A PHASE-III STUDY OF RECOMBINANT INTERLEUKIN-2, 5-FLUOROURACIL AND LEUCOVORIN VERSUS 5-FLUOROURACIL AND LEUCOVORIN IN PATIENTS WITH UNRESECTABLE OR METASTATIC COLORECTAL-CARCINOMA

135 patients with locally advanced or metastatic colorectal cancer wer e entered into a phase III trial evaluating the efficacy of chemoimmun otherapy [recombinant interleukin 2 (rIL2)/5-fluorouracil (5-FU) and l eucovorin (LV)] versus chemotherapy alone (5-FU/LV). A cycle of chemoi mmunotherapy comprised a constant intravenous infusion of rIL2 at a do se of 18 x 10(6) U/m(2)/24 h for 120 h, followed by three bolus inject ions of 5-FU (600 mg/m(2)) and LV (25 mg/m(2)) at weekly intervals. Pa tients receiving chemotherapy alone received 5-FU/LV at the same dose at weekly intervals for 6 weeks followed by a rest period of 2 weeks, constituting one cycle of therapy. A maximum of 6 months therapy was g iven in both arms of the study. The response rates (complete and parti al responses) were 17% in patients receiving rIL2/5-FU/LV versus 16% i n those in the 5-FU/LV arm of the study, Median survival and progressi on-free survival were comparable for the two groups of patients, altho ugh there was a trend for a prolongation of survival in patients recei ving chemoimmunotherapy compared with chemotherapy alone, beyond 12 mo nths. Retrospective subgroup analyses revealed a significantly increas ed survival in poor prognosis patients (ECOG 1) treated with rIL2/5-FU /LV when compared to those receiving chemotherapy alone. Therefore, fu rther studies evaluating the dose and duration of chemoimmunotherapy i n patients with metastatic colorectal cancer seem warranted.