Phase I/II study of PexaVec in combination with immune checkpoint inhibition in refractory metastatic colorectal cancer

Precision oncolytic viral therapy in colorectal cancer: Genetic targeting and immune modulation for personalized treatment (Review)

Colorectal cancer (CRC) is a leading health issue and treatments to eradicate it, such as conventional chemotherapy, are non‑selective and come with a number of complications. The present review focuses on the relatively new area of precision oncolytic viral therapy (OVT), with genetic targeting and immune modifications that offer a new future for CRC treatment. In the present review, an overview of the selection factors that are considered optimal for an oncolytic virus, mechanisms of oncolysis and immunomodulation applied to the OVT, as well as new strategies to improve the efficacy of this method are described. Additionally, cause‑and‑effect relationships are examined for OVT efficacy, mediated by the tumor microenvironment, and directions for genetic manipulation of viral specificity are explored. The possibility of synergy between OVT and immune checkpoint inhibitors and other treatment approaches are demonstrated. Incorporating the details of the present review, biomarker‑guided combination therapies in precision OVT for individualized CRC care, significant issues and future trends in this required area of medicine are highlighted. Increasingly, OVT is leaving the experimental stage and may become routine practice; it provides a new perspective on overcoming CRC and highlights the importance of further research and clinical work.

Molecular Alterations in TP53, WNT, PI3K, TGF-Beta, and RTK/RAS Pathways in Gastric Cancer Among Ethnically Heterogeneous Cohorts

BACKGROUND/OBJECTIVES

Gastric cancer (GC) remains a leading cause of cancer-related mortality worldwide, with significant racial and ethnic disparities in incidence, molecular characteristics, and patient outcomes. However, genomic studies focusing on Hispanic/Latino (H/L) populations remain scarce, limiting our understanding of ethnicity-specific molecular alterations. This study aims to characterize pathway-specific mutations in TP53, WNT, PI3K, TGF-Beta, and RTK/RAS signaling pathways in GC and compare mutation frequencies between H/L and Non-Hispanic White (NHW) patients. Additionally, we evaluate the impact of these alterations on overall survival using publicly available datasets.

METHODS

We conducted a bioinformatics analysis using publicly available GC datasets to assess mutation frequencies in TP53, WNT, PI3K, TGF-Beta, and RTK/RAS pathway genes. A total of 800 patients were included in the analysis, comprising 83 H/L patients and 717 NHW patients. Patients were stratified by ethnicity (H/L vs. NHW) to evaluate differences in mutation prevalence. Chi-squared tests were performed to compare mutation rates between groups and Kaplan-Meier survival analysis was used to assess overall survival differences based on pathway alterations among both H/L and NHW patients.

RESULTS

Significant differences were observed in the TP53 pathway and related genes when comparing GC in H/L patients to NHW patients. TP53 mutations were less prevalent in H/L patients (9.6% vs. 19%, p = 0.03). Borderline significant differences were noted in the WNT pathway when comparing GC in H/L patients to NHW GC patients, with WNT alterations more frequent in H/L GC (8.4% vs. 4%, p = 0.08) and APC mutations being significantly higher (3.6% vs. 0.8%, p = 0.05). Although alterations in PI3K, TGF-Beta, and RTK/RAS pathways were not statistically significant, borderline significance was observed in genes related to these pathways, including EGFR (p = 0.07), FGFR1 (p = 0.05), FGFR2 (p = 0.05), and PTPN11 (p = 0.05) in the PI3K pathway and SMAD4 (p = 0.08) in the TGF-Beta pathway. Survival analysis revealed no significant differences among H/L patients. However, NHW patients with TP53 and PI3K pathway alterations exhibited significant differences in overall survival, while those without TGF-Beta pathway alterations also showed a significant survival impact. In contrast, WNT pathway alterations were not associated with significant survival differences. These findings suggest that TP53, PI3K, and TGF-Beta pathway disruptions may have distinct prognostic implications in NHW GC patients.

CONCLUSIONS

This study provides one of the first ethnicity-focused analyses of TP53, WNT, PI3K, TGF-Beta, and RTK/RAS pathway alterations in GC, revealing significant racial/ethnic differences in pathway dysregulation. The findings suggest that TP53 and WNT alterations may play a critical role in GC among H/L patients, while PI3K and TGF-Beta alterations may have greater prognostic significance in NHW patients. These insights emphasize the need for precision medicine approaches that account for genetic heterogeneity and ethnicity-specific pathway alterations to improve cancer care and outcomes for underrepresented populations.

An updated review on immune checkpoint inhibitor-induced colitis: epidemiology, pathogenesis, treatment strategies, and the role of traditional Chinese medicine

Immune checkpoint inhibitor-induced colitis (irColitis) is a common and severe adverse reaction to immune checkpoint inhibitors (ICIs), significantly impacting the treatment outcomes and quality of life of cancer patients. Epidemiological studies indicate that the incidence of irColitis is associated with factors such as the type of ICIs, the patient's gender, age, and medical history. Although the exact pathophysiology remains unclear, irColitis is thought to be related to immune system activation and dysregulation, gut microbiota imbalance, and impaired epithelial barrier function. This review summarized the epidemiology, clinical presentation, diagnostic criteria, and pathogenesis of irColitis. Additionally, the standard and novel therapeutic strategies of irColitis, including corticosteroids, biologics, and gut microbiota interventions, more importantly the potential and application of Traditional Chinese Medicine (TCM). Future researches call for deeper mechanistic investigations, the development of biomarkers, and reveal the integration of TCM therapies within individual immunotherapy frameworks.

