Impact of the number of treatment courses on the clinical response of patients who receive high-dose bolus interleukin-2.

Abstract

To determine the impact of treatment with successive courses of high-dose bolus interleukin-2 (IL-2) on the incidence of clinical responses in patients with metastatic melanoma or renal cell cancer. A consecutive series of 350 patients with either metastatic melanoma or renal cell cancer who were treated with high-dose bolus IL-2 in the Surgery Branch, National Cancer Institute, between September 1985 and November 1996 was analyzed, with a median potential follow-up of 7.1 years. All patients were treated with 720,000 IU/kg of IL-2 administered by a 15-minute intravenous infusion every 8 hours for up to 5 days, as clinically tolerated per cycle. Patients were retreated according to clinical response and tolerance to the IL-2 therapy. Of the 149 patients with melanoma, 10 achieved complete responses (CRs) and 13 partial responses (PRs), for an overall response rate of 15.4%. Of the 201 patients with renal cell cancer, 18 achieved CRs and 20 PRs, for an overall response rate of 19.0%. Among responding patients, 21 of 23 with melanoma and 34 of 38 with renal cell cancer developed at least PRs after the first course of IL-2. Most patients with metastatic melanoma and renal cell cancer who achieved PRs or CRs to intravenous high-dose bolus IL-2 were identified after the first course of therapy. Those who demonstrated no response after two treatment courses failed to respond to additional IL-2 therapy. Based on this retrospective analysis, we recommend that patients who exhibit objective responses to treatment with high-dose bolus IL-2 receive additional treatment courses until either CR or IL-2 intolerance develops. Patients who do not achieve objective responses after two courses of IL-2 should receive no further treatment with this regimen.