Purpose: To identify prognostic factors associated with survival beyond 4 years and overall response in patients with metastatic melanoma treated with high-dose bolus i.v. interleukin-2 (IL-2) given either alone or in combination with a variety of melanoma vaccines.

Study Design: 684 consecutive patients with metastatic melanoma received high-dose bolus i.v. IL-2 either alone or in conjunction with a variety of melanoma vaccines. Treatments occurred between August 1, 1985 and January 1, 2006.

Results: The overall objective response rate was 13% for patients receiving IL-2 alone and 16% for patients who received IL-2 with vaccine. In patients treated with IL-2 alone (n = 305) and IL-2 with vaccine (n = 379), having an objective response was associated with survival beyond 4 years (P < 0.0001). No pretreatment factors could be identified that were strongly associated with increased rate of objective response or long-term survival in patients receiving IL-2 alone. In patients receiving IL-2 with vaccines, there were increased response rates in patients with s.c. or cutaneous disease only and lower response rates with visceral disease only. Patients who received the gp100:209-217(210M) peptide plus IL-2 showed a strong trend to increased objective responses compared with IL-2 alone (22% versus 12.8%; P = 0.01) and also compared with patients who received a variety of vaccines that did not include this immunogenic peptide (13.8%; P = 0.009).

Conclusion: IL-2 can produce a modest response rate in patients with metastatic melanoma including patients with durable complete responses. S.c. or cutaneous disease only and vaccination with gp100:209-217(210M) peptide was associated with significant increase in response rates.