BRAFV600E Mutant Metastatic Colorectal Cancer Research Articles

Clinicopathologic features and treatment efficacy of patients with BRAF V600E-mutated metastatic colorectal cancer: a multi-center real-world propensity score matching study.

Patients with BRAF 600E mutated mCRC are associated with specific clinicopathological features and poor prognosis. The relative efficacy of first-line FOLFOXIRI triplet chemotherapy or doublet chemotherapy combined with bevacizumab in patients with BRAF 600E mutated mCRC remains controversial. BRAF V600E-mutated mCRC patients from 3 institutions were included. The clinicopathological characteristics of the enrolled patients were analyzed. Overall survival (OS) of patients was divided into 4 fractions, including 0-25%, 25-50%, 50-75%,75-100% by quartile method. Patients with OS ranging from 0 to 25% were defined as the poor prognosis group, and patients with OS ranging from 75 to 100% were defined as the good prognosis group. A propensity score matching (PSM) analysis was performed to balance the baseline characteristics of patients treated with doublet chemotherapy and triplet chemotherapy combined with bevacizumab. Survival and tumor response of the two regimens were evaluated. A total of 125 patients with BRAF V600E-mutated mCRC were enrolled. The median OS of BRAF V600E-mutated mCRC was 14.9 months and the median PFS of first-line therapy was 6.1 months. According to the multivariate analysis and the difference in baseline characteristics between the poor prognosis group and the good prognosis group, poor differentiation and liver metastasis were negative independent prognostic factors for OS in patientsx with BRAF V600E-mutated mCRC. Patients treated with first-line triplets had a longer OS than those treated with doublets both before PSM (17.4 months vs. 13.4 months, p = 0.022) and after PSM (17.4 months vs. 10.4 months, p = 0.004). There was no significant benefit between triplet-drug group and doublet-drug group for PFS, ORR and DCR. Subgroup analysis showed that patients in the triplet-drug group had a better prognosis with the following favorable factors: age ≤ 60 years old, PS score of 0-1, liver metastases and multiple organ metastases. The overall prognosis of BRAF V600E mutant mCRC patients is poor. Poor differentiation and liver metastases were negative independent prognostic factors for OS. First-line triplet-drug therapy was associated with better OS, especially in patients with good physical condition and high tumor burden.

Expert consensus on the optimal management of BRAFV600E-mutant metastatic colorectal cancer in the Asia-Pacific region.

The burden of colorectal cancer (CRC) is high in the Asia-Pacific region, and several countries in this region have among the highest and/or fastest growing rates of CRC in the world. A significant proportion of patients will present with or develop metastatic CRC (mCRC), and BRAFV600E-mutant mCRC represents a particularly aggressive phenotype that is less responsive to standard chemotherapies. In light of recent therapeutic advances, an Asia-Pacific expert consensus panel was convened to develop evidence-based recommendations for the diagnosis, treatment, and management of patients with BRAFV600E-mutant mCRC. The expert panel comprised nine medical oncologists from Australia, Hong Kong, Singapore, and Taiwan (the authors), who met to review current literature and develop eight consensus statements that describe the optimal management of BRAFV600E-mutant mCRC in the Asia-Pacific region. As agreed by the expert panel, the consensus statements recommend molecular testing at diagnosis to guide individualized treatment decisions, propose optimal treatment pathways according to microsatellite stability status, advocate for more frequent monitoring of BRAFV600E-mutant mCRC, and discuss local treatment strategies for oligometastatic disease. Together, these expert consensus statements are intended to optimize treatment and improve outcomes for patients with BRAFV600E-mutant mCRC in the Asia-Pacific region.

MOGAT3-Mediated DAG Accumulation Drives Acquired Resistance to Anti-BRAF/EGFR Therapy in BRAFV600E-Mutant Metastatic Colorectal Cancer.

