LBA20 FOLFOXIRI plus bevacizumab (bev) plus atezolizumab (atezo) versus FOLFOXIRI plus bev as first-line treatment of unresectable metastatic colorectal cancer (mCRC) patients: Results of the phase II randomized AtezoTRIBE study by GONO

Transcription Factor E2F1 Enhances Hepatocellular Carcinoma Cell Proliferation and Stemness by Activating GINS1

Present studies report that high expression of GINS complex subunit 1 (GINS1) is notably pertinent to poor survival for hepatocellular carcinoma (HCC), but it remains unclear how GINS1 affects the progression of HCC. This study aims at investigating the mechanism by which GINS1 affects HCC cell proliferation and stemness. We performed bioinformatics analysis for determining GINS1 expression in HCC tissues, as well as the HCC patients' survival rate with different expression levels of GINS1. E2F transcription factor 1 (E2F1) was predicted as the upstream transcription factor of GINS1, and the binding relation between the two was verified by chromatin immunoprecipitation and dual-luciferase reporter assays. Quantitative real-time polymerase chain reaction was adopted to evaluate the expression of GINS1 and E2F1. The protein expression levels of GINS1, E2F1, and cell stemness-related genes (SOX-2, NANOG, OCT4, and CD133) were detected by Western blot. Afterward, the proliferative capacity and stemness of HCC tumor cells were determined through colony formation, cell counting kit-8, and sphere formation assays. Our study found the high expression of GINS1 and E2F1 in HCC, and overexpressed GINS1 markedly enhanced the sphere formation and proliferation of HCC cells, while silencing GINS1 led to the opposite results. Besides, E2F1 promoted the transcription of GINS1 by working as an upstream transcription factor. The results of the rescue experiment suggested that overexpressed E2F1 could offset the suppressive effect of GINS1 silencing on HCC cell stemness and proliferation. We demonstrated that the transcription factor E2F1 accelerated cell proliferation and stemness in HCC by activating GINS1 transcription. The results can provide new insight into the GINS1-related regulatory mechanism in HCC, which suggest that it may be an effective way for HCC treatment by targeting the E2F1/GINS1 axis.

Immunotherapy strategies and traditional Chinese medicine treatment for microsatellite stable metastatic colorectal cancer

The incidence and mortality of colorectal cancer (CRC) have increased year by year. In addition to traditional radiotherapy, chemotherapy, and targeted therapy, immunotherapy also brings hope to more patients with metastatic colorectal cancer (mCRC). However, these treatments are limited to patients with high microsatellite instability, and about 95% of mCRC patients with microsatellite stability (MSS) can not benefit from them. How to enhance the response of MSS mCRC patients to immunotherapy is the focus of current research. In recent years, it has been found that immunotherapy strategies are expected to improve the clinical efficacy for such patients, and the research reports of TCM combined with immunotherapy are increasing day by day. Therefore, this article aims to review the immunotherapy and traditional Chinese medicine treatment for MSS colorectal cancer.

Immunocheckpoint Inhibitors in Microsatellite-Stable or Proficient Mismatch Repair Metastatic Colorectal Cancer: Are We Entering a New Era?

Colorectal cancer (CRC) is the third most frequent cancer and the second leading cause of cancer-related deaths in Europe. About 5% of metastatic CRC (mCRC) are characterized by high microsatellite instability (MSI) due to a deficient DNA mismatch repair (dMMR), and this condition has been related to a high sensitivity to immunotherapy, in particular to the Immune Checkpoint Inhibitors (ICIs). In fact, in MSI-H or dMMR mCRC, treatment with ICIs induced remarkable response rates and prolonged survival. However, the majority of mCRC cases are mismatch-repair-proficient (pMMR) and microsatellite-stable (MSS), and unfortunately these conditions involve resistance to ICIs. This review aims to provide an overview of the strategies implemented to overcome ICI resistance and/or define subgroups of patients with MSS or dMMR mCRC who may benefit from immunotherapy.

