Pilot trial of combined BRAF and EGFR inhibition in BRAF-mutant metastatic colorectal cancer patients

Cellular and molecular mechanisms of gastrointestinal cancer liver metastases and drug resistance

Distant metastases and drug resistance account for poor survival of patients with gastrointestinal (GI) malignancies such as gastric cancer, pancreatic cancer, and colorectal cancer. GI cancers most commonly metastasize to the liver, which provides a unique immunosuppressive tumour microenvironment to support the development of a premetastatic niche for tumor cell colonization and metastatic outgrowth. Metastatic tumors often exhibit greater resistance to drugs than primary tumors, posing extra challenges in treatment. The liver metastases and drug resistance of GI cancers are regulated by complex, intertwined, and tumor-dependent cellular and molecular mechanisms that influence tumor cell behavior (e.g. epithelial-to-mesenchymal transition, or EMT), tumor microenvironment (TME) (e.g. the extracellular matrix, cancer-associated fibroblasts, and tumor-infiltrating immune cells), tumor cell-TME interactions (e.g. through cytokines and exosomes), liver microenvironment (e.g. hepatic stellate cells and macrophages), and the route and mechanism of tumor cell dissemination (e.g. circulating tumor cells). This review provides an overview of recent advances in the research on cellular and molecular mechanisms that regulate liver metastases and drug resistance of GI cancers. We also discuss recent advances in the development of mechanism-based therapy for these GI cancers. Targeting these cellular and molecular mechanisms, either alone or in combination, may potentially provide novel approaches to treat metastatic GI malignancies.

BRAFV600E-Mutant Metastatic Colorectal Cancer: Current Evidence, Future Directions, and Research Priorities

BRAFV600E-mutant metastatic colorectal cancer represents a distinct molecular phenotype known for its aggressive biological behavior, resistance to standard therapies, and poor survival rates. Improved understanding of the biology of the BRAF oncogene has led to the development of targeted therapies that have paved the way for a paradigm shift in managing this disease. However, despite significant recent advancements, responses to targeted therapies are short-lived, and several challenges remain. In this review, we discuss how progress in treating BRAFV600E-mutant metastatic colorectal cancer has been made through a better understanding of its unique biological and clinical features. We provide an overview of the evidence to support current treatment approaches and discuss critical areas of need and future research strategies that hold the potential to refine clinical practice further. We also discuss some challenging aspects of managing this disease, particularly the complexity of acquired resistance mechanisms that develop under the selective pressure of targeted therapies and rational strategies being investigated to overcome them.

Efficacy and safety of the combination of encorafenib/cetuximab with or without binimetinib in patients with BRAF V600E-mutated metastatic colorectal cancer: an AGEO real-world multicenter study

BACKGROUND

The combination of encorafenib with cetuximab has become the standard of care in patients with BRAF V600E-mutated metastatic colorectal cancer (mCRC) after a prior systemic therapy. This study aims to describe the efficacy and safety of encorafenib/cetuximab +/- binimetinib in patients with BRAF V600E-mutated mCRC in a real-world setting.

PATIENTS AND METHODS

This retrospective study included patients with BRAF V600E-mutated mCRC who received this combination from January 2020 to June 2022 in 30 centers.

RESULTS

A total of 201 patients were included, with 55% of women, a median age of 62 years, and an Eastern Cooperative Oncology Group performance status (ECOG-PS) >1 in 20% of cases. The main tumor characteristics were 60% of right-sided primary tumor, 11% of microsatellite instability/mismatch repair deficient phenotype, and liver and peritoneum being the two main metastatic sites (57% and 51%). Encorafenib/cetuximab +/- binimetinib was prescribed in the first, second, third, and beyond third line in 4%, 56%, 29%, and 11%, respectively, of cases, with the encorafenib/cetuximab/binimetinib combination for 21 patients (10%). With encorafenib/cetuximab treatment, 21% of patients experienced grade ≥3 adverse events (AEs), with each type of grade ≥3 AE observed in <5% of patients. The objective response rate was 32.2% and the disease control rate (DCR) was 71.2%. The median progression-free survival (PFS) was 4.5 months [95% confidence interval (CI) 3.9-5.4 months] and the median overall survival (OS) was 9.2 months (95% CI 7.8-10.8 months). In multivariable analysis, factors associated with a shorter PFS were synchronous metastases [hazard ratio (HR) 1.66, P = 0.04] and ECOG-PS >1 (HR 1.88, P = 0.007), and those associated with a shorter OS were the same factors (HR 1.71, P = 0.03 and HR 2.36, P < 0.001, respectively) in addition to treatment beyond the second line (HR 1.74, P = 0.003) and high carcinoembryonic antigen level (HR 1.72, P = 0.003).

CONCLUSION

This real-world study showed that in patients with BRAF V600E-mutated mCRC treated with encorafenib/cetuximab +/- binimetinib, efficacy and safety data confirm those reported in the BEACON registration trial. The main poor prognostic factors for this treatment are synchronous metastases and ECOG-PS >1.

A comprehensive overview of the molecular features and therapeutic targets in BRAFV600E-mutant colorectal cancer

As one of the most prevalent digestive system tumours, colorectal cancer (CRC) poses a significant threat to global human health. With the emergence of immunotherapy and target therapy, the prognosis for the majority of CRC patients has notably improved. However, the subset of patients with BRAF exon 15 p.V600E mutation (BRAFV600E) has not experienced remarkable benefits from these therapeutic advancements. Hence, researchers have undertaken foundational investigations into the molecular pathology of this specific subtype and clinical effectiveness of diverse therapeutic drug combinations. This review comprehensively summarised the distinctive molecular features and recent clinical research advancements in BRAF-mutant CRC. To explore potential therapeutic targets, this article conducted a systematic review of ongoing clinical trials involving patients with BRAFV600E-mutant CRC.

Therapeutic strategies targeting the epidermal growth factor receptor signaling pathway in metastatic colorectal cancer

More than 1.9 million new colorectal cancer (CRC) cases and 935000 deaths were estimated to occur worldwide in 2020, representing about one in ten cancer cases and deaths. Overall, colorectal ranks third in incidence, but second in mortality. More than half of the patients are in advanced stages at diagnosis. Treatment options are complex because of the heterogeneity of the patient population, including different molecular subtypes. Treatments have included conventional fluorouracil-based chemotherapy, targeted therapy, immunotherapy, etc. In recent years, with the development of genetic testing technology, more and more targeted drugs have been applied to the treatment of CRC, which has further prolonged the survival of metastatic CRC patients.

