Anastrozole and ZD1839 Compared With Fulvestrant and ZD1839 in Postmenopausal Women w/ Metastatic Breast Cancer

This randomized phase II trial is studying how well giving gefitinib together with anastrozole works compared to giving gefitinib together with fulvestrant in treating postmenopausal women with recurrent or metastatic breast cancer. Estrogen can stimulate the growth of breast cancer cells. Hormone therapy using anastrozole and fulvestrant may fight breast cancer by blocking the use of estrogen. Gefitinib (ZD1839) may stop the growth of cancer cells by blocking the enzymes necessary for their growth. It is not yet known whether gefitinib is more effective when combined with anastrozole or fulvestrant in treating breast cancer.

PRIMARY OBJECTIVES: I. Evaluate the antitumor activity of anastrozole given in combination with the EGFR tyrosine kinase inhibitor ZD1839, and of fulvestrant given in combination with the EGFR tyrosine kinase inhibitor ZD1839. II. Evaluate the safety of anastrozole given in combination with ZD1839 and fulvestrant given in combination with ZD1839. III. Evaluate the interaction of biological characteristics that predict for response of breast cancer to treatment with anastrozole and ZD1839 and with fulvestrant and ZD1839. OUTLINE: This is a randomized, open-label study. Patients are stratified according to prior hormonal therapy (yes vs. no) and dominant site of disease (soft tissue/lymph nodes vs. bone vs. visceral). Patients are randomized to 1 of 2 treatment arms. Arm I: Patients receive oral anastrozole and oral gefitinib once daily on days 1-28. Arm II: Patients receive fulvestrant intramuscularly on day 1 and oral gefitinib once daily on days 1-28. Courses in both arms repeat every 28 days in the absence of disease progression or unacceptable toxicity. Patients are followed every 3 months for 2 years and then every 6 months for 1 year.