COLUMBUS 7-year update: A randomized, open-label, phase III trial of encorafenib plus binimetinib versus vemurafenib or encorafenib in patients with BRAF V600E/K-mutant melanoma

Background: Treatment with encorafenib plus binimetinib and encorafenib monotherapy is associated with improved progression-free survival (PFS) and overall survival (OS) compared with vemurafenib in patients with BRAF V600E/K-mutant metastatic melanoma. We report results from the 7 -year analysis of COLUMBUS part 1 (NCT01909453) at 99.7 months (median duration between randomization and data cutoff). Methods: 577 patients with locally advanced unresectable or metastatic BRAF V600E/K-mutant melanoma who were treatment-naive or progressed after first -line immunotherapy were randomized 1:1:1 to encorafenib 450 mg once daily (QD) plus binimetinib 45 mg twice daily (BID) (n = 192), vemurafenib 960 mg BID (n = 191), or encorafenib monotherapy 300 mg QD (n = 194). No prior BRAF/MEK inhibitor was allowed. Results: Seven-year PFS and OS rates (95 % CI) were 21.2 % (14.7 -28.4 %) and 27.4 % (21.2 -33.9%) in the encorafenib plus binimetinib arm and 6.4 % (2.1 -14.0 %) and 18.2 % (12.8 -24.3 %) in the vemurafenib arm, respectively. Median melanoma-specific survival (95 % CI) was 36.8 months (27.7 -51.5 months) in the encorafenib plus binimetinib arm and 19.3 months (14.8-25.9 months) in the vemurafenib arm. Thirty-four longterm responders (complete/partial response ongoing at 7 years) were identified across arms. Conclusions: This is the longest follow-up from a phase III trial of BRAF/MEK inhibitor combination in BRAF V600E/K-mutant metastatic melanoma. Safety results were consistent with the known tolerability profile of encorafenib plus binimetinib. Results support the long-term efficacy and known safety of encorafenib plus binimetinib in this population and provide new insights on long-term responders. Interactive data visualization is available at the COLUMBUS dashboard (https://clinical-trials.dimensions.ai/columbus7/).