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

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

Updated Management of Colorectal Cancer Liver Metastases: Scientific Advances Driving Modern Therapeutic Innovations

Colorectal cancer is the second leading cause of cancer-related deaths in the United States and accounts for an estimated 1 million deaths annually worldwide. The liver is the most common site of metastatic spread from colorectal cancer, significantly driving both morbidity and mortality. Although remarkable advances have been made in recent years in the management for patients with colorectal cancer liver metastases, significant challenges remain in early detection, prevention of progression and recurrence, and in the development of more effective therapeutics. In 2017, our group held a multidisciplinary state-of-the-science symposium to discuss the rapidly evolving clinical and scientific advances in the field of colorectal liver metastases, including novel early detection and prognostic liquid biomarkers, identification of high-risk cohorts, advances in tumor-immune therapy, and different regional and systemic therapeutic strategies. Since that time, there have been scientific discoveries translating into therapeutic innovations addressing the current management challenges. These innovations are currently reshaping the treatment paradigms and spurring further scientific discovery. Herein, we present an updated discussion of both the scientific and clinical advances and future directions in the management of colorectal liver metastases, including adoptive T-cell therapies, novel blood-based biomarkers, and the role of the tumor microbiome. In addition, we provide a comprehensive overview detailing the role of modern multidisciplinary clinical approaches used in the management of patients with colorectal liver metastases, including considerations toward specific molecular tumor profiles identified on next generation sequencing, as well as quality of life implications for these innovative treatments.

Sintilimab plus bevacizumab and CapeOx (BBCAPX) on first-line treatment in patients with RAS mutant, microsatellite stable, metastatic colorectal cancer: study protocol of a randomized, open-label, multicentric study

BACKGROUND

Rat sarcoma viral oncogene homolog (RAS) gene mutation is a common molecular event in colorectal cancer (CRC). The prognosis of mCRC (metastatic colorectal cancer) patients with RAS mutation is poor and capecitabine and oxaliplatin (CapeOx) plus bevacizumab has shown to be one of the standard therapeutic regimens as first line for these patients with objective response rate (ORR) of ~ 50% and median progression-free survival (mPFS) of 8-9 months. Immunotherapy, especially anti-programmed death 1 (PD-1) monoclonal antibody has demonstrated ground-breaking results in deficient mismatch repair (dMMR) / microsatellite instability-high (MSI-H) mCRC patients. However, the response rate of in microsatellite stable (MSS) patients is extremely low. In addition, preclinical studies have demonstrated that anti-Vascular endothelial growth factor (VEGF) agents, such as bevacizumab, can induce tumor vascular normalization and enhance antitumor immunity. Previous study indicated the combination of chemotherapy, anti-VEGF agents (bevacizumab) with immune checkpoint inhibitors may have promising clinical activity in RAS mutant, MSS refractory mCRC patients. Based on these evidences, we will explore the combination of CapeOx with bevacizumab and sintilimab (anti-PD-1 monoclonal antibody) in RAS mutant, MSS mCRC patients as first-line therapy.

METHODS

This is a randomized, open-label, multicentric clinical trial. In the sintilimab arm, patients will receive sintilimab in combination with CapeOx and bevacizumab. In the control arm, patients will receive CapeOx and bevacizumab. This trial will recruit 494 patients from 20 centers and randomly (1:1) disseminated into two groups. The primary endpoint is the PFS. The secondary endpoints include overall survival, safety, ORR, and disease control rate.

DISCUSSION

This study may provide new ideas for optimizing oncology treatment planning for RAS mutant, MSS mCRC patients in the first-line set.

TRIAL REGISTRATION

This study is short for BBCAPX and has been registered at clinicaltrials.gov registry with identifier NCT05171660.