Combining Anti-epidermal Growth Factor Receptor (EGFR) Therapy with Immunotherapy in Metastatic Colorectal Cancer (mCRC)

INTRODUCTION

Monoclonal antibodies binding the EGFR, such as cetuximab and panitumumab, have been extensively used as targeted therapy for the treatment of mCRC. However, in clinical practice, it has been found that these treatment options have some limitations and fail to fully exploit their immunoregulatory activities. Meanwhile, because of the limited effects of current treatments, immunotherapy is being widely studied for patients with mCRC. However, previous immunotherapy trials in mCRC patients have had unsatisfactory outcomes as monotherapy. Thus, combinatorial treatment strategies are being researched.

AREAS COVERED

The authors retrieved relevant documents of combination therapy for mCRC from PubMed and Medline. This review elaborates on the knowledge of immunomodulatory effects of anti-EGFR therapy alone and in combination with immunotherapy for mCRC.

EXPERT OPINION

Although current treatment options have improved median overall survival (OS) for advanced disease to 30 months, the prognosis remains challenging for those with metastatic disease. More recently, the combination of anti-EGFR therapy with immunotherapy has been shown activity with complementary mechanisms. Hence, anti-EGFR therapy in combination with immunotherapy may hold the key to improving the therapeutic effect of refractory mCRC.

SEAMARK: phase II study of first-line encorafenib and cetuximab plus pembrolizumab for MSI-H/dMMR BRAFV600E-mutant mCRC

Patients with both BRAF V600E mutations and microsatellite instability-high (MSI-H)/mismatch repair-deficient (dMMR) metastatic colorectal cancer (mCRC) have poor prognosis. Currently, there are no specifically targeted first-line treatment options indicated for patients with mCRC whose tumors harbor both molecular aberrations. Pembrolizumab is a checkpoint inhibitor approved for the treatment of MSI-H/dMMR mCRC, and the BRAF inhibitor encorafenib, in combination with cetuximab, is approved for previously treated BRAF V600E-mutant mCRC. Combination of pembrolizumab with encorafenib and cetuximab may synergistically enhance antitumor activity in patients with BRAF V600E-mutant, MSI-H/dMMR mCRC. SEAMARK is a randomized phase II study comparing the efficacy of the combination of pembrolizumab with encorafenib and cetuximab versus pembrolizumab alone in patients with previously untreated BRAF V600E-mutant, MSI-H/dMMR mCRC.

BRAF - a tumour-agnostic drug target with lineage-specific dependencies

In June 2022, the FDA granted Accelerated Approval to the BRAF inhibitor dabrafenib in combination with the MEK inhibitor trametinib for the treatment of adult and paediatric patients (≥6 years of age) with unresectable or metastatic BRAFV600E-mutant solid tumours, except for BRAFV600E-mutant colorectal cancers. The histology-agnostic approval of dabrafenib plus trametinib marks the culmination of two decades of research into the landscape of BRAF mutations in human cancers, the biochemical mechanisms underlying BRAF-mediated tumorigenesis, and the clinical development of selective RAF and MEK inhibitors. Although the majority of patients with BRAFV600E-mutant tumours derive clinical benefit from BRAF inhibitor-based combinations, resistance to treatment develops in most. In this Review, we describe the biochemical basis for oncogenic BRAF-induced activation of MAPK signalling and pan-cancer and lineage-specific mechanisms of intrinsic, adaptive and acquired resistance to BRAF inhibitors. We also discuss novel RAF inhibitors and drug combinations designed to delay the emergence of treatment resistance and/or expand the population of patients with BRAF-mutant cancers who benefit from molecularly targeted therapies.

Artificial Intelligence in Predicting Microsatellite Instability and KRAS, BRAF Mutations from Whole-Slide Images in Colorectal Cancer: A Systematic Review

Mismatch repair deficiency (d-MMR)/microsatellite instability (MSI), KRAS, and BRAF mutational status are crucial for treating advanced colorectal cancer patients. Traditional methods like immunohistochemistry or polymerase chain reaction (PCR) can be challenged by artificial intelligence (AI) based on whole slide images (WSI) to predict tumor status. In this systematic review, we evaluated the role of AI in predicting MSI status, KRAS, and BRAF mutations in colorectal cancer. Studies published in PubMed up to June 2023 were included (n = 17), and we reported the risk of bias and the performance for each study. Some studies were impacted by the reduced number of slides included in the data set and the lack of external validation cohorts. Deep learning models for the d-MMR/MSI status showed a good performance in training cohorts (mean AUC = 0.89, [0.74-0.97]) but slightly less than expected in the validation cohort when available (mean AUC = 0.82, [0.63-0.98]). Contrary to the MSI status, the prediction of KRAS and BRAF mutations was less explored with a less robust methodology. The performance was lower, with a maximum of 0.77 in the training cohort, 0.58 in the validation cohort for KRAS, and 0.82 AUC in the training cohort for BRAF.

BRAF Inhibitors in BRAF-Mutated Colorectal Cancer: A Systematic Review

Colorectal cancer (CRC) is the second-leading cause of cancer-related deaths globally. BRAF mutation is present in about 10% of CRC patients and is associated with a poor response to chemotherapy. These patients have a relatively poor prognosis. This review aims to assess the efficacy and safety of BRAF inhibitors in BRAF-mutated CRC patients. A literature search was performed on PubMed and Embase, and clinical trials relevant to BRAF inhibitors in CRC were included. Data were extracted for efficacy and safety variables. Two randomized clinical trials (n = 765) and eight non-randomized trials (n = 281) were included based on inclusion criteria. In RCTs, an overall response was reported in 23% of the patients treated with BRAF inhibitor-based regimens compared to 2.5% with control regimens. The hazard ratio of overall survival was also significantly better with triplet encorafenib therapy at 0.52 (95% CI = 0.39-0.70). In single-arm trials, ORR was 17% and 34% in two-drug and three-drug regimens, respectively. BRAF inhibitor-based regimens were safe and effective in the treatment of BRAF-mutated CRC. Large-scale randomized trials are needed to find a suitable population for each regimen. PROSPERO registration No. CRD42023471627.

Anti-EGFR Antibodies in the Management of Advanced Colorectal Cancer

Colorectal cancer is the third most common cancer worldwide, and incidence is rising in younger individuals. Anti-EGFR antibodies, including cetuximab and panitumumab, have been incorporated into standard-of-care practice for patients with advanced disease. Herein, we review the molecular characteristics of these agents and the trials that lead to their approvals. Further, we discuss clinical implications of data regarding biomarkers that dictate treatment selection, different dosing strategies, and side effect management. Finally, we look towards the future and describe contexts in which these agents are currently being investigated clinically with a focus on combinations with MAPK-targeted therapies and immunotherapy. Overall, this review provides historical context, current clinical usage, and future directions for anti-EGFR antibodies in advanced colorectal cancer.

