Fruquintinib Enhances the Antitumor Immune Responses of Anti-Programmed Death Receptor-1 in Colorectal Cancer

Evaluation of efficacy and safety of targeted therapy and immune checkpoint inhibitors in metastatic colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is among the most prevalent and deadly cancers globally, particularly in China. Treatment challenges remain in advanced and metastatic cases, especially in third- and fourth-line settings. The combination of targeted therapies with immune checkpoint inhibitors (ICIs) has shown potential in addressing the limitations of single-agent treatments.

AIM

To evaluate the efficacy and safety of targeted therapy (TT) alone and in combination with ICIs for metastatic CRC (mCRC).

METHODS

A multicenter retrospective observational study was conducted to evaluate the efficacy and safety of TT alone and in combination with ICIs for mCRC. A total of 99 patients treated with regorafenib or fruquintinib, with or without ICIs, were enrolled. Propensity score matching (PSM) and inverse probability weighting (IPW) were employed to balance baseline characteristics. The primary endpoint was progression-free survival (PFS), while overall survival (OS) and safety were secondary.

RESULTS

Patients who received combined therapy showed significantly longer median PFS rates compared to those who underwent TT in all analyses (original: 6.0 vs 3.4 months, P < 0.01; PSM: 6.15 vs 4.25 months, P < 0.05; IPW: 5.6 vs 3.3 months, P < 0.01). Although the median OS showed a trend toward improvement in the combination group, the difference was insignificant. Cox regression analysis revealed that combining TT with ICIs significantly reduced the risk of disease progression (hazard ratio = 0.38, P < 0.001). Adverse events (AEs) were generally manageable with both regimens, while serious AEs (grade 3-4) were primarily hypertension, fatigue, and reduced platelet counts. All AEs were controlled effectively by symptomatic treatment or discontinuation of the drug, and no treatment-related deaths were observed.

CONCLUSION

The combination of TT with ICIs offers a significant advantage in terms of PFS for patients with advanced mCRC, accompanied by a favorable safety profile. These findings underscore the benefits of combination therapy in this setting, warranting further investigation in larger prospective clinical trials.

Fruquintinib for Adult Patients With Metastatic Colorectal Cancer

BACKGROUND

Metastatic colorectal cancer (mCRC) represents a major clinical challenge, particularly for refractory patients who have exhausted standard treatments. Fruquintinib is an oral vascular endothelial growth factor receptor (VEGFR) inhibitor that has been approved by FDA for adult patients with mCRC who received prior fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy, vascular endothelial growth factor (VEGF) inhibitor therapy, and an epidermal growth factor receptor targeted therapy if RAS wild type.

AREAS OF UNCERTAINTY

Despite advances in mCRC treatment, patients who progress after standard therapies face limited options. The efficacy of treatments tends to diminish and side effects can be intolerable. There is a need for therapies that can extend survival without worsening quality of life.

DATA SOURCES

In the pivotal FRESCO-2 phase 3 trial, 691 patients with heavily pretreated mCRC were studied. Fruquintinib was found to significantly improve survival times, with a median overall survival (OS) of 7.4 months compared with 4.8 months with a placebo. Progression-free survival (PFS) also showed significant improvement with fruquintinib of 3.7 months versus 1.8 months in the placebo group. This was the first trial to show that an oral VEGFR inhibitor can be effective in refractory patients.

THERAPEUTIC ADVANCE

Fruquintinib represents a new treatment option for patients with mCRC who have limited therapeutic options. Fruquintinib has demonstrated statistically significant improvements in OS and PFS, in heavily pretreated patients. The FRESCO-2 trial demonstrated its efficacy, even in patients previously treated with trifluridine-tipiracil or regorafenib, showing a 34% reduction in OS and improved PFS.

CONCLUSIONS

Fruquintinib, approved by FDA for heavily pretreated patients with mCRC, addresses an unmet need in this population. Future research should focus on optimizing its integration into treatment plans and identifying biomarkers for personalized therapy.

