Encorafenib plus cetuximab with or without binimetinib in patients with BRAF V600E-mutated metastatic colorectal cancer: real-life data from an Italian multicenter experience.

BACKGROUND: Encorafenib plus cetuximab with or without binimetinib showed increased objective response rate (ORR), progression-free survival (PFS), and overall survival (OS) compared with chemotherapy plus anti-EGFR in previously treated patients with BRAF V600E-mutated (mut) metastatic colorectal cancer (mCRC). Although no formal comparison was planned, addition of binimetinib to encorafenib plus cetuximab did not provide significant efficacy advantage. PATIENTS AND METHODS: This real-life study was aimed at evaluating safety, activity, and efficacy of encorafenib plus cetuximab with or without binimetinib in patients with BRAF V600E-mut mCRC treated at 21 Italian centers within a nominal use program launched in May 2019. RESULTS: Out of 133 patients included, 97 (73%) received encorafenib plus cetuximab (targeted doublet) and 36 (27%) the same therapy plus binimetinib (targeted triplet). Most patients had Eastern Cooperative Group Performance Status (ECOG-PS) of 0 or 1 (86%), right-sided primary tumor (69%), and synchronous disease (66%). Twenty (15%) tumors were DNA mismatch repair deficiency (dMMR)/microsatellite instability (MSI)-high. As many as 44 (34%) patients had received two or more prior lines of therapy, 122 (92%) were previously exposed to oxaliplatin, and 109 (82%) to anti-vascular endothelial growth factor (anti-VEGF). Most frequent adverse events were asthenia (62%) and anti-EGFR-related skin rash (52%). Any grade nausea (P = 0.03), vomiting (P = 0.04), and diarrhea (P = 0.07) were more frequent with the triplet therapy, while melanocytic nevi were less common (P = 0.06). Overall, ORR and disease control rate (DCR) were 23% and 69%, respectively, with numerically higher rates in the triplet group (ORR 31% versus 17%, P = 0.12; DCR 78% versus 65%, P = 0.23). Median PFS and OS were 4.5 and 7.2 months, respectively. Worse ECOG-PS, peritoneal metastases, and more than one prior treatment were independent poor prognostic factors for PFS and OS. Clonality of BRAF mutation measured as adjusted mutant allele fraction in tumor tissue was not associated with clinical outcome. CONCLUSIONS: Our real-life data are consistent with those from the BEACON trial in terms of safety, activity, and efficacy. Patients in good general condition and not heavily pretreated are those more likely to derive benefit from the targeted treatment.

Binimetinib, encorafenib and cetuximab (BEACON Trial) combination therapy for patients with BRAF V600E-mutant metastatic colorectal cancer.

BRAF V600E mutations are associated with 8-10% of metastatic colorectal cancers (mCRC) and carry a poor prognosis with limited therapeutic options. In contrast to metastatic melanoma, BRAF inhibition alone or in combination with mitogen-activated protein kinase kinase (MEK) inhibitors has shown little utility in the treatment of BRAF V600E-mutant mCRC. This is secondary to upstream activation of the epidermal growth factor receptor (EGFR) pathway and other escape mechanisms. Combining RAF and MEK inhibitors with inhibition of the EGFR pathway through an anti-EGFR receptor antibody (cetuximab) led to the BEACON clinical trial (binimetinib, encorafenib and cetuximab). Trial patients had undergone at least one prior line of chemotherapy. The trial met all its endpoints and is now included in NCCN (National Comprehensive Cancer Network) guidelines. Herein we provide updates in treatment options for patients with BRAF V600E-mutant mCRC, focusing on the practice-changing BEACON-triplet regimen, the first chemotherapy-free combination regimen for mCRC. This combination is being explored frontline in the ANCHOR clinical trial.