A Multiple-Model-Informed Drug-Development Approach for Optimal Regimen Selection of an Oncolytic Virus in Combination With Pembrolizumab

The antitumor efficacy of an intratumoral injection of a genetically engineered oncolytic vaccinia virus carrying human IL-7 and murine IL-12 genes (hIL-7/mIL-12-VV) was demonstrated in CT26.WT-bearing mice. In the CT26.WT-bearing mouse model, the efficacy of the combination of hIL-7/mIL-12-VV plus the anti-programmed cell death protein (PD)-1 antibody was determined to be correlated with the timing of administration: greater efficacy was observed when hIL-7/mIL-12-VV was administered before the anti-PD-1 agent instead of simultaneous administration. To identify an optimal dosing regimen for first-in-human clinical trials, a multiple model-informed drug-development (MIDD) approach was used through development of a quantitative systems pharmacology (QSP) model and an agent-based model (ABM). All models were built and verified using available literature and preclinical study data. Multiple dosing scenarios were explored using virtual populations by altering the interval between hIL-7/hIL-12-VV and pembrolizumab administration. In contrast with observations from preclinical studies, both the QSP and the ABM models demonstrated no antagonistic effect on the dose-dependent antitumor efficacy of hIL-7/hIL-12-VV by pembrolizumab in simulations of clinical therapy. Based on the MIDD strategy, it was recommended that the highest dose of hIL-7/hIL-12-VV and pembrolizumab should be administered on the same day, but with pembrolizumab administration following hIL-7/hIL-12-VV administration. Multiple different modeling approaches uniquely supported and informed the first-in-human clinical trial design by guiding the optimal dose and regimen selection.

Synergistic effects of immunotherapy and adjunctive therapies in prostate cancer management

In recent years, cancer immunotherapy has received widespread attention due to significant tumor clearance in some malignancies. Various immunotherapy approaches, including vaccines, immune checkpoint inhibitors, oncolytic virotherapy, bispecific T cell engagers, and adoptive T cell transfer, have completed or are undergoing clinical trials for prostate cancer. Despite immune checkpoint blockade's extraordinary effectiveness in treating a variety of cancers, targeted prostate cancer treatment using the immune system is still in its infancy. Multiple factors including the heterogeneity of prostate cancer, the cold tumor microenvironment, and a low level of neoantigens, contribute to the poor immunotherapy response. Significant effort is being devoted to improving immune-based prostate cancer therapy. Recently, several key discoveries demonstrate that prostate cancer immunotherapy agents may be used to promise better prognosis for patients as part of combination strategies with other agents targeting tumor-associated immune mechanism of resistance. Here, this review comprehensively examines the recent advancements in immunotherapy for prostate cancer, exploring its potential synergistic effects when combined with other treatment modalities to enhance clinical efficacy.

Tumor microbiome: roles in tumor initiation, progression, and therapy

Over the past few years, the tumor microbiome is increasingly recognized for its multifaceted involvement in cancer initiation, progression, and metastasis. With the application of 16S ribosomal ribonucleic acid (16S rRNA) sequencing, the intratumoral microbiome, also referred to as tumor-intrinsic or tumor-resident microbiome, has also been found to play a significant role in the tumor microenvironment (TME). Understanding their complex functions is critical for identifying new therapeutic avenues and improving treatment outcomes. This review first summarizes the origins and composition of these microbial communities, emphasizing their adapted diversity across a diverse range of tumor types and stages. Moreover, we outline the general mechanisms by which specific microbes induce tumor initiation, including the activation of carcinogenic pathways, deoxyribonucleic acid (DNA) damage, epigenetic modifications, and chronic inflammation. We further propose the tumor microbiome may evade immunity and promote angiogenesis to support tumor progression, while uncovering specific microbial influences on each step of the metastatic cascade, such as invasion, circulation, and seeding in secondary sites. Additionally, tumor microbiome is closely associated with drug resistance and influences therapeutic efficacy by modulating immune responses, drug metabolism, and apoptotic pathways. Furthermore, we explore innovative microbe-based therapeutic strategies, such as engineered bacteria, oncolytic virotherapy, and other modalities aimed at enhancing immunotherapeutic efficacy, paving the way for microbiome-centered cancer treatment frameworks.

Immunotherapy in colorectal cancer: Statuses and strategies

Colorectal cancer (CRC) is widely recognized as the third most prevalent malignancy globally and the second leading cause of cancer-related mortality. Traditional treatment modalities for CRC, including surgery, chemotherapy, and radiotherapy, can be utilized either individually or in combination. However, these treatments frequently result in significant side effects due to their non-specificity and cytotoxicity affecting all cells. Moreover, a considerable number of patients face relapses following these treatments. Consequently, it is imperative to explore more efficacious treatment interventions for CRC patients. Immunotherapy, an emerging frontier in oncology, represents a novel therapeutic approach that leverages the body's immune system to target cancer cells. The principal advantage of immunotherapy is its capacity to selectively target cancer cells while minimizing damage to healthy cells. Its recent adoption as a neoadjuvant therapy presents significant potential to transform the treatment landscape for both primary resectable and metastatic CRC. This review endeavors to offer a comprehensive overview of current strategies in CRC immunotherapy, critically analyze existing literature, underscore anticipated outcomes from ongoing clinical trials, and deliberate on the challenges and impediments encountered within the field of immunotherapy.