Efficacy and safety of fruquintinib combined with PD-1 inhibitors in the treatment of refractory metastatic colorectal cancer: a systematic review and meta-analysis

BACKGROUND

Fruquintinib, a VEGFR1-3 tyrosine kinase inhibitor, is approved for treating refractory metastatic colorectal cancer. Recent clinical practice has shown that combining fruquintinib with programmed cell death protein 1 (PD-1) inhibitors can achieve better efficacy.The objective of this study is to assess the efficacy and safety of combining PD-1inhibitors with fruquintinib.

METHODS

We systematically searched PubMed, Cochrane Library, Embase, Wanfang, and CNKI up to 28 August 2024 for studies comparing fruquintinib combined with PD-1 inhibitors to fruquintinib alone. RevMan software was used to perform meta-analyses of survival data for the included studies.

RESULTS

A total of 9 retrospective cohort studies and 1 randomized controlled trial were included, involving a total of 716 patients. Compared with the monotherapy group, the combination therapy group had a greater Overall Response Rate [RR = 2.45,95% CI (1.83, 3.56), p < 0.00001], Disease Control Rate [RR = 1.37,95% CI (1.64,4.79), p = 0.0002], and progression-free survival [HR = 0.64,95% CI (0.49, 0.84), p = 0.001]. However, there was no significant difference in overall survival between the two groups. The incidence of adverse effects was identical in both groups.

CONCLUSION

Fruquintinib combined with PD-1 inhibitors was more effective than fruquintinib alone in the treatment of advanced colorectal cancer, with acceptable safety.

REGISTRATION

PROSPERO (registration number CRD42024583116).

Enhancing Colorectal Cancer Treatment Through VEGF/VEGFR Inhibitors and Immunotherapy

OPINION STATEMENT

Colorectal cancer, ranking as the third most prevalent malignancy globally, substantially benefits from both immunotherapy and VEGF/VEGFR inhibitors. Nevertheless, the use of monotherapy proves inadequate in effectively tackling the heterogeneity of tumors and the intricacies of their microenvironment, frequently leading to drug resistance and immune evasion. This situation underscores the pressing need for innovative strategies aimed at augmenting the effectiveness and durability of treatments. Clinical research demonstrates that the combination of VEGF/VEGFR inhibitors (primarily including VEGF/VEGFR-targeted drugs and multi-kinase inhibitors) with immune checkpoint inhibitors creates a synergistic effect in the treatment of colorectal cancer. Our analysis explores how VEGF/VEGFR inhibitors recalibrate the tumor microenvironment, modulate immune cell functions, and influence the expression of immune checkpoints and cytokines. Furthermore, we critically evaluate the preclinical and clinical feasibility of these combined therapeutic approaches. Despite the potential for toxicity, the significant benefits and prospective applications of these strategies warrant thorough exploration. Exploring the synergistic mechanisms of these combined treatments has the potential to inaugurate a new paradigm in oncology, enabling more personalized and efficacious treatment modalities. Additionally, the synergy between VEGF/VEGFR inhibitors and nascent immunotherapies emerges as a promising field of inquiry.

Clinical Progress of Fruquintinib in Colorectal Cancer: An Overview

Colorectal cancer (CRC) is one of the most common malignancies worldwide, with high morbidity and mortality rates. Conventional treatments, including surgery, radiotherapy, and chemotherapy, have limited effects on advanced and metastatic CRC (mCRC). Fruquintinib, a novel and highly selective vascular endothelial growth factor receptor (VEGFR) inhibitor, has shown significant efficacy and tolerance in treating mCRC. The FRESCO and FRESCO-2 trials demonstrated that fruquintinib significantly prolongs progression-free survival and the overall survival of refractory mCRC patients, establishing it as the standard third-line treatment strategy for mCRC. In addition, the combination of fruquintinib with other anticancer drugs and immune checkpoint inhibitors demonstrated potential for enhanced efficacy, which warrants further exploration. In this review, we aimed to systematically summarize the current knowledge about the pharmacological mechanisms, pharmacokinetic characteristics, adverse events, and corresponding treatment options of fruquintinib and provide an update on the clinical trials related to fruquintinib in CRC by conducting a comprehensive literature search of PubMed and consulting the relevant clinical trials via ClinicalTrials.gov and the ChiCTR website, aiming to offer new insights into the role of fruquintinib in the comprehensive treatment of CRC.

