Multicenter randomized phase 2 trial of nivolumab with or without ipilimumab for melanoma brain metastases: 7-year follow-up of ABC

The phase 2 ABC trial, at four centers in Australia, randomized patients with asymptomatic melanoma brain metastases (MBM) and no previous brain-directed therapy to nivolumab plus ipilimumab (cohort A) or nivolumab alone (cohort B). Patients with previous brain-directed therapy, neurological symptoms, or leptomeningeal disease were non-randomized assigned to cohort C (nivolumab alone). Seven-year intracranial progression-free survival was 42% (95% CI 29-63) in cohort A, 15% (6-39) in cohort B, and 6% (1-42) in cohort C; whereas 7-year overall survival was 48% (34-68) in cohort A, 26% (13-51) in cohort B, and 13% (3-46) in cohort C. There were no new safety signals. The authors conclude that nivolumab plus ipilimumab maintains efficacy for at least 7 years in patients with asymptomatic MBM.