Oncolytic herpes simplex virus propagates tertiary lymphoid structure formation via CXCL10/CXCR3 to boost antitumor immunity

Inducing tertiary lymphoid structure (TLS) formation can fuel antitumor immunity. It is necessary to create mouse models containing TLS to explore strategies of TLS formation. Oncolytic herpes simplex virus-1 (oHSV) exhibited intense effects in preclinical and clinical trials. However, the role of oHSV in TLS formation remains to be elucidated. Here, we observed the presence of TLS in 4MOSC1 and MC38 subcutaneous tumour models. Interestingly, oHSV evoked TLS formation, and increased infiltration of B cells and stem-like TCF1+CD8+ T cells proliferation. Mechanistically, oHSV increased the expression of TLS-related chemokines, along with upregulated CXCL10/CXCR3 to facilitate TLS formation. Notably, CXCL10 and CXCR3 were favourable prognostic factors for cancer patients, and closely related with immune cells infiltration. Inhibiting CXCL10/CXCR3 reduced TCF1+CD8+ T cells and granzyme B expression, and impaired oHSV-mediated TLS formation. Furthermore, oHSV-mediated TLS formation revealed superior response and survival rate when combined with αPD-1 treatment. Collectively, these findings indicate that oHSV recruits stem-like TCF1+CD8+ T cells through CXCL10/CXCR3 pathway to propagate TLS formation, and warrants future antitumor immunity development.

Evaluation of immune checkpoint inhibitors for colorectal cancer: A network meta‑analysis

Colorectal cancer (CRC) is challenging to treat due to its high metastatic rate. Recent strategies have focused on combining immune checkpoint inhibitors (ICIs) with other treatments. The aim of the present study was to conduct a network meta-analysis of randomized controlled trials (RCTs) to assess the efficacy and adverse effects of different ICI treatments for CRC. A literature search for RCTs was conducted using PubMed, the Cochrane Library, Embase, ClinicalTrials.gov and Web of Science databases, covering the period from the inception of each database until April 2024. A total of 12 RCTs involving 2,050 participants were selected for inclusion in the analysis. The network meta-analysis employed the MetaInsight tool to assess multiple endpoints. The criteria for study selection were based on the Population, Intervention, Comparison, Outcome and Studies framework as follows: i) Population, patients with CRC; ii) intervention, studies using ICI to treat CRC; iii) comparison, active comparators, including placebo; iv) outcome, overall survival, progression-free survival, objective response rate and adverse events; and v) study design, RCTs. The results of the analysis revealed that programmed cell death-ligand 1 (PD-L1) inhibitors significantly improved overall survival time [mean difference (MD), 2.28 months; 95% confidence interval (CI), 0.44 to 4.11], while programmed cell death protein 1 (PD-1) inhibitors exhibited a superior progression-free survival time (MD, 4.79 months; 95% CI, 3.18 to 6.40) compared with active comparators. However, none of the ICI treatments had significant differences in odds ratios for the objective response rate and adverse events compared with active comparators. These findings indicate that treatment with PD-L1 and PD-1 inhibitors improved the overall survival time and delayed disease progression in patients with CRC. These findings offer valuable insights for future research aimed at improving CRC patient outcomes.

WNT and TGF-Beta Pathway Alterations in Early-Onset Colorectal Cancer Among Hispanic/Latino Populations

BACKGROUND/OBJECTIVES

One of the fastest-growing minority groups in the U.S. is the Hispanic/Latino population. Recent studies have shown how this population is being disproportionately affected by early-onset colorectal cancer (CRC). Compared to corresponding non-Hispanic White (NHW) patients, Hispanic/Latino patients have both higher incidence of disease and rates of mortality. Two well-established drivers of early-onset CRC in the general population are alterations in the WNT and TGF-Beta signaling pathways; however, the specific roles of these pathways in Hispanics/Latinos are poorly understood.

METHODS

Here, we assessed CRC mutations in the WNT and TGF-Beta pathways by conducting a bioinformatics analysis using cBioPortal. Cases of CRC were stratified both by age and ethnicity: (1) early-onset was defined as <50 years vs. late-onset as ≥50 years; (2) we compared early-onset in Hispanics/Latinos to early-onset in NHWs.

RESULTS

No significant differences were evident when we compared early-onset and late-onset CRC cases within the Hispanic/Latino cohort. These results are consistent with findings from large cohorts that do not specify ethnicity. However, we found significant differences when we compared early-onset CRC in Hispanic/Latino patients to early-onset CRC in NHW patients: specifically, alterations in the gene bone morphogenetic protein-7 (BMP7) were more frequent in early-onset CRC for the Hispanic/Latino patients. In addition to these findings, we observed that both NHW patients and Hispanic/Latino patients with early-onset disease had better clinical outcomes when there was evidence of WNT pathway alterations. Conversely, the absence of TGF-Beta pathway alterations was uniquely associated with improved outcomes exclusively in early-onset Hispanic/Latino patients.

