Nivolumab in patients with metastatic DNA mismatch repair-deficient or microsatellite instability-high colorectal cancer (CheckMate 142): an open-label, multicentre, phase 2 study

Biomarkers in head and neck squamous cell carcinoma: unraveling the path to precision immunotherapy

Recent strides in understanding the molecular underpinnings of head and neck cancers have sparked considerable interest in identifying precise biomarkers that can enhance prognostication and enable personalized treatment strategies. Immunotherapy has particularly revolutionized the therapeutic landscape for head and neck squamous cell carcinoma, offering new avenues for treatment. This review comprehensively examines the application and limitations of the established and emerging/novel biomarkers for head and neck squamous cell carcinoma. Established biomarkers, including well-characterized genetic mutations, protein expressions, and clinical factors, have been extensively studied and validated in clinical practice. Novel biomarkers identified through molecular analyses, including novel genetic alterations, immune-related markers, and molecular signatures, are currently being investigated and validated in preclinical and clinical settings. Biomarkers hold the potential to deepen our understanding of head and neck squamous cell carcinoma biology and guide therapeutic strategies. The evolving paradigm of predictive biomarkers facilitates the study of individual responses to specific treatments, including targeted therapy and immunotherapy.

Signaling pathways involved in colorectal cancer: pathogenesis and targeted therapy

Colorectal cancer (CRC) remains one of the leading causes of cancer-related mortality worldwide. Its complexity is influenced by various signal transduction networks that govern cellular proliferation, survival, differentiation, and apoptosis. The pathogenesis of CRC is a testament to the dysregulation of these signaling cascades, which culminates in the malignant transformation of colonic epithelium. This review aims to dissect the foundational signaling mechanisms implicated in CRC, to elucidate the generalized principles underpinning neoplastic evolution and progression. We discuss the molecular hallmarks of CRC, including the genomic, epigenomic and microbial features of CRC to highlight the role of signal transduction in the orchestration of the tumorigenic process. Concurrently, we review the advent of targeted and immune therapies in CRC, assessing their impact on the current clinical landscape. The development of these therapies has been informed by a deepening understanding of oncogenic signaling, leading to the identification of key nodes within these networks that can be exploited pharmacologically. Furthermore, we explore the potential of integrating AI to enhance the precision of therapeutic targeting and patient stratification, emphasizing their role in personalized medicine. In summary, our review captures the dynamic interplay between aberrant signaling in CRC pathogenesis and the concerted efforts to counteract these changes through targeted therapeutic strategies, ultimately aiming to pave the way for improved prognosis and personalized treatment modalities in colorectal cancer.

Predictors of response to immunotherapy in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related deaths globally. While treatment advancements have improved survival rates, primarily through targeted therapies based on KRAS, NRAS, and BRAF mutations, personalized treatment strategies for CRC remain limited. Immunotherapy, mainly immune checkpoint blockade, has shown efficacy in various cancers but is effective in only a small subset of patients with CRC with deficient mismatch repair (dMMR) proteins or high microsatellite instability (MSI). Recent research has challenged the notion that CRC is immunologically inert, revealing subsets with high immunogenicity and diverse lymphocytic infiltration. Identifying precise biomarkers beyond dMMR and MSI is crucial to expanding immunotherapy benefits. Hence, exploration has extended to various biomarker sources, such as the tumor microenvironment, genomic markers, and gut microbiota. Recent studies have introduced a novel classification system, consensus molecular subtypes, that aids in identifying patients with CRC with an immunogenic profile. These findings underscore the necessity of moving beyond single biomarkers and toward a comprehensive understanding of the immunological landscape in CRC, facilitating the development of more effective, personalized therapies.

Harmonizing tumor mutational burden analysis: Insights from a multicenter study using in silico reference data sets in clinical whole-exome sequencing (WES)

OBJECTIVES

Tumor mutational burden (TMB) is a significant biomarker for predicting immune checkpoint inhibitor response, but the clinical performance of whole-exome sequencing (WES)-based TMB estimation has received less attention compared to panel-based methods. This study aimed to assess the reliability and comparability of WES-based TMB analysis among laboratories under routine testing conditions.

METHODS

A multicenter study was conducted involving 24 laboratories in China using in silico reference data sets. The accuracy and comparability of TMB estimation were evaluated using matched tumor-normal data sets. Factors such as accuracy of variant calls, limit of detection (LOD) of WES test, size of regions of interest (ROIs) used for TMB calculation, and TMB cutoff points were analyzed.

RESULTS

The laboratories consistently underestimated the expected TMB scores in matched tumor-normal samples, with only 50% falling within the ±30% TMB interval. Samples with low TMB score (<2.5) received the consensus interpretation. Accuracy of variant calls, LOD of the WES test, ROI, and TMB cutoff points were important factors causing interlaboratory deviations.

CONCLUSIONS

This study highlights real-world challenges in WES-based TMB analysis that need to be improved and optimized. This research will aid in the selection of more reasonable analytical procedures to minimize potential methodologic biases in estimating TMB in clinical exome sequencing tests. Harmonizing TMB estimation in clinical testing conditions is crucial for accurately evaluating patients' response to immunotherapy.

Preclinical investigations and a first-in-human phase 1a trial of JS007, a novel anti-CTLA-4 antibody, in patients with advanced solid tumors

BACKGROUND

Blocking cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) shows substantial antitumor efficacy. Here, we report the preclinical data and outcomes of a first-in-human phase 1a trial of JS007, a novel anti-CTLA-4 antibody, in advanced solid tumors.

METHODS

In preclinical studies, both in vitro characteristics and in vivo characteristics of JS007 were investigated. The clinical trial included a dose escalation phase and a dose expansion phase. Eligible patients with previously treated advanced solid tumors were enrolled. In the dose escalation phase, JS007 was administered intravenously every 3 weeks at doses of 0.03, 0.3, 1, 3, and 10 mg/kg. Then, 3 and 10 mg/kg were chosen for the dose expansion phase. The primary endpoints included the maximum tolerated dose (MTD) of JS007 based on dose-limiting toxicities (DLTs) and safety.

RESULTS

JS007 could effectively bind to CTLA-4 and induce an immune response in vitro. Potent in vivo antitumor activity of JS007 was observed. Increased T cell infiltration and T regulatory (Treg) cell depletion in tumor microenvironment of cancer cell xenografts were detected after treated with JS007. Pharmacological analysis in experimental animals showed a dose-proportional increase in exposure. In the clinical trial, a total of 28 patients were treated with JS007 across 5 dose levels. No DLTs occurred. The MTD did not reach at the highest dose tested (10 mg/kg). Twenty-three (82.1%) patients experienced at least one treatment-related adverse event (TRAE). The incidence of Grade ≥ 3 TRAEs was 28.6% (8/28) with alanine aminotransferase increase (7.1%, 2/28) being the most frequently reported TRAE. No severe immune-related adverse event (irAE) occurred. Pharmacological profiles of JS007 in patients were similar to those in animal models. Serum concentration of JS007 showed a dose-dependent escalation, and the half-life of JS007 was 9.4 ~ 12.2 days. Treatment-induced anti-drug antibody was detected in 2 patients. The disease control rate was 50% (14/28), and the median overall survival was 14.7 months.

CONCLUSIONS

JS007 preliminarily demonstrates good tolerance and encouraging antitumor activity in patients with previously treated advanced solid tumors.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT05049265 (Sep 20, 2021).

Immunotherapy for Microsatellite-Stable Metastatic Colorectal Cancer: Can we close the Gap between Potential and Practice?

PURPOSE OF REVIEW

This review will explore various strategies to rendering MSS mCRCs susceptible to ICI. Moreover, we will provide an overview of potential biomarkers that may aid to better patient selection, and discuss ongoing efforts in this area of research.

RECENT FINDINGS

Colorectal cancer (CRC) ranks among the top three most common cancers worldwide. While significant advances in treatment strategies have improved the prognosis for patients in the early stages of the disease, treatment options for metastatic CRC (mCRC) remain limited. Although immune checkpoint inhibitors (ICI) have revolutionized the treatment of several malignancies, its efficacy in mCRC is largely confined to patients exhibiting a high microsatellite instability status (MSI-H). However, the vast majority of mCRC patients do not exhibit a MSI-H, but are microsatellite stable (MSS). In these patients ICIs are largely ineffective. So far, ICIs do not play a crucial role in patients with MSS mCRC, despite the promising data for inducing long-term remissions in other tumour entities. For this reason, novel treatment strategies are needed to overcome the primary resistance upon ICI in patients with MSS.