Treatment of metastatic colorectal cancer with BRAF V600E mutation: A multicenter real-world study in China

BACKGROUND

BRAF V600E mutant-metastatic colorectal cancer (mCRC) is characterized by its short survival time. Treatment approaches vary depending on whether or not the metastases are initially resectable. The benefit of metastasectomy remains unclear, and the optimal first-line treatment is controversial. This study aimed to describe the prognosis of BRAF V600E mutant-mCRC, analyze the recurrence pattern in resectable patients, and explore the optimal first-line treatment for unresectable patients.

METHODS

Patients diagnosed with BRAF V600E mutant-mCRC between February 2014 and January 2022 in five hospitals were enrolled. Date on clinical and pathological characteristics, treatment features, and survival outcomes were collected.

RESULTS

Of the 220 included patients, 64 initially resectable patients had a significantly longer overall survival (OS) (37.07 vs. 20.20 months, P < 0.001) than initially unresectable patients. Of 156 unresectable patients, 54 received doublet (FOLFOX, XELOX or FOLFIRI) or triplet (FOLFOXIRI) chemotherapies (Chemo), 55 received Chemo plus Bevacizumab (Chemo+Bev), and 33 received vemurafenib plus cetuximab and irinotecan (VIC). The VIC regimen had a better progression-free survival (PFS) (12.70 months) than the Chemo (6.70 months, P < 0.001) and Chemo+Bev (8.8 months, P = 0.044) regimens. Patients treated with VIC had the best overall response rate (60.16%, P < 0.001), disease control rate (93.94%, P < 0.001) and conversional resection rate (24.24%, P = 0.003).

CONCLUSIONS

Metastasectomy is beneficial to the survival of patients with BRAF V600E mutant-mCRC. For initially unresectable patients, VIC as first-line therapy is associated with a better prognosis and efficacy than doublet and triplet chemotherapy with or without bevacizumab.

Can immunotherapy reinforce chemotherapy efficacy? a new perspective on colorectal cancer treatment

As one of the main threats to human life (the fourth most dangerous and prevalent cancer), colorectal cancer affects many people yearly, decreases patients' quality of life, and causes irreparable financial and social damages. In addition, this type of cancer can metastasize and involve the liver in advanced stages. However, current treatments can't completely eradicate this disease. Chemotherapy and subsequent surgery can be mentioned among the current main treatments for this disease. Chemotherapy has many side effects, and regarding the treatment of this type of tumor, chemotherapy can lead to liver damage, such as steatohepatitis, steatosis, and sinus damage. These damages can eventually lead to liver failure and loss of its functions. Therefore, it seems that other treatments can be used in addition to chemotherapy to increase its efficiency and reduce its side effects. Biological therapies and immunotherapy are one of the leading suggestions for combined treatment. Antibodies (immune checkpoint blockers) and cell therapy (DC and CAR-T cells) are among the immune system-based treatments used to treat tumors. Immunotherapy targets various aspects of the tumor that may lead to 1) the recruitment of immune cells, 2) increasing the immunogenicity of tumor cells, and 3) leading to the elimination of inhibitory mechanisms established by the tumor. Therefore, immunotherapy can be used as a complementary treatment along with chemotherapy. This review will discuss different chemotherapy and immunotherapy methods for colorectal cancer. Then we will talk about the studies that have dealt with combined treatment.

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.

Progress of research on molecular targeted therapies for colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies, accounting for approximately 10% of global cancer incidence and mortality. Approximately 20% of patients with CRC present metastatic disease (mCRC) at the time of diagnosis. Moreover, up to 50% of patients with localized disease eventually metastasize. mCRC encompasses a complex cascade of reactions involving multiple factors and processes, leading to a diverse array of molecular mechanisms. Improved comprehension of the pathways underlying cancer cell development and proliferation, coupled with the accessibility of relevant targeted agents, has propelled advancements in CRC treatment, ultimately leading to enhanced survival rates. Mutations in various pathways and location of the primary tumor in CRC influences the efficacy of targeted agents. This review summarizes available targeted agents for different CRC pathways, with a focus on recent advances in anti-angiogenic and anti-epidermal growth factor receptor agents, BRAF mutations, and human epidermal growth factor receptor 2-associated targeted agents.

Beyond EGFR inhibitors in advanced colorectal cancer: Targeting BRAF and HER2

The addition of antiepidermal growth factor receptor (EGFR) monoclonal antibodies, cetuximab or panitumumab, to conventional chemotherapy has improved clinical outcomes for rat sarcoma virus (RAS) wild-type advanced colorectal cancer patients, however, durable responses and 5-year overall survival rates remain limited. BRAF V600E somatic mutation and human epidermal growth factor receptor (HER2) amplification/overexpression have been separately implicated in primary resistance to anti-EGFR therapeutic strategies via aberrant activation of the mitogen-activated protein kinase (MAPK) signaling pathway, resulting in poorer outcomes. In addition to being a negative predictive biomarker for anti-EGFR therapy, BRAF V600E mutation and HER2 amplification/overexpression serve as positive predictors of response to therapies targeting these respective tumor promoters. This review will highlight key clinical studies that support the rational use of v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) and HER2-targeted therapies, often in combination with other targeted agents, cytotoxic chemotherapy, and immune checkpoint inhibitors. We discuss current challenges with BRAF and HER2-targeted therapies in metastatic colorectal cancer and potential opportunities for improvement.

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

INTRODUCTION

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.

AREAS COVERED

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.

EXPERT OPINION

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.

HPIP is an essential scaffolding protein running through the EGFR-RAS-ERK pathway and drives tumorigenesis

The EGFR-RAS-ERK pathway plays a key role in cancer development and progression. However, the integral assembly of EGFR-RAS-ERK signaling complexes from the upstream component EGFR to the downstream component ERK is largely unknown. Here, we show that hematopoietic PBX-interacting protein (HPIP) interacts with all classical components of the EGFR-RAS-ERK pathway and forms at least two complexes with overlapping components. Experiments of HPIP knockout or knockdown and chemical inhibition of HPIP expression showed that HPIP is required for EGFR-RAS-ERK signaling complex formation, EGFR-RAS-ERK signaling activation, and EGFR-RAS-ERK signaling-mediated promotion of aerobic glycolysis as well as cancer cell growth in vitro and in vivo. HPIP expression is correlated with EGFR-RAS-ERK signaling activation and predicts worse clinical outcomes in patients with lung cancer. These results provide insights into EGFR-RAS-ERK signaling complex formation and EGFR-RAS-ERK signaling regulation and suggest that HPIP may be a promising therapeutic target for cancer with dysregulated EGFR-RAS-ERK signaling.

