Regorafenib plus toripalimab in patients with metastatic colorectal cancer: a phase Ib/II clinical trial and gut microbiome analysis

Immunotherapy in Colorectal Cancer - Finding the Achilles' Heel

AbstractColorectal cancer treatment has evolved considerably in the last decade with the development of immunotherapies. Immune checkpoint inhibitor therapies have brisk and durable responses in patients with advanced microsatellite instability-high colorectal cancer, both surgically resectable and unresectable; however, patients with microsatellite stable colorectal cancer in general do not respond to the same therapy. Emerging evidence shows that immune checkpoint inhibitors may elicit responses in subsets of patients with microsatellite stable colorectal cancer, especially when combined with other anticancer agents that can modulate the tumor microenvironment. Therefore, rationally designed therapeutic combinations involving immune checkpoint inhibitors, as well as the development of predictive biomarkers for optimal patient selection, have emerged as two key areas of active research. In addition, other immunotherapeutic agents such as cell-based therapies and bispecific T-cell engagers are beginning to be studied in preclinical and early-phase settings. Although by no means a universal treatment strategy, immunotherapy can elicit responses in microsatellite stable colorectal cancer and further research is needed to extend their benefit to patients with microsatellite stable colorectal cancer. Here, we review the current state of immunotherapeutic regimens for microsatellite stable colorectal cancer.

Combined anti-PD-1, HDAC inhibitor and anti-VEGF for MSS/pMMR colorectal cancer: a randomized phase 2 trial

Epigenetic modifications of chromatin, including histone acetylation, and tumor angiogenesis play pivotal roles in creating an immunosuppressive tumor microenvironment. In the randomized phase 2 CAPability-01 trial, we investigated the potential efficacy of combining the programmed cell death protein-1 (PD-1) monoclonal antibody sintilimab with the histone deacetylase inhibitor (HDACi) chidamide with or without the anti-vascular endothelial growth factor (VEGF) monoclonal antibody bevacizumab in patients with unresectable chemotherapy-refractory locally advanced or metastatic microsatellite stable/proficient mismatch repair (MSS/pMMR) colorectal cancer. Forty-eight patients were randomly assigned to either the doublet arm (sintilimab and chidamide, n = 23) or the triplet arm (sintilimab, chidamide and bevacizumab, n = 25). The primary endpoint of progression-free survival (PFS) rate at 18 weeks (18wPFS rate) was met with a rate of 43.8% (21 of 48) for the entire study population. Secondary endpoint results include a median PFS of 3.7 months, an overall response rate of 29.2% (14 of 48), a disease control rate of 56.3% (27 of 48) and a median duration of response of 12.0 months. The secondary endpoint of median overall survival time was not mature. The triplet arm exhibited significantly improved outcomes compared to the doublet arm, with a greater 18wPFS rate (64.0% versus 21.7%, P = 0.003), higher overall response rate (44.0% versus 13.0%, P = 0.027) and longer median PFS rate (7.3 months versus 1.5 months, P = 0.006). The most common treatment-emergent adverse events observed in both the triplet and doublet arms included proteinuria, thrombocytopenia, neutropenia, anemia, leukopenia and diarrhea. There were two treatment-related fatalities (hepatic failure and pneumonitis). Analysis of bulk RNA sequencing data from the patients suggested that the triplet combination enhanced CD8+ T cell infiltration, resulting in a more immunologically active tumor microenvironment. Our study suggests that the combination of a PD-1 antibody, an HDACi, and a VEGF antibody could be a promising treatment regimen for patients with MSS/pMMR advanced colorectal cancer. ClinicalTrials.gov registration: NCT04724239 .

Clinical and biomarker results from a phase II trial of combined cabozantinib and durvalumab in patients with chemotherapy-refractory colorectal cancer (CRC): CAMILLA CRC cohort

CAMILLA is a basket trial (NCT03539822) evaluating cabozantinib plus the ICI durvalumab in chemorefractory gastrointestinal cancer. Herein, are the phase II colorectal cohort results. 29 patients were evaluable. 100% had confirmed pMMR/MSS tumors. Primary endpoint was met with ORR of 27.6% (95% CI 12.7-47.2%). Secondary endpoints of 4-month PFS rate was 44.83% (95% CI 26.5-64.3%); and median OS was 9.1 months (95% CI 5.8-20.2). Grade≥3 TRAE occurred in 39%. In post-hoc analysis of patients with RAS wild type tumors, ORR was 50% and median PFS and OS were 6.3 and 21.5 months respectively. Exploratory spatial transcriptomic profiling of pretreatment tumors showed upregulation of VEGF and MET signaling, increased extracellular matrix activity and preexisting anti-tumor immune responses coexisting with immune suppressive features like T cell migration barriers in responders versus non-responders. Cabozantinib plus durvalumab demonstrated anti-tumor activity, manageable toxicity, and have led to the activation of the phase III STELLAR-303 trial.

Gut microbiota influences the efficiency of immune checkpoint inhibitors by modulating the immune system (Review)

Immune checkpoint inhibitors (ICIs) are commonly utilized in tumor treatment. However, they still have limitations, including insufficient effectiveness and unavoidable adverse events. It has been demonstrated that gut microbiota can influence the effectiveness of ICIs, although the precise mechanism remains unclear. Gut microbiota plays a crucial role in the formation and development of the immune system. Gut microbiota and their associated metabolites play a regulatory role in immune balance. Tumor occurrence and development are linked to their ability to evade recognition and destruction by the immune system. The purpose of ICIs treatment is to reinitiate the immune system's elimination of tumor cells. Thus, the immune system acts as a communication bridge between gut microbiota and ICIs. Varied composition and characteristics of gut microbiota result in diverse outcomes in ICIs treatment. Certain gut microbiota-related metabolites also influence the therapeutic efficacy of ICIs to some extent. The administration of antibiotics before or during ICIs treatment can diminish treatment effectiveness. The utilization of probiotics and fecal transplantation can partially alter the outcome of ICIs treatment. The present review synthesized previous studies to examine the association between gut microbiota and ICIs, elucidated the role of gut microbiota and its associated factors in ICIs treatment, and offered direction for future research.

Regorafenib monotherapy or combined with an immune-checkpoint inhibitor as later-line treatment for metastatic colorectal cancer: a multicenter, real-world retrospective study in China

OBJECTIVE

To evaluate the efficacy and safety of regorafenib monotherapy or in combination with immune-checkpoint inhibitor while treating Chinese patients with metastatic colorectal cancer (mCRC): a real-world study.

METHODS

The data of patients with metastatic colorectal cancer who received regorafenib-containing regimen as the third or later line treatment at ten Chinese hospitals from Aug 2017 to Jun 2020 were retrospectively analyzed, including dosing details, survival data as well as adverse events. Survival analysis was further performed for patients administrated with regorafenib monotherapy and combined with an immune-checkpoint inhibitor based on Kaplan-Meier and Cox regression methods. The primary endpoint was overall survival.

RESULTS

A total of 537 patients were included with a median age of 61, among whom 376 received regorafenib monotherapy and 245 received regorafenib combined with immune-checkpoint inhibitors. The clinicopathological characteristics of the two groups at baseline were mainly balanced. No significant difference in progression-free survival (PFS) was observed in patients receiving regorafenib monotherapy or combination therapy (3.8 vs. 5.5 months, p = 0.170). In contrast, patients receiving combination therapy had a more prolonged overall survival (OS) than those receiving regorafenib monotherapy (13.5 vs. 10.0 months, p = 0.001). The treatment regimen and regorafenib dosage were significant prognostic factors in the multivariate analysis. Significant benefits in PFS and OS were achieved in KRAS mutant and anti-angiogenesis treatment-naïve subgroups receiving combination therapy compared to monotherapy. No apparent increase was recorded in treatment-related adverse events in patients receiving combination therapy.

CONCLUSION

Regorafenib plus an immune-checkpoint inhibitor has already been a widely adopted strategy in the later-line treatment for mCRC in the real world. The combination therapy yielded a significantly prolonged overall survival than regorafenib alone, with a manageable safety profile in Chinese patients, and warrants further investigation.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT04835324. Registered 6th April 2021.

The current status and prospect of immunotherapy in colorectal cancer

Metastatic colorectal cancer (mCRC) is a heterogeneous disease. We reviewed the current clinical trials on immunotherapy in metastatic colorectal cancer with high microsatellite instability and microsatellite stability. Owing to the advances in immunotherapy, its use has gradually expanded from second- and third-line therapies to first-line, early neoadjuvant, and adjuvant therapies. Based on current research results, immunotherapy has shown very good results in dMMR/MSI-H patients, whether it is neoadjuvant therapy for operable patients or first-line or multi-line therapy for advanced patients. KEYNOTE 016 study also showed that patients with MSS were basically ineffective in single immunotherapy. Moreover, immunotherapy for colorectal cancer may also require identification of new biomarkers.

