PURPOSE A randomized, double-blind, placebo-controlled trial was performed to compare the toxicity and biologic effects of treatment with high-dose intravenous (IV) bolus interleukin-2 (IL-2) plus the recombinant human soluble p75 tumor necrosis factor (TNF) receptor immunoglobulin G (IgG) chimera (rhuTNFR:Fc) with high-dose IL-2 alone in patients with advanced melanoma and renal cell carcinoma. PATIENTS AND METHODS Twenty patients with advanced melanoma or renal cell carcinoma were randomized to receive IL-2 (Chiron, Emeryville, CA) 600,000 IU/kg every 8 hours on days 1 to 5 and 15 to 19 (maximum, 28 doses) combined with placebo or the rhuTNFR:Fc fusion protein (Immunex, Seattle, WA) 10 mg/m2 on days 1 and 15 and 5 mg/m2 on days 3, 5, 17, and 19. The impact of rhuTNFR:Fc on IL-2 toxicity and biologic effects was evaluated. RESULTS No clinically significant difference in toxicity was observed in the two treatment arms. The adjusted median number of IL-2 doses administered during cycle 1 was 24.5 (range, seven to 28) and 21.5 (range, five to 27) for the placebo and rhuTNFR:Fc arms, respectively (P = .544). IL-2-induced TNF bioactivity, neutrophil chemotactic defect, and serum IL-6, IL-8, and IL-1 receptor antagonist (IL-1RA) induction were suppressed by rhuTNFR:Fc. Two of nine assessable patients (22%) on IL-2/placebo and three of 10 patients (30%) on IL-2/rhuTNFR:Fc responded. CONCLUSION Despite evidence of in vitro neutralization of TNF functional activity and partial inhibition of other secondary biologic effects of IL-2, rhuTNFR:Fc does not reduce the clinical toxicity associated with high-dose IL-2 therapy. These results suggest that the toxicity and antitumor effects of IL-2 treatment are independent of circulating TNF.
In vitro induction of endogenous tumor necrosis factor (TNF) and its cytotoxicity against renal cell carcinoma (RCC).
