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

PURPOSE: In the phase III CheckMate 238 study, adjuvant nivolumab significantly improved recurrence-free survival (RFS) and distant metastasis-free survival versus ipilimumab 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 programmed death cell ligand 1 (PD-L1) expression and received nivolumab 3 mg/kg every 2 weeks or ipilimumab 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 nivolumab remained superior to ipilimumab (HR = 0.72; 95% confidence interval, 0.60-0.86; 5-year rates of 50% vs. 39%). Five-year distant metastasis-free survival (DMFS) rates were 58% with nivolumab versus 51% with ipilimumab. Five-year overall survival (OS) rates were 76% with nivolumab and 72% with ipilimumab (75% data maturity: 228 of 302 planned events). Higher levels of tumor mutational burden (TMB), tumor PD-L1, intratumoral CD8+ T cells and IFNγ-associated gene expression signature, and lower levels of peripheral serum C-reactive protein were associated with improved RFS and OS with both nivolumab and ipilimumab, albeit with limited clinically meaningful predictive value. CONCLUSIONS: Nivolumab is a proven adjuvant treatment for resected melanoma at high risk of recurrence, with sustained, long-term improvement in RFS and DMFS compared with ipilimumab and high OS rates. Identification of additional biomarkers is needed to better predict treatment outcome. See related commentary by Augustin and Luke, p. 3253.

Encephalitis Associated With Immune Checkpoint Inhibitor Treatment in Patients With Melanoma.

Since the approval of immune checkpoint anti-programmed cell death protein 1 antibodies (pembrolizumab and nivolumab) and anti-cytotoxic T-lymphocyte-associated protein 4 (ipilimumab) in combination or monotherapy, significant advances have been made in the treatment of metastatic melanoma. The nonspecific immune stimulation resulting from these drugs can case a wide range of side effects in many organs including the nervous system, named immune-related adverse events. Few immune-related encephalitis associated with these antibodies have been described in the literature. It is a rare complication (<1% of the total of immune-related adverse events) but it can be fatal if not diagnosed and treated on time. We describe 3 cases of patients with melanoma, which were treated with a combination of ipilimumab-nivolumab (case 1), ipilimumab monotherapy (case 2), and nivolumab monotherapy (case 3), who developed an encephalitis which was related to immune checkpoint therapy.