BRAFV600E-mutant metastatic colorectal cancer (mCRC) is associated with poor prognosis. The combination of anti-BRAF/EGFR (encorafenib/cetuximab) treatment for patients with BRAFV600E-mutant mCRC improved clinical benefits; unfortunately, inevitable acquired resistance limits the treatment outcome, and the mechanism has not been validated. Here, we discovered that monoacylglycerol O-Acyltransferase 3 (MOGAT3) mediated diacylglycerol (DAG) accumulation contributed to acquired resistance to encorafenib/cetuximab by dissecting BRAFV600E-mutant mCRC patient-derived xenograft (PDX) model exposed to encorafenib/cetuximab administration. Mechanistically, upregulated MOGAT3 promotes DAG synthesis and reduces fatty acid oxidation (FAO)-promoting DAG accumulation and activating PKCα-CRAF-MEK-ERK, driving acquired resistance. Resistance-induced hypoxia promotes MOGAT3 transcriptional elevation; simultaneously, MOGAT3-mediated DAG accumulation increases HIF1A expression in translation level through PKCα-CRAF-eIF4E activation, strengthening the resistance status. Intriguingly, reducing intratumoral DAG by fenofibrate or Pf-06471553 restores the antitumor efficacy of encorafenib/cetuximab on resistant BRAFV600E-mutant mCRC, interrupted PKCα-CRAF-MEK-ERK signaling. These findings reveal the critical metabolite DAG as a modulator of encorafenib/cetuximab efficacy in BRAFV600E-mutant mCRC, suggesting that fenofibrate may prove beneficial for resistant BRAFV600E-mutant mCRC patients.

Durable Remission After Targeted Therapy in BRAF V600E–Mutant Metastatic Colorectal Cancer: Case Report

ABSTRACT BRAF mutation leads to constitutive activation of the MAPK pathway and is associated with the immune-activating molecular subtype of colorectal cancer. Targeted therapy for BRAF V600E–mutant metastatic colorectal cancer (CRC) has significantly improved outcomes for these patients when combined with anti–epithelial growth factor receptor (EGFR) therapy. However, most patients ultimately develop disease progression. We report a case of a patient with metastatic-deficient mismatch repair, BRAF V600E–mutated CRC, who achieved a durable complete response to vemurafenib plus cetuximab and chemotherapy despite initial high burden of disease, including peritoneal involvement. Recent clinical trials of combined anti-EGFR/anti–BRAF V600E therapy in BRAF V600E-mutant CRCs have found a few instances of robust response. Further study of combined targeted and chemotherapeutic regimens and the immunogenic properties of BRAF mutation may yield promising results.

515MO Encorafenib + cetuximab (EC) + FOLFIRI for BRAF V600E-mutant metastatic colorectal cancer (mCRC): Updated results from the BREAKWATER safety lead-in (SLI)

515MO Encorafenib + cetuximab (EC) + FOLFIRI for BRAF V600E-mutant metastatic colorectal cancer (mCRC): Updated results from the BREAKWATER safety lead-in (SLI)

Encorafenib plus cetuximab in patients with metastatic, BRAF V600E-mutated, colorectal carcinoma: First effectiveness data of the European multi-centric, multi-national, non-interventional study—BERING-CRC.

3551 Background: Targeted treatment with encorafenib plus cetuximab (E+C) represents the standard of care for patients with BRAF V600E-mutant metastatic colorectal cancer after prior systemic therapy. The approval was based on the data from the BEACON CRC trial; updated data of the trial showed a median progression free survival (mPFS) of 4.3 months and a median overall survival (mOS) of 9.3 months for the treatment with E+C compared to a mPFS of 1.5 months and a mOS of 5.9 months with chemotherapy plus cetuximab (hazard ratio [HR], 0.61 [95% CI, 0.48 to 0.77]) and an objective response rate (ORR) of 20% compared to 2%. The tolerability profile was consistent with the known safety profile of each agent and was generally well tolerated. As data from controlled clinical trials are based on a selected patient population, the non-interventional study (NIS) BERING CRC investigates the use of E+C at real-world conditions in a broader patient population. Methods: BERING CRC is an ongoing multi-national, multi-centric, prospective, longitudinal NIS. It represents the first NIS to investigate the real-world use of E+C in BRAF V600E-mutant metastatic colorectal cancer in Germany, Austria and Switzerland. The study aims to enroll 300 patients (pts) from 124 sites, treated according to the label. The primary study objective is to assess the 1-year OS rate. Secondary endpoints include effectiveness outcomes, quality of life, safety and tolerability of the treatment. The influence of prognostic factors on efficacy, as well as safety and tolerability will also be assessed. Results: Here we present the first planned effectiveness analysis based on the initial 100 enrolled pts (95 treated / 95 evaluable; median observation time: 5.9 mo). This analysis set showed an older patient population compared to the BEACON trial with a median age of 67 yrs (BEACON: 61 yrs) and fewer ECOG PS 0 patients (0/1/2/3: BERING 36/50/8/2 % vs BEACON 51/47/2/0 %). 96% presented with distant metastases (liver: 54%), with an involvement of ≥3 organ systems in 14%. E+C was mainly administered after one prior systemic therapy (73%). ORR was 24%, mPFS 5.3 months and mOS 10.3 months. Treatment emergent adverse events (TEAE) were reported in 73% of pts (grade 3/4: 38%). Main TEAE (≥10%, all grades) were: rash (12%) and nausea (11%). Conclusions: This first effectiveness analysis of BERING CRC shows the use of E+C in a real-world population. Despite the older study population and less ECOG PS 0 patients as compared to the pivotal study, the observed treatment effectiveness and safety profile are consistent with data from the BEACON CRC study. The recruitment of this study is ongoing and future analysis of the study will include an additional analysis of subgroups, effectiveness and QoL. Clinical trial information: NCT04673955 .

