A randomised phase 2 study comparing different dose approaches of induction treatment of regorafenib in previously treated metastatic colorectal cancer patients (REARRANGE trial).

PURPOSE: The purpose of this article is to evaluate the safety of two regorafenib dose-escalation approaches in refractory metastatic colorectal cancer (mCRC) patients. PATIENTS AND METHODS: Patients with mCRC and progression during or within 3 months following their last standard chemotherapy regimen were randomised to receive the approved dose of regorafenib of 160 mg QD (arm A) or 120 mg QD (arm B) administered as 3 weeks of treatment followed by 1 week off, or 160 mg QD 1 week on/1 week off (arm C). The primary end-point was the percentage of patients with G3/G4 treatment-related adverse events (AEs) in each arm. RESULTS: There were 299 patients randomly assigned to arm A (n = 101), arm B (n = 99), or arm C (n = 99); 297 initiated treatments (arm A n = 100, arm B n = 98, arm C n = 99: population for safety analyses). G3/4 treatment-related AEs occurred in 60%, 55%, and 54% of patients in arms A, B, and C, respectively. The most common G3/4 AEs were hypertension (19, 12, and 20 patients), fatigue (20, 14, and 15 patients), hypokalemia (11, 7, and 10 patients), and hand-foot skin reaction (8, 7, and 3 patients). Median overall survival was 7.4 (IQR 4.0-13.7) months in arm A, 8.6 (IQR 3.8-13.4) in arm B, and 7.1 (IQR 4.4-12.4) in arm C. CONCLUSIONS: The alternative regorafenib dosing schedules were feasible and safe in patients with mCRC who had been previously treated with standard therapy. There was a higher numerical improvement on the most clinically relevant AEs in the intermittent dosing arm, particularly during the relevant first two cycles. GOV IDENTIFIER: NCT02835924.

Up-to-date role of aflibercept in the treatment of colorectal cancer.

Introduction: Colorectal cancer (CRC) is a major public health problem. Despite major progress understanding the biological basis of this tumor added to the incorporation of optimized diagnostic and therapeutic strategies, prognosis after progression on first-line standard treatment remains poor. Several antiangiogenic treatments have demonstrated improvement in overall survival (OS) in the second-line treatment being aflibercept, a fully humanized recombinant protein, one of them. The results of the VELOUR study showed that the addition of aflibercept to second-line FOLFIRI improved OS and progression-free survival.Areas covered: A literature review of published clinical studies was performed in order to discuss the clinical data on aflibercept in mCRC from early drug development to real-world data.Expert opinion: The combination of aflibercept with FOLFIRI provides a statistical improvement in OS and in all the efficacy endpoints analyzed in the VELOUR trial, showing efficacy independently on time to progression, molecular status, prior biological treatment, or age. Further studies are needed to find new biomarkers and molecular characterization in order to better select patients that could benefit from this treatment.

BRAF, MEK and EGFR inhibition as treatment strategies in BRAF V600E metastatic colorectal cancer.

INTRODUCTION: BRAF driver mutations are found in up to 15% of patients with colorectal cancer (CRC) and lead to constitutive activation of BRAF kinase and sustained RAS/RAF/MEK/ERK pathway signaling. BRAF mutations define a sub-population characterized by a poor prognosis and dismal median survival. Following successful outcomes with BRAF inhibition in BRAF mutant metastatic melanoma, this approach was evaluated in metastatic colorectal cancer (mCRC). The development and combination of targeted therapies against multiple signaling pathways has proved particularly successful, with improved survival and response rates. AREAS COVERED: This review addresses the development of therapeutic strategies with inhibitors targeting MAPK/ERK and EGFR signaling in BRAF V600E mutated mCRC, focusing on encorafenib, binimetinib and cetuximab. A pharmacological and clinical review of these drugs and the therapeutic approaches behind their optimization are presented. EXPERT OPINION: Exploiting knowledge of the mechanisms of resistance to BRAF inhibitors has been crucial to developing effective therapeutic strategies in BRAF-V600E mutant mCRC. The BEACON trial is a successful example of this approach, using encorafenib and cetuximab with or without binimetinib in patients with previously treated BRAF V600E mutant mCRC, showing an impressive improvement in clinical outcomes and tolerable toxicity compared with chemotherapy, establishing a new standard of care in this setting.

Molecular subtypes and the evolution of treatment management in metastatic colorectal cancer.

Colorectal cancer (CRC) is a heterogeneous disease representing a therapeutic challenge, which is further complicated by the common occurrence of several molecular alterations that confer resistance to standard chemotherapy and targeted agents. Mechanisms of resistance have been identified at multiple levels in the epidermal growth factor receptor (EGFR) pathway, including mutations in KRAS, NRAS, and BRAF V600E, and in the HER2 and MET receptors. These alterations represent oncogenic drivers that may co-exist in the same tumor with other primary and acquired alterations via a clonal selection process. Other molecular alterations include DNA damage repair mechanisms and rare kinase fusions, potentially offering a rationale for new therapeutic strategies. In recent years, genomic analysis has been expanded by a more complex study of epigenomic, transcriptomic, and microenvironment features. The Consensus Molecular Subtype (CMS) classification describes four CRC subtypes with distinct biological characteristics that show prognostic and potential predictive value in the clinical setting. Here, we review the panorama of actionable targets in CRC, and the developments in more recent molecular tests, such as liquid biopsy analysis, which are increasingly offering clinicians a means of ensuring optimal tailored treatments for patients with metastatic CRC according to their evolving molecular profile and treatment history.