Fruquintinib Plus Sintilimab in Patients with Treatment-Naive and Previously Treated Advanced Renal Cell Carcinoma: Results from a Phase Ib/II Clinical Trial

BACKGROUND

Antiangiogenic inhibitors plus immune checkpoint inhibitors have synergistic antitumor activity and have improved treatment outcomes in patients with renal cell carcinoma (RCC).

OBJECTIVE

We report the RCC cohort from a phase Ib/II study in Chinese patients evaluating the efficacy and safety of fruquintinib plus sintilimab in treating advanced clear cell RCC (ccRCC).

PATIENTS AND METHODS

Eligible patients had pathologically confirmed advanced ccRCC. Patients received fruquintinib 5 mg once daily, 2 weeks on/1 week off, plus sintilimab 200 mg every 3 weeks in 3-week cycles. The primary endpoint was investigator-assessed objective response rate (ORR) per Response Evaluation Criteria in Solid Tumors, version 1.1.

RESULTS

By March 31, 2023, 42 patients (median age 58.9 years; 81.0% male) had been treated in the RCC cohort. Among treatment-naive patients (n = 22), confirmed ORR was 68.2% (95% confidence interval [CI] 45.1-86.1). The median progression-free survival (PFS) was not reached, and 18-month PFS rate was 59.4%. Among previously treated patients (n = 20), the confirmed ORR was 60.0% (95% CI 36.1-80.9), and the median PFS was 15.9 (95% CI 5.4-19.3) months. All patients had adverse events related to study treatment, 52.4% of which were grade ≥ 3 in severity. Treatment-related adverse events with an incidence of ≥ 40% included proteinuria, hypothyroidism, hypercholesterolemia, hypertriglyceridemia, and hypoalbuminemia.

CONCLUSIONS

Fruquintinib plus sintilimab demonstrated promising efficacy in advanced ccRCC and was well tolerated. A phase III study (FRUSICA-02) using this combination regimen in patients with previously treated advanced ccRCC is ongoing.

TRIAL REGISTRATION NUMBER

The study was registered with ClinicalTrials.gov (NCT03903705).

Clinical research progress of fruquintinib in the treatment of malignant tumors

Malignant tumors represent an important cause of mortality within the global population. Tumor angiogenesis, recognized as one of the key hallmarks of malignant tumors, is crucial for supplying essential nutrients and oxygen for tumor growth. Vascular endothelial growth factor (VEGF) and its receptor (VEGFR) are key drivers of tumor angiogenesis. Targeted therapeutic interventions not only effectively inhibit tumor growth by specifically blocking tumor angiogenesis but have also made breakthroughs in the treatment of malignant tumors. Fruquintinib, an anti-angiogenic small molecule drug developed independently in China, functions as a potent tyrosine kinase inhibitor with high selectivity. It effectively curtails tumor growth by binding to and inhibiting VEGFR-1, VEGFR-2, and VEGFR-3. Additionally, fruquintinib offers several advantages including minimal off-target toxicity, robust resistance profiles, and commendable efficacy. This agent can be used alone or in combination with other treatments. It has shown high effectiveness and survival benefits across various malignant tumors such as colorectal cancer, gastric cancer, non-small cell lung cancer, breast cancer, and other malignant tumors. Therefore, this article conducts a systematic review encompassing the mechanism of action, pharmacokinetics, clinical efficacy, and safety profile of fruquintinib. Through this review, we aimed to offer a reference for the clinical application and subsequent development of fruquintinib.