91P Clinical outcomes of patients (Pts) with BRAF V600E-mutant metastatic colorectal cancer (mCRC) treated with first-line (1L) chemotherapy regimens

91P Clinical outcomes of patients (Pts) with BRAF V600E-mutant metastatic colorectal cancer (mCRC) treated with first-line (1L) chemotherapy regimens

Efficacy-effectiveness analysis on survival in a population-based real-world study of BRAF-mutated metastatic colorectal cancer patients treated with encorafenib-cetuximab.

Encorafenib-cetuximab has been approved for pretreated BRAFV600E-mutated metastatic colorectal cancer (mCRC) patients based on efficacy demonstrated in the randomized phase III BEACON trial. The aim of this real-world effectiveness study is to improve knowledge on the generalizability of trial results. This population-based real-world study includes all mCRC patients in the Netherlands treated with encorafenib-cetuximab since approval. Individual patient data and pathology reports were collected. Overall survival (OS) was compared to BEACON and subgroup analyses were conducted for patients who would have been eligible and ineligible for BEACON. 166 patients were included with a median follow-up time of 14.5 months. Median OS was 6.7 months (95% CI:6.0-8.3) and differed from BEACON (9.3 months; 95% CI:8.0-11.3, p-value 0.002). Thirty-six percent of real-world patients would have been ineligible for the BEACON trial. Trial ineligible subgroups with symptomatic brain metastases and WHO performance status ≥2 had the poorest median OS of 5.0 months (95% CI:4.0-NR) and 3.9 months (95% CI:2.4-NR). This real-world cohort of mCRC patients treated with encorafenib-cetuximab showed a clinically relevant efficacy-effectiveness gap for OS. The chance of survival benefit from encorafenib-cetuximab in patients with brain metastases and/or WHO performance status ≥2 is negligible as neither efficacy nor effectiveness has been demonstrated.

Updates in BRAF V600E-Mutated Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second leading cause of cancer death. Approximately one in five patients with CRC present with metastatic disease at diagnosis. The BRAF V600E mutation occurs in 8–12% of patients with metastatic colorectal cancer (mCRC), and is characterised by an aggressive clinical course and poor prognosis. This article is based on a webinar discussion in March 2024, between two experts in gastrointestinal cancers, Chiara Cremolini, University of Pisa, Italy; and Julien Taieb, Georges Pompidou European Hospital, Université Paris-Cité, France, both of whom have a wealth of experience and expertise in the clinical management of CRC. The experts described the most important recent advances in the treatment of BRAF V600E-mutated mCRC, including data presented at the European Society for Medical Oncology (ESMO) Congress in October 2023, and the American Society of Clinical Oncology (ASCO) Gastrointestinal (GI) Cancers Symposium in January 2024. Cremolini and Taieb gave valuable insights into topics such as the aggressive nature of BRAF V600E-mutated mCRC, and how this impacts choice of treatment, patient outcomes, and quality of life, as well as the importance of early testing and monitoring. The experts also discussed how the BRAF V600E mutation impacts treatment response and outcomes in patients with microsatellite unstable (microsatellite instability [MSI]) versus microsatellite stable (MSS) tumours, and recent key clinical trials in BRAF V600E-mutated mCRC. The importance of surgery in the multidisciplinary management of patients with BRAF V600E-mutated mCRC, BRAF as a prognostic marker in resected CRC, and real-world studies in this field were also explored. Finally, Cremolini and Taieb described what the future of the management of patients with BRAF V600E-mutated mCRC might look like, and which advancements in research they would like to see.

