Refractory Metastatic Colorectal Cancer: Current Challenges and Future Prospects

Targeting the CDK7-MDK axis to suppresses irinotecan resistance in colorectal cancer

AIMS

Colorectal cancer (CRC) remains a major global health issue, with metastatic cases presenting poor prognosis despite advances in chemotherapy and targeted therapy. Irinotecan, a key drug for advanced CRC treatment, faces challenges owing to the development of resistance. This study aimed to understand the mechanisms underlying irinotecan resistance in colorectal cancer.

MAIN METHODS

We created a cell line resistant to irinotecan using HT29 cells. These resistant cells were utilized to investigate the role of the CDK7-MDK axis. We employed bulk RNA sequencing, conducted in vivo experiments with mice, and analyzed patient tissues to examine the effects of the CDK7-MDK axis on the cellular response to irinotecan.

KEY FINDINGS

Our findings revealed that HT29 cells resistant to irinotecan, a crucial colorectal cancer medication, exhibited significant phenotypic and molecular alterations compared to their parental counterparts, including elevated stem cell characteristics and increased levels of cytokines and drug resistance proteins. Notably, CDK7 expression was substantially higher in these resistant cells, and targeting CDK7 effectively decreased their survival and tumor growth, enhancing irinotecan sensitivity. RNA-seq analysis indicated that suppression of CDK7 in irinotecan-resistant HT29 cells significantly reduced Midkine (MDK) expression. Decreased CDK7 and MDK levels, achieved through siRNA and the CDK7 inhibitor THZ1, enhanced the sensitivity of resistant HT29 cells to irinotecan.

SIGNIFICANCE

Our study sheds light on how CDK7 and MDK influence irinotecan resistance in colorectal and highlights the potential of MDK-targeted therapies. We hypothesized that irinotecan sensitivity and overall treatment efficacy would improve by inhibiting MDK. This finding encourages a careful yet proactive investigation of MDK as a therapeutic target to enhance outcomes in colorectal cancer patients.

Efficacy and safety of trifluridine/tipiracil plus bevacizumab across different subgroups of patients with refractory colorectal cancer: a meta-analysis

Introduction

Metastatic colorectal cancer (mCRC) patients who are refractory to initial treatment lines exhibit a challenging clinical scenario characterised by a poor prognosis and constrained therapeutic options. This systematic review and meta-analysis assess the integration of bevacizumab into trifluridine-tipiracil (TFD/TPI) therapy for mCRC, examining its benefits across patient subgroups and evaluating safety relative to TFD/TPI monotherapy.

Materials and methods

Following preferred reporting items for systematic reviews and meta-analysis statements, we conducted a thorough literature search from 15 October to 11 November 2023, covering MEDLINE, Embase and the Cochrane database. Data extraction and quality assessment followed Cochrane guidelines, and hazard or odds ratios with 95% confidence intervals (CI) were pooled (p < 0.05 significance threshold). The study protocol is registered in PROSPERO (CRD42023484695).

Results

Analysing 770 database results, we included two randomised controlled trials and five observational studies covering over 4,000 patients. Combined therapy exhibited significant improvements in overall survival (OS) hazard ratios (HR 0.60; 95% CI 0.49-0.72; p < 0.01) and progression-free survival (HR 0.48; 95% CI 0.40-0.59; p < 0.01). Subgroups, including prior bevacizumab exposure (HR 0.70; 95% CI 0.64-0.77; p < 0.01) and mutated RAS gene (HR 0.64; 95% CI 0.53-0.77; p < 0.01), demonstrated improvements in OSwith bevacizumab.

Conclusion

This meta-analysis underscores the heightened efficacy of TFD/TPI combined with bevacizumab for refractory mCRC compared to TFD/TPI monotherapy across diverse subgroups. Combined therapy has increased grade ≥3 neutropenia and hypertension, while monotherapy is associated with fatigue and anemia.

