Purpose: To update response duration and survival data for patients with metastatic melanoma receiving the high-dose IV bolus recombinant interleukin (IL)-2 regimen.
Patients and methods: Two hundred seventy assessable patients were entered into eight clinical trials conducted between 1985 and 1993. IL-2 600,000 or 720,000 IU/kg was administered by 15-minute intravenous infusion every 8 hours for up to 14 consecutive doses over 5 days as clinically tolerated with maximum support, including pressors. A second, identical cycle of treatment was scheduled following 6 to 9 days of rest, and courses could be repeated every 6 to 12 weeks in stable or responding patients. Responding patients received up to five courses (two cycles/course) of treatment. All data were updated through December 1998 using report forms completed by the clinical investigators.
Results: The objective overall response rate was unchanged from the previous report. Tumor responses were seen in 16% of patients, with complete responses in 17 (6%) and partial responses in 26 (10%). Median survival for the group as a whole is now 12 months. Median follow-up time for surviving patients exceeds 7 years. Median duration of response for the 43 responding patients and the 26 patients with partial responses remained unchanged at 8.9 and 5.9 months, respectively. Response durations ranged from 1.5 to > 122 months. The median duration of complete responses has yet to be reached, but is at least 59 months. Thirty-one patients (11%) were alive as of last contact; 28 were confirmed, including 18 responding patients. Three patients were lost to follow-up at > 1, > 13, and > 104 months. Twelve responding patients remained continually disease- or progression-free from > 70 to > 150 months following initiation of therapy. Disease progression was not observed in any patient who was responding as of the last report or in any patient responding for longer than 30 months.
Conclusion: These data continue to support the notion that high-dose IL-2 produces durable responses in some patients with metastatic melanoma and should be considered a therapeutic option for appropriately selected patients with this disease.