COLUMBIA-1: a randomised study of durvalumab plus oleclumab in combination with chemotherapy and bevacizumab in metastatic microsatellite-stable colorectal cancer

BACKGROUND

To determine whether the addition of durvalumab (anti-PD-L1) and oleclumab (anti-CD73) to standard-of-care treatment (FOLFOX and bevacizumab) enhances the anti-tumour effect in patients with metastatic colorectal cancer (mCRC).

METHODS

COLUMBIA-1 (NCT04068610) was a Phase Ib (feasibility; Part 1)/Phase II (randomised; Part 2) trial in patients with treatment-naïve microsatellite stable mCRC. Patients in Part 2 were randomised to receive standard-of-care (control arm) or standard-of-care plus durvalumab and oleclumab (experimental arm). Primary objectives included safety and efficacy.

RESULTS

Seven patients were enrolled in Part 1 and 52 in Part 2 (n = 26 in each arm). Grade ≥3 treatment-emergent adverse events (TEAE) occurred in 80.8% and 65.4% of patients in the control and experimental arms of Part 2, respectively, with 26.9% and 46.3% experiencing serious TEAEs. The confirmed objective response rate (ORR) was numerically higher in the experimental arm compared with the control arm (61.5% [95% confidence interval (CI), 40.6-79.8] vs 46.2% [95% CI, 26.6-66.6]) but did not meet the statistically significant threshold in either arm.

CONCLUSION

The safety profile of FOLFOX and bevacizumab in combination with durvalumab and oleclumab was manageable; however, the efficacy results do not warrant further development of this combination in patients with microsatellite stable mCRC.

REGISTRATION

NCT04068610.

Mismatch repair deficiency: how reliable is the two-antibody approach? A national real-life study

AIMS

Traditionally, mismatch repair (MMR) status is determined by a panel of four antibodies (MLH1, PMS2, MSH2, MSH6). If all proteins are retained, cases are MMR proficient (pMMR), while loss of one or more proteins is indicative of MMR deficiency (dMMR). This approach has been challenged in favour of a two-antibody approach, using PMS2 and MSH6 as a first screening. Their retainment is deemed sufficient to declare cases pMMR. In this study we aim to verify the validity of the two-antibody approach.

METHODS AND RESULTS

We performed a nationwide study in colorectal cancer (CRC) and endometrial cancer (EC) diagnosed between 2016 and 2023, including 47,657 patients to evaluate the two-antibody approach. In 0.17% and 0.4% of cases of CRC and EC, respectively, dMMR cases would be missed with the two-antibody approach. Subgroup analyses pointed towards slightly increased miss rates in younger patients (under the age of 50 years) in both groups and identified special subtypes (signet ring cell carcinoma, medullary carcinoma, and mucinous carcinoma in CRC and clear cell carcinoma in EC) with increased miss rates. For these specific subgroups, a low threshold should be used for further testing. In case of ambiguous or heterogeneous staining patterns, four antibodies should be used.

CONCLUSION

In general, the application of a two-antibody MMR testing strategy does not lead to considerable failure of dMMR identification and saves costs.

A new strategy for immunotherapy of microsatellite-stable (MSS)-type advanced colorectal cancer: Multi-pathway combination therapy with PD-1/PD-L1 inhibitors

Colorectal cancer (CRC) is a frequent gastrointestinal malignancy with high rates of morbidity and mortality; 85% of these tumours are proficient mismatch repair (pMMR)-microsatellite instability-low (MSI-L)/microsatellite stable (MSS) CRC known as 'cold' tumours that are resistant to immunosuppressive drugs. Monotherapy with programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) inhibitors is ineffective for treating MSS CRC, making immunotherapy for MSS CRC a bottleneck. Recent studies have found that the multi-pathway regimens combined with PD-1/PD-L1 inhibitors can enhance the efficacy of anti-PD-1/PD-L1 in MSS CRC by increasing the number of CD8+ T cells, upregulating PD-L1 expression and improving the tumour microenvironment. This paper reviews the research progress of PD-1/PD-L1 inhibitors in combination with cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) inhibitors, oncolytic virus, intestinal flora, antiangiogenic agents, chemotherapy, radiotherapy and epigenetic drugs for the treatment of pMMR-MSI-L/MSS CRC.

Pan-cancer evaluation of tumor-infiltrating lymphocytes and programmed cell death protein ligand-1 in metastatic biopsies and matched primary tumors

Tumor immunological characterization includes evaluation of tumor-infiltrating lymphocytes (TILs) and programmed cell death protein ligand-1 (PD-L1) expression. This study investigated TIL distribution, its prognostic value, and PD-L1 expression in metastatic and matched primary tumors (PTs). Specimens from 550 pan-cancer patients of the SHIVA01 trial (NCT01771458) with available metastatic biopsy and 111 matched PTs were evaluated for TILs and PD-L1. Combined positive score (CPS), tumor proportion score (TPS), and immune cell (IC) score were determined. TILs and PD-L1 were assessed according to PT organ of origin, histological subtype, and metastatic biopsy site. We found that TIL distribution in metastases did not vary according to PT organ of origin, histological subtype, or metastatic biopsy site, with a median of 10% (range: 0-70). TILs were decreased in metastases compared to PT (20% [5-60] versus 10% [0-40], p < 0.0001). CPS varied according to histological subtype (p = 0.02) and biopsy site (p < 0.02). TPS varied according to PT organ of origin (p = 0.003), histological subtype (p = 0.0004), and metastatic biopsy site (p = 0.00004). TPS was higher in metastases than in PT (p < 0.0001). TILs in metastases did not correlate with overall survival. In conclusion, metastases harbored fewer TILs than matched PT, regardless of PT organ of origin, histological subtype, and metastatic biopsy site. PD-L1 expression increased with disease progression. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The Innate Immune Landscape of dMMR/MSI Cancers Predicts the Outcome of Nivolumab Treatment: Results from the Drug Rediscovery Protocol

PURPOSE

The treatment efficacy of nivolumab was evaluated in patients with advanced, treatment-refractory solid mismatch repair deficiency/microsatellite-instable (dMMR/MSI) tumors, and in-depth biomarker analyses were performed to inform precision immunotherapy approaches.

PATIENTS AND METHODS

Patients with dMMR/MSI tumors who exhausted standard-of-care treatment options were enrolled in the Drug Rediscovery Protocol, a pan-cancer clinical trial that treats patients with cancer based on their tumor molecular profile with off-label anticancer drugs (NCT02925234). Patients received nivolumab (four cycles of 240 mg every 2 weeks, thereafter 480 mg every 4 weeks). The primary endpoint was clinical benefit (CB: objective response or stable disease ≥16 weeks). Whole-genome sequencing and RNA sequencing were performed on pretreatment tumor biopsies.

RESULTS

A total of 130 evaluable patients were enrolled with 16 different cancer types. CB was observed in 62% [95% confidence interval (CI), 53-70], with an objective response in 45% (95% CI, 36-54). After a median follow-up of 14.5 months (95% CI, 13-19), the median progression-free survival was 18 months (95% CI, 9-not reached), and the median overall survival was not reached. Whereas CB was not, or only weakly, associated with markers of adaptive immune cell infiltration, CB was strongly associated with expression of a broad set of innate immune receptors/ligands. This clearly contrasted findings in melanoma, in which markers of adaptive immunity dominated the biomarker landscape.

CONCLUSIONS

Nivolumab proved highly effective in advanced dMMR/MSI tumors. Expression of key innate immune receptors/ligands was the main predictor of a good treatment outcome, contrasting findings in melanoma and strengthening the rationale for tumor type-specific biomarkers for guiding immunotherapy.

Deficient mismatch repair and BRAF-V600E-mutated metastatic colorectal cancer responds to nivolumab therapy after progression under bevacizumab plus FOLFIRI

Nivolumab, a PD-1 immune checkpoint inhibitor, has been demonstrated to be clinically effective in patients with deficient mismatch repair (dMMR) and BRAF-V600E-mutated metastatic colorectal cancer (mCRC). We present the case of an 81-year-old Taiwanese woman with mCRC who responded favorably to nivolumab for 20 months after the failure of bevacizumab plus FOLFIRI (5-fluorouracil, folinic acid, and irinotecan) treatment. The woman visited our institute and received a diagnosis of ascending colon cancer in December 2019. She underwent right hemicolectomy; the pathologic stage was T3N1bM0, stage IIIb. After 7 months, multiple liver metastases had developed and bevacizumab plus FOLFIRI were administered. However, the disease progressed even after targeted therapy plus chemotherapy. Since February 2021, she has received 3 mg/kg nivolumab biweekly and the best objective response has been found to be partial response as per the response evaluation criteria in solid tumors criteria. No severe adverse events have occurred. The patient has received 33 cycles of nivolumab over 20 months without exhibiting eventual tumor progression. Nivolumab could be considered for dMMR and BRAF-V600E-mutated mCRC that has progressed despite treatment with bevacizumab plus FOLFIRI.