Incorporating traditional and emerging biomarkers in the clinical management of metastatic colorectal cancer: an update.

INTRODUCTION: Molecular profiling has led to significantly longer survival in metastatic colorectal cancer (mCRC) patients. Clinical guidelines recommend testing for KRAS/NRAS, BRAF and MSI status, and new biomarkers such as HER2 amplification and NTRK fusions have emerged more recently in refractory CRC, supported by overwhelming clinical relevance. These biomarkers can guide treatment management to improve clinical outcomes in these patients. AREAS COVERED: Preclinical and clinical data over the last decade were reviewed for known and novel biomarkers with clinical implications in refractory CRC. Molecular alterations are described for classic and novel biomarkers, and data for completed and ongoing studies with targeted and immunotherapies are presented. EXPERT OPINION: Use of targeted therapies based on biomarker testing in CRC has enabled impressive improvements in clinical outcomes in refractory patients. BRAF, MSI, NRAS and KRAS should be tested upfront in all patients given their indisputable therapeutic implications. Other molecular alterations such as HER2 and NTRK are emerging. Testing for these alterations may further improve outcomes for refractory CRC patients. Nonetheless, many key aspects remain to be defined including the optimal timing and technique for testing, the most adequate panel, and whether all patients should be tested for all alterations.

Impact of circulating tumor DNA mutant allele fraction on prognosis in RAS-mutant metastatic colorectal cancer.

Despite major advances in the treatment of metastatic colorectal cancer (mCRC), the survival rate remains very poor. This study aims at exploring the prognostic value of RAS-mutant allele fraction (MAF) in plasma in mCRC. Forty-seven plasma samples from 37 RAS-mutated patients with nonresectable metastases were tested for RAS in circulating tumor DNA using BEAMing before first- and/or second-line treatment. RAS MAF was correlated with several clinical parameters (number of metastatic sites, hepatic volume, carcinoembryonic antigen, CA19-9 levels, primary site location, and treatment line) and clinical outcome [progression-free survival (PFS) and overall survival (OS)]. An independent cohort of 32 patients from the CAPRI-GOIM trial was assessed for clinical outcome based on plasma baseline MAF. RAS MAF analysis at baseline revealed a significant correlation with longer OS [Hazard ratios (HR) = 3.514; P = 0.00066]. Patients with lower MAF also showed a tendency to longer PFS, although not statistically significant. Multivariate analysis showed RAS MAFs as an independent prognostic factor in both OS (HR = 2.73; P = 0.006) and first-line PFS (HR = 3.74; P = 0.049). Tumor response to treatment in patients with higher MAF was progression disease (P = 0.007). Patients with low MAFs at baseline in the CAPRI-GOIM group also showed better OS [HR = 3.84; 95% confidence intervals (CI) 1.5-9.6; P = 0.004] and better PFS (HR = 2.5; 95% CI: 1.07-5.62; P = 0.033). This minimally invasive test may help in adding an independent factor to better estimate outcomes before initiating treatment. Further prospective studies using MAF as a stratification factor could further validate its utility in clinical practice.

Triple-drug chemotherapy regimens in combination with an anti-EGFR agent in metastatic colorectal cancer - prospects from phase II clinical trials.

INTRODUCTION: The addition of monoclonal antibody (mAb) epidermal growth factor receptor (EGFR) inhibitors to classic chemotherapy doublet backbones has improved survival of metastatic colorectal cancer (mCRC). However, the role of triple-drug chemotherapy regimens in combination with an anti-EGFR mAb inhibitor is not yet clear. AREAS COVERED: The activity of triple-drug chemotherapy regimens when combined with an anti-EGFR mAb in mCRC patients is examined. We describe the overall safety and tolerability profiles based on a literature review of all published phase I and II clinical trials in this setting. Drug exposure, tumor mutational status, and metastases resectability are discussed. A review of PubMed and abstracts of major oncology congresses from 2009 to 2018, with MeSH and full-text search terms for clinical trials of anti-EGFR for 'metastatic' or 'advanced' 'colorectal cancer/adenocarcinoma' was implemented. Only English language publications were included. EXPERT OPINION: Efficacy data from phase II trials are promising, but the safety profiles are not as encouraging; the development of severe diarrhea and acneiform rash limit the drug exposure that is critical for improved outcomes. Phase II studies of these triplet chemotherapy/anti-EGFR mAb combinations have focused on conversion therapy in liver-limited disease or in the first-line setting in advanced disease. The identification of biomarkers of response and toxicity may support the use of personalized medicine and more precise design of phase III trials.

Analysis of Fusobacterium persistence and antibiotic response in colorectal cancer.

Colorectal cancers comprise a complex mixture of malignant cells, nontransformed cells, and microorganisms. Fusobacterium nucleatum is among the most prevalent bacterial species in colorectal cancer tissues. Here we show that colonization of human colorectal cancers with Fusobacterium and its associated microbiome-including Bacteroides, Selenomonas, and Prevotella species-is maintained in distal metastases, demonstrating microbiome stability between paired primary and metastatic tumors. In situ hybridization analysis revealed that Fusobacterium is predominantly associated with cancer cells in the metastatic lesions. Mouse xenografts of human primary colorectal adenocarcinomas were found to retain viable Fusobacterium and its associated microbiome through successive passages. Treatment of mice bearing a colon cancer xenograft with the antibiotic metronidazole reduced Fusobacterium load, cancer cell proliferation, and overall tumor growth. These observations argue for further investigation of antimicrobial interventions as a potential treatment for patients with Fusobacterium-associated colorectal cancer.