Immunotherapy following regional chemotherapy treatment of advanced extremity melanoma

Purpose. Following regional chemotherapy (RC) for melanoma, approximately 75 % of patients will progress. The role of immunotherapy after RC has not been well established. Methods. A prospective, single-institution database of 243 patients with in-transit melanoma (1995-2013) was queried for patients who had progression of disease after RC with melphalan and subsequently received systemic immunotherapy. Fifteen patients received IL-2 only, 12 received ipilimumab only, and 6 received IL-2 followed by ipilimumab. Fisher's exact test was used to determine if there was a difference in number of complete responders after immunotherapy. Results. With IL-2 alone, all patients progressed. After ipilimumab alone, three patients had a complete response and nine had progressive disease. Six additional patients received IL-2 first then ipilimumab. All six progressed on IL-2 but three went on to have a complete response to ipilimumab while three progressed. The use of ipilimumab at any time in patients who progressed after RC was associated with higher rate of complete response compared to use of IL-2 alone (33 vs. 0 %; p = 0.021). Conclusions. Patients with progression after regional therapy for melanoma may benefit from immunologic therapy. In this group of patients, immune checkpoint blockade with ipilimumab has a higher complete response rate than T cell stimulation with IL-2, with no complete responders in the IL-2 only group. Furthermore, the complete response rate for ipilimumab in our cohort is higher than reported response rates in the literature for ipilimumab alone, suggesting that the effects of immunotherapy may be bolstered by previous regional treatment.