Safety and Efficacy of Encorafenib, Binimetinib, and Cetuximab for BRAFV600E-Mutant Metastatic Colorectal Cancer: Results of the Japanese Expanded Access Program

BackgroundThe phase 3 BEACON CRC study demonstrated the survival benefits of encorafenib and cetuximab, with or without binimetinib (the BEACON triplet or doublet regimen), for BRAFV600E-mutant metastatic colorectal cancer (mCRC). This expanded access program (EAP) and subsequent follow-up study assessed the efficacy and safety of the BEACON triplet regimen in Japanese patients with BRAFV600E-mutant mCRC. Materials and MethodsThe EAP was an open-label, single-arm study including Japanese patients with BRAFV600E-mutant mCRC whose disease progressed after 1 to 2 prior regimens. The patients received the BEACON triplet regimen with 28-day cycles. The subsequent follow-up study assessed the survival outcomes following EAP completion. Safety was assessed only during the EAP. ResultsAmong the 86 enrolled patients, 81 received the BEACON triplet regimen. The objective response rate and median progression-free survival were 27.6% (95% confidence interval [CI], 18.0%-39.1%) and 5.26 (95% CI, 4.14-5.52) months, respectively. Grade 3 to 4 adverse events and treatment-related adverse events occurred in 43.2% and 28.4% of patients, respectively. No new safety signals were observed during the EAP. Among 58 patients with confirmed survival at EAP completion, 57 were included in the follow-up study. With a median observation period of 9.17 months through the EAP and follow-up study, the median overall survival was 10.38 (95% CI, 9.00-16.16) months. ConclusionThe efficacy and safety of the BEACON triplet regimen in Japanese patients with BRAFV600E-mutant mCRC were consistent with those reported in the BEACON CRC trial, supporting its use as a standard treatment for pretreated patients with BRAFV600E-mutant mCRC.

Real-world evaluation of clinical outcomes and long-term survivors in patients with BRAF-V600E metastatic colorectal cancer.

166 Background: BRAF-V600E mutant metastatic colorectal cancer (BRAF-V600E mCRC) is associated with poor prognosis but confers response to combination BRAF/EGFR blockade. The goal of this study is to evaluate the clinicopathologic features and natural history of BRAF-V600E mCRC in the era prior to combination BRAF/EGFR inhibitors. Methods: This is a retrospective study of patients treated at the Ottawa Hospital Cancer Centre with BRAF-V600E mCRC who did not receive combination BRAF/EGFR therapy. Patients diagnosed with colorectal cancer prior to March 31, 2021, were included. Demographic, clinical, pathologic and cancer characteristics were abstracted from electronic medical records. Outcomes of interest included duration of therapy, as a surrogate of progression free survival, and overall survival (OS). Long-term survivor was defined as OS greater than 2 years. Results: 74 patients were included. Median age was 70 years (IQR=61-78), and 39 (53%) patients were female. There were 17 (23%) patients alive at the end of the follow-up period. 31 (42%) patients had poorly differentiated grade and 26 (35%) were mismatch repair deficient (dMMR). Locations of metastases included liver (40, 54%), peritoneum (30, 41%), lung (18, 24%), bone (5, 7%) and brain (5, 7%). Overall, 64 (86%) patients received first line systemic therapy, 19 (26%) second line, and 5 (7%) third line (see Table). Median duration of therapy in the first line was 4.3 months (IQR=2.0-9.6), second line was 2.9 months (IQR=1.4-4.1), and third line 1.0 months (IQR=1.0-1.9). Overall survival in the entire cohort was 13.2 months (IQR=4.6-25.4). Importantly, 21 (28%) patients were long-term survivors, of which 8 (11%) were dMMR. Conclusions: Patients with BRAF-V600E mCRC generally have poor clinical outcomes with traditional systemic therapies. In this study, we identified approximately 25% of patients who are long-term survivors (OS >2 years). This reflects the real-world heterogeneity of clinical outcomes for patients with BRAF-V600E mCRC who did not receive BRAF/EGFR targeted therapy.[Table: see text]

Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Association of PD-L1 and PD-L2 expression and tumor-infiltrating lymphocytes in BRAF V600E-mutated metastatic colorectal cancer: GI-SCREEN post-hoc analysis

Association of PD-L1 and PD-L2 expression and tumor-infiltrating lymphocytes in BRAF V600E-mutated metastatic colorectal cancer: GI-SCREEN post-hoc analysis

Commentary on Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Commentary on Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Encorafenib plus cetuximab in patients with BRAFV600E-mutated metastatic colorectal cancer — Polish multicenter experience

Predictive Impact of RNF43 Mutations in Patients With Proficient Mismatch Repair/Microsatellite Stable BRAFV600E-Mutated Metastatic Colorectal Cancer Treated With Target Therapy or Chemotherapy.

