Neo-adjuvant Therapy With Anastrozole Plus Pazopanib in Stage II and III ER+ Breast Cancer

This phase II trial studies how well giving pazopanib hydrochloride and anastrozole before surgery works in treating patients with stage II-III estrogen receptor-positive breast cancer. Pazopanib hydrochloride and anastrozole may stop the growth of tumor cells by blocking some of the enzymes needed for cell growth. Giving pazopanib hydrochloride and anastrozole together before surgery may make the tumor smaller and reduce the amount of normal cells that have to be removed

OBJECTIVES: I. To determine the pathologic complete response (pCR) rate at surgery. SECONDARY OBJECTIVES: I. To evaluate alternative measurements of anti-tumor activity: proportion of patients achieving sustained decrease in antigen KI-67 (ki-67) at 12 weeks of therapy with anastrozole plus pazopanib (pazopanib hydrochloride); proportion of patients achieving down-staging to a pathologic stage 0 or 1 at surgery. II. To assess qualitative and quantitative toxicity of this combination, with special emphasis on the frequency of events grade 3 or greater, or the occurrence of unexpected toxicities. OUTLINE: Patients receive pazopanib hydrochloride\* orally (PO) once daily (QD) and anastrozole PO QD for 6 months in the absence of disease progression or unacceptable toxicity. Patients then undergo definitive surgery. NOTE: \*Pazopanib hydrochloride is stopped 7-14 days before surgery.