The next bastion to be conquered in immunotherapy: microsatellite stable colorectal cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths worldwide, and its incidence continues to rise, particularly in developing countries. The advent of immune checkpoint inhibitors (ICIs) has represented a significant advancement in CRC treatment. Deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H) serves as a biomarker for immunotherapy, with dMMR/MSI-H CRC exhibiting significantly better response rates to immunotherapy compared to proficient mismatch repair (pMMR)or microsatellite stable (MSS) CRC. While some progress has been made in the treatment of pMMR/MSS CRC in recent years, it remains a challenging issue in clinical practice. The tumor microenvironment (TME) plays a crucial role not only in the development and progression of CRC but also in determining the response to immunotherapy. Understanding the characteristics of the TME in pMMR/MSS CRC could offer new insights to enhance the efficacy of immunotherapy. In this review, we provide an overview of the current research progress on the TME characteristics and advancements in immunotherapy for pMMR/MSS CRC.

RNA Expression-Based Analysis to Predict Response in Patients with Metastatic Mismatch Repair Proficient Colorectal Cancer Treated with Regorafenib and Nivolumab

INTRODUCTION

We previously conducted a phase I/Ib study (NCT03712943) with regorafenib and nivolumab in patients with refractory metastatic mismatch repair proficient (pMMR) colorectal cancer (CRC). This study aimed to investigate the role of Xerna™ TME Panel in predicting the treatment response.

METHODS

Twenty-two archival pretreatment tumor samples were subjected to the Xerna™ TME Panel, a machine learning-based RNA-sequencing biomarker assay. The Xerna tumor microenvironment (TME) subtypes were evaluated for correlation with overall survival (OS), progression-free survival (PFS), disease control rate (DCR), and other biomarkers including KRAS, PD-L1, CD8 expression, and Treg cells in TME.

RESULTS

Based on Xerna™ TME Panel, 4 patients with immune-active (IA) subtype and 6 patients with immune-suppressed subtype were classified as biomarker-positive, and five with angiogenic (A) subtype and seven with immune desert subtype were biomarker-negative. While not reaching statistical significance, Xerna TME biomarker-positive patients seemed to have longer median PFS (7.9 vs. 4.1 months, p = 0.254), median OS (15.75 vs. 11.9 months, p = 0.378), and higher DCR (70% vs. 58%, p = 0.675). The IA subtype in our cohort had higher levels of CD4+ FOXP3+ Treg cells, whereas the A subtype showed lower levels of Treg cells.

CONCLUSION

Xerna™ TME Panel analysis in patients with refractory metastatic pMMR CRC who were treated with regorafenib plus nivolumab might be of value for predictive clinical benefit. Further studies are needed to evaluate the predictive role of Xerna™ TME Panel analysis in patients with refractory metastatic pMMR CRC.

Exploring the Role of the Gut and Intratumoral Microbiomes in Tumor Progression and Metastasis

Cancer cell dissemination involves invasion, migration, resistance to stressors in the circulation, extravasation, colonization, and other functions responsible for macroscopic metastases. By enhancing invasiveness, motility, and intravasation, the epithelial-to-mesenchymal transition (EMT) process promotes the generation of circulating tumor cells and their collective migration. Preclinical and clinical studies have documented intensive crosstalk between the gut microbiome, host organism, and immune system. According to the findings, polymorphic microbes might play diverse roles in tumorigenesis, cancer progression, and therapy response. Microbial imbalances and changes in the levels of bacterial metabolites and toxins promote cancer progression via EMT and angiogenesis. In contrast, a favorable microbial composition, together with microbiota-derived metabolites, such as short-chain fatty acids (SCFAs), can attenuate the processes of tumor initiation, disease progression, and the formation of distant metastases. In this review, we highlight the role of the intratumoral and gut microbiomes in cancer cell invasion, migration, and metastatic ability and outline the potential options for microbiota modulation. As shown in murine models, probiotics inhibited tumor development, reduced tumor volume, and suppressed angiogenesis and metastasis. Moreover, modulation of an unfavorable microbiome might improve efficacy and reduce treatment-related toxicities, bringing clinical benefit to patients with metastatic cancer.

Gut microbiota and tumor-associated macrophages: potential in tumor diagnosis and treatment

Avoiding immune destruction and polymorphic microbiomes are two key hallmarks of cancer. The tumor microenvironment (TME) is essential for the development of solid tumors, and the function of tumor-associated macrophages (TAMs) in the TME is closely linked to tumor prognosis. Therefore, research on TAMs could improve the progression and control of certain tumor patients. Additionally, the intestinal flora plays a crucial role in metabolizing substances and maintaining a symbiotic relationship with the host through a complex network of interactions. Recent experimental and clinical studies have suggested a potential link between gut microbiome and TME, particularly in regulating TAMs. Understanding this association could improve the efficacy of tumor immunotherapy. This review highlights the regulatory role of intestinal flora on TAMs, with a focus on gut microbiota and their metabolites. The implications of this association for tumor diagnosis and treatment are also discussed, providing a promising avenue for future clinical treatment strategies.

China special issue on gastrointestinal tumors-Cetuximab retreatment plus camrelizumab and liposomal irinotecan in patients with RAS wild-type metastatic colorectal cancer: Cohort B of the phase II CRACK study

Patients with metastatic colorectal cancer (mCRC) have poor long-term survival. Rechallenge with anti-epidermal growth factor receptor (anti-EGFR) based therapy has shown certain activity as late-line therapy. To further improve clinical outcomes, we evaluated the antitumor efficacy and safety of cetuximab in combination with camrelizumab and liposomal irinotecan in patients with RASwt mCRC pretreated with anti-EGFR-based therapy. Patients with RASwt mCRC who had received at least two prior systemic therapies, including anti-EGFR-based treatment in the metastatic or unresectable disease setting, were enrolled in cohort B. Patients were treated with cetuximab (500 mg/m2 ) and camrelizumab (200 mg) plus liposomal irinotecan (HR070803, 60 mg/m2 ) intravenously once every 2 weeks. The primary endpoint was the objective response rate (ORR) by RECIST v1.1. The secondary endpoints included disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and safety. At the data cutoff (23 November 2022), 19 patients were enrolled in the two stages, and 16 were evaluable for efficacy analyses. The ORR was 25% (95% confidence interval [CI]: 10.2%-49.5%), and DCR was 75% (95% CI: 50.5%-89.8%). The median PFS and OS were 6.9 (95% CI: 2.6-11.2) and 15.1 (95% CI: 6.1-24.0) months, respectively. Grade 3 treatment-related adverse events (TRAEs) occurred in 15.8% (3/19) of patients. No grade ≥4 TRAEs were found in the safety population. Our study suggests that anti-EGFR retreatment therapy with cetuximab plus camrelizumab and liposomal irinotecan (HR070803) is a promising late-line treatment option with good antitumor activity and well-tolerated toxicity in RASwt mCRC patients.

Fruquintinib in combination with sintilimab or TAS-102 as third-line or above treatment in patients with metastatic colorectal cancer: a real-world study

Background

For metastatic colorectal cancer (mCRC), the efficacy of third-line or above treatments is not ideal. Combining targeted vascular endothelial growth factor (VEGF) or vascular endothelial growth factor receptor (VEGFR) biological agents with chemotherapy or anti-programmed death receptor 1 (PD-1) treatment can bring longer survival benefits to patients with mCRC compared with the application of a single drug. In this study, fruquintinib was used as the research drug, and the main purpose was to compare the efficacy and safety of fruquintinib in combination with sintilimab (FS) or trifluridine and tipiracil (TAS-102) (FT) in the third-line or above treatment in mCRC patients.

Methods

Based on real-world clinical practice, mCRC patients who progressed after second-line or higher-line chemotherapy regimens and received FS or FT as third-line or above treatment from December 2020 to November 2022 were analyzed. Progression-free survival (PFS) was the primary endpoint. Safety, disease control rate (DCR) and objective response rate (ORR) were secondary end points.

Results

In the FS group, 47 patients received FS, and in the FT group, 45 patients received FT. The DCR values in the FS and FT groups were 80.9% (38/47) and 55.6% (25/45), respectively (P<0.05). The median PFS (mPFS) in the FS group was 6.0 months, and the mPFS in the FT group was 3.5 months (P<0.05). Most adverse events (AEs) were grade 1-2 in severity.

Conclusions

As a third-line or above regimen in mCRC patients, compared to FT, treatment with FS provides a higher DCR and longer mPFS and is better tolerated. The combination of fruquintinib and sintilimab may become a new treatment option for mCRC patients.

