A PHASE-II TRIAL OF CONTINUOUS-INFUSION RECOMBINANT INTERLEUKIN-2 IN PATIENTS WITH ADVANCED RENAL-CELL CARCINOMA - A SOUTHWEST-ONCOLOGY-GROUP STUDY

A multicenter, phase II trial of continuous-infusion interleukin 2 (IL -2) was done in the Southwest Oncology Group to evaluate the efficacy and safety of this treatment in a broad-based population of patients w ith metastatic renal-cell carcinoma. Forty-seven patients from ii diff erent institutions were entered in this study, with 43 eligible. Two t echnically ineligible patients who received treatment and for whom rec ords are available are included in the data analysis. Thus, there are 45 analyzable patients. Of these patients, performance status was 0 in 58% and 1 in 42%. Thirty-one patients had a prior nephrectomy, and 12 patients had received prior therapy. IL-2 was initially given at a do se of 4.5 x 10(6) Roche U/m(2)/day, 4 days a week, for 4 weeks in a ro w, followed by a 3-week rest period. Because of the difficulty in obta ining reimbursement for the hospitalization required on the days of IL -2 administration, after 10 patients had been entered, the treatment r egimen was changed to 6 x 10(6) Roche U/m(2)/day for 4 days as an inpa tient, followed by 2 weeks of potential outpatient treatment at a dose of 3 x 10(6) Roche U/m(2)/day for 4 days each week. This was followed by a 2-week rest period. Within the 45 analyzable patients, there wer e 0 complete responses and 6 partial responses, for a response rate of 13% (95% confidence interval 5.1-27%). Responses occurred in lung met astases, nodal disease, and in one patient with bone metastases and th e primary kidney tumor. Response durations were 1 month, 1 month, 14months, 19 months, 26+ months, and 27 months. Of 12 patients with a ne phrectomy and only lung metastases, 4 showed partial responses. Medial survival for all analyzable patients is 15 months (95% confidence int erval 8-20 months). Toxicity was significant, with nausea and vomiting , diarrhea, fever and chills, dermatologic changes, and fatigue the mo st frequent. There were 18 instances of grade 4 toxicity, with the mos t common grade 4 toxicity, respiratory, found in 8 patients. There wer e two early deaths of probable heart-related causes while receiving tr eatment. A continuous-infusion IL-2 regimen that allows some potential outpatient treatment shows effectiveness and toxicity similar to that in other multicenter IL-2 infusion trials and high-dose intravenous b olus regimens.