Background: Treatment using interleukin-2 (IL-2) alone or in conjunction with lymphokine-activated killer (LAK) cells has been shown to mediate disease regression in selected patients with advanced cancer.
Purpose: This prospective randomized trial was designed to determine whether the administration of LAK cells in conjunction with high-dose IL-2 alters response and survival rates, compared with those for IL-2 alone, in patients with advanced cancer.
Methods: The 181 patients who had metastatic cancer that had failed to respond to standard therapy or who had disease for which no effective therapy existed received treatment with high-dose IL-2 alone or with LAK cells plus IL-2. Both treatment groups were to receive the same dose of IL-2 administered according to the same schedule. IL-2 doses were omitted depending on the tolerance of the patient. Of the 181 patients, 97 had renal cell cancer and 54 had melanoma.
Results: Median potential follow-up was 63.2 months. There were 10 complete responses among the 85 assessable patients who received IL-2 plus LAK cells, compared with four among the 79 who received IL-2 alone. There were 14 and 12 partial responses, respectively. Complete response continues in seven patients at 50-66 months. The 36-month actuarial survival with IL-2 plus LAK cells was 31%, compared with 17% with IL-2 alone (two-sided P value [P2] = .089). A trend toward improved survival was seen for patients with melanoma who received IL-2 plus LAK cells, compared with those who received IL-2 alone (24-month survival: 32% versus 15%; 48-month survival: 18% versus 4%; P2 = .064 [corrected]). None of 26 patients with melanoma who received IL-2 alone are alive; five of 28 who received IL-2 plus LAK cells are alive, and three continue in complete response. No difference in survival was seen in patients with renal cell cancer in the two treatment groups. There were six treatment-related deaths (3.3%); three were due to myocardial infarction. Other toxic effects resolved by discontinuation of IL-2. Many toxic effects were related to increased vascular permeability induced by IL-2.
Conclusions: Some patients with metastatic cancer have prolonged remission when they are treated with high-dose IL-2 alone or in conjunction with LAK cells. Our results suggest a trend toward increased survival when IL-2 is given with LAK cells in patients with melanoma, but no trend was observed for patients with renal cell cancer.
Implications: As these studies continue, efforts are underway to develop improved immunotherapies using tumor-infiltrating lymphocytes (TIL) and gene-modified TIL.