The BEETS (JACCRO CC-18) trial: an observational and translational study of BRAF-mutated metastatic colorectal cancer

For BRAF V600E-mutated metastatic colorectal cancer (mCRC), the BEACON phase 3 trial showed survival benefit of triplet therapy with cetuximab (anti-EGFR antibody), encorafenib (BRAF inhibitor) and binimetinib (MEK inhibitor) as well as doublet therapy with cetuximab and encorafenib over irinotecan-based chemotherapy plus anti-EGFR antibody. Both regimens are standards of care in Japan, but definite biomarkers for predicting efficacy and selecting treatment remain lacking. The mechanisms underlying resistance to these regimens also warrant urgent exploration to further evolve treatment. This prospective observational/translational study evaluated real-word clinical outcomes with cetuximab and encorafenib with or without binimetinib for BRAF-mutated mCRC patients and investigated biomarkers for response and resistance by collecting blood samples before and after treatment. Clinical Trial Registration: UMIN000045530 (https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000051983).

Targeted Therapies in Colorectal Cancer: Recent Advances in Biomarkers, Landmark Trials, and Future Perspectives

In 2022, approximately 600,000 cancer deaths were expected; more than 50,000 of those deaths would be from colorectal cancer (CRC). The CRC mortality rate in the US has decreased in recent decades, with a 51% drop between 1976 and 2014. This drop is attributed, in part, to the tremendous therapeutic improvements, especially after the 2000s, in addition to increased social awareness regarding risk factors and diagnostic improvement. Five-fluorouracil, irinotecan, capecitabine, and later oxaliplatin were the mainstays of mCRC treatment from the 1960s to 2002. Since then, more than a dozen drugs have been approved for the disease, betting on a new chapter in medicine, precision oncology, which uses patient and tumor characteristics to guide the therapeutic choice. Thus, this review will summarize the current literature on targeted therapies, highlighting the molecular biomarkers involved and their pathways.

A Phase Ib/II Trial of Combined BRAF and EGFR Inhibition in BRAF V600E Positive Metastatic Colorectal Cancer and Other Cancers: The EVICT (Erlotinib and Vemurafenib In Combination Trial) Study

PURPOSE

BRAF V600E mutant metastatic colorectal cancer represents a significant clinical problem, with combination approaches being developed clinically with oral BRAF inhibitors combined with EGFR-targeting antibodies. While compelling preclinical data have highlighted the effectiveness of combination therapy with vemurafenib and small-molecule EGFR inhibitors, gefitinib or erlotinib, in colorectal cancer, this therapeutic strategy has not been investigated in clinical studies.

PATIENTS AND METHODS

We conducted a phase Ib/II dose-escalation/expansion trial investigating the safety/efficacy of the BRAF inhibitor vemurafenib and EGFR inhibitor erlotinib.

RESULTS

Thirty-two patients with BRAF V600E positive metastatic colorectal cancer (mCRC) and 7 patients with other cancers were enrolled. No dose-limiting toxicities were observed in escalation, with vemurafenib 960 mg twice daily with erlotinib 150 mg daily selected as the recommended phase II dose. Among 31 evaluable patients with mCRC and 7 with other cancers, overall response rates were 32% [10/31, 16% (5/31) confirmed] and 43% (3/7), respectively, with clinical benefit rates of 65% and 100%. Early ctDNA dynamics were predictive of treatment efficacy, and serial ctDNA monitoring revealed distinct patterns of convergent genomic evolution associated with acquired treatment resistance, with frequent emergence of MAPK pathway alterations, including polyclonal KRAS, NRAS, and MAP2K1 mutations, and MET amplification.

CONCLUSIONS

The Erlotinib and Vemurafenib In Combination Trial study demonstrated a safe and novel combination of two oral inhibitors targeting BRAF and EGFR. The dynamic assessment of serial ctDNA was a useful measure of underlying genomic changes in response to this combination and in understanding potential mechanisms of resistance.

Survival comparison of first-line treatment regimens in patients with braf-mutated advanced colorectal cancer: a multicenter retrospective study

BACKGROUND

Patients with V-Raf murine sarcoma viral oncogene homolog B1 (BRAF) V600E-mutated advanced colorectal cancer (CRC) have a poor prognosis, and treatment options that can improve outcome are still under investigation. The purpose of this study was to discuss the differences of overall survival (OS) and progression-free survival (PFS) between patients with BRAF V600E-mutated advanced CRC who were treated with chemotherapy alone and chemotherapy combined with targeted therapy in advanced first-line therapy.

METHODS

Grouping of 61 patients according to first-line treatment regimen (chemotherapy alone/chemotherapy combined with bevacizumab). Kaplan-Meier method and log-rank test were used to compare OS and PFS. Cox proportional hazards regression model was used to measure the risk of first-line medication therapies while correcting for confounding factors that may affect PFS and OS.

RESULTS

There was no significant difference in OS between patients treated with chemotherapy alone and those treated with chemotherapy combined with bevacizumab (P = 0.93; HR, 1.027; 95% CI, 0.555-1.901). Likewise, there was no significant difference in PFS between the two groups (P = 0.29; HR, 0.734; 95% CI, 0.413-1.304). Subgroup analysis showed that OS and PFS of different treatment regimens were not significantly different among subgroups. Multivariate analysis suggested that surgical treatment of primary tumor (P = 0.001; HR, 0.326; 95% CI, 0.169-0.631) and presence of liver metastasis (P = 0.009; HR, 2.399; 95% CI, 1.242-4.635) may serve as independent prognostic indicators in patients with BRAF-mutated advanced CRC. Surgical treatment of the primary tumor (P = 0.041; HR, 0.523; 95% CI, 0.280-0.974) was significantly associated with PFS too.

CONCLUSION

For patients with BRAF V600E-mutated advanced CRC, chemotherapy alone did not differ significantly in OS and PFS compared with chemotherapy + bevacizumab for advanced first-line therapy. Chemotherapy combined with targeted therapy did not render a survival benefit to these patients, demonstrating that the importance of developing new treatment options for this population.

Resistance to targeted therapy in metastatic colorectal cancer: Current status and new developments

Colorectal cancer (CRC) is one of the most lethal and common malignancies in the world. Chemotherapy has been the conventional treatment for metastatic CRC (mCRC) patients. However, the effects of chemotherapy have been unsatisfactory. With the advent of targeted therapy, the survival of patients with CRC have been prolonged. Over the past 20 years, targeted therapy for CRC has achieved substantial progress. However, targeted therapy has the same challenge of drug resistance as chemotherapy. Consequently, exploring the resistance mechanism and finding strategies to address the resistance to targeted therapy, along with searching for novel effective regimens, is a constant challenge in the mCRC treatment, and it is also a hot research topic. In this review, we focus on the current status on resistance to existing targeted therapies in mCRC and discuss future developments.

