Intraperitoneal oncolytic virotherapy for patients with malignant ascites: Characterization of clinical efficacy and antitumor immune response

IL-15/IL-15Rα-secreting bioengineered adipocytes reactivate NK/CD8+ T cells in ovarian and colon cancer ascites

Malignant ascites (MA) presents a complex clinical challenge, linked inextricably to poor prognosis, chemoresistance, and metastasis of peritoneal carcinomatosis (PC). However, standard therapeutic approaches for managing or preventing MA secondary to PC remain unavailable. Here we display that a bioengineered adipocyte, encapsulating long-chain fatty acids and concurrently secreting IL-15 and IL-15 receptor α (IL-15Rα), markedly extends the half-life and bioactivity of IL-15. The bioengineered adipocyte consists of an IL-15-P2A-IL-15Rα-T2A-mCherry cDNA sequence stable transfected 3T3-F442A preadipocyte cell line and dcosahexaenoic acid (DHA) are simultaneously encapsulated in the lipid droplets of mature adipocytes, which release it into the MA upon tumor cell-triggered lipolysis. We demonstrate that the bioengineered adipocytes led to specific expansion and activation of NK/CD8+ T cells response to the IL-15/IL-15Rα complex in MA, thereby reversing immuno-suppressive phenotype of ascitic immune cells and enabling them to recognize and attack cancer cells. This synergistic therapeutic strategy exhibits therapeutical manipulation of the ascitic immune cells, restores normal immune functioning, and suppresses cancer cell metastasis and tumor growth in ovarian cancer and colon cancer, all while minimizing systemic adverse effects.

Contemporary Management of Malignant Ascites

INTRODUCTION

Malignant ascites (MA) develops when malignant disease of the peritoneum causes excess fluid to accumulate in the abdominal cavity. It portends a poor prognosis and is associated with debilitating symptoms. While several palliative therapies exist, none have proven curative or free from side effects and complications. This review article describes experimental therapies on the horizon and the contemporary management of MA.

MATERIALS AND METHODS

A literature review was performed using MEDLINE/PubMed, in which studies of emerging or experimental therapies under investigation for the management of MA were reviewed. Current therapies were also reviewed to provide important context. Data, including study design, sample size, primary and secondary outcomes, and side effects were recorded and described. Studies were then categorized into distinct sections and subsections, with tables corresponding to each section.

RESULTS

Five current therapies, including paracentesis, diuretics, peritoneovenous shunting, permanent catheters, and intraperitoneal chemotherapy, are described. Their limitations in effectively managing MA are highlighted. The "Experimental therapies" section is subsectioned into several categories, with the major studies corresponding to each section thoroughly described regarding methods, results, and validity. A final section describes treatments for mucinous ascites, which has distinct characteristics.

CONCLUSIONS

While each of the experimental therapies described offers unique benefits and has demonstrated some promise in managing MA, they all have limitations that have thus far prevented any one of them from being routinely used in practice. MA remains a challenging condition to treat, warranting further research into novel therapies.

Challenges and strategies toward oncolytic virotherapy for leptomeningeal metastasis

Meningeal metastasis (LM) is commonly seen in the advanced stages of cancer patients, often leading to a rapid decline in survival time and quality of life. Currently, there is still a lack of standardized treatments. Oncolytic viruses (OVs) are a class of emerging cancer therapeutics with the advantages of selectively replicating in cancer cells, delivering various eukaryotic transgenes, inducing immunogenic cell death, and promoting anti-tumor immunity. Some studies applying OVs intrathoracically or intraperitoneally for the treatment of malignant pleural and peritoneal effusions have shown promising therapeutic effects. If OVs could be applied to treat LM, it would bring significant survival benefits to patients with LM. In this review, we analyzed past research on the use of viruses to treat meningeal metastasis, summarized the efficacy and safety demonstrated by the research results, and analyzed the feasibility of oncolytic virus therapy for meningeal metastasis. We also summarized the existing data to provide guidance for the development of OVs that can be injected into the cerebrospinal fluid (CSF).

