A phase II study of recombinant alpha interferon in patients with recurrent or metastatic breast cancer.

Thirty-three patients with advanced breast cancer were treated with a recombinant alpha interferon (rIFN-alpha 2). All patients were ambulatory (performance status greater than or equal to 50 Karnofsky scale) and almost all had received previous chemotherapy. Large intravenous dosages of 30 to 50 X 10(6) IU/m2 were given for five consecutive days every two to three weeks to 22 patients and smaller subcutaneous dosage of 2 X 10(6) IU/m2 three times a week to 11 patients. No complete or partial responses were seen. Two patients had stable disease and the remainder progressed. Flu-like syndromes were seen in all patients. Nausea, vomiting, and anorexia were frequent. Hypotension and confusion were noted in six and five patients, respectively. Life-threatening leukopenia was noted in two patients receiving intravenous dosage and thrombocytopenia was noted in one; no sepsis or bleeding complications were noted. In this study, a highly purified and biologically active rIFN-alpha 2 was not associated with activity in previously treated women with metastatic breast cancer.