Regorafenib alone or in combination with high/low-dose radiotherapy plus toripalimab as third-line treatment in patients with metastatic colorectal cancer: protocol for a prospective, randomized, controlled phase II clinical trial (SLOT)

Combination strategies to improve immunotherapy response in microsatellite stable metastatic colorectal cancer (MSS mCRC) remain an unmet need. Several single-arm clinical trials have shown promising synergistic effects between regorafenib and ICIs; however, some contradictory results have also been reported. Randomized controlled trials are needed to further validate the combination of regorafenib with ICIs. In addition, low-dose radiotherapy has been demonstrated to induce local immune responses by reprogramming the tumor microenvironment when combined with high-dose radiotherapy and ICIs. In this study, we designed a prospective, randomized, controlled phase II trial to investigate the efficacy and safety of regorafenib in combination with high/low-dose radiotherapy plus toripalimab in MSS mCRC compared to regorafenib alone. Patients with MSS metastatic adenocarcinoma of the colon or rectum will be enrolled and randomly assigned into two arms: a control arm and an experimental arm. Patients in the control arm will receive regorafenib monotherapy (120 mg once daily on days 1-21 of each 28 days cycle). Patients in the experimental arm will first receive one cycle of regorafenib (80 mg once daily on days 1-21 of each 28 days cycle) and toripalimab (240mg, q3w), followed by high-dose (4-8 fractions of 8-12Gy) and low-dose (1-10Gy at 0.5-2Gy/fraction) radiotherapy, and then continue regorafenib and toripalimab treatment. The primary endpoint is the objective response rate, and the secondary endpoints are disease control rate, duration of remission, median progress-free survival, median overall survival, and adverse events. Recruitment started in August 2023 and is ongoing.

Clinical Trial Registration

https://clinicaltrials.gov/study/NCT05963490?cond=NCT05963490&rank=1, identifier NCT05963490.

Role of gut microbiome in cancer immunotherapy: from predictive biomarker to therapeutic target

Immunotherapy has emerged as an effective treatment for various types of cancers. Recent studies have highlighted a significant correlation between the gut microbiome and patients' response to immunotherapy. Several characteristics of the gut microbiome, such as community structures, taxonomic compositions, and molecular functions, have been identified as crucial biomarkers for predicting immunotherapy response and immune-related adverse events (irAEs). Unlike other -omics, the gut microbiome can serve as not only biomarkers but also potential targets for enhancing the efficacy of immunotherapy. Approaches for modulating the gut microbiome include probiotics/prebiotics supplementation, dietary interventions, fecal microbiota transplantation (FMT), and antibiotic administration. This review primarily focuses on elucidating the potential role of the gut microbiome in predicting the response to cancer immunotherapy and improving its efficacy. Notably, we explore reasons behind inconsistent findings observed in different studies, and highlight the underlying benefits of antibiotics in liver cancer immunotherapy.

Metastasis organotropism in colorectal cancer: advancing toward innovative therapies

Distant metastasis remains a leading cause of mortality among patients with colorectal cancer (CRC). Organotropism, referring to the propensity of metastasis to target specific organs, is a well-documented phenomenon in CRC, with the liver, lungs, and peritoneum being preferred sites. Prior to establishing premetastatic niches within host organs, CRC cells secrete substances that promote metastatic organotropism. Given the pivotal role of organotropism in CRC metastasis, a comprehensive understanding of its molecular underpinnings is crucial for biomarker-based diagnosis, innovative treatment development, and ultimately, improved patient outcomes. In this review, we focus on metabolic reprogramming, tumor-derived exosomes, the immune system, and cancer cell-organ interactions to outline the molecular mechanisms of CRC organotropic metastasis. Furthermore, we consider the prospect of targeting metastatic organotropism for CRC therapy.

Refractory microsatellite stable metastatic colorectal cancer with ERBB2/ERBB3 mutation may be preferred population for regorafenib plus PD-1 inhibitor therapy: a real-world study

Background

Microsatellite stable (MSS) colorectal cancer (CRC) has been referred to as the "cold tumor" because of almost no response to anti-programmed death-1 (PD-1) antibody. A recent REGONIVO trial showed that regorafenib plus nivolumab had an encouraging efficacy in MSS metastatic CRC (mCRC). However, only a small subset of patients may benefit from the combination therapy. We aim to evaluate the efficacy and safety data of immune checkpoint inhibitors combined with regorafenib in refractory MSS mCRC and to discover biomarkers that can effectively stratify the beneficial patient population.

Methods

We retrospectively analyzed patients with MSS mCRC who received regorafenib combined with anti-PD-1 antibody therapy. The objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and status of gene mutation were reviewed and evaluated.

Results

Twenty-one patients received combination treatment. At a median treatment duration of 4 months, one patient achieved complete response, three patients achieved partial response, and two patients achieved stable disease as the best response. The ORR and DCR were 19% and 28.5% in the overall population, respectively. The median PFS was 4 months, and the median OS was 25 months. Only erbb2 receptor tyrosine kinase 2/erbb3 receptor tyrosine kinase 3 (ERBB2/ERBB3) mutation status was confirmed to be a potential predictive factor for effective treatment. In patients with ERBB2/ERBB3 mutation, ORR, DCR, and PFS exhibited significant improvements in comparison with that in wild-type patients. Grade 3 or higher treatment-related adverse events occurred in three patients (14.3%).

Conclusions

Regorafenib in combination with PD-1 inhibitor provides a feasible treatment regimen for refractory MSS mCRC with tolerated toxicity. Patients with ERBB2/ERBB3 mutation may be the preferred population for this combination regimen.

Low molecular weight heparin synergistically enhances the efficacy of adoptive and anti-PD-1-based immunotherapy by increasing lymphocyte infiltration in colorectal cancer

BACKGROUND

Immunotherapy, including adoptive cell therapy (ACT) and immune checkpoint inhibitors (ICIs), has a limited effect in most patients with colorectal cancer (CRC), and the efficacy is further limited in patients with liver metastasis. Lack of antitumor lymphocyte infiltration could be a major cause, and there remains an urgent need for more potent and safer therapies for CRC.

METHODS

In this study, the antitumoral synergism of low molecular weight heparin (LMWH) combined with immunotherapy in the microsatellite stable (MSS) highly aggressive murine model of CRC was fully evaluated.

RESULTS

Dual LMWH and ACT objectively mediated the stagnation of tumor growth and inhibition of liver metastasis, neither LMWH nor ACT alone had any antitumoral activity on them. The combination of LMWH and ACT obviously increased the infiltration of intratumor CD8+ T cells, as revealed by multiplex immunohistochemistry, purified CD8+ T-cell transfer assay, and IVIM in vivo imaging. Mechanistically, evaluation of changes in the tumor microenvironment revealed that LMWH improved tumor vascular normalization and facilitated the trafficking of activated CD8+ T cells into tumors. Similarly, LMWH combined with anti-programmed cell death protein 1 (PD-1) therapy provided superior antitumor activity as compared with the single PD-1 blockade in murine CT26 tumor models.

CONCLUSIONS

LMWH could enhance ACT and ICIs-based immunotherapy by increasing lymphocyte infiltration into tumors, especially cytotoxic CD8+ T cells. These results indicate that combining LMWH with an immunotherapy strategy presents a promising and safe approach for CRC treatment, especially in MSS tumors.

Case Report: Genetic and immune microenvironmental characteristics of a rectal cancer patient with MSS/PD-L1-negative recurrent hepatopulmonary metastasis who achieved complete remission after treatment with PD-1 inhibitor

Currently, microsatellite high instability (MSI-H)/mismatch repair protein deletion (dMMR) has become a crucial biomarker for utilizing immune checkpoint inhibitors in patients with advanced colorectal cancer (mCRC). However, the proportion of MSI-H/dMMR in advanced patients is only about 5% and mCRC patients with microsatellite stability (MSS)/proficient mismatch repair (pMMR) exhibit poor responses to immunotherapy. Although diverse immune combination therapy regimens have been examined in patients with advanced colorectal cancer who demonstrate MSS/pMMR, these approaches have not yielded favorable efficacy and only a limited proportion of patients have benefited, especially for advanced colorectal cancer patients with liver metastases. Therefore, the mechanism of benefit and potential biomarkers of immunotherapy in patients with MSS/pMMR mCRC deserve more in-depth exploration. Here, we present a case study of a rectal cancer patient with MSS and PD-L1-negative recurrent hepatopulmonary metastases who attained complete remission (CR) and sustained benefits with immunotherapy after systemic therapy had failed. The analysis of the patient's genetic and immune microenvironmental characteristics revealed that mutations in DNA damage repair (DDR) pathway genes and the existence of abundant tumor-infiltrating lymphocytes could contribute to his potential benefit.

