Recombinant leukocyte A interferon in advanced breast cancer. Results of a phase II efficacy trial.

Nineteen patients with advanced refractory metastatic breast cancer no longer responsive to chemotherapy were treated in the first phase II efficacy trial of recombinant leukocyte A interferon (IFL-rA), a highly purified single molecular species of alpha interferon prepared by recombinant DNA methods. Patients received a previously determined maximum tolerated dose for this agent (50 X 10(6) U/m2 body surface area) by intramuscular injection three times weekly for up to 3 months. The symptoms of toxicity observed in this trial resemble those previously reported for alpha interferons and include fever, chills, fatigue, anorexia, and leukopenia. All patients required dose reductions, most often for reasons of severe fatigue. Of the 17 patients evaluable for tumor response, one patient had stable disease and 16 had evidence of tumor progression. We conclude that IFL-rA is not an active agent in the treatment of advanced, refractory breast cancer when used at a maximum tolerated dose on this treatment schedule.