Salvage Surgery for Unifocal Progressive Metastatic Mismatch Repair-Deficient GI Cancer Responding to Immune Checkpoint Inhibition

Case series describing excellent outcomes for patients with dMMR GI cancer after resection of a single progressive lesion under immunotherapy.

Neoadjuvant Treatment in Rectal Cancer

A major advance in rectal cancer was the evidence supporting short-course radiotherapy and long-course chemoradiotherapy. Both have been shown to improve local outcomes. Total neoadjuvant therapy (TNT) is the new kid on the block that provides further benefit of improving local responses as well as reducing systemic relapses, thus increasing overall survival. Details of the four key TNT trials are discussed. They pave the way for nonoperative management for patients who achieve clinical complete responses.

Third-line treatment and beyond in metastatic colorectal cancer: What do we have and what can we expect?

Colorectal cancer remains the third most common cancer worldwide and the second cause of cancer-related death. Treatment advances and precision oncological medicine for these tumours have been stalled in comparison to those for other common tumours such as lung and breast cancer. However, the recent publication of the SUNLIGHT trial results with the trifluridine/tipiracil (TAS-102)-bevacizumab combination and the irruption of new molecular targets with guided treatments have opened new possibilities in third-line metastatic colorectal cancer management. Anti-EGFR rechallenge, anti-HER2 targeted therapies or the promising results of Pressurised Intraperitoneal Aerosol Chemotherapy (PIPAC), are some of the available options that may modify what is presumably third-line colorectal treatment. Hereby, we present the evidence of the different treatment options in third-line colorectal cancer and beyond, as well as the possibilities of sequencing them.

Mechanism of immune checkpoint inhibitor resistance in colorectal cancer patients and its interventional strategies

The remarkable efficacy demonstrated by immune checkpoint inhibitors (ICIs) in melanoma treatment has driven their widespread use in the treatment of a variety of solid tumours, and they have now become one of the mainstays of oncology treatment, especially in the field of colorectal cancer, where they have demonstrated great potential. However, in long-term large-sample studies, it was found that the response to ICIs is low, and there are problems of primary and acquired resistance, which seriously affect their therapeutic effect. In this paper, we will review the mechanism of resistance to ICIs in patients with colorectal cancer and the progress in research of interventional strategies for ICI resistance, aiming to provide new ideas for the solution of the problem of clinical drug resistance to ICIs.

Personalised medicine based on host genetics and microbiota applied to colorectal cancer

Colorectal cancer (CRC) ranks second in incidence and third in cancer mortality worldwide. This situation, together with the understanding of the heterogeneity of the disease, has highlighted the need to develop a more individualised approach to its prevention, diagnosis and treatment through personalised medicine. This approach aims to stratify patients according to risk, predict disease progression and determine the most appropriate treatment. It is essential to identify patients who may respond adequately to treatment and those who may be resistant to treatment to avoid unnecessary therapies and minimise adverse side effects. Current research is focused on identifying biomarkers such as specific mutated genes, the type of mutations and molecular profiles critical for the individualisation of CRC diagnosis, prognosis and treatment guidance. In addition, the study of the intestinal microbiota as biomarkers is being incorporated due to the growing scientific evidence supporting its influence on this disease. This article comprehensively addresses the use of current and emerging diagnostic, prognostic and predictive biomarkers in precision medicine against CRC. The effects of host genetics and gut microbiota composition on new approaches to treating this disease are discussed. How the gut microbiota could mitigate the side effects of treatment is reviewed. In addition, strategies to modulate the gut microbiota, such as dietary interventions, antibiotics, and transplantation of faecal microbiota and phages, are discussed to improve CRC prevention and treatment. These findings provide a solid foundation for future research and improving the care of CRC patients.

Colorectal cancer: Recent advances in management and treatment

Colorectal cancer (CRC) is the third most common cancer worldwide, and the second most common cause of cancer-related death. In 2020, the estimated number of deaths due to CRC was approximately 930000, accounting for 10% of all cancer deaths worldwide. Accordingly, there is a vast amount of ongoing research aiming to find new and improved treatment modalities for CRC that can potentially increase survival and decrease overall morbidity and mortality. Current management strategies for CRC include surgical procedures for resectable cases, and radiotherapy, chemotherapy, and immunotherapy, in addition to their combination, for non-resectable tumors. Despite these options, CRC remains incurable in 50% of cases. Nonetheless, significant improvements in research techniques have allowed for treatment approaches for CRC to be frequently updated, leading to the availability of new drugs and therapeutic strategies. This review summarizes the most recent therapeutic approaches for CRC, with special emphasis on new strategies that are currently being studied and have great potential to improve the prognosis and lifespan of patients with CRC.

Sarcopenia predicts immune-related adverse events due to anti-PD-1/PD-L1 therapy in patients with advanced lung cancer

Introduction

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of a number of patients with advanced cancer, and while this has resulted in increased survival times, it has also led to the emergence of novel immune-related adverse events (irAEs). In individuals with advanced cancer, sarcopenia is a significant symptom of cachexia and is linked to poor nutritional status and increased mortality. The present study aimed to evaluate sarcopenia and other risk variables that can affect the emergence of irAEs in patients with lung cancer.

Methods

A single-center retrospective analysis of 129 patients with advanced lung cancer treated with programmed cell death protein-1 (PD-1)/programmed cell death ligand-1 (PD-L1) checkpoint inhibitors was conducted from August 2020 to August 2022. Data on baseline characteristics and adverse events of participants were collected. Computed tomography was used to determine the skeletal muscle index at the third lumbar vertebra (L3-SMI) and whether sarcopenia is present.

Results

The median age of all participants was 60 years old (range, 52-66 years), with men accounting for 68.9% of the total patient cohort. The present study showed that 44 (34%) participants presented with any degree of irAEs, and 79 (61.2%) patients presented with sarcopenia. There were no statistically significant differences in baseline characteristics, such as age and sex, between patients who presented with irAEs and those without irAEs. Using logistic regression analysis, individuals with sarcopenia were 2.635-times more likely to experience any grade of irAEs than those without sarcopenia.

Discussion

irAEs are prevalent side effects of PD-1/PD-L1 inhibitor therapy for patients with cancer. By diagnosing and treating sarcopenia early, it is possible to lower the potential risk of irAEs in patients with advanced cancer. Furthermore, sarcopenia can be utilized as a predictor of irAEs.

The Importance of Predictive Biomarkers and Their Correlation with the Response to Immunotherapy in Solid Tumors-Impact on Clinical Practice

Background/Objectives: Immunotherapy has changed the therapeutic approach for various solid tumors, especially lung tumors, malignant melanoma, renal and urogenital carcinomas, demonstrating significant antitumor activity, with tolerable safety profiles and durable responses. However, not all patients benefit from immunotherapy, underscoring the need for predictive biomarkers that can identify those most likely to respond to treatment. Methods: The integration of predictive biomarkers into clinical practice for immune checkpoint inhibitors (ICI) holds great promise for personalized cancer treatment. Programmed death ligand 1 (PD-L1) expression, tumor mutational burden (TMB), microsatellite instability (MSI), gene expression profiles and circulating tumor DNA (ctDNA) have shown potential in predicting ICI responses across various cancers. Results: Challenges such as standardization, validation, regulatory approval, and cost-effectiveness must be addressed to realize their full potential. Predictive biomarkers are crucial for optimizing the clinical use of ICIs in cancer therapy. Conclusions: While significant progress has been made, further research and collaboration among clinicians, researchers, and regulatory institutes are essential to overcome the challenges of clinical implementation. However, little is known about the relationship between local and systemic immune responses and the correlation with response to oncological therapies and patient survival.

Evaluation of the efficacy and safety of first- and second-line immunotherapy in patients with metastatic colorectal cancer: a systematic review and network meta-analysis based on randomized controlled trials

Background

A multitude of randomized controlled trials (RCTs) conducted in both the initial and subsequent treatment settings for patients diagnosed with metastatic colorectal cancer (mCRC) have provided clinical evidence supporting the efficacy of immunotherapy with the use of immune checkpoint inhibitors (ICIs). In light of these findings, the U.S. Food and Drug Administration (FDA) has authorized the use of several ICIs in specific subpopulations of mCRC patients. Nevertheless, there remains a dearth of direct comparative RCTs evaluating various treatment options. Consequently, the most effective ICI therapeutic strategy for microsatellite-stable (MSS) subgroup and microsatellite instability (MSI) subgroup in the first- and second-line therapies remains undefined. To address this gap, the present study employs a Bayesian network meta-analysis to ascertain the most effective first- and second-line ICI therapeutic strategies.

