Interleukin-2: use in solid tumors.

Recombinant interleukin-2 (rIL-2) is a cytokine that has a central immunoregulatory role in controlling T cell function and growth. Clinical trials of rIL-2 regimens in various solid tumors have been initiated, and 337 patients at the Cleveland Clinic Foundation have been treated in a sequence of trials. The studies have involved rIL-2 or polyethylene-glycol conjugated rIL-2 (PEG-IL-2) as single agents, combinations of rIL-2 with recombinant interferon alpha, IL-4, or doxorubicin, and trials of rIL-2 with tumor infiltrating lymphocytes (TILs). These studies are summarized and involve Phase I or Phase II investigations in patients with renal cell carcinoma (191 patients), malignant melanoma (49 patients) or miscellaneous solid tumors (97 patients). Response rates in each category, respectively, were 12%, 20% and 2%. Toxicity varied depending on the regimen and generally reflected the dose and schedule of rIL-2 being employed. This series of clinical studies demonstrates the role of rIL-2 in various malignancies and documents the activity in patients with malignant melanoma and renal cell carcinoma. Additional studies to investigate potential mechanisms of antitumor activity and response determinants are underway.