Society for Immunotherapy of Cancer (SITC) clinical practice guideline on immunotherapy for the treatment of gastrointestinal cancer

Gastrointestinal (GI) cancers, including esophageal, gastroesophageal junction, gastric, duodenal and distal small bowel, biliary tract, pancreatic, colon, rectal, and anal cancer, comprise a heterogeneous group of malignancies that impose a significant global burden. Immunotherapy has transformed the treatment landscape for several GI cancers, offering some patients durable responses and prolonged survival. Specifically, immune checkpoint inhibitors (ICIs) directed against programmed cell death protein 1 (PD-1), either as monotherapies or in combination regimens, have gained tissue site-specific regulatory approvals for the treatment of metastatic disease and in the resectable setting. Indications for ICIs in GI cancer, however, have differing biomarker and histology requirements depending on the anatomic site of origin. Furthermore, ICIs are associated with unique toxicity profiles compared with other systemic treatments that have long been the mainstay for GI cancer, such as chemotherapy. With the goal of improving patient care by providing guidance to the oncology community, the Society for Immunotherapy of Cancer (SITC) convened a panel of experts to develop this clinical practice guideline on immunotherapy for the treatment of GI cancer. Drawing from published data and clinical experience, the expert panel developed evidence- and consensus-based recommendations for healthcare professionals using ICIs to treat GI cancers, with topics including biomarker testing, therapy selection, and patient education and quality of life considerations, among others.

Update on Emerging Therapies for Advanced Colorectal Cancer

Colorectal cancer (CRC) is the third most common malignancy worldwide. It is projected to increase by 3.2 million new cases and account for 1.6 million deaths by 2040. Mortality is largely due to limited treatment options for patients who present with advanced disease. Thus, the development of effective and tolerable therapies is crucial. Chemotherapy has been the backbone of systemic treatment of advanced CRC, but utility has been limited because of invariable resistance to therapy, narrow mechanisms of action, and unfavorable toxicity profile. Tumors that are mismatch repair-deficient have demonstrated remarkable response to immune checkpoint inhibitor therapy. However, most CRC tumors are mismatch repair-proficient and represent an unmet medical need. Although ERBB2 amplification occurs only in a few cases, it is associated with left-sided tumors and a higher incidence of brain metastasis. Numerous combinations of HER2 inhibitors have demonstrated efficacy, and antibody-drug conjugates against HER2 represent innovative strategies in this area. The KRAS protein has been classically considered undruggable. Fortunately, new agents targeting KRAS G12C mutation represent a paradigm shift in the management of affected patients and could lead the advancement in drug development for the more common KRAS mutations. Furthermore, aberrant DNA damage response is present in 15%-20% of CRCs, and emerging innovative combinations with poly (ADP-ribose) polymerase (PARP) inhibitors could improve the current therapeutic landscape. Multiple novel biomarker-driven approaches in the management of patients with advanced CRC tumors are reviewed in this article.

Therapeutic landscape and future direction of metastatic colorectal cancer

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

New developments in targeted therapy for metastatic colorectal cancer

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

Immune Checkpoint Inhibitor-Based Combination Therapy for Colorectal Cancer: An Overview

Colorectal cancer (CRC) is one of the most common diseases in the world. Tumor immunotherapy is an innovative cancer treatment that acts by activating the human body's autoimmune system. Immune checkpoint block has been shown to be effective in DNA deficient mismatch repair/microsatellite instability-high CRC. However, the therapeutic effect for proficient mismatch repair/microsatellite stability patients still requires further study and optimization. At present, the main CRC strategy is to combine other therapeutic methods, such as chemotherapy, targeted therapy, and radiotherapy. Here, we review the current status and the latest progress of immune checkpoint inhibitors in the treatment of CRC. At the same time, we consider therapeutic opportunities for transforming cold to hot, as well as perspectives on possible future therapies, which may be in great demand for drug-resistant patients.

