Trastuzumab and Letrozole in Treating Postmenopausal Women With Progressive Advanced Breast Cancer

Inclusion Criteria

• •DISEASE CHARACTERISTICS:
• •Histologically or cytologically confirmed breast cancer
• •* Advanced disease
• •Measurable disease, defined as ≥ 1 unidimensionally measurable lesion outside previously irradiated areas that is ≥ 20 mm OR ≥ 10 mm if the slice thickness of the CT scan or MRI is ≤ 5 mm
• •* No nonmeasurable lesions as the only site of measurable disease, including any of the following:
• •* Osteoblastic bone metastases
• •* Ascites
• •* Pleural or pericardial effusions
• •* Carcinomatous lymphangitis of the lung
• •Progressive disease after prior treatment with a nonsteroidal aromatase inhibitor (e.g., letrozole or anastrozole) in an adjuvant or advanced disease setting
• •HER-2 amplification ≥ 2 by fluorescence in situ hybridization
• •No clinical symptoms or history of CNS or leptomeningeal metastases (no imaging is required)
• •No visceral involvement with risk for organ dysfunction
• •Hormone receptor status:
• •* Estrogen receptor- and/or progesterone receptor-positive tumor
• •PATIENT CHARACTERISTICS:
• •Age
• •18 and over
• •Sex
• •Female
• •Menopausal status
• •Postmenopausal, defined by 1 of the following:
• •* At least 55 years of age
• •* Less than 55 years of age with spontaneous cessation of menses for ≥ 1 year
• •* Less than 55 years of age with spontaneous cessation of menses within the past year, but amenorrheic with biochemical evidence of postmenopausal status
• •* Underwent prior bilateral oophorectomy
• •* Radiation or chemically induced menopause (treatment with luteinizing hormone-releasing hormone antagonists must continue during study treatment)
• •Performance status
• •WHO 0-1
• •Life expectancy
• •Not specified
• •Hematopoietic
• •WBC ≥ 3,000/mm\^3
• •Platelet count ≥ 100,000/mm\^3
• •Hepatic
• •AST and ALT ≤ 2 times upper limit of normal
• •Renal
• •Creatinine clearance \> 30 mL/min
• •Cardiovascular
• •No uncontrolled cardiac disease, including any of the following:
• •* Unstable angina
• •* Arrhythmia
• •* Hypertension
• •No history of congestive heart failure
• •No myocardial infarction within the past 6 months
• •LVEF \> 50% by echocardiogram
• •Pulmonary
• •No severe dyspnea at rest
• •Other
• •No other malignancy within the past 5 years except adequately treated carcinoma in situ of the cervix or localized nonmelanoma skin cancer
• •No psychiatric disability that would preclude study participation or giving informed consent
• •No active autoimmune disease
• •No uncontrolled diabetes
• •No other serious underlying medical condition that would preclude study participation
• •PRIOR CONCURRENT THERAPY:
• •Biologic therapy
• •No prior trastuzumab (Herceptin®)
• •Chemotherapy
• •Prior neoadjuvant or adjuvant chemotherapy allowed
• •No prior palliative chemotherapy
• •Endocrine therapy
• •See Disease Characteristics
• •Radiotherapy
• •See Disease Characteristics
• •Surgery
• •Not specified
• •Other
• •More than 1 month since prior experimental drugs on another clinical trial
• •No concurrent drugs that contraindicate study treatment
• •No other concurrent anticancer drugs
• •No other concurrent investigational drugs