoxicity of Effector Cells Isolated From Subjects Receiving Trastuzumab With Either G-CSF or a Saline Placebo Against a Her-2 Overexpressing Target in Vitro
Buffy coat effector cells were isolated by centrifugation from heparinized blood, and washed and counted. SKBR3 target cells were labeled with 51-Cr at 100 uCi per 5 x 105 cells for 1 hour at 37 C, washed and effector cells and target cells were plated at a ratio of 70:1 in 96 well microtiter plates, with trastuzumab 2 ug/ml and with no antibody. After addition of the target cells, the plate was centrifuged gently at 1200 rpm to pellet cells, the plate was incubated for 4 hours at 37C, and 100 uL of supernatant was measured on a gamma counter set for 51Cr counting for 1 minute per tube. Specific lysis in % is defined as follows: % specific lysis = (counts released into the supernatant under experimental conditions - spontaneous counts released into the supernatant) / (maximum counts released into the supernatant - spontaneous counts released into the supernatant) Specific lysis at Day 12 was compared to specific lysis at baseline between the G-CSF group and the placebo group.
Time frame: Baseline and 12 days
Antibody Dependent Cell-mediated Cytotoxicity of Effector Cells Isolated From Subjects Receiving Chemotherapy, Trastuzumab, and G-CSF Against a Her-2 Overexpressing Target in Vitro
Buffy coat effector cells were isolated by centrifugation from heparinized blood, washed, and counted. SKBR3 target cells were labeled with 51-Cr at 100 uCi per 5 x 105 cells for 1 hour at 37 C, washed and effector cells and target cells were plated at a ratio of 70:1 in 96 well microtiter plates, with trastuzumab 2 ug/ml and with no antibody. After addition of the target cells, the plate was centrifuged gently at 1200 rpm to pellet cells, the plate was incubated for 4 hours at 37C, and 100 uL of supernatant was measured on a gamma counter set for 51Cr counting for 1 minute per tube. Specific lysis in % is defined as follows: % specific lysis = (counts released into the supernatant under experimental conditions - spontaneous counts released into the supernatant) / (maximum counts released into the supernatant - spontaneous counts released into the supernatant) Specific lysis at Week 14 was compared to specific lysis at baseline for 17 patients with week 14 samples available.
Time frame: Baseline and 14 weeks
Clinical Response Rate of the Combination of Trastuzumab, G-CSF, and Vinorelbine in Subjects With Her-2 Overexpressing Metastatic Breast Cancer
19 subjects (11 on the G-CSF arm and 8 on the placebo arm) completed 14 weeks of treatment and completed restaging at that time. Responses were evaluated by RECIST criteria.
Time frame: 14 weeks
Safety of the Combination of Trastuzumab, G-CSF, and Vinorelbine in Subjects With Her-2 Overexpressing Metastatic Breast Cancer
Adverse events were graded per RECIST v4.0. There were two severe adverse events: Grade 3 mental status changes in one subject on the G-CSF arm, and Grade 3 febrile neutropenia in one subject on the Placebo arm. Refer to Adverse Events Table for specifics.
Time frame: 14 weeks
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