Methods

A comprehensive literature search was conducted across multiple databases, including PubMed, EMBASE, Cochrane Library, and Web of Science, with the retrieval date ranging from the databases' inception to August 20, 2024. A total of 875 studies were identified, and seven were ultimately included in the analysis after a screening process. A systematic review and network meta-analysis were conducted on the basis of the search results.

Results

This comprehensive analysis, comprising seven RCTs, evaluated first-line and second-line immunotherapy regimens in 1,358 patients diagnosed with mCRC. The treatments under investigation consisted of five initial treatments, including three focusing on MSS patients and two on MSI patients, as well as two secondary immunotherapy regimens, both focusing on MSS patients. A total of 1051 individuals underwent first-line treatment, while 307 received second-line treatment. The application of ICIs proved to offer varying degrees clinical benefits when compared to standard-of-care therapy alone, both in two subgroups of the first and the second treatment phases. Of particular note is the performance of Nivolumab combination with ipilimumab, which demonstrated superior efficacy in improving progression-free survival (PFS) (HR=0.21; 95% CI, 0.13-0.34),. Moreover, the treatment demonstrated an optimal safety profile, with a relatively low risk of adverse events (OR = 0.33; 95% CI, 0.19-0.56), compared to other first-line treatment modalities for MSI subgroup. Regarding MSS subgroup, the improvement of PFS by Nivolumab plus standard-of-care (SOC) was relatively significant (HR = 0.74; 95% CI, 0.53-1.02). In the realm of second-line therapies for MSS subgroup, the administration of Atezolizumab plus SOC has proven to be an effective approach for prolonging PFS, exhibiting an HR of 0.66 (95% CI, 0.44-0.99). These findings underscore the clinical benefits and safety profiles of ICIs in the treatment of mCRC across various treatment lines.

Conclusions

The clinical application of ICIs in both first- and second-line treatment strategies for patients with mCRC yields substantial therapeutic benefits. A detailed assessment in this study indicates that first-line treatment with Nivolumab combination with ipilimumab may represent an efficacious and well-tolerated therapeutic approach for MSI subgroup. In terms of MSS subgroup in first-line therapy, Nivolumab plus SOC may be a relative superior choice. In the context of second-line therapy for MSS subgroup, it is evident that a combination of Atezolizumab and SOC represents a preferable option for enhancing PFS. Furthermore, it is noteworthy that other ICIs treatment regimens also exhibit great value in various aspects, with the potential to inform the development of future clinical treatment guidelines and provide a stronger rationale for the selection of ICIs in both first- and second-line therapeutic strategies for mCRC.

Systematic review registration

https://www.crd.york.ac.uk/prospero/#recordDetails, identifier CRD42024543400.

PROTAC-mediated conditional degradation of the WRN helicase as a potential strategy for selective killing of cancer cells with microsatellite instability

Multiple studies have demonstrated that cancer cells with microsatellite instability (MSI) are intolerant to loss of the Werner syndrome helicase (WRN), whereas microsatellite-stable (MSS) cancer cells are not. Therefore, WRN represents a promising new synthetic lethal target for developing drugs to treat cancers with MSI. Given the uncertainty of how effective inhibitors of WRN activity will prove in clinical trials, and the likelihood of tumours developing resistance to WRN inhibitors, alternative strategies for impeding WRN function are needed. Proteolysis-targeting chimeras (PROTACs) are heterobifunctional small molecules that target specific proteins for degradation. Here, we engineered the WRN locus so that the gene product is fused to a bromodomain (Bd)-tag, enabling conditional WRN degradation with the AGB-1 PROTAC specific for the Bd-tag. Our data revealed that WRN degradation is highly toxic in MSI but not MSS cell lines. In MSI cells, WRN degradation caused G2/M arrest, chromosome breakage and ATM kinase activation. We also describe a multi-colour cell-based platform for facile testing of selective toxicity in MSI versus MSS cell lines. Together, our data show that a degrader approach is a potentially powerful way of targeting WRN in MSI cancers and paves the way for the development of WRN-specific PROTAC compounds.

Efficacy of Pembrolizumab and Biomarker Analysis in Patients with WGS-Based Intermediate to High Tumor Mutational Load: Results from the Drug Rediscovery Protocol

PURPOSE

To evaluate the efficacy of pembrolizumab across multiple cancer types harboring different levels of whole-genome sequencing-based tumor mutational load (TML; total of nonsynonymous mutations across the genome) in patients included in the Drug Rediscovery Protocol (NCT02925234).

PATIENTS AND METHODS

Patients with solid, treatment-refractory, microsatellite-stable tumors were enrolled in cohort A: breast cancer cohort harboring a TML of 140 to 290, cohort B: tumor-agnostic cohort harboring a TML of 140 to 290, and cohort C: tumor-agnostic cohort harboring a TML >290. Patients received pembrolizumab 200 mg every 3 weeks. The primary endpoint was clinical benefit [CB; objective response or stable disease (SD) ≥16 weeks]. Pretreatment tumor biopsies were obtained for whole-genome sequencing and RNA sequencing.

RESULTS

Seventy-two evaluable patients with 26 different histotypes were enrolled. The CB rate was 13% in cohort A [3/24 with partial response (PR)], 21% in cohort B (3/24 with SD; 2/24 with PR), and 42% in cohort C (4/24 with SD; 6/24 with PR). In cohort C, neoantigen burden estimates and expression of inflammation and innate immune biomarkers were significantly associated with CB. Similar associations were not identified in cohorts A and B. In cohort A, CB was significantly associated with mutations in the chromatin remodeling gene PBRM1, whereas in cohort B, CB was significantly associated with expression of MICA/MICB and butyrophilins. CB and clonal TML were not significantly associated.

CONCLUSIONS

Although pembrolizumab lacked activity in cohort A, cohorts B and C met the study's primary endpoint. Further research is warranted to refine the selection of patients with tumors harboring lower TMLs and may benefit from a focus on innate immunity. See related commentary by Hsu and Yen, p. 3652.

Safety and Efficacy of Vicriviroc (MK-7690) in Combination With Pembrolizumab in Patients With Advanced or Metastatic Microsatellite Stable Colorectal Cancer

BACKGROUND

Pembrolizumab, a monoclonal antibody against PD-1, has shown limited efficacy in patients with microsatellite stable or mismatch repair proficient (MSS/pMMR) metastatic colorectal cancer (CRC). We evaluated vicriviroc (small-molecule C-C motif chemokine ligand 5 antagonist) plus pembrolizumab in patients with advanced or metastatic MSS/pMMR CRC.

PATIENTS AND METHODS

This open-label, phase 2 trial (NCT03631407) enrolled adults with histologically confirmed, locally advanced, unresectable or metastatic CRC that was MSS per local assessment. All patients had received previous treatment with standard therapies. Patients were randomized 1:1 to vicriviroc 150 mg orally once daily plus pembrolizumab 200 mg intravenously every 3 weeks or vicriviroc 250 mg orally once daily plus pembrolizumab 200 mg intravenously every 3 weeks for up to 35 cycles (2 years). Primary endpoints were the objective response rate (ORR) as assessed by the investigator per RECIST v1.1, dose-limiting toxicities (DLTs), adverse events (AEs), and discontinuations due to AEs.

RESULTS

Forty patients were enrolled and treated. ORR was 5% (95% CI, 0.1%-24.9%) in both treatment groups. There were no complete responses; 1 patient in each treatment group experienced a partial response. No patient in the vicriviroc 150 mg plus pembrolizumab group experienced a DLT. Two patients in the vicriviroc 250 mg plus pembrolizumab group experienced DLTs (1 grade 4 encephalopathy and 1 grade 4 pneumonitis).

CONCLUSION

The combination of vicriviroc at doses of 150 or 250 mg plus pembrolizumab 200 mg showed limited antitumor activity in patients with advanced or metastatic MSS/pMMR CRC. Toxicity with the combination was manageable.

Clinical and Molecular Variables Associated With Early Progression to Checkpoint Inhibitors in MSI-High Metastatic Colorectal Cancer: A Retrospective Cohort Study

BACKGROUND

About one third of patients with deficient mismatch repair/microsatellite instability-high metastatic colorectal cancer (dMMR/MSI-H mCRC) experience primary resistance or early progression on immune checkpoint inhibitors (ICI), while others benefit from exceptionally long-lasting responses. In this single-centre retrospective study, we aimed to identify variables associated with improved overall survival (OS) as well as early disease progression.

METHODS

All dMMR/MSI-H mCRC patients treated with ICI between 2014 and 2022 were included. Baseline patient demographics, tumour characteristics as well response and outcome data were recorded. OS was estimated using the Kaplan-Meier method. Uni- and multivariate cox regression analysis was used to identify parameters associated with improved OS. Clinicopathological factors associated with early progression (≤ 12 months after treatment initiation) were assessed using uni- and multivariate logistic regression analysis.

