Binimetinib versus dacarbazine in patients with advanced NRAS-mutant melanoma (NEMO): a multicentre, open-label, randomised, phase 3 trial

Background There are no established therapies specific for NRAS-mutant melanoma despite the emergence of immunotherapy. We aimed to assess the efficacy and safety of the MEK inhibitor binimetinib versus that of dacarbazine in patients with advanced NRAS-mutant melanoma. Methods NEMO is an ongoing, randomised, open-label phase 3 study done at 118 hospitals in 26 countries. Patients with advanced, unresectable, American Joint Committee on Cancer stage IIIC or stage IV NRAS-mutant melanoma who were previously untreated or had progressed on or after previous immunotherapy were randomised (2: 1) to receive either binimetinib 45 mg orally twice daily or dacarbazine 1000 mg/m 2 intravenously every 3 weeks. Randomisation was stratified by stage, performance status, and previous immunotherapy. The primary endpoint was progression-free survival assessed by blinded central review in the intention-to-treat population. Safety analyses were done in the safety population, consisting of all patients who received at least one study drug dose and one post-baseline safety assessment. This study is registered with ClinicalTrials.gov, number NCT01763164 and with EudraCT, number 2012-003593-51. Findings Between Aug 19, 2013, and April 28, 2015, 402 patients were enrolled and randomly assigned, 269 to binimetinib and 133 to dacarbazine. Median follow-up was 1.7 months (IQR 1.4-4.1). Median progression-free survival was 2.8 months (95% CI 2.8-3.6) in the binimetinib group and 1.5 months (1.5-1.7) in the dacarbazine group (hazard ratio 0.62 [95% CI 0.47-0.80]; one-sided p< 0.001). Grade 3-4 adverse events seen in at least 5% of patients the safety population in either group were increased creatine phosphokinase (52 [19%] of 269 patients in the binimetinib group vs none of 114 in the dacarbazine group), hypertension (20 [7%] vs two [2%]), anaemia (five [2%] vs six [5%]), and neutropenia (two [1%] vs ten [9%]). Serious adverse events (all grades) occurred in 91 (34%) patients in the binimetinib group and 25 (22%) patients in the dacarbazine group. Interpretation Binimetinib improved progression-free survival compared with dacarbazine and was tolerable. Binimetinib might represent a new treatment option for patients with NRAS-mutant melanoma after failure of immunotherapy.