Acute inflammatory reaction during anti-angiogenesis therapy combined with immunotherapy as a possible indicator of the therapeutic effect: Three case reports and literature review

The posterior line treatment of unresectable advanced or metastatic gastrointestinal (GI) tumors has always been a challenging point. In particular, for patients with microsatellite stable (MSS)/mismatch repair proficient (pMMR) 0GI tumors, the difficulty of treatment is exacerbated due to their insensitivity to immune drugs. Accordingly, finding a new comprehensive therapy to improve the treatment effect is urgent. In this study, we report the treatment histories of three patients with MSS/pMMR GI tumors who achieved satisfactory effects by using a comprehensive treatment regimen of apatinib combined with camrelizumab and TAS-102 after the failure of first- or second-line regimens. The specific contents of the treatment plan were as follows: apatinib (500 mg/d) was administered orally for 10 days, followed by camrelizumab (200 mg, ivgtt, day 1, 14 days/cycle) and TAS-102 (20 mg, oral, days 1-21, 28 days/cycle). Apatinib (500 mg/d) was maintained during treatment. Subsequently, we discuss the possible mechanism of this combination and review the relevant literature, and introduce clinical trials on anti-angiogenesis therapy combined with immunotherapy.

MODUL cohort 2: an adaptable, randomized, signal-seeking trial of fluoropyrimidine plus bevacizumab with or without atezolizumab maintenance therapy for BRAFwt metastatic colorectal cancer

Background

MODUL is an adaptable, signal-seeking trial designed to test novel agents in predefined patient subgroups in first-line metastatic colorectal cancer (mCRC).

Patients and methods

Patients with measurable, unresectable, previously untreated mCRC received induction with ≤8 cycles of FOLFOX + bevacizumab followed by randomization to maintenance treatment comprising control [fluoropyrimidine (FP)/bevacizumab: 5-fluorouracil 1600-2400 mg/m² 46-h intravenous (i.v.) infusion day 1 q2 weeks plus leucovorin 400 mg/m² 2-h infusion i.v. day 1 q2 weeks or capecitabine 1000 mg/m² b.i.d. orally days 1-14 every 21 days; bevacizumab 5 mg/kg 15-30-min i.v. infusion q2 weeks] or experimental treatment in one of four biomarker-driven cohorts. In patients with BRAF wild-type (BRAF^wt) tumors (cohort 2), experimental treatment was FP/bevacizumab + atezolizumab (800 mg 60-min i.v. infusion q2 weeks). Primary efficacy endpoint was progression-free survival (PFS; intent-to-treat population). Enrollment is complete; efficacy and safety findings from cohort 2 are presented.

Results

Four hundred and forty-five patients with BRAF^wt mCRC were randomized (2 : 1) to maintenance in cohort 2. At a median follow-up of 10.5 months, PFS outcome hypothesis was not met [hazard ratio (HR) 0.92; 95% confidence interval (CI) 0.72-1.17; P = 0.48]; overall survival (OS) was immature. At a median follow-up of 20.3 months (2-year survival follow-up), PFS benefit was also not met (HR 0.95; 95% CI 0.77-1.18; P = 0.666); OS HR with nearly two-thirds of patients with events was 0.83 (95% CI 0.65-1.05; P = 0.117). No new safety signals were identified. The most common grade ≥3 treatment-emergent adverse events (TEAEs) for experimental versus control arms were hypertension (6.1% versus 4.2%), diarrhea (3.1% versus 2.1%), and palmar-plantar erythrodysesthesia syndrome (1.0% versus 2.5%). Four patients experienced TEAEs with fatal outcome, two were study treatment-related: hepatic failure (experimental arm) and large intestine perforation (control arm; bevacizumab-related).

Conclusions

Adding atezolizumab to FP/bevacizumab as first-line maintenance treatment after FOLFOX + bevacizumab induction for BRAF^wt mCRC did not improve efficacy outcomes.

