PRIOR CONCURRENT THERAPY: Biologic therapy: No prior immunotherapy for breast cancer Chemotherapy: No prior chemotherapy for breast cancer Endocrine therapy: No prior hormonal therapy for breast cancer No concurrent corticosteroids except for chronic methylprednisolone or equivalent for more than 6 months duration at no more than 20 mg/day Radiotherapy: Not specified Surgery: Not specified Other: At least 3 weeks since prior investigational drugs