Oncolytic adenovirus MEM-288 encoding membrane-stable CD40L and IFNβ induces an anti-tumor immune response in high grade serous ovarian cancer

Single agent immune checkpoint inhibitors have been ineffective for patients with advanced stage and recurrent high grade serous ovarian cancer (HGSOC). Using pre-clinical models of HGSOC, we evaluated the anti-tumor and immune stimulatory effects of an oncolytic adenovirus, MEM-288. This conditionally replicative virus encodes a modified membrane stable CD40L and IFNβ. We demonstrated this virus successfully infects HGSOC cell lines and primary human ascites samples in vitro. We evaluated the anti-tumor and immunostimulatory activity in vivo in immune competent mouse models. Intraperitoneal delivery of MEM-288 decreased ascites and solid tumor burden compared to controls, and treatment generated a systemic anti-tumor immune response. The tumor microenvironment had a higher proportion of anti-tumor macrophages and decreased markers of angiogenesis. MEM-288 is a promising immunotherapy agent in HGSOC, with further pre-clinical studies required to understand the mechanism of action in the peritoneal microenvironment and clinical activity in combination with other therapies.

Spatially Resolved Niche and Tumor Microenvironmental Alterations in Gastric Cancer Peritoneal Metastases

BACKGROUND & AIMS

Peritoneal metastasis (PM) in gastric cancer (GC) is associated with poor prognosis and significant morbidity. We sought to understand the genomic, transcriptomic, and tumor microenvironment (TME) features that contribute to peritoneal organotropism in GC.

METHODS

We conducted a comprehensive multi-omic analysis of 548 samples from 326 patients, including primary tumors, matched normal tissues; peritoneal metastases, and adjacent-normal peritoneal tissues. We used whole exome sequencing, whole transcriptome sequencing, and digital spatial profiling to investigate molecular alterations, gene expression patterns, and TME characteristics associated with PM.

RESULTS

Our analysis identified specific genomic alterations in primary tumors, including mutations in ELF3, CDH1, and PIGR, and TME signatures, such as stromal infiltration and M2 macrophage enrichment, associated with increased risk of PM. We observed distinct transcriptional programs and immune compositions in GCPM compared with liver metastases, highlighting the importance of the TME in transcoelomic metastasis. We found differential expression of therapeutic targets between primary tumors and PM, with lower CLDN18.2 and FGFR2b expression in PM. We unravel the roles of the TME in niche reprogramming within the peritoneum, and provide evidence of pre-metastatic niche conditioning even in early GC without clinical PM. These findings were further validated using a humanized mouse model, which demonstrated niche remodeling in the peritoneum during transcoelomic metastasis.

CONCLUSION

Our study provides a comprehensive molecular characterization of GCPM and unveils key biological principles underlying transcoelomic metastasis. The identified predictive markers, therapeutic targets, and TME alterations offer potential avenues for targeted interventions and improved patient outcomes.

Oncolytic adenovirus in treating malignant ascites: A phase II trial and longitudinal single-cell study

Malignant ascites is a common complication resulting from the peritoneal spread of malignancies, and currently lacks effective treatments. We conducted a phase II trial (NCT04771676) to investigate the efficacy and safety of oncolytic adenovirus H101 and virotherapy-induced immune response in 25 patients with malignant ascites. Oncolytic virotherapy achieved an increased median time to repeat paracentesis of 45 days (95% confidence interval 16.5-73.5 days), compared with the preset control value of 13 days. Therapy was well-tolerated, with pyrexia, fatigue, nausea, and abdominal pain as the most common toxicities. Longitudinal single-cell profiling identified marked oncolysis, early virus replication, and enhanced CD8+ T cells-macrophages immune checkpoint crosstalk, especially in responsive patients. H101 also triggered a proliferative burst of CXCR6+ and GZMK+CD8+ T cells with promoted tumor-specific cytotoxicity. Further establishment of oncolytic virus-induced T cell expansion signature (OiTE) implicated the potential benefits for H101-responsive patients from subsequent anti-PD(L)1 therapy. Patients with upregulated immune-signaling pathways in tumor cells and a higher proportion of CLEC10A+ dendritic cells and GZMK+CD8+ T cells at baseline showed a superior response to H101 treatment. Our study demonstrates promising clinical responses and tolerability of oncolytic adenovirus in treating malignant ascites and provides insights into the relevant cellular processes following oncolytic virotherapy.

