The first 3 patients enrolled in the study receive high-dose interleukin-2 (IL-2) IV over 15 minutes, 3 times daily, on days 1-5 and 15-19 and denileukin diftitox IV over 15-60 minutes once daily on days 8-10. If no dose-limiting toxicity occurs after receiving denileukin diftitox, subsequent patients are randomized to 1 of 2 treatment arms.