Background: The objective of the current study was to evaluate the response rate, survival, and toxicity of treatment with cisplatin and high dose intravenous continuous infusion interleukin-2 (IL-2) with or without interferon-alpha-2a (IFN) in patients with metastatic melanoma.
Methods: One hundred and seventeen patients with metastatic melanoma randomly were assigned to receive cisplatin, 100 mg/m2, followed after a 3-day rest period by IL-2, 18 x 10(6) IU/m2, on Days 3-6 and Days 17-21 (Arm 1) or cisplatin and IL-2 using an identical schedule plus subcutaneous IFN, 9 x 10(6) U, 3 times a week during IL-2 administration (Arm 2). In the absence of disease progression or undue toxicity, the cycle could be repeated on Day 29. Patients who responded after two cycles eventually could receive a third cycle. One hundred and one patients were evaluable for toxicity and efficacy.
Results: On treatment Arm 1, 3 patients (6%) achieved a complete response (CR) and 5 patients (10%) achieved a partial response (PR) with a median response duration of 3.8 months for the CRs and 8.7 months for the PRs. On treatment Arm 2, 2 patients (3%) achieved a CR (durations of 5.9 and 33.1 months, respectively) and 11 patients (21%) a PR with a median response duration of 8.3 months. The median durations of overall survival were 10.4 months (range, 1.1-39.7+ months) and 10.9 months (range, 0.5-38.1+ months) for treatment Arms 1 and 2, respectively. The toxicity profile was consistent with the known side effects of this IL-2 intravenous regimen combined with cisplatin chemotherapy and IFN. Toxicity was more pronounced in treatment Arm 2 compared with treatment Arm 1. There were 2 and 4 patients, respectively, in treatment Arms 1 and 2 who died within 28 days after completion of treatment.
Conclusions: The observed overall response rates of 16% and 25% in treatment Arms 1 and 2, respectively, is lower than that expected with biochemotherapy; despite the fact that the objective of the trial was not to show any difference between the 2 treatment arms, our results indicate that the addition of IFN, at the dose and schedule used in this trial, fails to improve the activity of a cisplatin/IL-2 regimen significantly in patients with metastatic melanoma. Although response rates were relatively low, the median overall survival was nearly 1 year in both groups.