Phase I trial of escalating doses of interleukin-1 beta in combination with a fixed dose of interleukin-2

Interleukin-1 (IL-1) and IL-2 have synergistic antitumor and myelostimulatory activities. We investigated the clinical and biologic effects of IL-1/IL-2 therapy.

Twenty patients with metastatic cancer, divided into five cohorts, were treated with escalating doses of IL-1 beta (0.005 to 0.2 micrograms/kg/d) administered as a 30-minute intravenous (IV) infusion on days 1 to 4, combined with a fixed dose of IL-2 (0.1 mg/m2/d) administered by continuous IV infusion on days 1 to 4. The 4-day cycles were repeated weekly for up to 8 weeks in the absence of toxicity and/or progressive disease.

Patients tolerated up to 0.2 microgram/kg/d of IL-1 beta in combination with IL-2 without severe adverse effects. Peripheral-blood CD4-to-CD8 ratios and lymphokine-activated killer (LAK) activity were higher at the lower doses (0.005 to 0.05 microgram/kg/d) of IL-1 beta and higher than that of a cohort of patients treated with IL-2 alone. WBC counts, primarily neutrophils, increased significantly with higher doses of IL-1 beta (0.1 to 0.2 microgram/kg/d). Platelet counts were not significantly altered. Increases in serum IL-6, interferon gamma (IFN-gamma), and soluble IL-2 receptor levels were observed, but did not vary with IL-1 beta dose. Tumor regressions were observed in patients with colorectal cancer, melanoma, and renal cell carcinoma.

IL-1 beta cancer be administered in combination with IL-2 with acceptable toxicity. Our results suggest that the addition of even low-dose IL-1 beta to IL-2 may be associated with potentially beneficial biologic activity; higher doses of IL-1 beta (0.1 to 0.2 microgram/kg/d) may add potentially beneficial hematologic activity.