Update on overall survival in COLUMBUS: A randomized phase III trial of encorafenib (ENCO) plus binimetinib (BINI) versus vemurafenib (VEM) or ENCO in patients with BRAF V600-mutant melanoma

10012 Background: Treatment of patients with BRAF V600–mutant melanoma includes BRAF/MEK-inhibitor combinations based on demonstrated benefits on progression-free survival (PFS) and overall survival (OS). To better understand the proportion of patients who derive long-lived benefit and their characteristics, we performed an updated analysis of OS and other endpoints from the COLUMBUS trial. Methods: In Part 1 of COLUMBUS, 577 patients with advanced/metastatic BRAF V600‒mutant melanoma, untreated or progressed after first-line immunotherapy, were randomized 1:1:1 to ENCO 450 mg QD + BINI 45 mg BID (COMBO450) vs VEM 960 mg BID (VEM) or ENCO 300 mg QD (ENCO300). An updated analysis including PFS, OS, objective response rate (ORR), and safety was conducted after an additional 24 months’ follow-up from the initial analysis. The study is ongoing. Results: At data cutoff (November 2019, as-is data), events had occurred in 65%, 59%, and 75% of patients in the COMBO450, ENCO300, and VEM treatment arms, respectively. Across arms, median follow-up for OS was 60.6 months (mo), with median OS of 33.6 mo (95% CI, 24.4–39.2) for COMBO450, 23.5 mo (95% CI, 19.6–33.6) for ENCO300, and 16.9 mo (95% CI, 14.0–24.5) for VEM. Compared to VEM, COMBO450 decreased the risk of death by 38% (HR, 0.62 [95% CI, 0.49–0.79]). Updated median PFS was COMBO450, 14.9 mo (95% CI, 11.0–20.2), ENCO300, 9.6 mo (95% CI, 7.4–14.8), and VEM, 7.3 mo (95% CI, 5.6–7.9). PFS was longer for COMBO450 vs VEM (HR, 0.52 [95% CI, 0.40–0.67]). A landmark analysis showed a higher rate of OS for COMBO450 at each year analyzed, with OS rates at 4 years of 39%, 37%, and 26% COMBO450, ENCO300, and VEM, respectively. Updated safety analysis confirmed the beneficial long-term tolerability of COMBO450. Conclusions: In the COLUMBUS trial, results for updated PFS and OS with COMBO450 continue to demonstrate long-term benefits in patients with BRAF V600‒mutated melanoma. Clinical trial information: NCT01909453.