Deciphering the impact of aggregated autophagy-related genes TUBA1B and HSP90AA1 on colorectal cancer evolution: a single-cell sequencing study of the tumor microenvironment

BACKGROUND

Colorectal cancer (CRC) is the third most prevalent cancer worldwide, with the tumor microenvironment (TME) playing a crucial role in its progression. Aggregated autophagy (AA) has been recognized as a factor that exacerbates CRC progression. This study aims to study the relationship between aggregated autophagy and CRC using single-cell sequencing techniques. Our goal is to explain the heterogeneity of the TME and to explore the potential for targeted personalized therapies.

OBJECTIVE

To study the role of AA in CRC, we employed single-cell sequencing to discern distinct subpopulations within the TME. These subpopulations were characterized by their autophagy levels and further analyzed to identify specific biological processes and marker genes.

RESULTS

Our study revealed significant correlations between immune factors and both clinical and biological characteristics of the tumor microenvironment (TME), particularly in cells expressing TUBA1B and HSP90AA1. These immune factors were associated with T cell depletion, a reduction in protective factors, diminished efficacy of immune checkpoint blockade (ICB), and enhanced migration of cancer-associated fibroblasts (CAFs), resulting in pronounced inflammation. In vitro experiments showd that silencing TUBA1B and HSP90AA1 using siRNA (Si-TUBA1B and Si-HSP90AA1) significantly reduced the expression of IL-6, IL-7, CXCL1, and CXCL2 and inhibition of tumor cell growth in Caco-2 and Colo-205 cell lines. This reduction led to a substantial alleviation of chronic inflammation and highlighted the heterogeneous nature of the TME.

CONCLUSION

This study marks an initial foray into understanding how AA-associated processes may potentiate the TME and weaken immune function. Our findings provide insights into the complex dynamics of the TME and highlight potential targets for therapeutic intervention, suggesting a key role for AA in the advancement of colorectal cancer.

Efficacy and safety of hepatic arterial infusion chemotherapy combined with fruquintinib and tislelizumab for patients with microsatellite stable colorectal cancer liver metastasis following failure of multiple-line therapy

BACKGROUND AND AIM

The prognosis of microsatellite stable (MSS)-colorectal cancer liver metastasis (CRCLM) following failure of multi-line therapy remains dismal. The aim of this study is to evaluate the efficacy and safety of hepatic arterial infusion chemotherapy (HAIC) plus fruquintinib and tislelizumab (HAIC-F-T treatment) for MSS-CRCLM which failed from multiple-line therapy.

METHODS

From February 2021 to June 2023, 45 patients with MSS-CRCLM after failure of multiple-line therapy who received HAIC combined with fruquintinib and tislelizumab (HAIC-F-T triple treatment) were enrolled. The combination therapy included HAIC regimens with oxaliplatin and 5-fluorouracil or irinotecan, oxaliplatin, and 5-fluorouracil on days 1-2, intravenous tislelizumab (200 mg) before HAIC on day 1, and oral fruquintinb (3 mg/d) on day 3-21, every 4 weeks. Overall survival (OS) and progression-free survival (PFS) were estimated using the Kaplan-Meier method.

RESULTS

The follow-up ended on June 22, 2024, with a median follow-up time of 17.5 months. The objective response rate was 42.2%, and the disease control rate was 82.2%. The median OS was 15.3 months (95% confidence interval [CI]:12.634-17.966), and the median PFS was 7.5 months (95% CI:5.318-9.682). The independent risk factors related to worse OS were previous PD-1 immunotherapy (P = 0.021) and the number of HAIC-F-T triple treatment cycles of ≤ 2 (P = 0.007). The incidence of grade 3 or higher adverse events (AEs) was 20%, with the most frequent grade 3 or higher AEs being abdominal pain (3/45, 6.7%).

CONCLUSION

HAIC combined with fruquintinib and tislelizumab may be an alternative salvage treatment for patients with MSS-CRCLM following failure of multiple-line therapy.

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.

Fruquintinib as new treatment option in metastatic colorectal cancer patients: is there an optimal sequence?

INTRODUCTION

Available treatments for colorectal cancer are limited. However, in the last few years several advances and new treatment options became available and expanded the continuum of care in metastatic colorectal cancer (mCRC).