Successful Treatment of pMMR MSS IVB Colorectal Cancer Using Anti-VEGF and Anti-PD-1 Therapy in Combination of Gut Microbiota Transplantation: A Case Report

Immune checkpoint inhibitors (ICI) have shown great promise in treating advanced or metastatic colorectal cancer (mCRC), especially for CRC patients with deficient mismatch repair (dMMR) and high microsatellite instability (MSI-H). For the remainder of CRC patients presenting with proficient mismatch repair (pMMR) and microsatellite stable (MSS) or low microsatellite instability (MSI-L), ICI showed a low-level response. This study describes a 57-year-old Chinese man diagnosed with pMMR MSS IVb CRC with liver metastasis. Primarily, the patient was administered two consecutive treatments, one composed of an anti-EGFR and modified FOLFOX6 and the other composed of an anti-VEGF and FOLFOXIRI. Due to severe chemotherapy side effects, the patient discontinued treatment and decided to take a third investigational treatment, where an anti-PD-1 and an anti-VEGF were given in combination with fecal microbiota transplantation (FMT) capsules. The patient achieved a partial response (PR), and the tumor size decreased to the extent amenable to surgical resection. After surgery, the patient achieved a pathological complete response (pCR). Patients with pMMR MSS or MSI-L hardly benefit from anti-PD-1 immunotherapy. This study indicated that, to a limited extent, FMT might improve the response to ICI for pMMR MSS CRC patients.

Indole-3-propionic acid alleviates sepsis-associated acute liver injury by activating pregnane X receptor

BACKGROUND

The morbidity and mortality of sepsis are extremely high, which is a major problem plaguing human health. However, current drugs and measures for the prevention and treatment of sepsis have little effect. Sepsis-associated acute liver injury (SALI) is an independent risk factor for sepsis, which seriously affects the prognosis of sepsis. Studies have found that gut microbiota is closely related to SALI, and indole-3-propionic Acid (IPA) can activate Pregnane X receptor (PXR). However, the role of IPA and PXR in SALI has not been reported.

METHODS

This study aimed to explore the association between IPA and SALI. The clinical data of SALI patients were collected and IPA level in feces was detected. The sepsis model was established in wild-type mice and PXR knockout mice to investigate the role of IPA and PXR signaling in SALI.

RESULTS

We showed that the level of IPA in patients' feces is closely related to SALI, and the level of IPA in feces has a good ability to identify and diagnose SALI. IPA pretreatment significantly attenuated septic injury and SALI in wild-type mice, but not found in knockout PXR gene mice.

CONCLUSIONS

IPA alleviates SALI by activating PXR, which reveals a new mechanism of SALI, and provides potentially effective drugs and targets for the prevention of SALI.

Regorafenib, Ipilimumab, and Nivolumab for Patients With Microsatellite Stable Colorectal Cancer and Disease Progression With Prior Chemotherapy: A Phase 1 Nonrandomized Clinical Trial

Importance

Immunotherapy combinations with activity in patients with microsatellite stable (MSS) metastatic colorectal cancer need to be identified.

Objective

To determine the recommended phase 2 dose (RP2D) of regorafenib, ipilimumab, and nivolumab (RIN) and evaluate its activity in an expansion cohort of patients with MSS metastatic colorectal cancer.

Design, Setting, and Participants

This nonrandomized clinical trial was a single-center 3 + 3 dose de-escalation study with an effectiveness expansion cohort at the RP2D. After the identification of the RP2D, a study amendment was executed to explore a regorafenib dose optimization strategy to mitigate skin-related toxic effects. Study enrollment occurred between May 12, 2020, and January 21, 2022. The trial was conducted at a single academic center. A total of 39 patients with MSS metastatic colorectal cancer whose disease progressed after standard chemotherapy and who had not received prior regorafenib or anti-programmed cell death protein 1 therapy were included.

Interventions

Patients received regorafenib daily for 21 days every 4 weeks; fixed-dose ipilimumab, 1 mg/kg, intravenously every 6 weeks; and fixed-dose nivolumab, 240 mg intravenously every 2 weeks. Patients were treated until progression, unacceptable toxic effects, or completion of 2 years of therapy.

Main Outcomes and Measures

The primary end point was RP2D selection. Secondary end points were safety and overall response rate (ORR) according to the Response Evaluation Criteria in Solid Tumours at the RP2D level.

Results

A total of 39 patients were enrolled, 23 (59.0%) were female, median age was 54 years (range, 25-75 years), 3 were Black (7.7%), and 26 were White (66.7%). No dose-limiting toxic effects were noted in the first 9 patients at the starting dose of RIN, with regorafenib dosed at 80 mg daily. No dose de-escalation was needed. This dose was declared the RP2D. Twenty more patients were enrolled at this level. The ORR, median progression-free survival (PFS), and overall survival (OS) in the RP2D cohort were 27.6%, 4 months (IQR, 2-9 months), and 20 months (IQR, 7 months to not estimable), respectively. For the 22 patients without liver metastases, the ORR, PFS, and OS were 36.4%, 5 months (IQR, 2-11), and greater than 22 months, respectively. A dose optimization cohort with regorafenib at 40 mg/d on cycle 1 and 80 mg/d on cycle 2 and beyond was associated with lower skin and immune toxic effects but had limited activity with stable disease for 5 of 10 patients as the best response.

Conclusions and Relevance

Results of this nonrandomized clinical trial suggest that RIN at the RP2D demonstrated interesting clinical activity in patients with advanced MSS colorectal cancer without liver metastases. These findings should be confirmed in randomized clinical trials.

Trial Registration

ClinicalTrials.gov Identifier: NCT04362839.

Metastatic sites and lesion numbers cooperated to predict efficacy of PD-1 inhibitor-based combination therapy for patients with metastatic colorectal cancer

BACKGROUND

Limited data have been used to evaluate the efficacy of immunotherapy in metastatic colorectal cancer (mCRC). Furthermore, potential markers that can be used to identify responding patients and to further improve efficacy have not been fully explored.

METHODS AND RESULTS

In our study, we included a total of 97 patients with mCRC, who each received programmed death-1 (PD-1) inhibitor-based combination therapy at our center. All 12 hypermutated patients benefited from immunotherapy, with median progression-free survival (mPFS) reaching 28.3 months, regardless of liver metastasis. The objective response rate (ORR) of non-hypermutated patients was 16.5% (14/85), with an mPFS of 4.0 months. For non-hypermutated patients, multivariate analysis revealed that the combination of liver metastasis and baseline lesion number significantly stratified response and survival. The lesion-based analysis indicated that the lymph node was the most responsive, followed by the peritoneum and lung, with liver metastasis being the least responsive. None of the patients (0/7) with negative programmed ligand-1 (PD-L1) expression responded, and positive PD-L1 expression may serve as a biomarker (mPFS 5.7 vs. 2.2 months, p = 0.002) that can be used to further guide treatment in non-hypermutated mCRC with liver metastasis (CRLMs).

CONCLUSION

Patients with hypermutated mCRC benefited significantly from immunotherapy, whereas the non-hypermutated cohort with liver metastasis and numerous lesions showed less benefit. The lesion sites reflected varying levels of efficacy, among which PD-L1 potentially cooperated to guide the immunotherapy of CRLMs.

The Influence of the Microbiome on Metastatic Colorectal Cancer

The microbiome (bacteria, viruses, and fungi) that exist within a patient's gastrointestinal tract and throughout their body have been increasingly understood to play a critical role in a variety of disease, including a number of cancer histologies. These microbial colonies are reflective of a patient's overall health state, their exposome, and germline genetics. In the case of colorectal adenocarcinoma, significant progress has been made in understanding the mechanism the microbiome plays beyond mere associations in both disease initiation and progression. Importantly, this improved understanding holds the potential to further identify the role these microbes play in colorectal cancer. We hope this improved understanding will be able to be leveraged in the future through either biomarkers or next-generation therapeutics to augment contemporary treatment algorithms through the manipulation of a patient's microbiome-whether through diet, antibiotics, prebiotics, or novel therapeutics. Here we review the role of the microbiome in the setting of patients with stage IV colorectal adenocarcinoma in both the development and progression or disease as well as response to therapeutics.

Vertical level of blood cell division cycle 42 predicts response and survival benefits to PD-1 inhibitor-based regimen in metastatic colorectal cancer patients

Cell division cycle 42 (CDC42) regulates the development of colorectal cancer (CRC) by modulating cancer malignant behaviors and facilitating immune escape. Hence, this study aimed to explore the correlation of blood CDC42 with treatment response and survival benefit to programmed cell death-1 (PD-1) inhibitor-based regimens in inoperable metastatic CRC (mCRC) patients. Fifty-seven inoperable mCRC patients who received PD-1 inhibitor-based regimens were recruited. The CDC42 in peripheral blood mononuclear cell (PBMC) was detected using RT-qPCR in inoperable mCRC patients at baseline and after 2-cycle treatment. Besides, PBMC CDC42 in 20 healthy controls (HCs) was also detected. CDC42 was higher in inoperable mCRC patients compared to HCs (p < 0.001). Elevated CDC42 was related to a higher performance status score (p = 0.034), multiple metastatic sites (p = 0.028), and the presence of liver metastasis (p = 0.035) in inoperable mCRC patients. During the 2-cycle treatment, CDC42 was reduced (p < 0.001). Higher CDC42 at baseline (p = 0.016) and after 2-cycle treatment (p = 0.002) were both linked with decreased objective response rate. CDC42 high at baseline was related to shorter progression-free survival (PFS) (p = 0.015) and overall survival (OS) (p = 0.050). Moreover, CDC42 high after 2-cycle treatment was also related to unfavorable PFS (p < 0.001) and OS (p = 0.001). After adjustment using multivariate Cox's analyses, CDC42 high after 2-cycle treatment independently related to shorter PFS (hazard ratio (HR): 4.129, p < 0.001), and CDC42 reduction ≤230% also independently correlated with shorter OS (HR: 4.038, p < 0.001). The longitudinal change of blood CDC42 during PD-1 inhibitor-based regimen estimates treatment response and survival in inoperable mCRC patients.