Target therapy (TT) with encorafenib plus cetuximab is a standard option in patients with BRAFV600E-mutated (mut) pretreated metastatic colorectal cancer (mCRC). Recently, mutations in RNF43, encoding a negative regulator of the WNT pathway, were associated with longer progression-free survival (PFS) and overall survival (OS) in patients with proficient mismatch repair/microsatellite stable (pMMR/MSS) BRAFV600E-mut mCRC treated with TT. Here, we explored the effect of RNF43 mutations on the efficacy of second-line TT versus standard chemotherapy (CT). A retrospective cohort of patients with pMMR/MSS BRAFV600E-mut tumors, available RNF43 mutational status, and treated with second-line TT or oxaliplatin- and/or irinotecan-based CT was analyzed. One hundred thirty-two patients with pMMR/MSS BRAFV600E-mut mCRC were included. RNF43 was found mut in 34 (26%) cases. Among RNF43 mutants, TT was associated with longer PFS (7.7 v 3.0 months; P = .002) and higher overall response rate (ORR; 45% v 0%; P = .009) compared with CT. Conversely, among RNF43 wild-type (wt) patients, only a trend for longer PFS (4.5 v 3.7 months; P = .064) favoring TT, with no differences in ORR (P = .14), was observed. After excluding 36 patients receiving TT in third line or beyond, a longer OS (19.4 v 10.1 months; P = .022) and a numerically OS advantage (10.6 v 6.6 months; P = .068) were reported for TT both in the RNF43-mut and in the RNF43 wt groups. However, no interaction effect was reported between RNF43 mutational status and treatment in ORR (Pinteraction = .96), PFS (Pinteraction = .13), and OS (Pinteraction = .44). Patients with pMMR/MSS BRAFV600E-mut mCRC achieve benefit from TT versus CT independently of RNF43 mutational status, although a higher magnitude of benefit from TT is observed in RNF43-mut tumors. These findings deserve confirmation in concluded and ongoing randomized trials.

Ezrin Inhibition Overcomes Acquired Resistance to Vemurafenib in BRAFV600E-Mutated Colon Cancer and Melanoma Cells In Vitro.

Despite the advancements in targeted therapy for BRAFV600E-mutated metastatic colorectal cancer (mCRC), the development of resistance to BRAFV600E inhibition limits the response rate and durability of the treatment. Better understanding of the resistance mechanisms to BRAF inhibitors will facilitate the design of novel pharmacological strategies for BRAF-mutated mCRC. The aim of this study was to identify novel protein candidates involved in acquired resistance to BRAFV600E inhibitor vemurafenib in BRAFV600E-mutated colon cancer cells using an integrated proteomics approach. Bioinformatic analysis of obtained proteomics data indicated actin-cytoskeleton linker protein ezrin as a highly ranked protein significantly associated with vemurafenib resistance whose overexpression in the resistant cells was additionally confirmed at the gene and protein level. Ezrin inhibition by NSC305787 increased anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant cells in an additive manner, which was accompanied by downregulation of CD44 expression and inhibition of AKT/c-Myc activities. We also detected an increased ezrin expression in vemurafenib-resistant melanoma cells harbouring the BRAFV600E mutation. Importantly, ezrin inhibition potentiated anti-proliferative and pro-apoptotic effects of vemurafenib in the resistant melanoma cells in a synergistic manner. Altogether, our study suggests a role of ezrin in acquired resistance to vemurafenib in colon cancer and melanoma cells carrying the BRAFV600E mutation and supports further pre-clinical and clinical studies to explore the benefits of combined BRAF inhibitors and actin-targeting drugs as a potential therapeutic approach for BRAFV600E-mutated cancers.

Treatment of BRAF-V600E mutant metastatic colorectal cancer: new insights and biomarkers.

