Long-term survival outcomes with immune checkpoint inhibitors (ICI) in metastatic uveal melanoma (MUM).

Abstract

e21585 Background: The treatment of MUM remains highly unsatisfactory. Single agent ICI produce low response rates. Two recent phase II trials of combination Ipilimumab and Nivolumab yielded response rates of 12% and 18%. We report the long-term survival results of MUM patients (pts) treated with ICI in our institution. Methods: We conducted a retrospective analysis of all pts with a diagnosis of MUM in St Vincent’s University Hospital. Overall survival (OS) was calculated from time of first systemic relapse to death or latest follow-up. One-way ANOVA is used with p < 0.05 considered statistically significant. Results: Out of 244 pts with UM registered in our clinics between April 2008 to October 2020, 52 developed MUM. Median age at initial diagnosis 63 years. 26(50%) are females. Median duration of follow-up of the MUM pts is 35.1 months [2.71-123.2]. Median duration of follow-up from initiation of ICI therapy is 9.1 months [1.6-84.2]. First sites of metastases: liver only 71%, liver plus extrahepatic 17%, and extrahepatic only 12%. Fifteen pts (29%) underwent radical metastasectomy as initial treatment. Thirty-seven (71%) had non-resectable MUM and received systemic treatment (23 total: ICI = 18, chemotherapy = 4, BRAF inhibitors = 1), non-surgical locoregional therapies (5 total: chemosaturation = 3, radiofrequency ablation = 2) or supportive/palliative care (9) as first-line. An additional 22 pts received ICI as second or subsequent treatment, for a total of 40 treated with ICI. Of these, 17 received single agents ICI (Ipilimumab = 11, Pembrolizumab = 6), 13 received sequential Ipilimumab and anti-PD1, and 10 received combination Ipilimumab /Nivolumab. At the time of analysis on 31st October 2020, 9 out of 52 pts (17%) are alive at 2.6, 5.0,5.4,8.9,17.3, 54.7, 77.5, 83.1 and 121.7 months (the 6 longest all had ICI). The median OS is 14.3 months [0.6-121.7]. Pts treated with ICI demonstrated longer OS than pts who did not receive ICI [15.0 months, 5.0-121.7 vs 7.2 months, 0.6-34.6; p = 0.089]. The median OS is 24.9 months (sequential Ipilimumab and anti-PD1) vs 15.0 months (combination Ipilimumab/Nivolumab) vs 13.4 months (single agents). Of the three pts remain alive > 5 years, one is currently disease-free. Conclusions: Prolonged survival beyond five years is achieved by a minority of pts with MUM who receive ICI during their treatment history, although durable initial ICI-induced remission is very rare. Our data suggest that pts who receive two ICI drugs during their illness may have longer survival compared to those who receive only a single ICI.