Multiinstitutional phase II trial of intensive combination chemoimmunotherapy for metastatic melanoma

Abstract

Purpose: To evaluate the activity and toxicity of combined high-dose cisplatin, dacarbazine (DTIC), and tamoxifen chemotherapy and high-dose bolus interleukin-2 (IL-2) in patients with metastatic melanoma.

Patients and methods: Patients with metastatic melanoma, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and normal organ function were enrolled onto this multiinstitutional Cytokine Working Group trial. Patients received intensive chemoimmunotherapy consisting of cisplatin (50 mg/m2) and DTIC (350 mg/m2) intravenously (IV) on days 1 to 3 and 43 to 45, IL-2 600,000 IU/kg IV every 8 hours on days 12 to 16 and 26 to 30 (maximum, 28 doses), and tamoxifen 20 mg orally each day. Patients were evaluated for response at day 63 of each cycle, and responding patients were given a second cycle of therapy beginning on day 71 to 85.

Results: Thirty-eight patients were entered onto this study. Toxicities were as expected for the chemotherapy and immunotherapy components of this regimen. Overlapping toxicity consisted primarily of thrombocytopenia (76% of patients required platelet transfusions), neutropenia, anemia, fatigue, and weight loss. Despite these cytopenias, bleeding and infectious complications were rare. There were no treatment-related deaths. Three patients achieved a complete response (CR; 8%), and 13 achieved a partial response (PR). The overall objective response rate was 42% (95% confidence interval [CI], 26% to 58%). Six additional patients had greater than 50% tumor reduction at day 63, which did not persist until a subsequent evaluation. The median duration of response was 5 months (range, 2 to 20+), and the median survival duration was 11 months.

Conclusion: This intensive treatment regimen appears to possess activity in metastatic melanoma comparable, but not superior, to that of other less intensive cisplatin- and IL-2-based chemoimmunotherapy regimens. Although the toxicity and complexity of this regimen make it unsuitable for phase III testing and impractical for more widespread use, the results of this study support a potential favorable interaction between IL-2 and chemotherapy in this disease and highlight the need for appropriately designed phase III trials.