CONCLUSIONS

In toto, these findings underscore how the WNT and TGF-Beta pathways may act differently in different ethnic groups with early-onset CRC. These findings may set a stage for developing new therapies tailored for reducing cancer health disparities.

Efficacy and safety of PD-1/PD-L1 and CTLA-4 immune checkpoint inhibitors in the treatment of advanced colorectal cancer: a systematic review and meta-analysis

Background

The efficacy and safety of PD-1/PD-L1 inhibitors combined with CTLA-4 inhibitors in the treatment of advanced colorectal cancer is controversial. This meta-analysis aimed to evaluate the efficacy and safety of PD-1/PD-L1 inhibitors combined with CTLA-4 inhibitors for advanced colorectal cancer.

Methods

PubMed, Embase, the Cochrane Library, and Web of Science databases were systematically searched for relevant studies. Outcomes including median progression-free survival (mPFS), median overall survival (mOS), overall response rate (ORR), disease control rate (DCR), treatment-related adverse events (TRAEs) and ≥grade 3 TRAEs were extracted for further analysis. The risk of bias was assessed by subgroup analysis.

Results

12 articles with 566 patients were identified and subjected to meta-analysis. With regard to survival analysis, the pooled mOS and mPFS were 6.66 months (95%CI 4.85-9.16) and 2.92 months (95%CI 2.23-3.83), respectively. In terms of tumor response, the pooled ORR and DCR were 21% (95%CI 6%-41%) and 49% (95%CI 27%-71%), respectively. The pooled AEs rate and ≥ grade 3 AEs rate were 94% (95%CI 86%-99%) and 44% (95%CI 30%-58%).

Conclusion

PD-1/PD-L1 inhibitors combined with CTLA-4 inhibitors have shown promising clinical responses in the treatment of colorectal cancer (CRC). Although the incidence of adverse reactions is high, they are generally tolerable.

Systematic review registration

https://inplasy.com/, identifier INPLASY202480030.

Signaling pathways involved in colorectal cancer: pathogenesis and targeted therapy

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

Emerging roles of intratumor microbiota in cancer: tumorigenesis and management strategies

The intricate interplay between the host and its microbiota has garnered increasing attention in the past decade. Specifically, the emerging recognition of microorganisms within diverse cancer tissues, previously presumed sterile, has ignited a resurgence of enthusiasm and research endeavors. Four potential migratory routes have been identified as the sources of intratumoral microbial "dark matter," including direct invasion of mucosal barriers, spreading from normal adjacent tissue, hematogenous spread, and lymphatic drainage, which contribute to the highly heterogeneous features of intratumor microbiota. Importantly, multitudes of studies delineated the roles of intratumor microbiota in cancer initiation and progression, elucidating underlying mechanisms such as genetic alterations, epigenetic modifications, immune dysfunctions, activating oncogenic pathways, and inducing metastasis. With the deepening understanding of intratumoral microbial composition, novel microbiota-based strategies for early cancer diagnosis and prognostic stratification continue to emerge. Furthermore, intratumor microbiota exerts significant influence on the efficacy of cancer therapeutics, particularly immunotherapy, making it an enticing target for intervention in cancer treatment. In this review, we present a comprehensive discussion of the current understanding pertaining to the developmental history, heterogeneous profiles, underlying originations, and carcinogenic mechanisms of intratumor microbiota, and uncover its potential predictive and intervention values, as well as several inevitable challenges as a target for personalized cancer management strategies.

Dose Considerations for Vaccinia Oncolytic Virus Based on Retrospective Reanalysis of Early and Late Clinical Trials

Over the past decade, oncolytic viruses (OVs) have been developed as a promising treatment alone or in combination in immuno-oncology but have faced challenges in late-stage clinical trials. Our retrospective reanalysis of vaccinia oncolytic virus (VOV) clinical trials indicates that lower doses-rather than the maximum tolerated dose (MTD)-are associated with better tumor response rates. Patients who responded well to lower doses generally had prolonged survival rates in the early phase clinical trial. The association between poor outcomes and an increase in OV-induced neutrophils (OV-N) but not baseline neutrophil counts suggests the need for a comprehensive characterization of OV-N. Although this reanalysis is limited by patient heterogeneity-including differences in cancer type and stage, treatment schedules, and administration routes-it remains informative given the complexities of translational studies in the tumor-bearing mouse models of vaccinia oncolytic viruses. Notably, while OV-N increases with higher viral doses, the immune state shaped by tumor progression likely amplifies this tendency. These findings highlight the importance of OV-N immune modulation as well as dose optimization for the successful clinical development of VOV.