AREAS COVERED

Fruquintinib, a tyrosine kinase inhibitor, has been shown to be effective in heavily pretreated mCRC progressing to trifluridine-tipiracil (FTD/TPI) or regorafenib or both. Preclinical studies have shown that fruquintinib inhibits with high selectivity VEGFR 1-2-3, leading to a blockade in angiogenesis process, but also acts, with weak inhibition, on RET, FGFR-1, and c-kit kinases. Fruquintinib demonstrated good efficacy and tolerance in chemorefractory mCRC in two phase III trial: FRESCO and FRESCO 2. These results led to FDA approval of fruquintinib for pretreated mCRC patients who received prior fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy.

EXPERT OPINION

Fruquintinib is a valid therapeutic option for heavily pretreated mCRC patients. However, an optimal sequence of treatments is yet to be defined. In this review, we propose an algorithm for later lines of treatment to integrate fruquintinib as a standard of care together with the new therapeutic combinations that recently showed clinical benefit for chemorefractory mCRC, in both molecularly selected (e.g. KRASG12C or HER2 amplification) and in non-oncogenic driven patients.

Feasibility and Tolerability of Anlotinib Plus PD-1 Blockades for Patients with Treatment-Refractory Metastatic Colorectal Cancer: A Retrospective Exploratory Study

Objective

Therapeutic regimens are relatively scarce among patients with treatment-refractory metastatic colorectal cancer (CRC). This study aimed to determine the feasibility and tolerability of anlotinib plus PD-1 blockades in patients with treatment-refractory metastatic CRC retrospectively.

Methods

A total of 68 patients with previously treated metastatic CRC who received anlotinib plus PD-1 blockades in clinical practice were included in this study retrospectively. Demographic and clinical characteristics of the patients, therapeutic outcomes and safety profile during administration were collected and briefly analyzed. All subjects were followed up regularly. Therapeutic outcomes, including drug response and prognosis, were presented, and a safety profile was depicted to illustrate the adverse reactions.

Results

A total of 68 patients with treatment-refractory metastatic CRC who received anlotinib plus PD-1 blockades in clinical practice were included in the final analysis. Best therapeutic response during treatment indicated that partial response was observed in 11 patients, stable disease was noted in 41 patients, and progressive disease was found in 16 patients, producing an objective response rate of 16.2% (95% CI: 8.4%-27.1%) and a disease control rate of 76.5% (95% CI: 64.6%-85.9%). Prognostic analysis suggested that the median progression-free survival (PFS) of the 68 patients was 5.3 months (95% CI: 3.01-7.59), and the median overall survival (OS) was 12.5 months (95% CI: 9.40-15.60). Of the 11 patients who responded, the median duration of response was 6.7 months (95% CI: 2.89-10.53). Safety profile during treatment showed that patients experienced adverse reactions regardless of grade, and grade ≥3 adverse reactions were found in 61 patients (89.7%) and 41 patients (60.3%), respectively. Common adverse reactions were hypertension, myelosuppression (including leukopenia, neutropenia, thrombocytopenia, and anemia), fatigue, and hand-foot syndrome.

Conclusion

Anlotinib plus PD-1 blockades demonstrated encouraging efficacy and acceptable safety profile in patients with treatment-refractory metastatic CRC preliminarily in clinical practice. This conclusion should be confirmed in prospective clinical trials.

Significant response from fruquintinib plus anti-PD-1 immunotherapy for microsatellite stable metastatic colorectal cancer with liver and lung metastasis in the third line: case report

Background

There are limited treatment options available for patients with metastatic colorectal cancer (mCRC). About 95% of CRC patients have mismatch repair proficient/microsatellite stable (pMMR/MSS) tumors are virtually unresponsive to programmed cell death protein 1 (PD-1) antibody treatment. This report shows that a patient with pMMR/MSS mCRC achieved significant response and the longest progression-free survival (PFS) of 28 months currently reported from tyrosine kinase inhibitors (TKIs) targeting vascular endothelial growth factor receptor (VEGFR) family (VEGFR-1,2,3) (fruquintinib) plus anti-PD-1 immunotherapy in the third line, providing a new and promising treatment option for some MSS mCRC patients.

