Phase II trial of recombinant interleukin-1β in patients with metastatic renal cell carcinoma

Interleukin-1 (IL-1) plays a central role in the immune system, partly by stimulating the production of interleukin-2 (IL-2) and other cytokines by lymphocytes. In preclinical studies, recombinant interleukin-1 (rIL-1 beta) has shown antitumor activity. We conducted a phase II trial to evaluate the efficacy of rIL-1 in metastatic renal cell carcinoma (RCC). rIL-1 beta was given at a dose of 50 ng/kg i.v. daily for 5 days on a 28-day schedule. Nineteen patients were registered; 16 completed two cycles and were evaluable for response. There were no complete or partial responses to treatment. Toxicity was generally mild and typically involved grades I and II fever, rigors, hypotension, and weight gain. Severe neurologic toxicity was seen in two patients, grade IV seizures were seen in one, and grade III somnolence was seen in another. Analysis of soluble IL-2 receptor (sIL-2r) levels revealed an increase from a mean pretreatment level of 4,567 pg/ml to a mean of 6,124 pg/ml posttreatment (p < 0.001). The mean pretreatment IL-6 level was 51 pg/ml, increased to 84 pg/ml posttreatment (p < 0.05). Patients with bulky disease had higher sIL-2r levels, and patients with tumor fevers had higher IL-6 and sIL-2r levels than patients without fever did. A neutrophilic leukocytosis and a mild thrombocytosis were observed in response to rIL-1 beta administration. We conclude that rIL-1 beta in this dose and schedule is inactive in metastatic RCC.