Metabolism, toxicity and management of fruquintinib: a novel drug for metastatic colorectal cancer

INTRODUCTION

Colorectal cancer (CRC) is the third most diagnosed cancer globally and despite therapeutic strides, the prognosis for patients with metastatic disease (mCRC) remains poor. Fruquintinib is an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI) targeting VEGFR -1, -2, and -3, and has recently received approval by the U.S. Food and Drug Administration for treatment of mCRC refractory to standard chemotherapy, anti-VEGF therapy, and anti-epidermal growth factor receptor (EGFR) therapy.

AREAS COVERED

This article provides an overview of the pre-clinical data, pharmacokinetics, clinical efficacy, and safety profile of fruquintinib, as well as the management of clinical toxicities associated with fruquintinib.

EXPERT OPINION

Fruquintinib is a valuable additional treatment option for patients with refractory mCRC. The pivotal role of vigilant toxicity management cannot be understated. While fruquintinib offers a convenient and overall, well-tolerated treatment option, ongoing research is essential to determine its efficacy in different patient subsets, evaluate it in combination with chemotherapy and immunotherapy, and determine its role in earlier lines of therapy.

Efficacy and safety of anlotinib plus XELOX regimen as first-line therapy for mCRC: a single-arm, multicenter, phase II study (ALTER-C-001)

Background

Anlotinib showed encouraging anti-tumor activity in metastatic colorectal cancer (mCRC). This study was designed to assess the efficacy and safety of anlotinib plus XELOX as first-line therapy in mCRC patients.

Materials and Methods

Eligible patients aged ≥18 with mCRC were enrolled in this multicenter, single-arm, phase II, exploratory study. Patients received at least 6 cycles of anlotinib, oxaliplatin, and capecitabine as initial therapy. Subsequently, patients received anlotinib monotherapy as maintenance therapy until tumor progression or intolerable toxicity. The primary endpoint was progression-free survival (PFS).

Results

Thirty-one patients were included between December 2019 and March 2022. The median follow-up was 17.5 (95% CI, 3.0-17.5) months. The median PFS was 8.3 (95% CI, 6.3-10.0) months, with 6- and 12-month PFS rates of 82.3% (95% CI, 59.2%-93.0%) and 18.9% (95% CI, 4.8%-40.1%), respectively. Fifteen (48.4%) achieved partial response for an ORR of 48.4% (95% CI, 30.2%-66.9%). The disease control rate was 71.0% (95% CI, 52.0%-85.8%) due to 7 (22.6%) stable diseases. The median duration of response was 6.0 (95% CI, 3.6-8.0) months and 1 patient had the longest ongoing response of 17.3 months. Of 24 patients with evaluable imaging, 23 (74.2%) obtained tumor shrinkage. The median PFS (11.0 vs. 6.9 months) and ORR (66.7% vs. 60.0%) for patients with RAS/BRAF wild-type were numerically better than those with mutation. Three patients are still ongoing treatment. The grade 3 or more treatment-emergent adverse events (TEAEs) were mainly hypertension (12.9%) and decreased neutrophil count (12.9%). Four (12.9%) had serious TEAEs, primarily including abdominal pain and incomplete intestinal obstruction.

Conclusion

Anlotinib plus XELOX as first-line therapy in patients with mCRC showed anti-tumor activity and safety profile, which is worth further investigation.

Clinical Trial Registration

chictr.org.cn, identifier ChiCTR1900028417.

Precision Medicine in Metastatic Colorectal Cancer: Targeting ERBB2 (HER-2) Oncogene

Colorectal cancer (CRC) is the third most common cancer in terms of incidence rate in adults and the second most common cause of cancer-related death in Europe. The treatment of metastatic CRC (mCRC) is based on the use of chemotherapy, anti-vascular endothelial growth factor (VEGF), and anti-epidermal growth factor receptor (EGFR) for RAS wild-type tumors. Precision medicine tries to identify molecular alterations that could be treated with targeted therapies. ERBB2 amplification (also known as HER-2) has been identified in 2-3% of patients with mCRC, but there are currently no approved ERBB2-targeted therapies for mCRC. The purpose of this review is to describe the molecular structure of ERBB2, clinical features of these patients, diagnosis of ERBB2 alterations, and the most relevant clinical trials with ERBB2-targeted therapies in mCRC.

