A direct comparison of immunological and clinical effects of interleukin 2 with and without interferon-alpha in humans.

Interleukin 2 (IL-2) and interferon-alpha (IFN-alpha) are cytokines with synergistic antitumor effects in mouse models. The biological effects of this combination, however, have not been directly compared to each agent alone in humans. We conducted a Phase 1B trial of IL-2 plus or minus IFN-alpha in 38 cancer patients. The objectives of this trial were to determine which doses of IFN-alpha and IL-2 maximally enhanced biological responses, and to determine whether the combined administration of IFN-alpha and IL-2 would result in a potentiation of biological responses over IL-2 alone. Patients received 4 days of IL-2 (1.5 x 10(6) units/m2/day or 3.0 x 10(6) units/m2/day) as a continuous infusion followed by a 3-day rest period, weekly for 3 weeks, with a 3-week rest period between 2 treatment courses. IFN-alpha (0.5 x 10(6) or 5 x 10(6) units/m2/day) was administered s.c. on days 1-4 weekly for 3 weeks with one of the 3-week courses. Patients were randomized to receive either IL-2 alone for course 1, followed by IL-2/IFN-alpha for course 2, or IL-2/IFN-alpha in course 1, followed by IL-2 alone. Immunological parameters were evaluated before treatment, and 24 h after completion of the third week of IL-2. A statistically significant increase in the percentage of circulating natural killer cells (CD56), natural killer cells bearing the Fc receptor (CD16), and activated T cells (CD25) was observed following IL-2 alone, and following IL-2 plus IFN-alpha. Significant increases in lymphocyte-activated killer cell cytotoxicity, antibody cellular cytotoxicity, and serum IL-2 receptor were also observed following both IL-2 and IL-2 plus IFN-alpha. However, no significant differences were observed in the magnitude of the increase in the IL-2-alone group when compared to the IL-2 plus IFN-alpha group. The mean fluorescent intensity of monocytes positive for HLA-DR and Fc receptor expression also increased significantly in both groups, as did serum beta 2-microglobulin expression and indoleamine 2,3-dioxygenase activity. However, increases were not significantly different between patients receiving IL-2 alone and IL-2 plus IFN-alpha. No dose response effect for IFN-alpha was observed for any of the parameters assessed. Toxicities consisted primarily of constitutional toxicities, including fever, rigors, malaise, headache, anorexia, and a decrease in performance status. No clinically significant differences in toxicities were observed between courses consisting of IL-2 and those consisting of IFN-alpha and IL-2.(ABSTRACT TRUNCATED AT 400 WORDS)

RCT Entities:   Population Interventions Outcomes