Nivolumab (NIVO) plus relatlimab (RELA) vs NIVO in previously untreated metastatic or unresectable melanoma (RELATIVITY-047): Overall survival (OS) and melanoma-specific survival (MSS) outcomes at 3 years.

9524 Background: NIVO + RELA as a fixed-dose combination (FDC) demonstrated a statistically significant progression-free survival (PFS) benefit vs NIVO in RELATIVITY-047 (NCT03470922), with a clinically meaningful, but not statistically significant, improvement in OS and a numerically higher objective response rate (ORR), resulting in regulatory approval of the FDC. Here we report updated descriptive analyses with 3 years of follow-up. Methods: Patients (pts) were randomized 1:1 to receive NIVO 480 mg + RELA 160 mg FDC or NIVO 480 mg Q4W. PFS per RECIST v1.1 was assessed by blinded independent central review (BICR); secondary endpoints included OS and ORR per BICR. Exploratory analyses included MSS (death due to melanoma, with censoring of deaths due to other causes), CNS metastasis-free survival in specified populations, and efficacy on subsequent systemic therapy. Results: At database lock (19 Oct 2023), median follow-up was 33.8 months (mo; range, 0.3–64.2). NIVO + RELA continued to show a benefit vs NIVO for PFS, OS, ORR, and MSS (Table). NIVO + RELA was also favored over NIVO across the majority of key subgroups. Subsequent systemic therapy was received by 135 pts (38%) on NIVO + RELA and 141 pts (39%) on NIVO. Grade 3–4 treatment-related adverse events (TRAEs) occurred in 78 pts (22%) on NIVO + RELA and 43 pts (12%) on NIVO; TRAEs (any grade) led to treatment discontinuation in 63 pts (18%) and 35 pts (10%), respectively. No new treatment-related deaths were reported since the last analysis. Conclusions: At 3 years of follow-up, NIVO + RELA continued to show a benefit vs NIVO for PFS, OS, ORR, and MSS. OS and MSS demonstrated sustained improvement, with the OS HR 95% CI upper bound < 1. Efficacy results also continued to favor NIVO + RELA vs NIVO across the majority of prespecified subgroups. Safety of NIVO + RELA remained consistent with previous reports, with no new or unexpected safety signals. CNS metastasis-free survival and efficacy outcomes on subsequent systemic therapy will be presented. Clinical trial information: NCT03470922 . Table: see text