Challenges to addressing the unmet medical needs for immunotherapy targeting cold colorectal cancer

With the establishment of the immune surveillance mechanism since the 1950s, attempts have been made to activate the immune system for cancer treatment through the discovery of various cytokines or the development of antibodies up to now. The fruits of these efforts have contributed to the recognition of the 3^rd generation of anticancer immunotherapy as the mainstream of cancer treatment. However, the limitations of cancer immunotherapy are also being recognized through the conceptual establishment of cold tumors recently, and colorectal cancer (CRC) has become a major issue from this therapeutic point of view. Here, it is emphasized that non-clinical strategies to overcome the immunosuppressive environment and clinical trials based on these basic investigations are being made on the journey to achieve better treatment outcomes for the treatment of cold CRC.

Monitoring and Modulating Diet and Gut Microbes to Enhance Response and Reduce Toxicity to Cancer Treatment

The gut microbiome comprises a diverse array of microbial species that have been shown to dynamically modulate host immunity both locally and systemically, as well as contribute to tumorigenesis. In this review, we discuss the scientific evidence on the role that gut microbes and diet play in response and toxicity to cancer treatment. We highlight studies across multiple cancer cohorts that have shown an association between particular gut microbiome signatures and an improved response to immune checkpoint blockade, chemotherapy, and adoptive cell therapies, as well as the role of particular microbes in driving treatment-related toxicity and how the microbiome can be modulated through strategies, such as fecal transplant. We also summarize the current literature that implicate high fiber and ketogenic diets in improved response rates to immunotherapy and chemotherapy, respectively. Finally, we discuss the relevance of these findings in the context of patient care, advocate for a holistic approach to cancer treatment, and comment on the next frontier of targeted gut and tumor microbiome modulation through novel therapeutics, dietary intervention, and precision-medicine approaches.

Emerging roles of the gut microbiota in cancer immunotherapy

Gut microbiota represents a hidden treasure vault encompassing trillions of microorganisms that inhabit the intestinal epithelial barrier of the host. In the past decade, numerous in-vitro, animal and clinical studies have revealed the profound roles of gut microbiota in maintaining the homeostasis of various physiological functions, especially immune modulation, and remarkable differences in the configuration of microbial communities between cancers and healthy individuals. In addition, although considerable efforts have been devoted to cancer treatments, there remain many patients succumb to their disease with the incremental cancer burden worldwide. Nevertheless, compared with the stability of human genome, the plasticity of gut microbiota renders it a promising opportunity for individualized treatment. Meanwhile, burgeoning findings indicate that gut microbiota is involved in close interactions with the outcomes of diverse cancer immunotherapy protocols, including immune checkpoint blockade therapy, allogeneic hematopoietic stem cell transplantation, and chimeric antigen receptor T cell therapy. Here, we reviewed the evidence for the capacity of gut microflora to modulate cancer immunotherapies, and highlighted the opportunities of microbiota-based prognostic prediction, as well as microbiotherapy by targeting the microflora to potentiate anticancer efficacy while attenuating toxicity, which will be pivotal to the development of personalized cancer treatment strategies.

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.

Real-World Results of Raltitrexed Combined with S-1 and Bevacizumab in Heavily Pretreated Metastatic Colorectal Cancer

Purpose

Treatment options for refractory metastatic colorectal cancer (CRC) are scarce. This retrospective study aimed to evaluate the efficacy and safety of raltitrexed combined with S-1 and bevacizumab in patients with heavily pretreated metastatic CRC in a clinical real-world setting.

Patients and Methods

Records of patients with metastatic CRC refractory to standard therapies who initiated raltitrexed plus S-1 and bevacizumab from October 2017 to December 2021 were retrospectively reviewed at our institution. The study endpoints included median overall survival (OS), overall response rate (ORR), progression-free survival (PFS), disease control rate (DCR), and adverse events (AEs).

Results

Forty-four patients with metastatic CRC, who had previously undergone standard chemotherapy received the regimen comprising raltitrexed plus S-1 and bevacizumab. As of March 2022, the median follow-up was 23.2 months (95% confidence interval 15.8-30.6). The median OS and median PFS were 13.5 (95% CI 9.9-17.1) and 4.7 months (95% CI 3.6-5.8), respectively, with a 16-week PFS rate of 60.9%. Among 43 patients with measurable lesions, the ORR and DCR were 7.0% (3/43) and 65.1% (28/43), respectively. Patients without peritoneal metastases (P = 0.003, hazard ratio 0.160, 95% CI 0.048-0.531), lower carcinoembryonic antigen level (≤42.8 ng/mL) (P = 0.039, HR 0.382, 95% CI 0.153-0.952), and no previous treatment with both vascular endothelial growth factor inhibitors (VEGF) and S-1 (P = 0.020, HR 0.215, 95% CI 0.059-0.785) had better OS. The incidence of any grade of treatment-related AEs was 88.6%, most of which were mild to moderate, and no treatment-related deaths occurred.

Conclusion

Raltitrexed combined with S-1 and bevacizumab shows promising antitumor activity and safety and could be an alternative for patients with metastatic CRC who are refractory or intolerant to standard therapy.

Comparison of the efficacy and safety of fruquintinib and regorafenib in the treatment of metastatic colorectal cancer: A real-world study

Background

Fruquintinib and regorafenib have been approved for the third-line therapy of metastatic colorectal cancer (mCRC) in China. However, at present, there is a lack of head-to-head clinical trials on the comparison of efficacy and safety between the two drugs.

Materials and methods

The data of patients with mCRC who were treated with fruquintinib or regorafenib after the standard chemotherapy in Zhejiang Provincial People's Hospital from October 2018 to November 2021 were collected and analyzed. The primary endpoints were overall survival (OS), progression-free survival (PFS) and adverse events. The secondary endpoints were the appropriate sequence, objective remission rate (ORR) and disease control rate (DCR) of fruquintinib and regorafenib.

Results

A total of 105 patients were enrolled in this study. The ORR of fruquintinib group (n=55) and regorafenib group (n=50) were 6.1% and 2.0%; the DCR were 65.3% and 54.2%, respectively. There was no significant difference in median OS (mOS) and PFS (mPFS) between the two groups (mOS:14.2 vs12.0 months, p=0.057; mPFS:4.4 vs 3.5 months, p=0.150). Combined immunotherapy showed a synergistic effect. The mPFS and mOS of fruquintinib combined with anti-PD-1 therapy were longer than those of fruquintinib monotherapy (mPFS:5.9 vs 3.0 months, p=0.009; mOS:17.5 vs 11.3 months, p=0.008). The mOS of patients treated with regorafenib combined with anti-PD-1 therapy was 14.8 months higher than that of regorafenib monotherapy (p=0.045). When combined with anti-PD-1 therapy, the mPFS and mOS of fruquintinib was significantly longer than regorafenib (mPFS:5.9 vs 3.8 months, p=0.018; mOS:17.5 vs 14.8 months, p=0.044). In the treatment sequence, the OS of patients treated with regorafenib and then fruquintinib was significantly longer than that of the reverse treatment sequence (15.0 vs 8.3 months, p=0.019). The adverse reactions were generally similar, but the incidence of hand-foot syndrome of regorafenib was higher than that of fruquintinib, while fruquintinib was more prone to grade 3 hypertension.

Conclusion

Fruquintinib monotherapy showed better disease control rate and objective remission rate in the post-line therapy of metastasis colorectal cancer. Notably, the combination of PD-1 immunotherapy brought the additional effect, especially in the fruquintinib combined with anti-PD-1 therapy. Patients treated with regorafenib and then fruquintinib was significantly longer than that of the reverse treatment sequence. The toxicity of fruquintinib and regorafenib are similar.

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.

