Lapatinib in Treating Brain Metastases in Patients With Stage IV Breast Cancer and Brain Metastases

PRIMARY OBJECTIVES: I. To evaluate the objective response rate in the central nervous system (CNS) (complete plus partial responses), as assessed by standard MRI, to oral GW572016 among patients with progressive brain metastases from HER2-positive breast cancer. SECONDARY OBJECTIVES: I. To evaluate the site of first failure (CNS, extra-CNS, both, or death) and overall survival of patients treated with GW572016 for brain metastases. II. To evaluate the overall objective response rate (complete plus partial response) and time to first progression at any site. III. To assess quality of life (QOL), neurologic QOL, and cause of death in patients treated with GW572016 for brain metastases. IV. To determine the qualitative and quantitative toxicities associated with oral GW572016, given at a dose of 750 mg orally, twice daily. V. To evaluate the sensitivity of PET with dedicated brain sequences to detect brain metastases from breast cancer. VI. To explore the relationship between decline in PET uptake at 1 week and decline in PET uptake at 8 weeks. VII. To characterize the vessel patterns seen on MRI at baseline, 8 weeks, and 16 weeks of treatment with GW572016. VIII. To describe changes in serum HER2 ECD over time. IX. To describe the baseline EGFR, HER2, IGF-IR, and degree of HER2 gene amplification in primary tumor blocks. OUTLINE: This is an open-label, multicenter study. Patients receive oral lapatinib twice daily on days 1-28. Courses repeat every 28 days in the absence of disease progression or unacceptable toxicity. Quality of life is assessed at baseline and at 8 weeks. Patients are followed every 2 months. PROJECTED ACCRUAL: A total of 12-37 patients will be accrued for this study within 0.5-1.5 years.