Immunosuppressive tumor microenvironment and immunotherapy of hepatocellular carcinoma: current status and prospectives

Hepatocellular carcinoma (HCC) is a major health concern worldwide, with limited therapeutic options and poor prognosis. In recent years, immunotherapies such as immune checkpoint inhibitors (ICIs) have made great progress in the systemic treatment of HCC. The combination treatments based on ICIs have been the major trend in this area. Recently, dual immune checkpoint blockade with durvalumab plus tremelimumab has also emerged as an effective treatment for advanced HCC. However, the majority of HCC patients obtain limited benefits. Understanding the immunological rationale and exploring novel ways to improve the efficacy of immunotherapy has drawn much attention. In this review, we summarize the latest progress in this area, the ongoing clinical trials of immune-based combination therapies, as well as novel immunotherapy strategies such as chimeric antigen receptor T cells, personalized neoantigen vaccines, oncolytic viruses, and bispecific antibodies.

Molecular insights and promise of oncolytic virus based immunotherapy

Discovering a therapeutic that can counteract the aggressiveness of this disease's mechanism is crucial for improving survival rates for cancer patients and for better understanding the most different types of cancer. In recent years, using these viruses as an anticancer therapy has been thought to be successful. They mostly work by directly destroying cancer cells, activating the immune system to fight cancer, and expressing exogenous effector genes. For the treatment of tumors, oncolytic viruses (OVs), which can be modified to reproduce only in tumor tissues and lyse them while preserving the healthy non-neoplastic host cells and reinstating antitumor immunity which present a novel immunotherapeutic strategy. OVs can exist naturally or be created in a lab by altering existing viruses. These changes heralded the beginning of a new era of less harmful virus-based cancer therapy. We discuss three different types of oncolytic viruses that have already received regulatory approval to treat cancer as well as clinical research using oncolytic adenoviruses. The primary therapeutic applications, mechanism of action of oncolytic virus updates, future views of this therapy will be covered in this chapter.

Harnessing adenovirus in cancer immunotherapy: evoking cellular immunity and targeting delivery in cell-specific manner

Recombinant adenovirus (rAd) regimens, including replication-competent oncolytic adenovirus (OAV) and replication-deficient adenovirus, have been identified as potential cancer therapeutics. OAV presents advantages such as selective replication, oncolytic efficacy, and tumor microenvironment (TME) remodeling. In this perspective, the principles and advancements in developing OAV toolkits are reviewed. The burgeoning rAd may dictate efficacy of conventional cancer therapies as well as cancer immunotherapies, including cancer vaccines, synergy with adoptive cell therapy (ACT), and TME reshaping. Concurrently, we explored the potential of rAd hitchhiking to adoptive immune cells or stem cells, highlighting how this approach facilitates synergistic interactions between rAd and cellular therapeutics at tumor sites. Results from preclinical and clinical trials in which immune and stem cells were infected with rAd have been used to address significant oncological challenges, such as postsurgical residual tumor tissue and metastatic tissue. Briefly, rAd can eradicate tumors through various mechanisms, resulting from tumor immunogenicity, reprogramming of the TME, enhancement of cellular immunity, and effective tumor targeting. In this context, we argue that rAd holds immense potential for enhancing cellular immunity and synergistically improving antitumor effects in combination with novel cancer immunotherapies.

The combination treatment of oncolytic adenovirus H101 with nivolumab for refractory advanced hepatocellular carcinoma: an open-label, single-arm, pilot study

BACKGROUND

H101, an innovative oncolytic adenovirus, has shown potential in modifying the tumor microenvironment from immunologically 'cold' to 'hot'. When combined with nivolumab, a programmed cell death protein 1 inhibitor, this synergy may offer substantial therapeutic benefits beyond the capabilities of each agent alone.