Therapeutic landscape and future direction of metastatic colorectal cancer

In the era of targeted therapy based on genomic alterations, the treatment strategy for metastatic colorectal cancer (mCRC) has been changing. Before systemic treatment initiation, determination of tumour genomic status for KRAS and NRAS, BRAF^V600E mutations, ERBB2, and microsatellite instability and/or mismatch repair (MMR) status is recommended. In patients with deficient MMR and BRAF^V600E mCRC, randomized phase III trials have established the efficacy of pembrolizumab as first-line therapy and the combination of encorafenib and cetuximab as second-line or third-line therapy. In addition, new agents have been actively developed in other rare molecular fractions such as ERBB2 alterations and KRAS^G12C mutations. In March 2022, the combination of pertuzumab and trastuzumab for ERBB2-positive mCRC was approved in Japan, thereby combining real-world evidence from the SCRUM-Japan Registry. As the populations are highly fragmented owing to rare genomic alterations, various strategies in clinical development are expected. Clinical development of a tumour-agnostic approach, such as NTRK fusion and tumour mutational burden, has successfully introduced corresponding drugs to clinical practice. Considering the difficulty of randomized trials owing to cost-benefit and rarity, a promising solution could be real-world evidence utilized as an external control from the molecular-based disease registry.

New developments in targeted therapy for metastatic colorectal cancer

Colorectal cancer (CRC) is the second most lethal cancer worldwide and the prognosis of metastatic CRC (mCRC) remains poor. Recent advancements in translational research have led to the identification of several new therapeutic targets and improved the treatment outcome of patients with tumours harbouring BRAF V600E mutation, (HER2) ErBB2 alterations, NTRK gene fusions and KRAS(G12C) mutation. Improved understanding towards the mechanism of resistance to targeted therapy such as anti-epidermal growth factor receptor antibodies and the evolving role of therapeutic monitoring with circulating tumour DNA (ctDNA) has enabled the longitudinal tracking of clonal evolution during treatment and the individualization of subsequent treatments. To broaden the community-based implementation of precision oncology in directing targeted therapies for patients with gastrointestinal cancers including mCRC, the feasibility of 'Master Protocols' that utilizes ctDNA-based genotyping platforms is currently being evaluated. Such protocols encompass both observational and interventional clinical trials of novel targeted therapies conducted within a large clinical trial network. In this review, we will discuss the latest developments in targeted therapies, and therapeutic strategies for overcoming acquired drug resistance in patients with mCRC.

Recent Advancements, Limitations, and Future Perspectives of the use of Personalized Medicine in Treatment of Colon Cancer

Due to the heterogeneity of colon cancer, surgery, chemotherapy, and radiation are ineffective in all cases. The genomic profile and biomarkers associated with the process are considered in personalized medicine, along with the patient's personal history. It is based on the response of the targeted therapies to specific genetic variations. The patient's genetic transcriptomic and epigenetic features are evaluated, and the best therapeutic approach and diagnostic testing are identified through personalized medicine. This review aims to summarize all the necessary, updated information on colon cancer related to personalized medicine. Personalized medicine is gaining prominence as generalized treatments are finding it challenging to contain colon cancer cases which currently rank fourth among global cancer incidence while being the fifth largest in total death cases worldwide. In personalized therapy, patients are grouped into specific categories, and the best therapeutic approach is chosen based on evaluating their molecular features. Various personalized strategies are currently being explored in the treatment of colon cancer involving immunotherapy, phytochemicals, and other biomarker-specific targeted therapies. However, significant challenges must be overcome to integrate personalized medicine into healthcare systems completely. We look at the various signaling pathways and genetic and epigenetic alterations associated with colon cancer to understand and identify biomarkers useful in targeted therapy. The current personalized therapies available in colon cancer treatment and the strategies being explored to improve the existing methods are discussed. This review highlights the advantages and limitations of personalized medicine in colon cancer therapy. The current scenario of personalized medicine in developed countries and the challenges faced in middle- and low-income countries are also summarized. Finally, we discuss the future perspectives of personalized medicine in colon cancer and how it could be integrated into the healthcare systems.

The diverse landscape of dermatologic toxicities of non-immune checkpoint inhibitor monoclonal antibody-based cancer therapy

BACKGROUND

Since their first approval 25 years ago, monoclonal antibodies (mAbs) have become important targeted cancer therapeutics. However, dermatologic toxicities associated with non-immune checkpoint inhibitor (non-ICI) mAbs may complicate the course of cancer treatment. Data on the incidence and types of these reactions are limited.

METHODS

A comprehensive review was conducted on dermatologic toxicities associated with different classes of non-ICI mAbs approved for treatment of solid tumors and hematologic malignancies. The review included prospective Phase 1, 2, and 3 clinical trials; retrospective literature reviews; systematic reviews/meta-analyses; and case series/reports.

RESULTS

Dermatologic toxicities were associated with several types of non-ICI mAbs. Inflammatory reactions were the most common dermatologic toxicities, manifesting as maculopapular, urticarial, papulopustular/acneiform, and lichenoid/interface cutaneous adverse events (cAEs) with non-ICI mAbs. Immunobullous reactions were rare and a subset of non-ICI mAbs were associated with the development of vitiligo cAEs.

CONCLUSION

Dermatologic toxicities of non-ICI mAbs are diverse and mostly limited to inflammatory reactions. Awareness of the spectrum of the histopathologic patterns of cAE from non-ICI mAbs therapy is critical in the era of oncodermatology and oncodermatopathology.

Recent and Future Strategies to Overcome Resistance to Targeted Therapies and Immunotherapies in Metastatic Colorectal Cancer

Colorectal cancer (CRC) is the third most common cause of cancer-related deaths worldwide, and 20% of patients with CRC present at diagnosis with metastases. The treatment of metastatic CRC is based on a fluoropyrimidine-based chemotherapy plus additional agents such as oxaliplatin and irinotecan. To date, on the basis of the molecular background, targeted therapies (e.g., monoclonal antibodies against epidermal growth factor receptor or inhibiting angiogenesis) are administered to improve the treatment of metastatic CRC. In addition, more recently, immunological agents emerged as effective in patients with a defective mismatch repair system. The administration of targeted therapies and immunotherapy lead to a significant increase in the survival of patients; however these drugs do not always prove effective. In most cases the lack of effectiveness is due to the development of primary resistance, either a resistance-inducing factor is already present before treatment or resistance is acquired when it occurs after treatment initiation. In this review we describe the most relevant targeted therapies and immunotherapies and expand on the reasons for resistance to the different approved or under development targeted drugs. Then we showed the possible mechanisms and drugs that may lead to overcoming the primary or acquired resistance in metastatic CRC.

