Interleukin-2 (IL-2) and 5-(3,3-dimethyle-1-triazeno) imidazole-4-carboxamide (DTIC) for adjuvant therapy in resected high-risk primary and regionally metastatic melanoma.

Abstract

e21076 Background: High-dose interferon (IFN) and ipilimumab currently are the only approved adjuvant therapies for high-risk melanoma patients. We analyze the recurrence free survival (RFS), overall survival (OS), and toxicity profile of Interleukin-2 (IL-2) and 5-(3,3-Dimethyle-1-Triazeno) Imidazole-4-Carboxamide (DTIC) combination for resected high-risk primary and regionally metastatic melanoma patients as an alternative adjuvant therapy. Methods: Patients with stage IIB, IIC and stage III melanoma that were treated and received adjuvant IL-2/DTIC combination therapy at a single institution in the year 2000 to 2010 were retrospectively reviewed. No evidence of residual disease was noted prior to therapy. Regimen consisted of subcutaneous IL-2 at 12 x 106 units on days 1 through 4 every month and DTIC 750mg/m2 on day 1 of each cycle every 28 days for 6 cycles. Individual medical records were accessed to collect the data and the Kaplan-Meier method was used to estimate RFS and the OS. Results: Of the 112 patients included, all underwent surgery and then received adjuvant treatment. 109 patients were followed and 3 were lost to follow-up. 59% of the patients were male, 41% were female. 79 (70.5%) of the patients were alive at the time of analysis and 57 patients were currently event free. 69 (61.61%) of the patients completed all 6 months of adjuvant combination treatment with 22.3% of the patients requiring DTIC and 15.2% of the patients’ required IL-2 dose reduction. 2-year OS (from the day of surgery) was 92.85% (95% CI of 86.29-96.53) with RFS of 66.31% (95% CI of 56.92-74.49) and 5-year OS was 75.57% (95% CI of 64.72-83.50) with RFS of 53.05% (95% CI of 41.91-62.58). Conclusions: With little improvement in the RFS from IFN and high toxicity profile with ipilimumab, neither of these treatment regimens seem to be an ideal option. In our retrospective analysis, combination therapy with IL-2/DTIC appears to be beneficial and well tolerated as an alternative adjuvant treatment for patients with high-risk melanoma, but this observation requires further prospective validation.