primary analysis of the RANDOMIZED eortc-2139/columbus-ad trial: adjuvant encorafenib and binimetinib versus placebo in high-risk stage II BRAF-V600E/K melanoma

Purpose: Stage IIB/IIC melanoma has a high risk of recurrence after resection. Combined BRAF/MEK inhibitor therapy showed benefit in resected high-risk stage III and advanced melanoma. The objective of this study was to investigate its role in stage IIB/IIC. Methods: Adult patients with resected stage IIB/IIC cutaneous melanoma which had a BRAF V600E/K mutation were randomized 1:1 to receive encorafenib (enco) 450 mg QD + binimetinib (bini) 45 mg BID orally for one year or placebo. The study planned to randomize 815 patients and was designed to demonstrate superiority regarding recurrence-free survival (RFS). Following a premature termination of accrual, the study was amended with safety as the primary endpoint and RFS as secondary endpoint. Results: Between June 9, 2022, and October 9, 2023, 339 patients were screened for a BRAF mutation and 110 randomized. Data cutoff was 19 Nov. 2024, after the last patient discontinued study participation. Among randomized patients, 87 (79%) had a BRAF V600E mutation, and 39 (35%) AJCC8 stage IIC. Median follow-up was 12 and 7 months for enco/bini and placebo arms, respectively. Among 54 patients who initiated enco + bini, grade ≥ 3 treatment-related adverse events (AE) occurred in 13 (24%) patients, and 18 (33%) patients had an AE leading to permanent treatment discontinuation. RFS at 12 months was 86% (95% CI: 65-95%) in the enco + bini and 70% (95% CI: 46-85%) in the placebo arm, distant metastasis-free survival at 12 months was 92% (95% CI: 77-97%) for enco + bini and 82% (95% CI: 55-93%) for placebo. Conclusion: EORTC 2139 - Columbus-AD demonstrated a consistent and manageable safety profile and encouraging efficacy results for the combination of enco and bini in resected stage IIB/C BRAF V600E/K-mutated cutaneous melanomas.