Molecular Pathways and Mechanisms of BRAF in Cancer Therapy

With the identification of activating mutations in BRAF across a wide variety of malignancies, substantial effort was placed in designing safe and effective therapeutic strategies to target BRAF. These efforts have led to the development and regulatory approval of three BRAF inhibitors as well as five combinations of a BRAF inhibitor plus an additional agent(s) to manage cancer such as melanoma, non-small cell lung cancer, anaplastic thyroid cancer, and colorectal cancer. To date, each regimen is effective only in patients with tumors harboring BRAFV600 mutations and the duration of benefit is often short-lived. Further limitations preventing optimal management of BRAF-mutant malignancies are that treatments of non-V600 BRAF mutations have been less profound and combination therapy is likely necessary to overcome resistance mechanisms, but multi-drug regimens are often too toxic. With the emergence of a deeper understanding of how BRAF mutations signal through the RAS/MAPK pathway, newer RAF inhibitors are being developed that may be more effective and potentially safer and more rational combination therapies are being tested in the clinic. In this review, we identify the mechanics of RAF signaling through the RAS/MAPK pathway, present existing data on single-agent and combination RAF targeting efforts, describe emerging combinations, summarize the toxicity of the various agents in clinical testing, and speculate as to where the field may be headed.

Mechanisms and prospects of circular RNAs and their interacting signaling pathways in colorectal cancer

Colorectal cancer (CRC) is the leading malignant tumor in terms of morbidity and mortality worldwide, and its pathogenesis involves multiple factors, including environment, lifestyle, and genetics. Continuing evidence suggests that circular RNAs (circRNAs), as a novel non-coding RNA, constitute an important genetic variable in the pathogenesis of CRC. These circRNAs with covalently closed-loop structures exist objectively in organisms. They not only have the biological functions of regulating the expression of target genes, changing the activity of proteins, and translating proteins, but also play a key role in the proliferation, invasion, migration, and apoptosis of tumor cells. CRC is one of the most common cancers in which circRNAs are involved in tumorigenesis, metastasis, and drug resistance, and circRNAs have been demonstrated to function through crosstalk with multiple signaling pathways. Therefore, this review summarizes the biological and carcinogenic functions of circRNAs and their related PI3K/AKT, MAPK, Notch, JAK/STAT, Hippo/YAP, WNT/β-catenin, and VEGF signaling pathways in CRC. We further explore the clinical value of circRNAs and important signaling proteins in the diagnosis, prognosis, and treatment of CRC.

Encorafenib plus cetuximab for the treatment of BRAF-V600E-mutated metastatic colorectal cancer

B-type RAF (BRAF)-V600E mutations in metastatic colorectal cancer (mCRC) have been described in up to 12% of the patients. This mutation confers a bad prognostic and poor response with standard chemotherapy. Unlike the scenario for BRAF mutant melanoma, successful BRAF blockade in mCRC has emerged as a complex path, primarily due to the complex underlying biology of mCRC. The BEACON trial has reshaped the therapeutic landscape of BRAF mCRC demonstrating the benefit of the BRAF inhibitor encorafenib in combination with the anti-epidermal growth factor receptor cetuximab. This paper aims to review the main features of BRAF mCRC as well as to review the development of targeted therapy and biomarkers in this specific population. Finally, a deep insight into the underlying biology and molecular classification of BRAF-V600E mCRC has also been performed. The words 'BRAF-V600E mutation', 'colorectal cancer', 'BRAF inhibitors', 'consensus molecular subtypes', 'encorafenib', and 'cetuximab' were used to identify the clinical trials from phase I to phase III related to the development of BRAF inhibitors in this population. A deep search among international meetings (American Society of Clinical Oncology and European Society of Medical Oncology) has been performed to incorporate the last trials presented. BRAF-V600E mCRC is a challenging disease, mostly because of its molecular biology. The BEACON trial has been the most important therapeutic change in the last decade. Nevertheless, new information regarding biomarkers or novel combinations including BRAF inhibitors plus immune checkpoint inhibitors are also promising.

Clinical management of metastatic colorectal cancer in the era of precision medicine

Colorectal cancer (CRC) represents approximately 10% of all cancers and is the second most common cause of cancer deaths. Initial clinical presentation as metastatic CRC (mCRC) occurs in approximately 20% of patients. Moreover, up to 50% of patients with localized disease eventually develop metastases. Appropriate clinical management of these patients is still a challenging medical issue. Major efforts have been made to unveil the molecular landscape of mCRC. This has resulted in the identification of several druggable tumor molecular targets with the aim of developing personalized treatments for each patient. This review summarizes the improvements in the clinical management of patients with mCRC in the emerging era of precision medicine. In fact, molecular stratification, on which the current treatment algorithm for mCRC is based, although it does not completely represent the complexity of this disease, has been the first significant step toward clinically informative genetic profiling for implementing more effective therapeutic approaches. This has resulted in a clinically relevant increase in mCRC disease control and patient survival. The next steps in the clinical management of mCRC will be to integrate the comprehensive knowledge of tumor gene alterations, of tumor and microenvironment gene and protein expression profiling, of host immune competence as well as the application of the resulting dynamic changes to a precision medicine-based continuum of care for each patient. This approach could result in the identification of individual prognostic and predictive parameters, which could help the clinician in choosing the most appropriate therapeutic program(s) throughout the entire disease journey for each patient with mCRC. CA Cancer J Clin. 2022;72:000-000.

Targeting EGFR in melanoma - The sea of possibilities to overcome drug resistance

Melanoma is considered one of the most aggressive skin cancers. It spreads and metastasizes quickly and is intrinsically resistant to most conventional chemotherapeutics, thereby presenting a challenge to researchers and clinicians searching for effective therapeutic strategies to treat patients with melanoma. The use of inhibitors of mutated serine/threonine-protein kinase B-RAF (BRAF), e.g., vemurafenib and dabrafenib, has revolutionized melanoma chemotherapy. Unfortunately, the response to these drugs lasts a limited time due to the development of acquired resistance. One of the proteins responsible for this process is epidermal growth factor receptor (EGFR). In this review, we summarize the role of EGFR signaling in the multidrug resistance of melanomas and discuss possible applications of EGFR inhibitors to overcome the development of drug resistance in melanoma cells during therapy.

