Pilot study of immunotherapy with interleukin-2 after autologous stem celltransplantation in advanced breast cancers

Median survival for advanced breast cancer does not exceed 2 years. Immunot herapy following Hihg Dose Chemotherapy (HDC) and autologous stem cell tran splantation (ASCT) is a procedure that could hypothetically decrease relaps e rate. The mechanism implicated is induction of immune modulation and a po ssible Graft Versus Tumor effect (GVHT). Tolerance and feasibility of rIL-2 administered after HDC with ASCT was analyzed in twenty one advanced breas t cancer patients. The patients were treated either with intra-venous high- dose rIL-2 (9 patients) or subcutaneous low dose (12 patients). With infra- venous high-dose rIL-2, 50% of the scheduled dose was administered and 100% of the scheduled dose was administered at a lower dose in the subcutaneous route, rIL-2 was administered safely after HDC and ASCT, particularly in t he subcutaneous low dose arm. However no clinical beneficial effect was doc umented for these advanced heavily pretreated breast cancers. Immune modula tion with rIL-2 earlier requires further investigation.