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MODUL is an adaptable, signal-seeking trial of novel combinations in predefined subgroups of patients with mCRC.

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In cohort 2 (BRAF^wt mCRC), adding atezolizumab to FP/bevacizumab (bev) first-line maintenance therapy did not improve PFS or OS versus FP/bev.

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ORR and DCR were numerically but not statistically significantly higher with atezolizumab + FP/bev versus FP/bev.

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The safety profile of atezolizumab + FP/bev was consistent with previous findings with no new safety signals identified.

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Findings from MODUL cohort 2 indicate that immunotherapy has limited efficacy in patients with microsatellite stable mCRC.

Mismatch Repair-Deficient Colorectal Cancer: Building on Checkpoint Blockade

Colorectal cancer (CRC) with deficient DNA mismatch repair (dMMR) is characterized by hypermutation leading to abundant neoantigens that activate an antitumor immune response in the tumor microenvironment. Immune checkpoint inhibitors (ICIs) have transformed the treatment of this subset of CRC and other solid tumors with dMMR, by producing frequent and durable responses that extend patient survival. Recently, the anti-programmed death-1 (PD-1) antibody pembrolizumab was shown to produce significantly longer progression-free survival with fewer adverse events compared with chemotherapy as first-line treatment of metastatic CRC (mCRC) with dMMR. Accordingly, single-agent pembrolizumab represents a new standard of care for dMMR mCRCs including patients with Lynch syndrome and the more common sporadic cases. Furthermore, data indicate that the combination of PD-1 and cytotoxic T-cell lymphocyte-4 inhibitors was more effective than single-agent PD-1 inhibition in patients with dMMR mCRCs, suggesting nonredundant mechanisms of action. Although the benefit of ICIs is currently limited to metastatic disease, studies evaluating ICIs as neoadjuvant and adjuvant therapy in earlier-stage dMMR CRC are ongoing. Despite success of ICIs in the treatment of metastatic dMMR cancers, an appreciable proportion of these tumors demonstrate intrinsic or acquired resistance, and biomarkers to identify these patients are needed. Advances in the understanding of immunotherapy resistance mechanisms hold promise for both biomarker identification and development of novel strategies to circumvent treatment resistance. In this review, we present a comprehensive overview of the evidence for the role of immunotherapy in the treatment of dMMR CRC, discuss resistance mechanisms, and outline potential strategies to circumvent primary and secondary resistance with the goal of broadening the benefit of ICIs.

Prognostic and predictive molecular biomarkers in advanced colorectal cancer

The revolution of precision medicine has produced unprecedented seismic shifts in the treatment paradigm of advanced cancers. Among the major killers, colorectal cancer (CRC) is far behind the others. In fact, the great successes obtained in breast, NSCLC, melanoma, and genitourinary tract tumors have been observed only in fewer than 5 % metastatic colorectal cancer (mCRC): those with the mismatch repair deficiency (dMMR), a well-known predictive factor for to the outstanding efficacy of checkpoint inhibitors (CPI). The treatment of the remaining vast majority mCRC patients is still based upon only two molecular determinants: the RAS and BRAF mutational status. New promising biomarkers include HER2, tumor mutational burden (TMB) for its possible implications on CPI efficacy, and the extremely rare NTRK fusions. The Consensus Molecular Subtypes classification (CMS) is a good example of the efforts to combine different molecular features of this disease, although its relevance in clinical practice is still under investigation. In this Review, we focus on all these prognostic and predictive biomarkers, analyzing data from the most important clinical trials of the last years. We also try to rank them according to their prognostic and predictive power.