The long-term effectiveness and mechanism of oncolytic virotherapy combined with anti-PD-L1 antibody in colorectal cancer patient

Colorectal cancer (CRC) is known to be resistant to immunotherapy. In our phase-I clinical trial, one patient achieved a 313-day prolonged response during the combined treatment of oncolytic virotherapy and immunotherapy. To gain a deeper understanding of the potential molecular mechanisms, we performed a comprehensive multi-omics analysis on this patient and three non-responders. Our investigation unveiled that, initially, the tumor microenvironment (TME) of this responder presented minimal infiltration of T cells and natural killer cells, along with a relatively higher presence of macrophages compared to non-responders. Remarkably, during treatment, there was a progressive increase in CD4+ T cells, CD8+ T cells, and B cells in the responder's tumor tissue. This was accompanied by a significant upregulation of transcription factors associated with T-cell activation and cytotoxicity, including GATA3, EOMES, and RUNX3. Furthermore, dynamic monitoring of peripheral blood samples from the responder revealed a rapid decrease in circulating tumor DNA (ctDNA), suggesting its potential as an early blood biomarker of treatment efficacy. Collectively, our findings demonstrate the effectiveness of combined oncolytic virotherapy and immunotherapy in certain CRC patients and provide molecular evidence that virotherapy can potentially transform a "cold" TME into a "hot" one, thereby improving sensitivity to immunotherapy.

Exploring treatment options in cancer: Tumor treatment strategies

Traditional therapeutic approaches such as chemotherapy and radiation therapy have burdened cancer patients with onerous physical and psychological challenges. Encouragingly, the landscape of tumor treatment has undergone a comprehensive and remarkable transformation. Emerging as fervently pursued modalities are small molecule targeted agents, antibody-drug conjugates (ADCs), cell-based therapies, and gene therapy. These cutting-edge treatment modalities not only afford personalized and precise tumor targeting, but also provide patients with enhanced therapeutic comfort and the potential to impede disease progression. Nonetheless, it is acknowledged that these therapeutic strategies still harbour untapped potential for further advancement. Gaining a comprehensive understanding of the merits and limitations of these treatment modalities holds the promise of offering novel perspectives for clinical practice and foundational research endeavours. In this review, we discussed the different treatment modalities, including small molecule targeted drugs, peptide drugs, antibody drugs, cell therapy, and gene therapy. It will provide a detailed explanation of each method, addressing their status of development, clinical challenges, and potential solutions. The aim is to assist clinicians and researchers in gaining a deeper understanding of these diverse treatment options, enabling them to carry out effective treatment and advance their research more efficiently.

Neuroblastoma-A Review of Combination Immunotherapy

Neuroblastoma is the most common extracranial solid tumor found in childhood and is responsible for 15% of deaths among children with cancer. Although multimodal therapies focused on surgery, chemotherapy, radiotherapy, and stem cell transplants have favorable results in many cases, the use of conventional therapies has probably reached the limit their possibility. Almost half of the patients with neuroblastoma belong to the high-risk group. Patients in this group require a combination of several therapeutic approaches. It has been shown that various immunotherapies combined with conventional methods can work synergistically. Due to the development of such therapeutic methods, we present combinations and forms of combining immunotherapy, focusing on their mechanisms and benefits but also their limitations and potential side effects.

PD-L1 promotes oncolytic virus infection via a metabolic shift that inhibits the type I IFN pathway

While conventional wisdom initially postulated that PD-L1 serves as the inert ligand for PD-1, an emerging body of literature suggests that PD-L1 has cell-intrinsic functions in immune and cancer cells. In line with these studies, here we show that engagement of PD-L1 via cellular ligands or agonistic antibodies, including those used in the clinic, potently inhibits the type I interferon pathway in cancer cells. Hampered type I interferon responses in PD-L1-expressing cancer cells resulted in enhanced efficacy of oncolytic viruses in vitro and in vivo. Consistently, PD-L1 expression marked tumor explants from cancer patients that were best infected by oncolytic viruses. Mechanistically, PD-L1 promoted a metabolic shift characterized by enhanced glycolysis rate that resulted in increased lactate production. In turn, lactate inhibited type I IFN responses. In addition to adding mechanistic insight into PD-L1 intrinsic function, our results will also help guide the numerous ongoing efforts to combine PD-L1 antibodies with oncolytic virotherapy in clinical trials.

The therapeutic impact of programmed death - 1 in the treatment of colorectal cancer

Colorectal cancer (CRC) is the most common type of newly diagnosed cancer. Metastatic spread and multifactorial chemoresistance have limited the benefits of current therapies. Hence, it is imperative to identify new therapeutic agents to increase treatment efficacy. One of CRC's most promising immunotherapeutic targets is programmed death-1 (PD-1), a cell surface receptor that regulates immune responses. In this paper, we provide an overview of the therapeutic impact of PD-1 in the treatment of CRC. Cancer cells can exploit the PD-1 pathway by upregulating its programmed death-ligand 1 (PD-L1) ligand to evade immune surveillance. The binding of PD-L1 to PD-1 inhibits T cell function, leading to tumor immune escape. PD-1 inhibitors, such as pembrolizumab and nivolumab, block the PD-1/PD-L1 interaction. Clinical trials evaluating PD-1 inhibitors in advanced CRC have shown promising results. In patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) tumors characterized by high mutation rates and increased immunogenicity, PD-1 blockade has demonstrated remarkable efficacy. As a result, pembrolizumab and nivolumab have received accelerated approval by regulatory authorities for the treatment of MSI-H/dMMR metastatic CRC. Additionally, combination approaches, such as combining PD-1 inhibitors with other immunotherapies or targeted agents, are being explored. Despite the success of PD-1 inhibitors in CRC, challenges still exist. Immune-related adverse events can occur and require close monitoring. In conclusion, PD-1 inhibitors have demonstrated significant therapeutic impact, particularly in patients with MSI-H/dMMR tumors.