Case Description

This case details a 65-year-old male with CRC who was diagnosed with pT4aN2bM0, IIIC, and pMMR/MSS after curative surgery in August 2018. Subsequently, he received adjuvant chemotherapy [FOLFOX (folinic acid, fluorouracil, and oxaliplatin) for 5 cycles], first-line treatment (pelvic radiation plus capecitabine), and second-line treatment [TOMIRI (raltitrexed and irinotecan) plus cetuximab for 2 cycles]. Lung, liver, and pelvic cavity metastases worsened in October 2019. He began receiving the fruquintinib plus PD-1 inhibitor (FP) regimen as third-line treatment and after 3 cycles, the size of the lung lesions was significantly reduced and evaluated as partial response (PR), whereas the liver and pelvic cavity lesions remained stable. As of December 2021, he had received a total of 33 courses of FP regimen. In February 2022, liver metastases progressed. In brief, he achieved a long PFS of 28 months and an overall survival (OS) of 40 months from the third-line treatment. Additionally, the patient only experienced mild proteinuria after the combined treatment and tolerated well.

Conclusions

Fruquintinib combined with immunotherapy could exert good therapeutic effects with safety in MSS mCRC patients. And patients with lung metastasis may be the principal beneficiaries.

Current status and prospect of immunotherapy for colorectal cancer

PURPOSE

Colorectal cancer is the most common gastrointestinal tumor in China. While significant progress has been achieved in traditional chemotherapy, radiotherapy, and targeted therapy, the prognosis of advanced colorectal cancer is poor, and the five-year survival rate is unsatisfactory. There is an urgent need to explore new treatment modalities. In this review, we examined the latest progress of colorectal cancer immunotherapy and discussed its future prospects.

METHODS

We conducted a literature review to sort out the current status of immunotherapy for different types of colorectal cancer and discussed potential combination therapy options. Results Subsequent line therapy, first-line therapy and neoadjuvant therapy for MSI-H/dMMR colorectal cancer are discussed. In addition, combination therapy options for patients with MSS/pMMR colorectal cancer are presented. Finally, current valuable biomarkers for immunotherapy are highlighted.

RESULTS

Subsequent line therapy, first-line therapy and neoadjuvant therapy for MSI-H/dMMR colorectal cancer are discussed. In addition, combination therapy options for patients with MSS/pMMR colorectal cancer are presented. Finally, current valuable biomarkers for immunotherapy are highlighted.

CONCLUSION

This review discussed the current status of immunotherapy for different types of colorectal cancer and biomarkers for immunotherapy.

RIFLE: a Phase II trial of stereotactic ablative radiotherapy combined with fruquintinib and tislelizumab in metastatic colorectal cancer

Background

Currently, the prognosis for metastatic colorectal cancer (mCRC) still remains poor. The management of mCRC has become manifold because of the varied advances in the systemic and topical treatment approaches. For patients with limited number of metastases, radical local therapy plus systemic therapy can be a good choice to achieve long-term tumor control. In this study, we aimed to explore the efficacy and safety of the combination of fruquintinib, tislelizumab, and stereotactic ablative radiotherapy (SABR) in mCRC (RIFLE study).

Methods

RIFLE was designed as a single-center, single-arm, prospective Phase II clinical trial. A total of 68 mCRC patients who have failed the first-line standard treatment will be recruited in the safety run-in phase (n = 6) and the expansion phase (n = 62), respectively. Eligible patients will receive SABR followed by fruquintinib (5 mg, d1-14, once every day) and tislelizumab (200 mg, d1, once every 3 weeks) within 2 weeks from completion of radiation. The expansion phase starts when the safety of the treatment is determined (dose limiting toxicity occur in no more than one-sixth of patients in the run-in phase). The primary end point is the objective response rate. The secondary end points include the disease control rate, duration of response, 3-year progression-free survival rate, 3-year overall survival rate, and toxicity.