The presence of a BRAF-V600E mutation in metastatic colorectal cancer (mCRC) is observed in approximately 12% of cases and is associated with poor prognosis and aggressive disease. Unlike melanoma, the development of successful BRAF blockade in colorectal cancer has been complex. The phase III BEACON trial made significant progress in the development of BRAF inhibitors by establishing encorafenib-cetuximab as the new standard of care for patients with mCRC who have progressed to one or two previous lines of treatment. Nonetheless, not all patients respond to encorafenib-based combinations, and some responses are short-lived. Identifying new strategies to boost antitumor activity and improve survival is paramount. The development of targeted therapy for BRAF-V600E mCRC starting with BRAF inhibitors as monotherapy through novel combinations with anti-VEGF or anti-PD1 agents to enhance antitumor activity is reviewed, with a particular focus on the development of predictive and prognostic biomarkers. There is a crucial need to better understand tumor biology and develop accurate and reliable biomarkers to enhance the antitumor activity of encorafenib-based combinations. The RNF43 mutation is an accurate and reliable predictive biomarker of response, and combinations that target crosstalk between the MAPK pathway, the immune system, and WNT pathways seem promising.

Impact of encorafenib on survival of patients with BRAFV600E-mutant metastatic colorectal cancer in a real-world setting

PurposePatients with BRAFV600E-mutant metastatic colorectal cancer (mCRC) have a dismal prognosis. The best strategies in these patients remain elusive. Against this background, we report the clinical course of patients with BRAFV600E-mutant mCRC to retrieve the best treatment strategy.Patients and methodsClinico-pathological data were extracted from the electronic health records. Kaplan–Meier method was used to estimate overall (OS) and progression-free survival (PFS). Objective response rate (ORR) was assessed according to RECIST 1.1.ResultsIn total, 51 patients were enrolled. FOLFOXIRI was administered to 12 patients; 29 patients received FOLFOX or FOLFIRI as first-line treatment. Median OS was 17.6 months. Median PFS with FOLFOXIRI (13.0 months) was significantly prolonged (HR 0.325) as compared to FOLFOX/FOLFIRI (4.3 months). However, this failed to translate into an OS benefit (p = 0.433). Interestingly, addition of a monoclonal antibody to chemotherapy associated with superior OS (HR 0.523). A total of 64.7% patients received further-line therapy, which included a BRAF inhibitor in 17 patients. Targeted therapy associated with very favourable OS (25.1 months).ConclusionPatients with BRAFV600E-mutated mCRC benefit from the addition of an antibody to first-line chemotherapy. Further-line treatment including a BRAF inhibitor has a dramatic impact on survival.

FOLFOXIRI Plus Cetuximab or Bevacizumab as First-Line Treatment of BRAFV600E-Mutant Metastatic Colorectal Cancer: The Randomized Phase II FIRE-4.5 (AIO KRK0116) Study.

BRAFV600E mutation is associated with a poor outcome in metastatic colorectal cancer (mCRC). This clinical trial investigated the efficacy of triplet chemotherapy (fluorouracil, folinic acid, oxaliplatin, and irinotecan) combined with either cetuximab or bevacizumab in patients with previously untreated BRAFV600E-mutant mCRC. In this controlled, randomized, open-label phase II trial, 109 patients were randomly assigned, 107 of whom were included into the full analysis set (FAS). Patients were randomly assigned in a 2:1 ratio to receive either FOLFOXIRI plus cetuximab in the experimental arm (n = 72) or FOLFOXIRI plus bevacizumab in the control arm (n = 35). The primary end point was objective response rate (ORR) according to RECIST 1.1., evaluated in patients treated according to protocol (ATP population). Progression-free survival (PFS), overall survival (OS), toxicity, and feasibility were analyzed as secondary end points. Eighteen patients discontinued study treatment before the first tumor assessment, thus resulting in the ATP population of 89 patients. In these patients, ORR was 51% (30/59) in the cetuximab-based experimental arm and 67% (20/30) in the bevacizumab-based control arm (odds ratio, 1.93; 80% CI, 1.06 to 3.52; P = .92 [one-sided]). In the full analysis set, median PFS was significantly inferior in the experimental arm (6.7 months v 10.7 months; hazard ratio [HR], 1.89; P = .006). Median OS analyzed at an event rate of 64.5% showed a trend toward shorter survival in cetuximab-treated patients (12.9 months v 17.1 months; HR, 1.4; P = .20). To our knowledge, FIRE-4.5 is the first prospective and randomized study investigating first-line treatment of BRAFV600E-mutant mCRC. FOLFOXIRI plus cetuximab does not induce a higher ORR when compared with FOLFOXIRI plus bevacizumab in first-line treatment of BRAFV600E-mutant mCRC. Bevacizumab-based chemotherapy remains the preferable first-line treatment of patients with BRAFV600E-mutant mCRC.