Concomitant administration of recombinant human interleukin-2 and recombinant interferon -α-2a in cancer patients: a phase I study

Twenty-seven patients with metastatic cancer were treated with a daily continuous intravenous (IV) infusion of recombinant human interleukin-2 (rhIL-2) along with daily intramuscular recombinant interferon-alpha-2a (rIFN-α-2a) 4 days per week for 4 weeks with repeated treatment after 2 to 4 weeks of rest. The maximum-tolerated dose (MTD) was 3 million U/m²/d of rhIL-2 with 5 to 10 million U/m²/d of rIFN-α-2a. The dose-limiting toxicities are moderate hypotension requiring low doses of pressors and chronic fatigue associated with decreased performance status. Other common side effects included fever, chills, fluid retention, nausea/vomiting, erythrodermia, weight loss, elevated liver transaminase levels, anemia, thrombocytopenia, and CNS toxic effects. There were seven objective responses among 25 evaluable patients. Four major responses (one complete response and three partial responses) were observed among 10 patients with melanoma treated with the MTD level. These data suggest that for cancer patients, concomitant rhIL-2 and rIFN-α-2a therapy is tolerable and has manageable side effects. Further phase II studies will be needed to define the antitumor activity of this combination.