RESULTS

About 84 ICI-treated dMMR/MSI-H mCRC patients were included. Progressive disease occurred in 37 (44%) patients, but only in 11 (19%) patients with disease control at 12 months. Median OS was 80 months and improved outcome was associated with a lower neutrophile-to-lymphocyte ratio (NLR) (P = .004) and the presence of immune-related adverse events (irAEs) (P = .015). Early progression was associated with poor performance status (P = .036), a higher blood CRP level (P = .033) and absence of irAEs (P = .002).

CONCLUSION

Disease progression in ICI-treated dMMR/MSI-H mCRC rarely occurs in patients experiencing disease control for at least 12 months. Performance status, presence of immune-related adverse events, CRP levels, CEA levels and NLR can be helpful to identify those patients that may benefit from ICI treatment, guiding clinicians in therapeutic decisions.

Neoadjuvant immunotherapy in a locally advanced colon cancer patient with MSI-H and suspected Lynch syndrome: A case report

Carrilizumab, a PD-1 inhibitor, has shown therapeutic effectiveness in patients with late-stage or metastatic solid tumors exhibiting DNA mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H). dMMR/MSI-H cancer patients are known to be responsive to PD-1 inhibitors. However, the use of carrilizumab for preoperative immunotherapy in early, unresectable MSI-H/dMMR primary colon cancer lesions is relatively underexplored. We present the case of a 46-year-old male who sought medical attention at our institution due to a history of hematochezia for two weeks, right-sided abdominal pain for one week, and loose stools. Imaging indicated duodenal involvement, and a biopsy confirmed ascending colon adenocarcinoma with MSI-H status. Given that the patient's family exhibited a history of more than three confirmed cases of colorectal cancer spanning two generations, Lynch syndrome was considered. After four cycles of PD-1 antagonist immunotherapy with carrilizumab, the patient's symptoms resolved, and physical examination revealed no abdominal tenderness or palpable masses. Following radical colectomy, the primary tumor exhibited a pathological complete response. This case highlights the potential of preoperative neoadjuvant immunotherapy to improve staging accuracy and increase surgical resection rates in T4b MSI-H colon cancer patients without distant metastasis, suggesting a need for reconsideration of the treatment approach.

Preoperative short-course radiotherapy followed by chemotherapy and PD-1 inhibitor administration for locally advanced rectal cancer: A study protocol of a randomized phase II/III trial (STELLAR II study)

AIM

For patients with locally advanced rectal cancer, previous STELLAR studies have shown that a new adjuvant treatment paradigm of short-course radiotherapy followed by neoadjuvant chemotherapy can achieve pathological complete response rates superior to those of standard care; however, the 3-year DFS is inferior to neoadjuvant concurrent radiotherapy. Recent studies have shown that immune checkpoint inhibitors may improve the prognosis of rectal cancer and have good synergy with radiotherapy. Therefore, neoadjuvant chemotherapy combined with immune checkpoint inhibitors after a short course of radiotherapy has the potential to further improve complete response rates and prognosis.

METHOD

The STELLAR II study is a multicentre, open label, two-arm randomized, phase II/III trial of short-course radiotherapy followed by neoadjuvant chemotherapy concurrent with immunotherapy for locally advanced rectal cancer. A total of 588 patients with locally advanced rectal cancer (LARC) will be randomly assigned to the experimental and control groups. The experimental group will receive short-course radiotherapy and neoadjuvant chemotherapy in combination with sindilizumab, while the control group will receive short-course radiotherapy and neoadjuvant chemotherapy. Both groups will subsequently receive either total rectal mesenteric resection or a watch & wait (W&W) strategy. The phase II primary endpoint is the complete remission rate, and the secondary endpoints include grade 3-4 adverse events, perioperative complications, R0 resection rate, overall survival, local recurrence rate, distant metastasis rate and quality of life score. A seamless phase II/III randomized controlled design will be used to investigate the effectiveness and safety of the TNT strategy with the addition of immunotherapy. The trial opened, and the first patient was recruited on 31 August 2022. Trial registration number and date of registration: ClinicalTrials.gov NCT05484024, 29 July 2022.

DISCUSSION

The STELLAR II trial will prospectively evaluate the efficacy of TNT treatment strategies that incorporate immune checkpoint inhibitors. The trial will yield important information to guide routine management of patients with local advanced rectal cancer.

The aminophospholipid transporter, ATP8B3, as a potential biomarker and target for enhancing the therapeutic effect of PD-L1 blockade in colon adenocarcinoma

BACKGROUND

Colon adenocarcinoma (COAD) is a prevalent malignant tumor globally, contributing significantly to cancer-related mortality. COAD guidelines label MSI (Microsatellite instability) and MSS (Microsatellite stability) subtypes as global classification criteria and treatment strategy selection criteria for COAD. Various combination therapies involving PD-L1 inhibitors and adjuvant therapy to enhance anti-tumor efficacy.

METHODS

Datasets from single-cell RNA sequencing and bulk RNA sequencing in the TCGA and GEO databases were utilized to identify differentially expressed genes (DEGs). Furthermore, the correlation between ATP8B3 and PD-L1 was validated using siRNA, shRNA, and western blot analysis. Additionally, the association between ATP8B3 and immune checkpoint blockade (ICB) therapy was investigated through immune infiltration analysis and flow cytometry in both in vivo and in vitro assays.

RESULTS

In the COAD patient group, ATP8B3 significantly contributed to the establishment of an immunosuppressive microenvironment. Inhibiting ATP8B3 led to a reduction in PD-L1 expression in colon cancer cell lines. Additionally, ATP8B3 expression levels could serve as a potential guide for PD-L1 treatment in MSI-H COAD patients, with higher ATP8B3 expression associated with increased sensitivity to PD-L1 therapy. However, due to the lack of immuno-killer cells in the microenvironment of MSS subtypes, elevated ATP8B3 expression couldn't increase the sensitivity of MSS COAD patients to PD-L1 inhibitors.

CONCLUSION

Our research results support that Inhibiting ATP8B3 could enhance TIL (tumor-infiltrating lymphocyte) infiltration by reducing PD-L1 expression in MSI-H COAD, thereby serving as an effective strategy to improve PD-L1 blocker efficacy. The treatment strategy of combining ATP8B3 inhibitors and immunotherapy for MSI/MSS COAD patients will be the best choice.

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.

Exploring the potential of the TCR repertoire as a tumor biomarker (Review)

T cells play an important role in adaptive immunity. Mature T cells specifically recognize antigens on major histocompatibility complex molecules through T-cell receptors (TCRs). As the TCR repertoire is highly diverse, its analysis is vital in the assessment of T cells. Advances in sequencing technology have provided convenient methods for further investigation of the TCR repertoire. In the present review, the TCR structure and the mechanisms by which TCRs function in tumor recognition are described. In addition, the potential value of the TCR repertoire in tumor diagnosis is reviewed. Furthermore, the role of the TCR repertoire in tumor immunotherapy is introduced, and the relationships between the TCR repertoire and the effects of different tumor immunotherapies are discussed. Based on the reviewed literature, it may be concluded that the TCR repertoire has the potential to serve as a biomarker for tumor prognosis. However, a wider range of cancer types and more diverse subjects require evaluation in future research to establish the TCR repertoire as a biomarker of tumor immunity.

Clinical status and future prospects of neoadjuvant immunotherapy for localized mismatch repair-deficient cancers: a review

Frameshift mutations accumulate in cancers related to mismatch repair deficiency (dMMR), which has the potential to produce various neoantigens, representing a distinct subset of cancers that respond considerably to immunotherapy. In recent years, robust evidence has supported the first-line application of immunotherapy for patients with metastatic dMMR cancers, which provoked extensive investigations of the feasibility and efficacy of immunotherapy in up-front settings, including neoadjuvant therapy. Several completed trials with small sample sizes suggested that neoadjuvant immunotherapy can achieve an impressively high complete response rate, for the first time offering the potential of systemic therapy to cure cancer without the need for surgical resection. However, a difficult dilemma emerges: clinicians are now facing a selection between the standard of care with good evidence for proficient MMR but suboptimal for dMMR cancers and the emerging immunotherapy with promising results but only based on a limited number of patients with shorter duration of follow-up. This review aims to provide a comprehensive summary of the biological rationale and clinical status of neoadjuvant immunotherapy in patients with dMMR cancers. Furthermore, I elaborate on particular issues that must be taken into consideration for further advancement in the field.

