ONTAK® in Treating Patients With Advanced Breast Cancer That Did Not Respond to Previous Treatment

PRIMARY OBJECTIVES: I. To evaluate the safety of ONTAK infusion in patients with advanced refractory breast cancer. II. To evaluate the effect of ONTAK administration on peripheral blood T-regulatory cells. SECONDARY OBJECTIVES: I. To evaluate the incidence of IL-2R expression in tumor samples and investigate the correlation of tumor IL-2R expression and tumor response to ONTAK therapy. II. To evaluate levels of circulating sIL-2R before and after ONTAK therapy. III. To evaluate the effect of ONTAK on endogenous tumor specific immunity. IV. To evaluate the potential anti-tumor effects of ONTAK in patients with advanced refractory breast cancer. OUTLINE: Patients receive ONTAK IV over 1 hour on days 1-5. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up every 3 months for 1 year.