Colorectal cancer and gut microbiota studies in China

Colorectal cancer (CRC) is the third most common malignant tumor worldwide. The incidence and mortality rates of CRC have been increasing in China, possibly due to economic development, lifestyle, and dietary changes. Evidence suggests that gut microbiota plays an essential role in the tumorigenesis of CRC. Gut dysbiosis, specific pathogenic microbes, metabolites, virulence factors, and microbial carcinogenic mechanisms contribute to the initiation and progression of CRC. Gut microbiota biomarkers have potential translational applications in CRC screening and early diagnosis. Gut microbiota-related interventions could improve anti-tumor therapy's efficacy and severe intestinal toxic effects. Chinese researchers have made many achievements in the relationship between gut microbiota and CRC, although some challenges remain. This review summarizes the current evidence from China on the role of gut microbiota in CRC, mainly including the gut microbiota characteristics, especially Fusobacterium nucleatum and Parvimonas micra, which have been identified to be enriched in CRC patients; microbial pathogens such as F. nucleatum and enterotoxigenic Bacteroides fragilis, and P. micra, which Chinese scientists have extensively studied; diagnostic biomarkers especially F. nucleatum; therapeutic effects, including microecological agents represented by certain Lactobacillus strains, fecal microbiota transplantation, and traditional Chinese medicines such as Berberine and Curcumin. More efforts should be focused on exploring the underlying mechanisms of microbial pathogenesis of CRC and providing novel gut microbiota-related therapeutic and preventive strategies.

Efficacy of regorafenib combined with PD-1 inhibitors in elderly patients with advanced metastatic colorectal cancer

OBJECTIVE

This is the first clinical study that wants to investigate the treatment patterns, clinical outcomes, and prognostic factors of regorafenib plus PD-1 inhibitors therapy in Chinese elderly patients with advanced colorectal cancer.

METHODS

A cohort of metastatic colorectal cancer patients 60 years or older who received treatment with regorafenib combined with PD-1 inhibitors was included in our analysis. The endpoints included overall survival (OS), progression-free survival (PFS), and prognostic factors.

RESULTS

In total, 24 patients were enrolled with the median age of 68 years, and 62.5% were female. The median OS and PFS were 15.03 months (95% CI 7.0-23.0) and 4.0 months (95% CI 1.8-6.2), respectively. The objective response rate was 8.3%, and the disease control rate was 70.8%. Patients previously treated with regorafenib had a longer median PFS than those without (6.3 versus 2.8 months). In terms of final daily doses, it showed a trend toward better PFS (median PFS was 10.0 months) in high-dose group (daily dose above 80 mg of regorafenib) compared to low-dose group (daily dose no more than 80 mg of regorafenib) (median PFS was 3.5 months).

CONCLUSIONS

This real-world evidence confirms that Chinese elderly patients with advanced colorectal cancer may benefit from the treatment of regorafenib combined with PD-1 inhibitors, similarly with this combination therapy strategies in all age patients.

Predictive biomarkers of colon cancer immunotherapy: Present and future

Immunotherapy has revolutionized colon cancer treatment. Immune checkpoint inhibitors (ICIs) have shown clinical benefits for colon cancer patients, especially those with high microsatellite instability (MSI-H). In 2020, the US Food and Drug Administration (FDA)-approved ICI pembrolizumab as the first-line treatment for metastatic MSI-H colon cancer patients. Additionally, neoadjuvant immunotherapy has presented efficacy in treating early-stage colon cancer patients. Although MSI has been thought of as an effective predictive biomarker for colon cancer immunotherapy, only a small proportion of colon cancer patients were MSI-H, and certain colon cancer patients with MSI-H presented intrinsic or acquired resistance to immunotherapy. Thus, further search for predictive biomarkers to stratify patients is meaningful in colon cancer immunotherapy. Except for MSI, other biomarkers, such as PD-L1 expression level, tumor mutation burden (TMB), tumor-infiltrating lymphocytes (TILs), certain gut microbiota, ctDNA, and circulating immune cells were also proposed to be correlated with patient survival and ICI efficacy in some colon cancer clinical studies. Moreover, developing new diagnostic techniques helps identify accurate predictive biomarkers for colon cancer immunotherapy. In this review, we outline the reported predictive biomarkers in colon cancer immunotherapy and further discuss the prospects of technological changes for biomarker development in colon cancer immunotherapy.

Epigenetic-related gene mutations serve as potential biomarkers for immune checkpoint inhibitors in microsatellite-stable colorectal cancer

Background

Combination therapy with immune checkpoint inhibitors (ICIs) may benefit approximately 10-20% of microsatellite-stable colorectal cancer (MSS-CRC) patients. However, there is a lack of optimal biomarkers. This study aims to understand the predictive value of epigenetic-related gene mutations in ICIs therapy in MSS-CRC patients.

Methods

We analyzed DNA sequences and gene expression profiles from The Cancer Genome Atlas (TCGA) to examine their immunological features. The Harbin Medical University Cancer Hospital (HMUCH) clinical cohort of MSS-CRC patients was used to validate the efficacy of ICIs in patients with epigenetic-related gene mutations (Epigenetic_Mut).

Results

In TCGA, 18.35% of MSS-CRC patients (78/425) had epigenetic-related gene mutations. The Epigenetic_Mut group had a higher tumor mutation burden (TMB) and frameshift mutation (FS_mut) rates. In all MSS-CRC samples, Epigenetic_Mut was elevated in the immune subtype (CMS1) and had a strong correlation with immunological features. Epigenetic_Mut was also associated with favorable clinical outcomes in MSS-CRC patients receiving anti-PD-1-based therapy from the HMUCH cohort. Using immunohistochemistry and flow cytometry, we demonstrated that Epigenetic_Mut samples were associated with increased anti-tumor immune cells both in tumor tissues and peripheral blood.

Conclusion

MSS-CRC patients with epigenetic regulation impairment exhibit an immunologically active environment and may be more susceptible to treatment strategies based on ICIs.

Regorafenib with or without a programmed cell death protein 1 antibody as third‐line treatment for microsatellite stable metastatic colorectal cancer

BACKGROUND

Although the use of regorafenib plus nivolumab demonstrates promising outcomes in patients with refractory microsatellite stable (MSS) metastatic colorectal cancer (mCRC), this effect has not been substantiated in other studies. Moreover, a comparison between the outcomes of regorafenib and programmed cell death protein 1 (PD-1) antibody combination therapy and regorafenib monotherapy remains unexplored. In this study, we aimed to assess whether regorafenib and PD-1 antibody combination therapy is superior to regorafenib monotherapy as a third-line treatment for MSS mCRC.

METHODS

Patients with MSS mCRC who received regorafenib and PD-1 antibody or regorafenib monotherapy as third-line treatment were eligible for inclusion.

RESULTS

In total, 179 patients were enrolled, of which 84 were administered regorafenib combined with a PD-1 antibody and 95 were administered regorafenib monotherapy. Patients administered regorafenib combined with a PD-1 antibody had similar progression-free survival (PFS) as those on regorafenib monotherapy (median PFS was 2.4 months and 1.9 months, respectively, p = 0.086). The administration of regorafenib combined with a PD-1 antibody resulted in significantly longer PFS than that seen with regorafenib monotherapy in both male (5.2 months vs. 2.4 months, p = 0.001) and female (3.9 months vs. 1.8 months, p = 0.037) patients without liver metastasis. Female patients with liver metastasis who were administered regorafenib combined with a PD-1 antibody had shorter PFS than those administered regorafenib monotherapy (1.8 months vs. 2.0 months, p = 0.030).

CONCLUSION

Liver metastasis and sex are predictors of survival benefit following the addition of a PD-1 antibody to regorafenib in patients with MSS mCRC.

Efficacy and safety of anti-PD-1/PD-L1 therapy in the treatment of advanced colorectal cancer: a meta-analysis

Background

Immune checkpoint inhibitors have shown promise in microsatellite instability-high/mismatch repair deficient (MSI-H/dMMR) advanced colorectal cancer (CRC) immunotherapy, and many clinical trials have been conducted.

Objective

To evaluate the efficacy and safety of PD-1/PD-L1 inhibitors in advanced CRC.

Method

PubMed, Web of Science, Embase, and The Cochrane Library were searched for relevant studies up to September 2021. A retrospective cross-sectional data analysis was performed and Stata 16 software was used for analyses.

Results

Sixteen studies including 1503 patients were analyzed. The objective response rate (ORR) of anti-PD-1/PD-L1 was 23% (95% CI 0.14, 0.31); the overall 1-year survival rate (OSR) was 57% (95% CI 0.42, 0.73). The ORR of MSI-H/dMMR advanced CRC was 37% (95% CI 0.25, 0.48) and that of microsatellite stable/mismatch repair proficient (MSS/pMMR) disease was 11% (95% CI 0.06, 0.16). The ORR was 42% in the BRAF mutant subgroup and 19% in the RAS mutant group. The ORR was 14% in the PD-L1 ( +) subgroup and 32% in the PD-L1(-) subgroup. The rate of adverse effects was 85% (95% CI 0.80, 0.91).