Conclusions

The results of this trial will provide a novel insight into SABR in combination with PD-1 antibody and vascular endothelial growth factor receptor inhibitor in the systematic treatment of metastatic colorectal cancer, which is expected to provide new therapeutic strategies and improve the prognosis for mCRC patients.

Trial registration

NCT04948034 (ClinicalTrials.gov).

Evaluation of Fruquintinib in the Continuum of Care of Patients with Colorectal Cancer

The management of patients with metastatic colorectal cancer (mCRC) has the continuum of care as the treatment paradigm. To date, trifluridine/tipiracil, a biochemically modulated fluoropyrimidine, and regorafenib, a multi-kinase inhibitor, remain the main options for the majority of patients who progressed to standard doublet- or triplet-based chemotherapies, although a tailored approach could be indicated in certain circumstances. Being highly selective for vascular endothelial growth factor receptor (VEGFR)-1, -2 and -3, fruquintinib demonstrated a strong anti-tumor activity in preclinical models and received approval from China's National Medical Products Administration (NMPA) in 2018 for the treatment of patients with chemo-refractory mCRC. The approval was based on the results of the phase III FRESCO trial. Then, in order to overcome geographic differences in clinical practice, the FRESCO-2 trial was conducted in the US, Europe, Japan, and Australia. In a heavily pretreated patient population, the study met its primary endpoint, demonstrating an advantage of fruquintinib over a placebo in overall survival (OS). Here, we review the clinical development of fruquintinib and its perspectives in gastrointestinal cancers. Then, we discuss the introduction of fruquintinib in the continuum of care of CRC paying special attention to unmet needs, including the identification of cross-resistant and potentially susceptible populations, evaluation of radiological response, and identification of novel biomarkers of clinical benefit.

Case Report: MSS colorectal extrahepatic (non-liver) metastases as the dominant population for immunotherapy combined with multi-target tyrosine kinase inhibitors

Background

The microsatellite stability(MSS) subtype of Colorectal Cancer(CRC) represents approximately 95% of mCRC cases. Immunotherapy was not as encouraging as the data for MSS mCRC cancer. We report the treatment of a series of patients with extrahepatic metastasis of MSS colorectal cancer, which can provide reference and guidance for the treatment of non-hepatic metastasis of MSS colorectal.

Case presentation

This report describes 8 typical cases of successful MSS treatment with lung metastases of CRC. We systematically reviewed the clinical data and detailed medical history of one of these patients with extrahepatic metastasis from MSS colorectal cancer, and reviewed the literature to analyze and discuss the related epidemiological features, mechanisms and recent research findings of the special subgroup of the population.

Conclusions

Although MSS colon rectal cancer is still known as a cold tumor in the industry, immunotherapy combined with multi-targeted anti-vascular tyrosine kinase inhibitors had brought clinical benefits to patients with non-hepatic metastases from MSS colorectal cancer.

Relationship between Epithelial-to-Mesenchymal Transition and Tumor-Associated Macrophages in Colorectal Liver Metastases

The liver is the most common metastatic site in colorectal cancer (CRC) patients. Indeed, 25-30% of the cases develop colorectal liver metastasis (CLM), showing an extremely poor 5-year survival rate and resistance to conventional anticancer therapies. Tumor-associated macrophages (TAMs) provide a nurturing microenvironment for CRC metastasis, promoting epithelial-to-mesenchymal transition (EMT) through the TGF-β signaling pathway, thus driving tumor cells to acquire mesenchymal properties that allow them to migrate from the primary tumor and invade the new metastatic site. EMT is known to contribute to the disruption of blood vessel integrity and the generation of circulating tumor cells (CTCs), thus being closely related to high metastatic potential in numerous solid cancers. Despite the fact that it is well-recognized that the crosstalk between tumor cells and the inflammatory microenvironment is crucial in the EMT process, the association between the EMT and the role of TAMs is still poorly understood. In this review, we elaborated on the role that TAMs exert in the induction of EMT during CLM development. Since TAMs are the major source of TGF-β in the liver, we also focused on novel insights into their role in TGF-β-induced EMT.