Mechanisms of metastatic colorectal cancer

Despite extensive research and improvements in understanding colorectal cancer (CRC), its metastatic form continues to pose a substantial challenge, primarily owing to limited therapeutic options and a poor prognosis. This Review addresses the emerging focus on metastatic CRC (mCRC), which has historically been under-studied compared with primary CRC despite its lethality. We delve into two crucial aspects: the molecular and cellular determinants facilitating CRC metastasis and the principles guiding the evolution of metastatic disease. Initially, we examine the genetic alterations integral to CRC metastasis, connecting them to clinically marked characteristics of advanced CRC. Subsequently, we scrutinize the role of cellular heterogeneity and plasticity in metastatic spread and therapy resistance. Finally, we explore how the tumour microenvironment influences metastatic disease, emphasizing the effect of stromal gene programmes and the immune context. The ongoing research in these fields holds immense importance, as its future implications are projected to revolutionize the treatment of patients with mCRC, hopefully offering a promising outlook for their survival.

PD-1 blockade combined with chemotherapy and bevacizumab in DNA mismatch repair-proficient/microsatellite stable colorectal liver metastases

Background

Single-agent immunotherapy is less effective in patients with DNA mismatch repair-proficient/microsatellite stable (pMMR/MSS) metastatic colorectal cancer (mCRC). Whether pMMR/MSS mCRC patients benefit from combination immunotherapy remains unclear. This study aimed to evaluate the efficacy and safety of anti-programmed cell death protein 1 (PD-1) therapy combined with chemotherapy and bevacizumab in pMMR/MSS colorectal liver metastases (CRLM) patients.

Methods

A total of 12 patients with pMMR/MSS CRLM treated at The Sixth Affiliated Hospital of Sun Yat-sen University were enrolled. All patients were treated with at least 4 doses of PD-1 monoclonal antibody combined with chemotherapy and bevacizumab as neoadjuvant/adjuvant therapy.

Results

A total of 10 of the 12 patients received the combined therapies before primary tumor resection; the disease control rate (DCR) was 100% (10/10), and the objective response rate (ORR) was 70% (7/10). The ORR of liver metastases was 75% (9/12). Pathological complete response (pCR) was achieved in 1 primary tumor patient and 2 patients with hepatic lesions. A total of 5 patients underwent simultaneous resection of the primary tumor and liver metastases; 9 patients underwent microwave ablation for liver metastases. A total of 7 patients were assessed as having no evidence of disease (NED) with a median progression-free survival (PFS) interval of 9.2 (1.5-15.8) months after multimodality treatments for both primary and metastatic lesions. No severe immune-related adverse events (irAEs) and operational complications were observed.

Conclusions

PD-1 blockade combined with chemotherapy and bevacizumab might be safe and effective for patients with pMMR/MSS CRLM. This treatment strategy might lead to better tumor regression and a higher chance of achieving NED.

Immunomodulatory molecules in colorectal cancer liver metastasis

Colorectal cancer (CRC) ranks as the third most common cancer and the second leading cause of cancer-related deaths. According to clinical diagnosis and treatment, liver metastasis occurs in approximately 50 % of CRC patients, indicating a poor prognosis. The unique immune tolerance of the liver fosters an immunosuppressive tumor microenvironment (TME). In the context of tumors, numerous membrane and secreted proteins have been linked to tumor immune evasion as immunomodulatory molecules, but much remains unknown about how these proteins contribute to immune evasion in colorectal cancer liver metastasis (CRLM). This article reviews recently discovered membrane and secreted proteins with roles as both immunostimulatory and immunosuppressive molecules within the TME that influence immune evasion in CRC primary and metastatic lesions, particularly their mechanisms in promoting CRLM. This article also addresses screening strategies for identifying proteins involved in immune evasion in CRLM and provides insights into potential protein targets for treating CRLM.

Oncological characteristics, treatments and prognostic outcomes in MMR-deficient colorectal cancer

Colorectal cancer (CRC) ranks as the third most prevalent cancer globally. It's recognized that the molecular subtype of CRC, characterized by mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H), plays a critical role in determining appropriate treatment strategies. This review examines the current molecular classifications, focusing on dMMR/MSI-H CRC and its subtypes: Lynch syndrome (LS), Lynch-like syndrome (LLS), and sporadic cases. Despite advances in understanding of these genetic backgrounds, clinical trials have not conclusively differentiated the efficacy of immune checkpoint inhibitors among these subgroups. Therefore, while this review details the molecular characteristics and their general implications for treatment and prognosis, it also highlights the limitations and the need for more refined clinical studies to ascertain tailored therapeutic strategies for each subtype. Furthermore, this review summarizes completed and ongoing clinical studies, emphasizing the importance of developing treatments aligned more closely with molecular profiles. By discussing these aspects, the review seeks to provide a comprehensive analysis of oncological characteristics, presenting a detailed understanding of their implications for treatment and prognosis in dMMR/MSI-H CRC.

The prognostic value of programmed death-ligand 1 (PD-L1) expression in resected colorectal cancer without neoadjuvant therapy - differences between antibody clones and cell types

BACKGROUND

Programmed death-ligand 1 (PD-L1) expression on tumor cells is associated with poor prognosis in several malignancies, while partly contradictory and inconclusive results have been presented for colorectal cancer (CRC). This study aimed to evaluate PD-L1 as a prognostic biomarker in CRC by comparing three different antibody clones.

METHODS

Patients surgically treated for CRC between January 1st, 2007, and December 31st, 2015, in Kalmar County, Sweden, were retrospectively included. Tissue microarrays from 862 primary tumors without neoadjuvant treatment were assessed for immunohistochemical expression of PD-L1 in tumor cells (TC) and immune cells (IC) using clones 73-10, SP263, and 22C3. Cox regression proportional hazard models were used to estimate hazard ratios for overall survival (OS) and disease-free interval (DFI) in univariable and multivariable analyses, with 1% and 5% set as cut-offs for positive expression in TC and IC respectively.

RESULTS

PD-L1 expression in TC was found in 89 (10%) cases for clone 73-10, 76 (9%) for clone SP263, and 38 (4%) for clone 22C3, while the numbers for IC were 317 (37%) cases for clone 73-10, 264 (31%) for clone SP263, and 89 (10%) for clone 22C3. PD-L1 expression in IC was associated with prolonged OS and DFI in univariable analysis for all three clones. The link to prolonged DFI remained in multivariable analysis for 73-10 and SP263, but only for 73-10 regarding OS. PD-L1 expression in TC was not prognostic of OS in any analysis, while it was associated with prolonged DFI for SP263, and a trend was seen for 73-10. The link to prolonged DFI remained for SP263 and was strengthened for 73-10 in multivariable analysis.

CONCLUSIONS

The prognostic value of PD-L1 expression in both IC and TC differs between antibody clones, with 73-10 and SP263 being more reliable for prognostic information than 22C3 in resected CRC.

The challenge of molecular selection in liver-limited metastatic colorectal cancer for surgical resection: a systematic review and meta-analysis in the context of current and future approaches

Objectives

Treatment of metastatic colorectal cancer (mCRC) includes resection of liver metastases (LM), however, no validated biomarker identifies patients most likely to benefit from this procedure. This meta-analysis aimed to assess the impact of the most relevant molecular alterations in cancer-related genes of CRC (i.e., RAS, BRAF, SMAD4, PIK3CA) as prognostic markers of survival and disease recurrence in patients with mCRC surgically treated by LM resection.

Methods

A systematic literature review was performed to identify studies reporting data regarding survival and/or recurrence in patients that underwent complete liver resection for CRC LM, stratified according to RAS, BRAF, PIK3CA, and SMAD4 mutational status. Hazard ratios (HRs) from multivariate analyses were pooled in the meta-analysis and various adjustment strategies for confounding factors were combined. The search was conducted in numerous databases, including MEDLINE (PubMed), Embase, Cumulative Index to Nursing and Allied Health Literature (CINAHL) (EBSCO host), and WHO Global Index Medicus, through March 18th, 2022. Meta-analyses, editorials, letters to the editor, case reports, studies on other primary cancers, studies with primary metastatic sites other than the liver, studies lacking specific oncological outcome variables or genetic data, non-English language studies, and studies omitting residual disease data from liver metastasectomy were excluded. The remaining 47 studies were summarized in a descriptive table which outlines the key characteristics of each study and final results were graphically presented.

Results

RAS mutation status was negatively associated with overall survival (OS) (HR, 1.68; 95% CI, 1.54-1.84) and recurrence free survival (RFS) (HR, 1.46; 95% CI, 1.33-1.61). A negative association was also found for BRAF regarding OS (HR, 2.64; 95% CI, 2.15-3.24) and RFS (HR, 1.89; 95% CI, 1.32-2.73) and SMAD4 regarding OS (HR, 1.93; 95% CI, 1.56-2.38) and RFS (HR, 1.95; 95% CI, 1.31-2.91). For PIK3CA only three studies were eligible and no significant association with either OS or RFS could be highlighted.