Conclusion

Anti-PD-1/PD-L1 therapy in MSI-H/dMMR advanced CRC was associated with improved survival. Anti PD-1/PD-L1 combined with antiangiogenic drugs, targeted agents, or chemotherapy might be effective in MSS mCRC. Immunotherapy was effective for the BRAF mutant and KRAS/NRAS(RAS) mutant CRC. Low expression of PD-L1 was a potential predictive marker for positive response and outcome. The high incidence of adverse events at 85% was worthy of further investigation. Further analysis with a higher number of high-quality studies is needed to verify the conclusions.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12876-022-02511-7.

The Interplay between Anti-Angiogenics and Immunotherapy in Colorectal Cancer

Simple Summary

Colorectal cancer is a frequent and lethal neoplasm. The tumor often creates new vessels to grow and spread—a process called ‘angiogenesis’. Therefore, drugs blocking angiogenesis are effective against this malignancy. On the other side, immune checkpoint inhibitors, which unleash the immune system to fight against tumors, have limited efficacy in patients carrying instability of DNA regions called microsatellites. However, there is an interaction between angiogenic factors and the immune system. This gives a chance to combine anti-angiogenic agents and immune checkpoint inhibitors to improve the efficacy of treating this malignancy.

Abstract

Angiogenesis, a hallmark of cancer, plays a fundamental role in colorectal cancer (CRC). Anti-angiogenic drugs and chemotherapy represent a standard of care for treating metastatic disease. Immune checkpoint inhibitors (ICIs) have changed the therapeutic algorithm of many solid tumors. However, the efficacy of ICIs is limited to mCRC patients carrying microsatellite instability (MSI-H), which represent approximately 3–5% of mCRC. Emerging evidence suggests that anti-angiogenic drugs could exhibit immunomodulatory properties. Thus, there is a strong rationale for combining anti-angiogenics and ICIs to improve efficacy in the metastatic setting. Our review summarizes the pre-clinical and clinical evidence regarding the combination of anti-angiogenics and ICIs in mCRC to deepen the possible application in daily clinical practice.

Microsatellite stable metastatic colorectal cancer without liver metastasis may be preferred population for regorafenib or fruquintinib plus sintilimab as third-line or above therapy:A real-world study

Objectives

The antitumor activity of nivolumab plus regorafenib in colorectal cancer from a phase Ib REGONIVO study is encouraging. The present study was conducted to evaluate the efficacy and safety of regorafenib or fruquintinib plus sintilimab as third-line or above therapy in patients with microsatellite stable (MSS) metastatic colorectal cancer.

Methods

Patients with MSS metastatic colorectal cancer who have failed from prior treatment and received regorafenib or fruquintinib plus sintilimab as third-line or above therapy from January 2019 to December 2020 were prospectively analyzed based on real-world clinical practice. The primary end point was progression free survival (PFS). Secondary end points included objective response rate (ORR), disease control rate (DCR), overall survival (OS), and safety.

Results

42 patients received regorafenib plus sintilimab(RS), and the other 30 patients received fruquintinib plus sintilimab(FS). In the general population, the ORR and DCR were 13.9% and 70.8%, and the median PFS and OS was 4.2(95% CI=2.9-5.5) and 10.5 (95% CI=8.6-12.4) months, respectively. There were no statistically significant differences between RS and FS group in PFS (3.5(2.2-4.8) vs. 5.5(3.5-7.5) months, P=0.434) and OS (11.0(7.0-15.0) vs. 10.5(3.8-17.2) months, P=0.486). Subgroup analysis suggested that patients without liver metastasis responded well to this combination regimen (ORR: 21.4% vs. 9.1%) and obtained better OS (26(8.8-43.2) vs. 10.0(7.4-12.6) months, P=0.016). The incidence of Grade 3-4 adverse events (AEs) was 15.3% and the toxicities were generally tolerable and manageable.

Conclusions

Regorafenib or fruquintinib plus sintilimab as third-line or above therapy provide a feasible treatment regimen for MSS metastatic colorectal cancer with tolerated toxicity. Patients without liver metastasis may be the preferred population for this combination regimen.

The Crosstalk between Microbiome and Immunotherapeutics: Myth or Reality

The gut microbiome refers to microorganisms and their genetic material influencing local and systemic inflammation. Inflammation is known to contribute to cancer development, progression, and treatment. Evidence suggests that modulating the gut microbiome may affect responses to various cancer therapies. The gut microbiota has been suggested to have an impact on immunotherapy efficacy, especially the currently widely used immune checkpoint inhibitors in various malignancies. Microbial interventions like fecal microbiota transplantation, various probiotics, or even antibiotics can increase or decrease the tumor’s sensitivity to immunotherapy. However, not all tumors react in the same manner, highlighting the tumor microenvironment heterogeneity across tumor types and the influence this has on the crosstalk between the microbiome and therapy outcomes. In this study, we intend to review the association between the gut microbiota and immunotherapy response in cancer patients and the factors regulating this interaction.

Immunomodulatory effects of regorafenib: Enhancing the efficacy of anti-PD-1/PD-L1 therapy

Anti-PD-1/PD-L1 therapy has shown significant benefits in the treatment of a variety of malignancies. However, not all cancer patients can benefit from this strategy due to drug resistance. Therefore, there is an urgent need for methods that can effectively improve the efficacy of anti-PD-1/PD-L1 therapy. Combining anti-PD-1/PD-L1 therapy with regorafenib has been demonstrated as an effective method to enhance its therapeutic effect in several clinical studies. In this review, we describe common mechanisms of resistance to anti-PD-1/PD-L1 therapy, including lack of tumor immunogenicity, T cell dysfunction, and abnormal expression of PD-L1. Then, we illustrate the role of regorafenib in modifying the tumor microenvironment (TME) from multiple aspects, which is different from other tyrosine kinase inhibitors. Regorafenib not only has immunomodulatory effects on various immune cells, but can also regulate PD-L1 and MHC-I on tumor cells and promote normalization of abnormal blood vessels. Therefore, studies on the synergetic mechanism of the combination therapy may usher in a new era for cancer treatment and help us identify the most appropriate individuals for more precise treatment.

Efficacy, safety and predictors of combined fruquintinib with programmed death-1 inhibitors for advanced microsatellite-stable colorectal cancer: A retrospective study

Background

Research findings have revealed that combining anti-angiogenesis inhibitors with programmed death-1(PD-1) inhibitors can reverse the immunosuppressive tumor microenvironment and enhance the antitumor immune response. To explore the therapeutic options for breaking immune tolerance in microsatellite stability (MSS) or mismatch repair-proficiency (pMMR) advanced colorectal cancer (CRC), we assessed the efficacy, safety and predictors of the fruquintinib and PD-1 inhibitors combination in patients with MSS/pMMR advanced CRC in a real-world environment.

Methods

We conducted a single-center retrospective study by collecting relevant data on patients with MSS/pMMR advanced CRC who received fruquintinib coupled with PD-1 inhibitors in the First Affiliated Hospital of Zhengzhou University between August 2019 and November 2021, focusing on progression-free survival.

Results

We enrolled 110 eligible patients in this study between August 2019 and November 2021. At the deadline (January 20, 2022), 13 patients had objective responses. The objective response rate was 11.8% (13/110, 95% confidence interval [CI]: 6.4-18.2), the disease control rate was 70.0% (82/110, 95% CI: 60.9-78.2), and the progression-free survival was 5.4 months (95% CI: 4.0-6.8). Liver metastases (hazard ratio [HR]: 0.594, 95% CI: 0.363-0.973, P<0.05), alkaline phosphatase elevation (ALP>160U/L) (HR: 0.478, 95%CI: 0.241-0.948, P<0.05), fibrinogen elevation (FIB>4g/L) (HR: 0.517, 95% CI: 0.313-0.855, P<0.05), and an increase in the ALP level from the baseline after treatment (HR: 1.673, 95% CI: 1.040-2.690, P<0.05) were negative predictors of the progression-free survival. A total of 101 of 110 patients experienced treatment-related adverse events, including 14 who experienced grade 3 or above treatment-related adverse events, and no treatment-related deaths occurred. Hypertension was the most frequently encountered grade 3 treatment-related adverse event.

Conclusion

Fruquintinib combined with PD-1 inhibitors has antitumor activity and manageable safety in treating patients with MSS/pMMR advanced CRC. Liver metastases, ALP level and FIB level might be a prediction of the patient response to this therapy.

Phase II study of durvalumab (anti-PD-L1) and trametinib (MEKi) in microsatellite stable (MSS) metastatic colorectal cancer (mCRC)

Background

Monotherapy with immune checkpoint blockade is ineffective for patients (pts) with microsatellite stable (MSS) metastatic colorectal cancer (mCRC). This study investigates whether the combination of trametinib (T) with durvalumab (D) can alter the immune tumor microenvironment (TME) by successfully priming and activating T-cells.