Water-filtered infrared A radiation hyperthermia combined with immunotherapy for advanced gastrointestinal tumours

This study pioneered the use of WIRA whole-body infrared hyperthermia combined with ICI therapy to treat GIT and verified the feasibility and safety of HIT. The final results showed a DCR of 55.6%, with a median PFS of 53.5 days, median OS of 134 days, and an irAE incidence of 22.2%. Therefore, we believe that HIT can exert multiple synergistic sensitisation effects, thereby providing clinical benefits to patients with advanced GITs, increasing overall safety, and improving patients' QOL.

Recent progress in combination therapy of oncolytic vaccinia virus

In recent years, oncolytic viruses have emerged as promising agents for treating various cancers. An oncolytic virus is a non-pathogenic virus that, due to genetic manipulation, tends to replicate in and cause lysis of cancerous cells while leaving healthy cells unaffected. Among these viruses, vaccinia virus is an attractive platform for use as an oncolytic platform due to its 190 Kb genome with a high capacity for encoding therapeutic payloads. Combining oncolytic VV therapy with other conventional cancer treatments has been shown to be synergistic and more effective than monotherapies. Additionally, OVV can be used as a vector to deliver therapeutic payloads, alone or in combination with other treatments, to increase overall efficacy. Here, we present a comprehensive analysis of preclinical and clinical studies that have evaluated the efficacy of oncolytic vaccinia viruses in cancer immunotherapy. We discuss the outcomes of these studies, including tumor regression rates, overall survival benefits, and long-term responses. Moreover, we provide insights into the challenges and limitations associated with oncolytic vaccinia virus- based therapies, including immune evasion mechanisms, potential toxicities, and the development of resistance.

Redefining the battle against colorectal cancer: a comprehensive review of emerging immunotherapies and their clinical efficacy

Colorectal cancer (CRC) is the third most common cancer globally and presents a significant challenge owing to its high mortality rate and the limitations of traditional treatment options such as surgery, radiotherapy, and chemotherapy. While these treatments are foundational, they are often poorly effective owing to tumor resistance. Immunotherapy is a groundbreaking alternative that has recently emerged and offers new hope for success by exploiting the body's own immune system. This article aims to provide an extensive review of clinical trials evaluating the efficacy of various immunotherapies, including CRC vaccines, chimeric antigen receptor T-cell therapies, and immune checkpoint inhibitors. We also discuss combining CRC vaccines with monoclonal antibodies, delve into preclinical studies of novel cancer vaccines, and assess the impact of these treatment methods on patient outcomes. This review seeks to provide a deeper understanding of the current state of CRC treatment by evaluating innovative treatments and their potential to redefine the prognosis of patients with CRC.

Combined immune checkpoint inhibition with durvalumab and tremelimumab with and without radiofrequency ablation in patients with advanced biliary tract carcinoma

BACKGROUND

Current standard of care for advanced biliary tract cancer (BTC) is gemcitabine, cisplatin plus anti-PD1/PD-L1, but response rates are modest. The purpose of this study was to explore the efficacy and safety of durvalumab (anti-PD-L1) and tremelimumab (anti-CTLA-4), with and without an interventional radiology (IR) procedure in advanced BTC.

METHODS

Eligible patients with advanced BTC who had received or refused at least one prior line of systemic therapy were treated with tremelimumab and durvalumab for four combined doses followed by monthly durvalumab alone with and without an IR procedure until the progression of disease or unacceptable toxicity. Objective response was assessed through CT or MRI by Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) every 8 weeks. Adverse events (AEs) were recorded and managed. The primary endpoint was 6-month progression-free survival (PFS).

RESULTS

Twenty-three patients with advanced BTC were enrolled; 17 patients were assigned to treatment with durvalumab and tremelimumab (Durva/Treme); and 6 patients were treated with the combination of durvalumab, tremelimumab plus IR procedure (Durva/Treme + IR). The best clinical responses in the Durva/Treme arm were partial response (n = 1), stable disease (n = 5), progressive disease (n = 5), and in the Durva/Treme + IR arm: partial response (n = 0), stable disease (n = 3), progressive disease (n = 3). The median PFS was 2.2 months (95% CI: 1.3-3.1 months) in the Durva/Treme arm and 2.9 months (95% CI: 1.9-4.7 months) in the Durva/Treme + IR arm (p = 0.27). The median OS was 5.1 months (95% CI: 2.5-6.9 months) in the Durva/Treme arm and 5.8 months (95% CI: 2.9-40.1 months) in the Durva/Treme + IR arm (p = 0.31). The majority of AEs were grades 1-2.

CONCLUSION

Durva/Treme and Durva/Treme + IR showed similar efficacy. With a manageable safety profile. Larger studies are needed to fully characterize the efficacy of Durva/Treme ± IR in advanced BTC.