Molecular mechanisms underlying the resistance of BRAF V600E-mutant metastatic colorectal cancer to EGFR/BRAF inhibitors

Background

Combinatorial inhibition of epidermal growth factor receptor (EGFR) and BRAF shows remarkable clinical benefits in patients with BRAF V600E-mutant metastatic colorectal cancer (mCRC). However, the tumor may inevitably develop resistance to the targeted therapy, thereby limiting the response rate and durability. This study aimed to determine the genetic alterations associated with intrinsic and acquired resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC.

Methods

Targeted sequencing of 520 cancer-related genes was performed in tumor tissues and in plasma samples collected from patients with BRAF V600E-mutant mCRC, who were treated with EGFR/BRAF ± MEK inhibitors, before and after the targeted treatment. Clinical benefit was defined as an objective response or a stable disease lasting longer than the median progression-free survival (PFS).

Results

In all, 25 patients with BRAF V600E-mutant mCRC were included in this study. Those with RNF43 mutations (n = 8) were more likely to achieve clinical benefit from EGFR/BRAF inhibitors than those with wild-type RNF43 (87.5% versus 37.5%, p = 0.034). Genetic alterations in receptor tyrosine kinase genes (n = 6) were associated with worse PFS (p = 0.005). Among the 23 patients whose disease progressed after the EGFR/BRAF-targeted therapy, at least one acquired resistance-related mutation was detected in 12 patients. Acquired mutations were most frequently observed in the mitogen-activated protein kinase pathway-related genes (n = 9), including KRAS (G12D and Q61H/R), NRAS (Q61L/R/K and amplification), BRAF (amplification), and MEK1 (K57T). MET amplification and PIK3R1 Q579fs mutation emerged in three patients and one patient, respectively, after disease progression.

Conclusion

Multiple genetic alterations are associated with clinical benefits and resistance to EGFR/BRAF inhibitors in BRAF V600E-mutant mCRC. Our findings provide novel insights into strategies for overcoming resistance to EGFR/BRAF inhibitors in patients with BRAF V600E-mutant mCRC.

Drug Resistance in Colorectal Cancer: From Mechanism to Clinic

Colorectal cancer (CRC) is one of the leading causes of death worldwide. The 5-year survival rate is 90% for patients with early CRC, 70% for patients with locally advanced CRC, and 15% for patients with metastatic CRC (mCRC). In fact, most CRC patients are at an advanced stage at the time of diagnosis. Although chemotherapy, molecularly targeted therapy and immunotherapy have significantly improved patient survival, some patients are initially insensitive to these drugs or initially sensitive but quickly become insensitive, and the emergence of such primary and secondary drug resistance is a significant clinical challenge. The most direct cause of resistance is the aberrant anti-tumor drug metabolism, transportation or target. With more in-depth research, it is found that cell death pathways, carcinogenic signals, compensation feedback loop signal pathways and tumor immune microenvironment also play essential roles in the drug resistance mechanism. Here, we assess the current major mechanisms of CRC resistance and describe potential therapeutic interventions.

The Evolving Treatment Landscape in BRAF-V600E-Mutated Metastatic Colorectal Cancer

Between 8% and 12% of patients with metastatic colorectal cancer (mCRC) harbor a BRAF-V600E mutation in their tumors, which is associated with a poor response to standard chemotherapy and short overall survival. Moreover, nearly 30% of BRAF-V600E mCRC tumors also have microsatellite instability. Transcriptomic signatures suggest a strong immunogenic biologic background for most of these tumors. In contrast to the melanoma context, single-agent BRAF inhibition does not achieve clinical benefit in BRAF-V600E mCRC. Different preclinical/translational studies have elucidated that, in this context, upon BRAF inhibition, there is immediate signal upregulation via the EGFR, and therefore an anti-EGFR treatment should be added to the BRAF inhibitor. Several phase II studies have confirmed the activity of BRAF inhibitors combined with EGFR-directed monoclonal antibodies in patients with BRAF-V600E mCRC. The role of other mitogen-activated protein kinase inhibitors, such as mitogen-activated protein kinase kinase or PI3K inhibitors, remains unclear. The phase III BEACON clinical trial confirmed the BRAF/EGFR inhibitor combination of encorafenib/cetuximab as the new standard of care for BRAF-V600E mCRC after at least one previous line of systemic therapy. Novel approaches for managing BRAF-V600E mCRC include, among others, triple combinations of BRAF inhibitors and anti-EGFR antibodies combined with immune checkpoint inhibitors in the microsatellite instability population and evaluation of the encorafenib/cetuximab treatment in combination with standard chemotherapy with bevacizumab in the first-line setting.

Colorectal Cancer Heterogeneity and the Impact on Precision Medicine and Therapy Efficacy

Novel targeted therapies for metastatic colorectal cancer are needed to personalize treatments by guiding specific biomarkers selected on the genetic profile of patients. RAS and BRAF inhibitors have been developed for patients who become unresponsive to standard therapies. Sotorasib and adagrasib showed promising results in phase I/II basket trial and a phase III trial was planned with a combination of these RAS inhibitors and anti-EGFR monoclonal antibodies. Encorafenib and binimetinib were administered in phase II clinical trials for BRAF mutated patients. Pembrolizumab is now recommended in patients exhibiting microsatellite instability. Larotrectinib and entrectinib showed a fast and durable response with few and reversible adverse events in cases with NTRK fusions. Trastuzumab and trastuzumab deruxtecan exhibited promising and durable activity in HER-2-positive patients. In this review, the reasons for an extension of the molecular profile of patients were assessed and placed in the context of the advancements in the understanding of genetics. We highlight the differential effect of new targeted therapies through an ever-deeper characterization of tumor tissue. An overview of ongoing clinical trials is also provided.

Exploring biological heterogeneity and implications on novel treatment paradigm in BRAF-mutant metastatic colorectal cancer

Approximatively 8-15% of patients with metastatic colorectal cancer (mCRC) harbor mutation in BRAF gene. Recent advances in molecular biology enabled a better knowledge of the molecular heterogeneity within BRAF mutant (BRAF^MT) CRCs, including high rate of overlapping with MSI-H status and detection of non-V600E mutations related to more favorable behavior. Treatment armamentarium has been rapidly growing in this subgroup and includes targeted combinations and immunotherapy for concomitant MSI-H patients, thereby making BRAF^MT mCRC an innovative model for precision oncology. Nevertheless, duration of responses to targeted strategies remains unsatisfactory due to the development of secondary resistance, which is currently the field of major clinical research on BRAF^MT mCRC. This review explores the molecular, clinical and therapeutic landscape of BRAF^MT mCRC as well as an update on current treatment strategies and future perspectives in light of the heterogeneity of BRAF-mutated disease. Furthermore, a novel treatment algorithm for BRAF^MT mCRC will be proposed.

