Data from Adjuvant Nivolumab Versus Ipilimumab in Resected Stage III/IV Melanoma: 5-Year Efficacy and Biomarker Results From CheckMate 238

AbstractPurpose: In the phase III CheckMate 238 study, adjuvant nivolumab (NIVO) significantly improved recurrence-free survival (RFS) and distant metastasis-free survival versus ipilimumab (IPI) in patients with resected stage IIIB–C or stage IV melanoma, with benefit sustained at 4 years. We report updated 5-year efficacy and biomarker findings. Patients and Methods: Patients with resected stage IIIB–C/IV melanoma were stratified by stage and baseline PD-L1 expression and received NIVO 3 mg/kg every 2 weeks or IPI 10 mg/kg every 3 weeks for four doses and then every 12 weeks, both intravenously for 1 year until disease recurrence, unacceptable toxicity, or withdrawal of consent. The primary endpoint was RFS. Results: At a minimum follow-up of 62 months, RFS with NIVO remained superior to IPI (HR 0.72; 95% CI, 0.60–0.86; 5-year rates of 50% versus 39%). 5-year DMFS rates were 58% with NIVO versus 51% with IPI. Five-year OS rates were 76% with NIVO and 72% with IPI (75% data maturity: 228 of 302 planned events). Higher levels of TMB, tumor PD-L1, intratumoral CD8+ T cells and interferon-gamma–associated gene expression signature, and lower levels of peripheral serum C-reactive protein were associated with improved RFS and OS with both NIVO and IPI, albeit with limited clinically meaningful predictive value. Conclusion: NIVO is a proven adjuvant treatment for resected melanoma at high-risk of recurrence, with sustained, long-term improvement in RFS and DMFS compared with IPI and high OS rates. Identification of additional biomarkers are needed to better predict treatment outcome.