Nivolumab plus ipilimumab or nivolumab alone versus ipilimumab alone in advanced melanoma (CheckMate 067): 4-year outcomes of a multicentre, randomised, phase 3 trial

Background: Previously reported results from the phase 3 CheckMate 067 trial showed a significant improvement in objective responses, progression-free survival, and overall survival with nivolumab plus ipilimumab or nivolumab alone compared with ipilimumab alone in patients with advanced melanoma. The aim of this report is to provide 4-year updated efficacy and safety data from this study.

Methods: In this phase 3 trial, eligible patients were aged 18 years or older with previously untreated, unresectable, stage III or stage IV melanoma, known BRAF^V600 mutation status, and an Eastern Cooperative Oncology Group performance status of 0 or 1. Patients were randomly assigned 1:1:1 to receive intravenous nivolumab 1 mg/kg plus ipilimumab 3 mg/kg every 3 weeks for four doses, followed by nivolumab 3 mg/kg every 2 weeks, or nivolumab 3 mg/kg every 2 weeks plus placebo, or ipilimumab 3 mg/kg every 3 weeks for four doses plus placebo. Randomisation was done via an interactive voice response system with a permuted block schedule (block size of six) and stratification by PD-L1 status, BRAF mutation status, and metastasis stage. The patients, investigators, study site staff, and study funder were masked to the study drug administered. The co-primary endpoints were progression-free survival and overall survival. Efficacy analyses were done on the intention-to-treat population, whereas safety was assessed in all patients who received at least one dose of study drug. The results presented in this report reflect the 4-year update of the ongoing study with a database lock date of May 10, 2018. This study is registered with ClinicalTrials.gov, number NCT01844505.

Findings: Between July 3, 2013, and March 31, 2014, 945 patients were enrolled and randomly assigned to nivolumab plus ipilimumab (n=314), nivolumab (n=316), or ipilimumab (n=315). Median follow-up was 46·9 months (IQR 10·9-51·8) in the nivolumab plus ipilimumab group, 36·0 months (10·5-51·4) in the nivolumab group, and 18·6 months (7·6-49·5) in the ipilimumab group. At a minimum follow-up of 48 months from the date that the final patient was enrolled and randomised, median overall survival was not reached (95% CI 38·2-not reached) in the nivolumab plus ipilimumab group, 36·9 months (28·3-not reached) in the nivolumab group, and 19·9 months (16·9-24·6) in the ipilimumab group. The hazard ratio for death for the combination versus ipilimumab was 0·54 (95% CI 0·44-0·67; p<0·0001) and for nivolumab versus ipilimumab was 0·65 (0·53-0·79; p<0·0001). Median progression-free survival was 11·5 months (95% CI 8·7-19·3) in the nivolumab plus ipilimumab group, 6·9 months (5·1-10·2) in the nivolumab group, and 2·9 months (2·8-3·2) in the ipilimumab group. The hazard ratio for progression-free survival for the combination versus ipilimumab was 0·42 (95% CI 0·35-0·51; p<0·0001) and for nivolumab versus ipilimumab was 0·53 (0·44-0·64; p<0·0001). Treatment-related grade 3-4 adverse events were reported in 185 (59%) of 313 patients who received nivolumab plus ipilimumab, 70 (22%) of 313 who received nivolumab, and 86 (28%) of 311 who received ipilimumab. The most common treatment-related grade 3 adverse events were diarrhoea in the nivolumab plus ipilimumab group (29 [9%] of 313) and in the nivolumab group (nine [3%] of 313) and colitis in the ipilimumab group (23 [7%] of 311); the most common grade 4 adverse event in all three groups was increased lipase (15 [5%] of 313 in the combination group, ten [3%] of 313 in the nivolumab group, and four [1%] of 311 in the ipilimumab group). Serious adverse events were not analysed for the 4-year follow-up. In total for the study, there were four treatment-related deaths: two in the nivolumab plus ipilimumab group (one cardiomyopathy and one liver necrosis), one in the nivolumab group (neutropenia), and one in the ipilimumab group (colon perforation). No additional treatment-related deaths have occurred since the previous (3-year) analysis.

Interpretation: The results of this analysis at 4 years of follow-up show that a durable, sustained survival benefit can be achieved with first-line nivolumab plus ipilimumab or nivolumab alone in patients with advanced melanoma.

Funding: Bristol-Myers Squibb.