BRAF-mutated colorectal adenocarcinomas: pathological heterogeneity and clinical implications

Advances in molecular biology have markedly increased our understanding of the heterogeneous molecular landscape of colorectal cancer (CRC). Up to 15% of CRCs harbor the BRAF p.V600E somatic mutation (BRAFmt), a well-established negative prognostic marker in patients with metastatic CRC (mCRC). The BEACON CRC trial set a new standard of care in patients with progressive BRAFmt cancers, consisting of the combination of encorafenib and cetuximab. On these bases, BRAF mutational testing is now recommended in patients with mCRC. However, efforts are needed to further stratify patients carrying this mutation. Here, we discuss the heterogeneous pathologic and molecular landscape of BRAFmt CRCs, focusing on the promises and pitfalls of molecular diagnostics, on novel biomarkers to improve patients' stratification and on the current diagnostic scenario for CRC. We believe that a better stratification based on histopathological features and novel molecular biomarkers should be performed to optimize patient management and therapeutic decision-making.

Improved Survival over Time After Resection of Colorectal Liver Metastases and Clinical Impact of Multigene Alteration Testing in Patients with Metastatic Colorectal Cancer

BACKGROUND

The past 20 years have seen advances in colorectal cancer management. We sought to determine whether survival in patients undergoing resection of colorectal liver metastases (CLM) has improved in association with three landmark advances: introduction of irinotecan- and/or oxaliplatin-containing regimens, molecular targeted therapy, and multigene alteration testing.

METHODS

Patients undergoing CLM resection during 1998-2014 were identified and grouped by resection year. The influence of alterations in RAS, TP53, and SMAD4 was evaluated and validated in an external cohort including patients with unresectable metastatic colorectal cancer.

RESULTS

Of 1961 patients, 1599 met the inclusion criteria. Irinotecan- and/or oxaliplatin-containing regimens and molecular targeted therapy were used for more than 50% of patients starting in 2001 and starting in 2006, respectively, so patients were grouped as undergoing resection during 1998-2000, 2001-2005, or 2006-2014. Liver resectability indications expanded over time. The 5-year overall survival (OS) rate was significantly better in 2006-2014, vs. 2001-2005 (56.5% vs. 44.1%, P < 0.001). RAS alteration was associated with worse 5-year OS than RAS wild-type (44.8% vs. 63.3%, P < 0.001). However, OS did not differ significantly between patients with RAS alteration and wild-type TP53 and SMAD4 and patients with RAS wild-type in our cohort (P = 0.899) or the external cohort (P = 0.932). Of 312 patients with genetic sequencing data, 178 (57.1%) had clinically actionable alterations.

CONCLUSION

OS after CLM resection has improved with advances in medical therapy and surgical technique. Multigene alteration testing is useful for prognostication and identification of potential therapeutic targets.

Efficacy of BRAF inhibitor and anti-EGFR antibody in colorectal neuroendocrine carcinoma

Neuroendocrine neoplasms of the colon and rectum are colorectal epithelial neoplasms with neuroendocrine differentiation. A platinum regimen used for small cell lung cancer is the currently recommended chemotherapy for gastroenteropancreatic neuroendocrine carcinomas (GEP-NECs), regardless of the organ. The BRAF V600E mutation has been recently reported as a druggable driver mutation in colorectal NECs. In BRAF V600E mutant colorectal cancer, a combination of BRAF inhibitor and anti-epidermal growth factor receptor (EGFR) antibody, with or without a MEK inhibitor, is recommended. Here, we report the case of 77-year-old man who had lymph node recurrence after surgery for primary ascending colonic NEC. Two cytotoxic regimens, cisplatin plus irinotecan and modified FOLFOX6, were administered as first- and second-line chemotherapies with no remarkable response observed. At this point, genetic analysis confirmed the tumor harbored a BRAF V600E mutation. Thus, a regimen of BRAF inhibitor plus anti-EGFR antibody was administered. After commencing this regimen, carcinoembryonic antigen levels decreased within normal range, and there was dramatic shrinkage of the lymph node metastases observed by chest and abdominal computed tomography scans. To our knowledge, this is the first reported case of a colorectal NEC responding to a BRAF inhibitor and anti-EGFR antibody.

Ongoing and evolving clinical trials enhancing future colorectal cancer treatment strategies

INTRODUCTION

Molecular profiling has led to significantly longer survival in metastatic colorectal cancer (CRC) patients. Clinical guidelines recommend testing for KRAS/NRAS, BRAF and MSI status and over the last few years several promising new biomarkers have also been identified. Circulating tumor DNA has reshaped the prognosis of localized CRC. These genomic findings can guide treatment management to improve clinical outcomes.

AREAS COVERED

Preclinical and clinical data over the last decade were reviewed for known and novel biomarkers with clinical implications in refractory and metastatic CRC. In the localized stage, al clinical trials involving new approaches such as liquid biopsy or neoadjuvant immunotherapy are also discussed. Molecular alterations and targeted agents are described, and data from completed and ongoing studies with targeted therapy and immunotherapies are presented.

EXPERT OPINION

The implementation of liquid biopsies in the localized CRC setting has reshaped management of this disease. The expanded use of biomarkers to guide the treatment of patients with CRC has revealed a level of complexity arising from interactions between different biomarkers. Prevalence of most established targetable biomarkers is low, however the number of identified biomarkers in CRC is increasing. Thus, metastatic CRC may ultimately be considered an umbrella diagnosis encompassing numerous rare disease subtypes.

CENPO regulated proliferation and apoptosis of colorectal cancer in a p53-dependent manner

Colorectal cancer (CRC) is considered to be a leading cause of cancer-related death. Centromere protein O (CENPO) can prevent the separation of sister chromatids and cell death after spindle injury. Nevertheless, the role of CENPO in CRC has not been reported. The expression level of CENPO in CRC was revealed by TCGA database and immunohistochemical (IHC) staining. Subsequently, the loss-of-function assays were performed to identified the role of CENPO in CRC in vitro and in vivo. Our data demonstrated that CENPO was highly expressed in CRC. The expression of CENPO was positively correlated with the deterioration of CRC. Moreover, CENPO knockdown inhibited the malignant phenotypes of CRC cells, which was characterized by slowed proliferation, cycle repression at G2, promotion of apoptosis, reduced migration and weakened tumorigenesis. Furthermore, CENPO knockdown downregulated the expression of N-cadherin, Vimentin, Snail, CCND1, PIK3CA and inhibited AKT phosphorylation in CRC cells. Moreover, the function of CENPO in regulating proliferation and apoptosis depended on p53. In summary, CENPO may play a promoting role in CRC through the epithelial mesenchymal transition (EMT) and PI3K/AKT signaling pathway, which can be regarded as a molecular therapeutic target for CRC.