Conclusion

RAS, BRAF, and SMAD4 are negatively associated with OS and RFS in patients undergoing curative liver metastasectomy from colorectal cancer. No conclusion can be drawn for PIK3CA due to the limited literature availability. These data support the integration of RAS, BRAF, and SMAD4 mutational status in the surgical decision-making for colorectal liver metastasis. Nevertheless, we have to consider several limitations, the major ones being the pooling of results from studies that evaluated patient outcomes as either disease-free survival (DFS) or RFS; the inclusion of patients with minimal residual disease and unconsidered potential confounding factors, such as variability in resectability definitions, chemotherapy use, and a potential interaction between biological markers and pre- and post-resection pharmacological treatments.

Discovery and validation of a 10-gene predictive signature for response to adjuvant chemotherapy in stage II and III colon cancer

Identifying patients with stage II and III colon cancer who will benefit from 5-fluorouracil (5-FU)-based adjuvant chemotherapy is crucial for the advancement of personalized cancer therapy. We employ a semi-supervised machine learning approach to analyze a large dataset with 933 stage II and III colon cancer samples. Our analysis leverages gene regulatory networks to discover an 18-gene prognostic signature and to explore a 10-gene signature that potentially predicts chemotherapy benefits. The 10-gene signature demonstrates strong prognostic power and shows promising potential to predict chemotherapy benefits. We establish a robust clinical assay on the NanoString nCounter platform, validated in a retrospective formalin-fixed paraffin-embedded (FFPE) cohort, which represents an important step toward clinical application. Our study lays the groundwork for improving adjuvant chemotherapy and potentially expanding into immunotherapy decision-making in colon cancer. Future prospective studies are needed to validate and establish the clinical utility of the 10-gene signature in clinical settings.

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.

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1

BACKGROUND

Bevacizumab, an anti-vascular endothelial growth factor (VEGF) monoclonal antibody, inhibits angiogenesis and reduces tumor growth. Serum VEGF-C, lactate dehydrogenase, and inflammatory markers have been reported as predictive markers related to bevacizumab treatment. Programmed cell death ligand 1 (PD-L1) could act upon VEGF receptor 2 to induce cancer cell angiogenesis and metastasis.

AIM

To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer (CRC) according to the expression of PD-L1.

METHODS

This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24, 2014 and February 28, 2022, at Samsung Medical Center (Seoul, South Korea). Analysis of patient data included evaluation of PD-L1 expression by the combined positive score (CPS). We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with CRC.

RESULTS

A total of 124 patients was included in this analysis. Almost all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line chemotherapy. While 77% of patients received FOLFOX, 23% received FOLFIRI as backbone first-line chemotherapy. The numbers of patients with a PD-L1 CPS of 1 or more, 5 or more, or 10 or more were 105 (85%), 64 (52%), and 32 (26%), respectively. The results showed no significant difference in progression-free survival (PFS) and overall survival (OS) with bevacizumab treatment between patients with PD-L1 CPS less than 1 and those with PD-L1 CPS of 1 or more (PD-L1 < 1% vs PD-L1 ≥ 1%; PFS: P = 0.93, OS: P = 0.33), between patients with PD-L1 CPS less than 5 and of 5 or more (PD-L1 < 5% vs PD-L1 ≥ 5%; PFS: P = 0.409, OS: P = 0.746), and between patients with PD-L1 CPS less than 10 and of 10 or more (PD-L1 < 10% vs PD-L1 ≥ 10%; PFS: P = 0.529, OS: P = 0.568).

CONCLUSION

Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

Nilotinib boosts the efficacy of anti-PDL1 therapy in colorectal cancer by restoring the expression of MHC-I

BACKGROUND

Although immune checkpoint inhibitors (ICIs) have revolutionized the landscape of cancer treatment, only a minority of colorectal cancer (CRC) patients respond to them. Enhancing tumor immunogenicity by increasing major histocompatibility complex I (MHC-I) surface expression is a promising strategy to boost the antitumor efficacy of ICIs.

METHODS

Dual luciferase reporter assays were performed to find drug candidates that can increase MHC-I expression. The effect of nilotinib on MHC-I expression was verified by dual luciferase reporter assays, qRT-PCR, flow cytometry and western blotting. The biological functions of nilotinib were evaluated through a series of in vitro and in vivo experiments. Using RNA-seq analysis, immunofluorescence assays, western blotting, flow cytometry, rescue experiments and microarray chip assays, the underlying molecular mechanisms were investigated.

RESULTS

Nilotinib induces MHC-I expression in CRC cells, enhances CD8+ T-cell cytotoxicity and subsequently enhances the antitumor effects of anti-PDL1 in both microsatellite instability and microsatellite stable models. Mechanistically, nilotinib promotes MHC-I mRNA expression via the cGAS-STING-NF-κB pathway and reduces MHC-I degradation by suppressing PCSK9 expression in CRC cells. PCSK9 may serve as a potential therapeutic target for CRC, with nilotinib potentially targeting PCSK9 to exert anti-CRC effects.

CONCLUSION

This study reveals a previously unknown role of nilotinib in antitumor immunity by inducing MHC-I expression in CRC cells. Our findings suggest that combining nilotinib with anti-PDL1 therapy may be an effective strategy for the treatment of CRC.

Reinvigoration of cytotoxic T lymphocytes in microsatellite instability-high colon adenocarcinoma through lysosomal degradation of PD-L1

Compensation and intracellular storage of PD-L1 may compromise the efficacy of antibody drugs targeting the conformational blockade of PD1/PD-L1 on the cell surface. Alternative therapies aiming to reduce the overall cellular abundance of PD-L1 thus might overcome resistance to conventional immune checkpoint blockade. Here we show by bioinformatics analysis that colon adenocarcinoma (COAD) with high microsatellite instability (MSI-H) presents the most promising potential for this therapeutic intervention, and that overall PD-L1 abundance could be controlled via HSC70-mediated lysosomal degradation. Proteomic and metabolomic analyses of mice COAD with MSI-H in situ unveil a prominent acidic tumor microenvironment. To harness these properties, an artificial protein, IgP β, is engineered using pH-responsive peptidic foldamers. This features customized peptide patterns and designed molecular function to facilitate interaction between neoplastic PD-L1 and HSC70. IgP β effectively reduces neoplastic PD-L1 levels via HSC70-mediated lysosomal degradation, thereby persistently revitalizing the action of tumor-infiltrating CD8 + T cells. Notably, the anti-tumor effect of lysosomal-degradation-based therapy surpasses that of antibody-based immune checkpoint blockade for MSI-H COAD in multiple mouse models. The presented strategy expands the use of peptidic foldamers in discovering artificial protein drugs for targeted cancer immunotherapy.

Dysfunctional tumor-infiltrating Vδ1 + T lymphocytes in microsatellite-stable colorectal cancer

Although γδ T cells are known to participate in immune dysregulation in solid tumors, their relevance to human microsatellite-stable (MSS) colorectal cancer (CRC) is still undefined. Here, using integrated gene expression analysis and T cell receptor sequencing, we characterized γδ T cells in MSS CRC, with a focus on Vδ1 + T cells. We identified Vδ1+ T cells with shared motifs in the third complementarity-determining region of the δ-chain, reflective of antigen recognition. Changes in gene and protein expression levels suggested a dysfunctional effector state of Vδ1+ T cells in MSS CRC, distinct from Vδ1+ T cells in microsatellite-instable (MSI). Interaction analysis highlighted an immunosuppressive role of fibroblasts in the dysregulation of Vδ1+ T cells in MSS CRC via the TIGIT-NECTIN2 axis. Blocking this pathway with a TIGIT antibody partially restored cytotoxicity of the dysfunctional Vδ1 phenotype. These results define an operative pathway in γδ T cells in MSS CRC.

Recent developments in immunotherapy for gastrointestinal tract cancers

The past few decades have witnessed the rise of immunotherapy for Gastrointestinal (GI) tract cancers. The role of immune checkpoint inhibitors (ICIs), particularly programmed death protein 1 (PD-1) and PD ligand-1 antibodies, has become increasingly pivotal in the treatment of advanced and perioperative GI tract cancers. Currently, anti-PD-1 plus chemotherapy is considered as first-line regimen for unselected advanced gastric/gastroesophageal junction adenocarcinoma (G/GEJC), mismatch repair deficient (dMMR)/microsatellite instability-high (MSI-H) colorectal cancer (CRC), and advanced esophageal cancer (EC). In addition, the encouraging performance of claudin18.2-redirected chimeric antigen receptor T-cell (CAR-T) therapy in later-line GI tract cancers brings new hope for cell therapy in solid tumour treatment. Nevertheless, immunotherapy for GI tumour remains yet precise, and researchers are dedicated to further maximising and optimising the efficacy. This review summarises the important research, latest progress, and future directions of immunotherapy for GI tract cancers including EC, G/GEJC, and CRC.

