PRIOR CONCURRENT THERAPY: Biologic therapy: No concurrent trastuzumab (Herceptin) Chemotherapy: No more than 2 prior chemotherapy regimens, including trastuzumab One regimen in adjuvant setting and one in metastatic setting OR Two regimens in metastatic setting No concurrent chemotherapy Endocrine therapy: See Disease Characteristics At least 6 months since prior raloxifene for osteoporosis No prior hormonal, antiestrogen, or aromatase inhibitors other than tamoxifen for breast cancer At least 4 weeks since prior tamoxifen No concurrent hormonal replacement therapy, other antiestrogens (including raloxifene), aromatase inhibitors, or systemic steroids (except physiologic replacement doses) Radiotherapy: See Disease Characteristics Surgery: See Disease Characteristics Other: At least 4 weeks since prior investigational drug No concurrent warfarin exept low dose warfarin for port maintenance No other concurrent investigational agent No concurrent immunosuppressive therapy