New immunotherapy approaches for colorectal cancer: focusing on CAR-T cell, BiTE, and oncolytic viruses

Colorectal cancer is one of the most common causes of mortality worldwide. There are several potential risk factors responsible for the initiation and progression of colorectal cancer, including age, family history, a history of inflammatory bowel disease, and lifestyle factors such as physical activity and diet. For decades, there has been a vast amount of study on treatment approaches for colorectal cancer, which has led to conventional therapies such as chemotherapy, surgery, etc. Considering the high prevalence and incidence rate, scholars believe there is an urgent need for an alternative, more efficacious treatment with fewer adverse effects than the abovementioned treatments. Immunotherapy has emerged as a potential treatment alternative in a few years and has become one of the fastest-evolving therapeutic methods. Immunotherapy works by activating or enhancing the immune system's power to identify and attack cancerous cells. This review summarizes the most crucial new immunotherapy methods under investigation for colorectal cancer treatment, including Immune checkpoint inhibitors, CAR-T cell therapy, BiTEs, Tumor-infiltrating lymphocytes, and Oncolytic virus therapy. Furthermore, this study discusses the application of combination therapy, precision medicine, biomarker discovery, overcoming resistance, and immune-related adverse effects. Video Abstract.

VB-111 (ofranergene obadenovec) in combination with nivolumab in patients with microsatellite stable colorectal liver metastases: a single center, single arm, phase II trial

BACKGROUND

Microsatellite stable colorectal liver metastases (MSS CLM) maintain an immunosuppressive tumor microenvironment (TME). Historically, immune-based approaches have been ineffective. VB-111 (ofranergene obadenovec) is a genetically-modified adenoviral vector targeting the TME; its unique dual mechanism induces an immune response and disrupts neovascularization. Checkpoint inhibition may synergize the immune response induced by viral-mediated anti-angiogenic gene therapy. We aimed to examine the safety and antitumor activity of VB-111 and nivolumab in patients with refractory MSS CLM and to characterize immunological treatment-response.

METHODS

This was a phase II study of adult patients with histologically-confirmed MSS CLM who progressed on prior therapy. A priming dose of VB-111 1×1013 viral particles was given intravenously 2 weeks prior to starting biweekly nivolumab 240 mg and continued every 6 weeks. The combination continued until disease progression or unacceptable toxicity. The primary objectives were overall response rate and safety/tolerability. Secondary objectives included median overall survival and progression-free survival. Correlative studies were performed on paired tumor biopsies and blood.

RESULTS

Between August 2020 and December 2021, 14 patients were enrolled with median age 50.5 years (40-75), and 14% were women. Median follow-up was 5.5 months. Of the 10 evaluable patients, the combination of VB-111 and nivolumab failed to demonstrate radiographic responses; at best, 2 patients had stable disease. Median overall survival was 5.5 months (95% CI: 2.3 to 10.8), and median progression-free survival was 1.8 months (95% CI: 1.4 to 1.9). The most common grade 3-4 treatment-related adverse events were fever/chills, influenza-like symptoms, and lymphopenia. No treatment-related deaths were reported. Qualitative analysis of immunohistochemical staining of paired tumor biopsies did not demonstrate significant immune infiltration after treatment, except for one patient who had exceptional survival (26.0 months). Immune analysis of peripheral blood mononuclear cells showed an increase of PD-1highKi67highCD8+ T cells and HLA-DRhigh T cells after VB-111 priming dose. Plasma cytokines interleukin-10 and tumor necrosis factor-α increased after treatment with both drugs.

CONCLUSION

In patients with MSS CLM, VB-111 and nivolumab did not improve overall response rate or survival but were tolerated with minimal toxicities. While challenging to distinguish between antiviral or antitumor, correlative studies demonstrated an immune response with activation and proliferation of CD8+ T cells systemically that was poorly sustained.

TRIAL REGISTRATION NUMBER

NCT04166383.

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.

Advancements and challenges in oncolytic virus therapy for gastrointestinal tumors

BACKGROUND

Tumors of the gastrointestinal tract impose a substantial healthcare burden due to their prevalence and challenging prognosis.

METHODS

We conducted a review of peer-reviewed scientific literature using reputable databases (PubMed, Scopus, Web of Science) with a focus on oncolytic virus therapy within the context of gastrointestinal tumors. Our search covered the period up to the study's completion in June 2023.

INCLUSION AND EXCLUSION CRITERIA

This study includes articles from peer-reviewed scientific journals, written in English, that specifically address oncolytic virus therapy for gastrointestinal tumors, encompassing genetic engineering advances, combined therapeutic strategies, and safety and efficacy concerns. Excluded are articles not meeting these criteria or focusing on non-primary gastrointestinal metastatic tumors.

RESULTS

Our review revealed the remarkable specificity of oncolytic viruses in targeting tumor cells and their potential to enhance anti-tumor immune responses. However, challenges related to safety and efficacy persist, underscoring the need for ongoing research and improvement.

CONCLUSION

This study highlights the promising role of oncolytic virus therapy in enhancing gastrointestinal tumor treatments. Continued investigation and innovative combination therapies hold the key to reducing the burden of these tumors on patients and healthcare systems.