PD-1 blockade plus COX inhibitors in dMMR metastatic colorectal cancer: Clinical, genomic, and immunologic analyses from the PCOX trial

BACKGROUND

Approximately 20% of patients with DNA mismatch repair deficiency (dMMR) metastatic colorectal cancer do not respond to anti-programmed death-1 (PD-1) ligand therapy, and baseline biomarkers of response are lacking.

METHODS

We conducted a phase 2 study to evaluate the efficacy of cyclooxygenase (COX) inhibitors in combination with anti-PD-1 therapy in patients with dMMR metastatic colorectal cancer. The primary endpoint was objective response rate. The secondary endpoints included progression-free survival (PFS), overall survival (OS), disease control rate, duration of response, and safety.

FINDINGS

A total of 30 patients were enrolled, and the objective response rate was 73.3%, meeting the predefined endpoint of 68%. The median PFS and median OS were not reached at a median follow-up period of 50.8 months. Disease control was achieved in 28 patients (93.3%). The median duration of response was not reached. The combination was well tolerated. Multiomics analysis revealed that the antigen processing and presentation pathway was positively associated with treatment response and PFS. Higher TAPBP expression was predictive of better PFS (log-rank p = 0.003), and this prognostic significance was confirmed in an immunotherapy validation cohort.

CONCLUSIONS

Thus, COX inhibitors combined with PD-1 blockade may be effective and safe treatment options for patients with dMMR metastatic colorectal cancer, and TAPBP may serve as a biomarker for immune checkpoint inhibitor therapy (this study was registered at ClinicalTrials.gov: NCT03638297).

FUNDING

Funded by the National Natural Science Foundation of China (81974369) and the program of Guangdong Provincial Clinical Research Center for Digestive Diseases (2020B1111170004).

Exploring Predictive and Prognostic Biomarkers in Colorectal Cancer: A Comprehensive Review

Colorectal cancer (CRC) remains the second leading cause of cancer-related mortality worldwide. While immune checkpoint inhibitors have significantly improved patient outcomes, their effectiveness is mostly limited to tumors with microsatellite instability (MSI-H/dMMR) or an increased tumor mutational burden, which comprise 10% of cases. Advancing personalized medicine in CRC hinges on identifying predictive biomarkers to guide treatment decisions. This comprehensive review examines established tissue markers such as KRAS and HER2, highlighting their roles in resistance to anti-EGFR agents and discussing advances in targeted therapies for these markers. Additionally, this review summarizes encouraging data on promising therapeutic targets and highlights the clinical utility of liquid biopsies. By synthesizing current evidence and identifying knowledge gaps, this review provides clinicians and researchers with a contemporary understanding of the biomarker landscape in CRC. Finally, the review examines future directions and challenges in translating promising biomarkers into clinical practice, with the goal of enhancing personalized medicine approaches for colorectal cancer patients.

The gut microbiota derived metabolite trimethylamine N-oxide: Its important role in cancer and other diseases

An expanding body of research indicates a correlation between the gut microbiota and various diseases. Metabolites produced by the gut microbiota act as mediators between the gut microbiota and the host, interacting with multiple systems in the human body to regulate physiological or pathological functions. However, further investigation is still required to elucidate the underlying mechanisms. One such metabolite involved in choline metabolism by gut microbes is trimethylamine (TMA), which can traverse the intestinal epithelial barrier and enter the bloodstream, ultimately reaching the liver where it undergoes oxidation catalyzed by flavin-containing monooxygenase 3 (FMO3) to form trimethylamine N-oxide (TMAO). While some TMAO is eliminated through renal excretion, remaining amounts circulate in the bloodstream, leading to systemic inflammation, endoplasmic reticulum (ER) stress, mitochondrial stress, and disruption of normal physiological functions in humans. As a representative microbial metabolite originating from the gut, TMAO has significant potential both as a biomarker for monitoring disease occurrence and progression and for tailoring personalized treatment strategies for patients. This review provides an extensive overview of TMAO sources and its metabolism in human blood, as well as its impact on several major human diseases. Additionally, we explore the latest research areas related to TMAO along with future directions.

Neoadjuvant immunotherapy leads to complete pathologic response in locally advanced colon cancer

Immunotherapy is considered first line in patients with dMMR metastatic colorectal cancer (CRC). Recent studies have also shown promising results with neoadjuvant immunotherapy in locally advanced CRC. We report a case in which neoadjuvant immunotherapy with pembrolizumab resulted in complete pathologic response at time of resection as well as saved the patient the morbidity associated with a hepatectomy. We also completed a scoping review of the literature which suggests promising tumor responses with treatment in dMMR CRC. Further randomized control trials to determine the magnitude of response and optimal regimen are needed.

Multifactorial risk prediction analysis of liver metastasis in colorectal cancer: incorporating programmed cell death ligand 1 combined positive score and other factors

BACKGROUND

The occurrence of liver metastasis significantly affects the prognosis of colorectal cancer (CRC). Existing research indicates that primary tumor location, vascular invasion, lymph node metastasis, and abnormal preoperative tumor markers are risk factors for CRC liver metastasis. Positive expression of programmed cell death ligand 1 (PD-L1) may serve as a favorable prognostic marker for nasopharyngeal and gastric cancers, in which combined positive score (CPS) quantifies the level of PD-L1 expression. This study aimed to explore CPS as a potential risk factor for CRC liver metastasis and integrate other independent risk factors to establish a novel predictive model for CRC liver metastasis.

METHODS

A retrospective analysis was conducted on 437 patients with CRC pathologically diagnosed at The Second Xiangya Hospital of Central South University from January 1, 2019, to December 31, 2021. Data were collected, including CPS, age, gender (male and female), primary tumor location, Ki-67 expression, pathologic differentiation, neural invasion, vascular invasion, lymph node metastasis, and preoperative tumor markers. The optimal cutoff point for the continuous variable CPS was determined using the Youden index, and all CPSs were dichotomized into high- and low-risk groups based on this threshold (scores below the threshold were considered high risk, and score above the threshold were considered low risk). Univariate logistic regression analysis was employed to identify risk factors for CRC liver metastasis, followed by multivariate logistic regression analysis to integrate the selected risk factors. The predictive model was validated through the construction of receiver operating characteristic (ROC) curves, calibration curves, and decision curve analysis (DCA). A nomogram was constructed for visualization.

RESULTS

The determined cutoff point for PD-L1 CPS was 4.5, with scores below this threshold indicating a high risk of CRC liver metastasis. In addition, primary tumor origin other than the rectum, presence of pericolonic lymph node metastasis, and abnormal levels of tumor markers carcinoembryonic antigen and cancer antigen 19-9 were identified as independent risk factors for CRC liver metastasis. The constructed clinical prediction model demonstrated good predictive ability and accuracy, with an area under the ROC curve of 0.871 (95% CI, 0.838-0.904).

CONCLUSION

The exploration and validation of CPS as a novel predictor of CRC liver metastasis were performed. Based on these findings, a new clinical prediction model for CRC liver metastasis was developed by integrating other independent risk factors. The DCA, clinical impact curve, and nomogram graph constructed on the basis of this model have significant clinical implications and guide clinical practice.

Colorectal medullary carcinoma: a pathological subtype with intense immune response and potential to benefit from immune checkpoint inhibitors

INTRODUCTION

Different pathological types of colorectal cancer have distinguished immune landscape, and the efficacy of immunotherapy will be completely different. Colorectal medullary carcinoma, accounting for 2.2-3.2%, is characterized by massive lymphocyte infiltration. However, the attention to the immune characteristics of colorectal medullary carcinoma is insufficient.

AREA COVERED

We searched the literature about colorectal medullary carcinoma on PubMed through November 2023to investigate the hallmarks of colorectal medullary carcinoma's immune landscape, compare medullary carcinoma originating from different organs and provide theoretical evidence for precise treatment, including applying immunotherapy and BRAF inhibitors.

EXPERT OPINION

Colorectal medullary carcinoma is a pathological subtype with intense immune response, with six immune characteristics and has the potential to benefit from immunotherapy. Mismatch repair deficiency, ARID1A missing and BRAF V600E mutation often occurs. IFN-γ pathway is activated and PD-L1 expression is increased. Abundant lymphocyte infiltration performs tumor killing function. In addition, BRAF mutation plays an important role in the occurrence and development, and we can consider the combination of BRAF inhibitors and immunotherapy in patients with BRAF mutant. The exploration of colorectal medullary carcinoma will arouse researchers' attention to the correlation between pathological subtypes and immune response, and promote the process of precise immunotherapy.