Methods

Open-label, single-center, phase II trial with primary endpoint of immune-related response rate for combination of T+D in refractory MSS mCRC pts (NCT03428126). T is 2 mg/day orally starting 1 week prior to D, which is given 1500 mg intravenously every 4 weeks. Simon 2-stage design used to enroll 29 pts into first stage, requiring a response in two or more pts to proceed to stage 2. Tumor biopsies were collected at baseline (BL) and early on-treatment (OT) at week 4.

Results

Twenty nine treated pts include 48% females, median age 48 years (range 28–75), and median prior therapies 2 (range 1–5). No grade (G) 4 or 5 treatment-related adverse events (TRAE). The most common TRAE of any grade was acneiform rash, 17% being G3. One of 29 pts had confirmed partial response (PR) lasting 9.3 months (mo) for an overall response rate of 3.4%. Seven pts had stable disease (SD) and five pts (1 PR, 4 SD) demonstrated decrease in total carcinoembryonic antigen ng/mL (best percentage reduction: 94%, 95%, 42%, 34%, and 22%, respectively). Median progression-free survival was 3.2 mo (range 1.1–9.3 months). Three pts with both liver and lung metastases demonstrated discrepant responses in which clinical benefit was present in the lung metastases but not liver metastases. Comparison of BL and 4-week OT tumor tissue flow cytometry demonstrated no changes in T-cell infiltration but upregulation expression of PD-1 and Tim3 on CD8 T cells. However, expression of PD-1 and Tim3 as single markers and as coexpressed markers was observed to increase OT relative to BL (p=0.03, p=0.06 and p=0.06, respectively).

Conclusions

T+D demonstrated acceptable tolerability in pts with refractory MSS mCRC. The response rate in the first stage of the study did not meet efficacy criteria to proceed to the second stage. Specific site of metastatic disease may impact outcomes in novel immunotherapy combination trials.

Trial registration number

NCT03428126.

Exploring immunotherapy in colorectal cancer

Chemotherapy combined with or without targeted therapy is the fundamental treatment for metastatic colorectal cancer (mCRC). Due to the adverse effects of chemotherapeutic drugs and the biological characteristics of the tumor cells, it is difficult to make breakthroughs in traditional strategies. The immune checkpoint blockades (ICB) therapy has made significant progress in the treatment of advanced malignant tumors, and patients who benefit from this therapy may obtain a long-lasting response. Unfortunately, immunotherapy is only effective in a limited number of patients with microsatellite instability-high (MSI-H), and segment initial responders can subsequently develop acquired resistance. From September 4, 2014, the first anti-PD-1/PD-L1 drug Pembrolizumab was approved by the FDA for the second-line treatment of advanced malignant melanoma. Subsequently, it was approved for mCRC second-line treatment in 2017. Immunotherapy has rapidly developed in the past 7 years. The in-depth research of the ICB treatment indicated that the mechanism of colorectal cancer immune-resistance has become gradually clear, and new predictive biomarkers are constantly emerging. Clinical trials examining the effect of immune checkpoints are actively carried out, in order to produce long-lasting effects for mCRC patients. This review summarizes the treatment strategies for mCRC patients, discusses the mechanism and application of ICB in mCRC treatment, outlines the potential markers of the ICB efficacy, lists the key results of the clinical trials, and collects the recent basic research results, in order to provide a theoretical basis and practical direction for immunotherapy strategies.

Regorafenib in Refractory Metastatic Colorectal Cancer: A Multi-Center Retrospective Study

Background

Regorafenib improves progression-free survival (PFS) and overall survival (OS) in patients with refractory metastatic colorectal cancer (mCRC). Here, we report the treatment patterns of regorafenib in the third- or late-line setting for mCRC in four centers in China.

Patients and Methods

Patients with refractory mCRC in four centers in China administered regorafenib from February 1, 2018 to June 31, 2021 were enrolled. Patients were grouped into 3 cohorts, namely, the monotherapy (regorafenib alone), chemo (regorafenib plus chemotherapy), and immune [regorafenib plus anti-PD1 (programmed cell death 1) antibodies] groups. Demographic, clinical, survival and safety data were retrospectively analyzed.

Results

A total of 177 patients were included in this study. Of them, 116 (65.5%) were treated with regorafenib alone, while 28 (15.9%) and 33 (18.6%) were administered regorafenib plus chemotherapy and anti-PD1 antibodies, respectively. The median followed-up time was 9.2 months. The disease control rate (DCR) was 40.7%. The median PFS (mPFS) was 2.43 months and the median OS (mOS) was 12.2 months. The immune group had longer median PFS (3.5 m vs. 2.2 m, p = 0.043) compared with the monotherapy group. Patients administered regorafenib plus chemotherapy had longer median OS (15.9 m vs. 8.4 m, p = 0.032) compared with the monotherapy group. Patients who began regorafenib treatment at 120 mg had longer median PFS and OS compared with those who began at 80 mg (PFS: 3.7 m vs. 2.0 m; p <0.001; OS: 13.4 m vs. 10.2 m; p = 0.005). Patients with a final dose of 120 mg had longer median PFS and OS compared with the 80 mg or less group (PFS: 5.0 m vs. 2.3 m; p = 0.045; OS: UR (unreach) vs. 10.9 m; p = 0.003). There were 87.0% (154/177) patients who experienced AEs. Three groups had similar rates of AEs (86.2% vs. 89.3% vs. 87.9%; p = 0.89).

Conclusion

Patients administered regorafenib alone or regorafenib in combination with other agents were relieved to some extent, with a disease control rate of 40.7%. Regorafenib plus anti-PD1 antibodies showed better PFS, while regorafenib plus chemotherapy had the most benefit in OS. There was no significant difference among three groups in terms of AEs.

Toripalimab: the First Domestic Anti-Tumor PD-1 Antibody in China

Toripalimab (Tuoyi™) is a selective, recombinant, humanized monoclonal antibody against programmed death protein 1 (PD-1) developed by Shanghai Junshi Bioscience Co., Ltd. Toripalimab is able to bind to PD-1 and block the interaction with its ligands. The binding of toripalimab to PD-1 is mainly attributed to the heavy chain of the former and the FG loop of the latter. Toripalimab received a conditional approval in China for the treatment of melanoma (second-line) in December, 2018. It has also received approvals to treat nasopharyngeal carcinoma (first-line and third-line) and urothelial carcinoma (second-line) in 2021. Additionally, several orphan drug designations were granted to toripalimab by the US Food and Drug Administration. Toripalimab has exhibited primary anti-tumor effects in tumors such as melanoma, lung cancer, digestive tract tumors, hepatobiliary and pancreatic tumors, neuroendocrine neoplasms, nasopharyngeal carcinoma and urothelial carcinoma. It showed a satisfactory anti-tumor effect and long-term survival benefits in Chinese melanoma patients, while the combination of axitinib with toripalimab exhibited an impressive result in metastatic mucosal melanoma. As a checkpoint inhibitor, toripalimab was generally well-tolerated in the enrolled patients. Due to different study populations, comparisons could not be made directly between toripalimab and other drugs in most cases. Nevertheless, the introduction of toripalimab may offer a valuable choice for decision-making in the treatment of tumors in the future.

Preliminary Efficacy and Safety of Camrelizumab in Combination With XELOX Plus Bevacizumab or Regorafenib in Patients With Metastatic Colorectal Cancer: A Retrospective Study

Background

For a majority of patients with metastatic colorectal cancer (mCRC) with MS stable (MSS) or mismatch repair proficient (pMMR), the role of immunotherapy is undetermined. This study investigated the efficacy and safety of camrelizumab when added to XELOX chemotherapy plus bevacizumab or regorafenib as first-line therapy for mCRC.

Materials and Methods

Medical records of mCRC patients who received camrelizumab and XELOX plus bevacizumab or regorafenib at the First Hospital of Quanzhou Affiliated to Fujian Medical University between June 1, 2019, and April 30, 2021, were retrospectively collected. The objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and side effects of the drug were recorded and reviewed.

Results

Twenty-five eligible patients received combination therapy, including bevacizumab in 19 patients and regorafenib in 6. Twenty-one patients had pMMR/MSS and one MSI-H. Of the 25 patients who could be evaluated for efficacy, 18 (72%) achieved PR, 6 (24%) achieved SD, and 1 (4%) achieved PD. The ORR and DCR were 72% (18/25) and 96% (24/25), respectively. The median progression-free survival (PFS) was 11.2 months (95% CI 8.9–13.9), and OS had not yet been reached. The combination regimen of regorafenib in six (24%) patients was unassociated with treatment outcomes. Most AEs were either grade 1 or 2, and treatment-related grade 3 toxicities were observed in 8/25 (32%) patients.

Conclusion

Camrelizumab combined with XELOX plus bevacizumab or regorafenib was feasible, producing high rates of responses as first-line therapy in unselected Chinese patients with MSS mCRC. The toxicities were generally tolerable and manageable. Prospective randomized trials with large sample sizes are needed to evaluate these findings.