Biomarkers for immunotherapy of hepatocellular carcinoma

Immune-checkpoint inhibitors (ICIs) are now widely used for the treatment of patients with advanced-stage hepatocellular carcinoma (HCC). Two different ICI-containing regimens, atezolizumab plus bevacizumab and tremelimumab plus durvalumab, are now approved standard-of-care first-line therapies in this setting. However, and despite substantial improvements in survival outcomes relative to sorafenib, most patients with advanced-stage HCC do not derive durable benefit from these regimens. Advances in genome sequencing including the use of single-cell RNA sequencing (both of tumour material and blood samples), as well as immune cell identification strategies and other techniques such as radiomics and analysis of the microbiota, have created considerable potential for the identification of novel predictive biomarkers enabling the accurate selection of patients who are most likely to derive benefit from ICIs. In this Review, we summarize data on the immunology of HCC and the outcomes in patients receiving ICIs for the treatment of this disease. We then provide an overview of current biomarker use and developments in the past 5 years, including gene signatures, circulating tumour cells, high-dimensional flow cytometry, single-cell RNA sequencing as well as approaches involving the microbiome, radiomics and clinical markers. Novel concepts for further biomarker development in HCC are then discussed including biomarker-driven trials, spatial transcriptomics and integrated 'big data' analysis approaches. These concepts all have the potential to better identify patients who are most likely to benefit from ICIs and to promote the development of new treatment approaches.

Clinical Applications of Combined Immunotherapy Approaches in Gastrointestinal Cancer: A Case-Based Review

Malignant neoplasms arising from the gastrointestinal (GI) tract are among the most common types of cancer with high mortality rates. Despite advances in treatment in a small subgroup harboring targetable mutations, the outcome remains poor, accounting for one in three cancer-related deaths observed globally. As a promising therapeutic option in various tumor types, immunotherapy with immune checkpoint inhibitors has also been evaluated in GI cancer, albeit with limited efficacy except for a small subgroup expressing microsatellite instability. In the quest for more effective treatment options, energetic efforts have been placed to evaluate the role of several immunotherapy approaches comprising of cancer vaccines, adoptive cell therapies and immune checkpoint inhibitors. In this review, we report our experience with a personalized dendritic cell cancer vaccine and cytokine-induced killer cell therapy in three patients with GI cancers and summarize current clinical data on combined immunotherapy strategies.

Preclinical and clinical trials of oncolytic vaccinia virus in cancer immunotherapy: a comprehensive review

Oncolytic virotherapy has emerged as a promising treatment for human cancers owing to an ability to elicit curative effects via systemic administration. Tumor cells often create an unfavorable immunosuppressive microenvironment that degrade viral structures and impede viral replication; however, recent studies have established that viruses altered via genetic modifications can serve as effective oncolytic agents to combat hostile tumor environments. Specifically, oncolytic vaccinia virus (OVV) has gained popularity owing to its safety, potential for systemic delivery, and large gene insertion capacity. This review highlights current research on the use of engineered mutated viruses and gene-armed OVVs to reverse the tumor microenvironment and enhance antitumor activity in vitro and in vivo, and provides an overview of ongoing clinical trials and combination therapies. In addition, we discuss the potential benefits and drawbacks of OVV as a cancer therapy, and explore different perspectives in this field.

Oncolytic Viruses and Immune Checkpoint Inhibitors: The "Hot" New Power Couple

Immune checkpoint inhibitors (ICIs) have revolutionized cancer care and shown remarkable efficacy clinically. This efficacy is, however, limited to subsets of patients with significant infiltration of lymphocytes into the tumour microenvironment. To extend their efficacy to patients who fail to respond or achieve durable responses, it is now becoming evident that complex combinations of immunomodulatory agents may be required to extend efficacy to patients with immunologically "cold" tumours. Oncolytic viruses (OVs) have the capacity to selectively replicate within and kill tumour cells, resulting in the induction of immunogenic cell death and the augmentation of anti-tumour immunity, and have emerged as a promising modality for combination therapy to overcome the limitations seen with ICIs. Pre-clinical and clinical data have demonstrated that OVs can increase immune cell infiltration into the tumour and induce anti-tumour immunity, thus changing a "cold" tumour microenvironment that is commonly associated with poor response to ICIs, to a "hot" microenvironment which can render patients more susceptible to ICIs. Here, we review the major viral vector platforms used in OV clinical trials, their success when used as a monotherapy and when combined with adjuvant ICIs, as well as pre-clinical studies looking at the effectiveness of encoding OVs to deliver ICIs locally to the tumour microenvironment through transgene expression.

Next-Generation Approaches to Immuno-Oncology in GI Cancers

Immunotherapy has only had a modest impact on the treatment of advanced GI malignancies. Microsatellite-stable colorectal cancer and pancreatic adenocarcinoma, the most common GI tumors, have not benefited from treatment with standard immune checkpoint inhibitors. With this huge unmet need, multiple approaches are being tried to overcome barriers to better anticancer outcomes. This article reviews a number of novel approaches to immunotherapy for these tumors. These include the use of novel checkpoint inhibitors such as a modified anti-cytotoxic T lymphocyte-associated antigen-4 antibody and antibodies to lymphocyte-activation gene 3, T cell immunoreceptor with immunoglobulin and ITIM domains, T-cell immunoglobulin-3, CD47, and combinations with signal transduction inhibitors. We will discuss other trials that aim to elicit an antitumor T-cell response using cancer vaccines and oncolytic viruses. Finally, we review attempts to replicate in GI cancers the frequent and durable responses seen in hematologic malignancies with immune cell therapies.