FFCD 1709-SIRTCI phase II trial: Selective internal radiation therapy plus Xelox, Bevacizumab and Atezolizumab in liver-dominant metastatic colorectal cancer

Immune checkpoint inhibitors (ICI) have high efficacy in metastatic colorectal cancer (mCRC) with microsatellite instability (MSI) but not in microsatellite stable (MSS) tumour due to the low tumour mutational burden. Selective internal radiation therapy (SIRT) could enhance neoantigen production thus triggering systemic anti-tumoral immune response (abscopal effect). In addition, Oxalipatin can induce immunogenic cell death and Bevacizumab can decrease the exhaustion of tumour infiltrating lymphocyte. In combination, these treatments could act synergistically to sensitize MSS mCRCs to ICI SIRTCI is a prospective, multicentre, open-label, phase II, non-comparative single-arm study evaluating the efficacy and safety of SIRT plus Xelox, Bevacizumab and Atezolizumab (anti-programmed death-ligand 1) in patients with liver-dominant MSS mCRC. The primary objective is progression-free survival at 9 months. The main inclusion criteria are patients with MSS mCRC with liver-dominant disease, initially unresectable disease and with no prior oncologic treatment for metastatic disease. The trial started in November 2020 and has included 10 out of the 52 planned patients.

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

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

Immunotherapy for Microsatellite Stable Colorectal Cancers: Challenges and Novel Therapeutic Avenues

With the development of immune checkpoint inhibitors, immunotherapy researchers have facilitated substantial progress for patients with mismatch repair deficient/microsatellite instability-high colorectal cancer, which has led to practice changes at a head-spinning pace. However, this benefit has not been translated into microsatellite stable colorectal cancer, which carries the hallmarks of chromosomal instability. So far, clinical trials have not shown any substantial clinical benefits of immune checkpoint inhibitor therapy for patients with microsatellite stable colorectal cancer, which has been disappointing. Recently, combinations of immune checkpoint inhibitors with tyrosine kinase inhibitors and targeted therapies have been investigated for potential synergistic effects that may increase antitumor activity in the tumor microenvironment and achieve more substantial clinical and radiologic responses. In this article, we discuss the current state of the science for the use of immune checkpoint inhibitors in microsatellite stable colorectal cancers, and we review the molecular underpinnings of inherited physiologic barriers for the delivery of effective immunotherapy. We also elaborate on existing therapeutic opportunities to convert microsatellite stable colorectal cancer into an "immune hot" cancer, which may define the future treatment paradigm of colorectal cancer for which there is a great unmet need.

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

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

ESMO Congress 2021: highlights from the EORTC gastrointestinal tract cancer group's perspective

There has been no major change of practice in gastrointestinal oncology at the European Society for Medical Oncology (ESMO) symposium 2021, but confirmation that immunotherapy in combination with chemotherapy has become standard of care in several indications. The European Organisation for Research and Treatment of Cancer (EORTC) Gastrointestinal Track Cancer Group has selected important phase II and III trials presented during the symposium across all gastrointestinal cancers as well as early reports on new drugs or new combinations that may change practice in the future.

Latest evidence on immune checkpoint inhibitors in metastatic colorectal cancer: A 2022 update

The long-term remissions induced by immune-checkpoint inhibitors (ICIs) in many types of cancers have opened up the possibility of a broader use of immunotherapy in less immunogenic but genetically heterogeneous tumours. Regarding metastatic colorectal cancer (mCRC), in first-line setting, pembrolizumab has been approved as preferred option and nivolumab, alone or in combination with ipilimumab as alternative option for patients with mismatch-repair-deficient and microsatellite instability-high (dMMR/MSI-H) disease, independently of their eligibility for intensive chemotherapy. In subsequent lines, both these immunotherapeutic regimens (e.g., pembrolizumab and nivolumab+/-ipilimumab) as well as dostarlimab-gxly are currently recommended for patients with dMMR/MSI-H chemo-resistant mCRC who have not previously received an ICI. Beginning from the rationale behind the immune-mediated interplay in the dMMR/MSI-H bowel microenvironment, we provide here an update on the evolution status of all available, approved or not, ICIs in mCRC, describing their efficacy and toxicity profile with an emphasis on the pivotal trials supporting current colorectal indications. For each ICI agent, the results from combinations under investigation, particularly for those being upgraded in clinical phasing, the perspectives but also the limitations of main ongoing trials are thoroughly discussed. In the close future, upcoming data are expected to confirm the clinical benefit of ICIs and to further expand their role in mCRC.

