Purpose: In prior studies of high-dose interleukin-2 (IL-2) therapy in the treatment of metastatic renal cell carcinoma, the majority of patients were asymptomatic (65% of patients had Eastern Cooperative Oncology Group [ECOG] scores of 0 [no cancer-related symptoms]). These studies demonstrated that an ECOG score of 0 predicted an objective antitumor response to IL-2 (P = 0.03). The current study determined the response frequency to high-dose IL-2 therapy in a primarily symptomatic patient population (ECOG = 1 [presence of cancer-related symptoms] for 57.3% of patients). The IL-2 therapy was administered in a non-intensive care unit (non-ICU).
Patients and methods: In this single-institution study of high-dose IL-2 therapy, 124 patients were consecutively enrolled and treated with the drug. Antitumor responses and safety were assessed by radiographic methods and the occurrence of grade 3 and 4 adverse events, respectively.
Results: The frequency of objective responses was 14.5% (18 of 124 patients). Seven patients (5.6%) and 11 patients (8.9%) experienced complete responses (CRs) and partial responses (PRs), respectively. Two of 7 patients (28.6%) with CR and 7 of 11 patients (63.6%) with PR had ECOG scores of 1. The median response duration is 18 months for all responders (CR plus PR). The median survival duration is 15 months for all patients. It was not possible to estimate the median survival duration for all responders because the majority of responding patients were alive at close of study. All patients with CR and 5 patients with PR were alive at close of study. The frequency of grade 3 and 4 adverse events was comparable to or less than published data and IL-2 was safely administered in a non-intensive care unit.
Conclusion: The frequency of objective antitumor responses in patients with ECOG scores of 1 suggests that high-dose IL-2 therapy may have comparable effectiveness in symptomatic and asymptomatic patients. High-dose IL-2 can be administered in a non-ICU setting with acceptable toxicity and the chance of clinical benefit.