RADT-07. CLINICAL OUTCOMES OF MELANOMA BRAIN METASTASES TREATED WITH NIVOLUMAB AND IPILIMUMAB ALONE VERSUS NIVOLUMAB AND IPILIMUMAB WITH STEREOTACTIC RADIOSURGERY

Abstract

Abstract BACKGROUND Upfront dual checkpoint blockade has demonstrated efficacy in new melanoma brain metastases (MBM) of asymptomatic patients. Whether combination stereotactic radiosurgery (SRS) with dual checkpoint blockade improves outcomes over dual checkpoint blockade alone is unknown. We evaluated clinical outcomes of new MBM receiving nivolumab and ipilimumab, with and without SRS. METHODS 52 patients with 171 MBM receiving nivolumab and ipilimumab for untreated MBM between 2015 and 2022 were identified at our institution. Patient and tumor characteristics including age, Karnofsky Performance Status (KPS), presence of symptoms, cancer history, MBM burden, and toleration of therapy were recorded. Outcomes measured from initiation of MBM-directed therapy included overall survival (OS), local control (LC), distant intracranial control (DIC), and intracranial control (ICC). Time-to-event analysis was conducted with the Kaplan-Meier method. RESULTS 25 patients with 74 MBM received nivolumab and ipilimumab alone. 27 patients with 97 MBM received concurrent SRS. No differences in age (p = 0.72), KPS (p = 0.94), presence of symptoms (p = 0.87), prior MBM (p = 0.90), prior MBM-directed surgery (p = 0.77) or SRS (p = 0.65), MBM size (p = 0.36), MBM number (p = 0.36), or treatment completion (p = 0.12) were seen. Median follow-up was 22.7 months. There was a trend towards higher rates of nivolumab and ipilimumab course completion in the combination group (44% vs. 24%; p = 0.12). The combination therapy group received prior immunotherapy more often than the monotherapy group (52% vs. 8.0%; p = 0.0003). OS, DIC, and ICC were similar (p = 0.16, p = 0.32, p = 0.57, respectively) with overall 12-month OS 70.7%, DIC 56.8%, and ICC 49.4%. The combination therapy group had higher 12-month LC compared to the monotherapy group (91% vs. 64%; p = 0.001). CONCLUSION In our analysis, SRS with nivolumab and ipilimumab shows superior LC compared to nivolumab and ipilimumab alone despite our combination cohort being more advanced with higher rates of prior immunotherapy. Further prospective study of combination nivolumab and ipilimumab with SRS is warranted.