Immune Checkpoint Inhibitors in Mismatch Repair Proficient/Microsatellite Stable Metastatic Colorectal Cancer Patients: Insights from the AtezoTRIBE and MAYA Trials

Simple Summary

Immune-checkpoint inhibitors (ICI) show modest activity and efficacy in microsatellite stable (MSS) metastatic colorectal cancer (mCRC) patients harbouring a proficient mismatch repair system (pMMR). Recently, two phase 2 trials -AtezoTRIBE and MAYA- have challenged this dogma through the administration of an intense first-line chemotherapy backbone consisting of FOLFOXIRI/bevacizumab in patients unselected for their microsatellite status, and immune priming with temozolomide in chemorefractory pMMR/MSS patients with silencing of O6-methylguanine-DNA methyltransferase (MGMT), respectively, reporting promising results. We here present the founding biological rationale of these two studies and their main findings. At the same time, we stress their strengths and drawbacks and open questions still to be address in future clinical investigations.

Abstract

In metastatic colorectal cancer (mCRC), remarkable advances have been achieved with immune checkpoint inhibitors (ICIs) targeting PD-1/PD-L1 and CTLA-4, only in a small subset of tumours (4–5%), harbouring a deficient mismatch repair system (dMMR)/microsatellite instability–high (MSI-H) or mutations in the catalytic subunit of polymerase epsilon (POLE). Within this framework, several combination strategies have been investigated to sensitize proficient mismatch repair (pMMR)/microsatellite stable (MSS) mCRC to ICIs, with disappointing results so far. However, at the last ESMO meeting, two phase II trials AtezoTRIBE and MAYA provided promising results in this field. In the comparative AtezoTRIBE trial, the addition of atezolizumab to FOLFOXIRI (5-fluoruracil, oxaliplatin and irinotecan) and bevacizumab led to a significant advantage in terms of progression free survival (PFS) in a population of untreated mCRC patients, not selected according to MMR/MSI status. In the single-arm MAYA trial, immune priming with temozolomide in pMMR/MSS chemo-resistant mCRC patients with silencing of O6-methylguanine-DNA methyltransferase (MGMT) allowed reporting signals of sensitivity to the subsequent therapy with nivolumab and a low dose of ipilimumab in some patients. Here, we discuss the rationale, results, criticisms and research perspectives opened by these two studies.

Combined Treatment with Immunotherapy-Based Strategies for MSS Metastatic Colorectal Cancer

In recent years, deepening knowledge of the complex interactions between the immune system and cancer cells has led to the advent of effective immunotherapies that have revolutionized the therapeutic paradigm of several cancer types. However, colorectal cancer (CRC) is one of the tumor types in which immunotherapy has proven less effective. While there is solid clinical evidence for the therapeutic role of immune checkpoint inhibitors in mismatch repair-deficient (dMMR) and in highly microsatellite instable (MSI-H) metastatic CRC (mCRC), blockade of CTLA-4 or PD-L1/PD-1 as monotherapy has not conferred any major clinical benefit to patients with MMR-proficient (pMMR) or microsatellite stable (MSS) mCRC, reflecting 95% of the CRC population. There thus remains a high unmet medical need for the development of novel immunotherapy approaches for the vast majority of patients with pMMR or MSS/MSI-low (MSI-L) mCRC. Defining the molecular mechanisms for immunogenicity in mCRC and mediating immune resistance in MSS mCRC is needed to develop predictive biomarkers and effective therapeutic combination strategies. Here we review available clinical data from combinatorial therapeutic approaches using immunotherapy-based strategies for MSS mCRC.