We conducted a multicenter, phase II trial of continuous-infusion recombinant interleukin-2 (rIL-2) and lymphokine-activated killer (LAK) cells. Patients had advanced cancer, measurable disease, and a good performance level. Treatment included a 5-day continuous infusion of 18 x 10(6) IU/m2/d of rIL-2 followed by 1 day of rest, 4 days of leukapheresis to collect cells for in vitro augmentation of cellular cytotoxicity, and 5 more days of rIL-2 infusion with reinfusion of LAK cells for 3 successive days. Therapy was repeated after 2 weeks. There were 117 patients enrolled: 63% were males, with a median age of 51 years. Eighty-two percent were managed in oncology units, and 18% were in intensive care units. Six patients died within 1 month of initiating therapy. In renal cell carcinoma, the response rate was one of 31 patients (3%), with a median survival of 10.7 months. In melanoma, the response rate was four of 33 patients (12%), with a median survival of 6.1 months. For all other histologies, response rate was three of 53 patients (5%), with a median survival of 7.4 months. All responders were asymptomatic when therapy was initiated. This trial confirms the feasibility of administering continuous rIL-2 and LAK cells outside the intensive care unit environment. Antitumor activity in melanoma was similar to that seen in multicenter trials of bolus rIL-2 and LAK cells. Activity in renal cell cancer was disappointing.