Interleukin-12 in Treating Women With Metastatic Breast Cancer Who Have Received High-Dose Chemotherapy and Peripheral Stem Cell Transplantation

OBJECTIVES: I. Determine the toxic effect profile and maximum tolerated dose of interleukin-12 (rhIL-12) in women with advanced breast cancer who have undergone high dose chemotherapy with stem cell rescue. II. Determine the effect of rhIL-12 on cellular and humoral immune systems following high dose chemotherapy. III. Explore the effect on treatment failure of rhIL-12 after high dose chemotherapy with stem cell rescue.

OUTLINE: This is a dose escalation study of interleukin-12 (rhIL-12). RhIL-12 therapy begins 3-5 weeks after discharge from the chemotherapy/stem cell transplant hospitalization or 2-3 weeks after completion of posttransplant radiation. Patients receive rhIL-12 subcutaneously twice a week for 12 consecutive weeks. Treatment continues in the absence of disease progression or unacceptable toxicity. Cohorts of 3-6 patients are treated at each dose level of rhIL-12. The maximum tolerated dose is defined as the dose at which no more than 1 of 6 patients experiences dose limiting toxicity. Patients are followed every 2 months after treatment.

PROJECTED ACCRUAL: Approximately 6-35 patients will be accrued for this study within 1-2 years.