A phase II study of advanced colorectal cancer patients treated with combination 5-fluorouracil plus leucovorin and subcutaneous interleukin-2 plus alpha interferon

Twenty-one patients with advanced, pretreated colorectal cancer in disease progression were entered in a phase II study to investigate the use of 5-fluorouracil (5FU)+leucovorin with subcutaneous Interleukin-2+alpha interferon (α-IFN). Eighteen of these patients were evaluable for response to treatment: 1 partial response (PR) (duration 8 months), 9 stable disease (SD) (median duration of 6.5 months, range 2-15) and 8 progressive disease (PD). The PR patient survived for 15 months, the SD patients for a median of 11 months and 8 months for PD patients. Toxicity evaluated in the 21 patients reached grade 4 for mucositis in two cases. Grade 3 toxicity was observed more frequently for fever (52.3%) and diarrhea (33.3%) and was most probably the result of the combined side-effect of chemotherapy and the biological response modifiers (BRMs). Treatment was, for the most part, carried out on an out-patient basis as originally planned. In 15 patients tests were carried out to verify whether any immuno-activation had taken place. Significant increases were found during the course of therapy regarding cluster of differentiation activation (HLA-DR, CD71, CS25). Different curves were observed during the course of treatment with respect to the CD8 value, which proved higher in SD patients than in PD patients. Our study would seem to suggest that the addition of BRMs to 5FU+leucovorin could increase survival. The next step, however, must be to determine lower doses of IL-2 for subcutaneous administration in order to reduce toxicity but maintain the same immunostimulation.