Paradigm shift from palliation to cure in metastatic microsatellite high colorectal carcinoma with immune checkpoint inhibitors

Colorectal carcinoma (CRC) is one of the most frequently diagnosed malignancies worldwide with a high mortality rate. CRC is often plagued with significant treatment-related morbidity and mortality, and metastatic progression is common. With the advent of immunotherapy, inoperable and advanced cancers have shown favorable response. Immunotherapy has paved the way for survival of all those with advanced metastatic disease whose treatment was limited to palliative care. We explore the case of a 28-year-old female with advanced metastatic CRC refractory to chemotherapy and targeted therapy, managed with PD-1 inhibitor with complete clinical and pathological response in a relatively short period of time. The notion of upfront immunotherapy for advanced metastatic CRC with microsatellite instability is definitely reinforced by the favorable response seen in our case, and we hope that these findings would help reduce the dependence on chemotherapy as the mainstay therapeutic for advanced CRC.

Prediction of survival in patients with advanced, refractory colorectal cancer in treatment with trifluridine/tipiracil: real-world vs clinical trial data

Trifluridine/tipiracil increases overall survival (OS) in patients with refractory, metastatic colorectal cancer (mCRC). A post hoc exploratory analysis of the RECOURSE randomized clinical trial (RCT) established two categories, a good prognosis corresponding to subjects having a low tumor burden and indolent disease. Other models in refractory mCRC are the FAS-CORRECT and Colon Life nomogram. The main objective was to externally validate the prognostic factors of the RECOURSE and FAS-CORRECT trials, and the Colon Life nomogram in a multicenter, real-world series of mCRC treated in 3rd and successive lines with trifluridine/tipiracil. The secondary aim was to develop an OS predictive model, TAS-RECOSMO. Between 2016 and 2019, 244 patients were recruited. Median OS was 8.15 vs 8.12 months for the poor (85% of the subjects) and good (15%) prognosis groups from the RESOURCE trial, respectively, log-rank p = 0.9. The most common grade 3-4 toxicities were neutropenia (17%), asthenia (6%), and anemia (5%). The AFT lognormal model TAS-RECOSMO included six variables: ECOG-PS, KRAS/NRAS/BRAF mutation status, time between diagnosis of metastasis and beginning of trifluridine/tipiracil, NLR, CEA, and alkaline phosphatase. The model's bootstrapped bias-corrected c-index was 0.682 (95% CI, 0.636-0.722). The factors from the Colon Life model, FAS-CORRECT, and RECOURSE displayed a c-index of 0.690, 0.630, and 0.507, respectively. TAS-RECOSMO, FAS-CORRECT, and the Colon Life nomogram appear to predict OS in patients with refractory mCCR who begin trifluridine/tipiracil treatment in the real world. The prognostic groups of the RECOURCE RCT were unable to capture the situation of real-world subjects treated with trifluridine/tipiracil in this series.

An update on the use of immunotherapy in patients with colorectal cancer

Introduction: Colorectal cancer (CRC) is the third most common malignancy worldwide, with recent trends demonstrating increasing incidence amongst younger patients. Despite multiple treatment options, metastatic disease remains incurable. A new therapeutic strategy to harness the host immune system, specifically with immune checkpoint inhibitors, now has reported results from a number of clinical trials. Areas covered: This review will discuss in detail microsatellite instability (MSI) and other biomarkers for response to immunotherapy, summarize the pivotal clinical trials of immune checkpoint inhibitors in early-stage and metastatic MSI colorectal cancer, explore strategies to induce treatment responses in MSS CRC and highlight the emerging treatments and novel immune-based therapies under investigation. Expert opinion: Immunotherapy is now a standard of care for the proportion of CRC patients with MSI. While overall survival data are still awaited, the promise of profound and durable responses is highly anticipated. The lack of efficacy in MSS CRC is disappointing and strategies to convert these 'cold' tumors are needed. Further elucidation of optimal use of treatment sequences, combinations and novel agents will improve outcomes.