PATIENTS AND METHODS

In this pilot study, we assessed the efficacy and safety of combining H101 with nivolumab in advanced hepatocellular carcinoma (HCC) patients who failed prior systemic therapy. The participants received initial oncolytic virus (OV) pretreatment with intratumoral H101 injections (5.0 × 1011 vp/0.5 ml/vial, two vials per lesion) on days 1 and 3. Combination therapy started on day 8, with H101 administered every 2 or 4 weeks and nivolumab (240 mg) injections every 2 weeks. Treatment continued up to 12 months or until disease progression, intolerable toxicity, consent withdrawal, or study conclusion. The primary endpoint was the objective response rate (ORR).

RESULTS

Between March 2020 and March 2022, 18 of 21 screened patients were assessable, showing an ORR of 11.1% [two cases of partial response (PR) and five cases of stable disease], with extrahepatic injections often leading to favorable outcomes. The disease control rate stood at 38.9%, with a 6-month survival rate of 88.9%. Median progression-free survival was 2.69 months, and overall survival (OS) was 15.04 months. Common adverse events included low-grade fever (100%) and pain related to centesis (33.3%), and no grade 3/4 events were reported. Significantly, local H101 injection showed potential in reversing immune checkpoint inhibitor resistance, evidenced by over 2.5 years of extended OS in PR cases with low α-fetoprotein. Additionally, decreasing neutrophil-to-lymphocyte ratio during OV pretreatment may predict positive outcomes.

CONCLUSIONS

This study demonstrates the potential efficacy of combining H101 with nivolumab in treating refractory advanced HCC, with well-tolerated toxicities.

Recombinant Human Adenovirus Type 5 (H101) Intra-Tumor Therapy in Patients with Persistent, Recurrent, or Metastatic Cervical Cancer: Genomic Profiling Relating to Clinical Efficacy

Objective

Genomic profiles relating to H101 treatment-induced alterations are yet to be achieved. Here, we evaluated the impact of H101 via exome-sequencing approaches aiming to probe for potential biomarkers that are actionable in the treatment of persistent/recurrent/metastatic (P/R/M) cervical cancer.

Methods

Whole exome sequencing (WES) was performd on paired pre- and post-H101 samples from 17 P/R/M cervical cancer patients who received serial intra-tumor injections of H101. Somatic mutations, including high-frequency mutations, microsatellite instability (MSI) status, tumor mutation burden (TMB), clonal evolution, and mutational signature were analyzed.

Results

The median follow-up time after the H101 treatment was 14 months. Complete response was achieved in 9 patients, 3 patients achieved partial response, and 2 patients had stable disease, resulting in an objective response rate (ORR) of 70.6% (95% CI: 46.4%-96.7%). WES analysis showed no difference in treatment-related mutation characteristics, including non-synonymous-SNVs and TMB status. Patients with lower TMB were correlated with improved H101 response rates (P=0.044), whereas the same was not evident in high MSI (MSI-H) versus non-MSI-H patients (P=0.528). We observed a few high-frequency mutation genes (TTN, KMT2D, ALDOA, DNAH7, ADAP1, PTPN23, and THEMIS2) that probably carry functional importance in response to H101 treatment, among which KMT2D and ADAP1 mutations were associated with inferior progression-free survival (PFS) and/or overall survival (OS) (P<0.05). Notably, H101 treatment-induced accumulating subclones or clusters in primary tumors and some (Signature 2) were associated with shorter PFS.

Conclusion

We conducted an unprecedented work via a WES-based approach and provided preliminary insights into H101 treatment-induced genetic aberrations in which some genes (TTN, KMT2D, ALDOA, DNAH7, ADAP1, PTPN23, and THEMIS2) could be considered potential therapeutic targets of H101-containing treatment in cervical carcinoma. Moreover, the therapy-associated characteristics such as clonal evolution and a mutational signature may warrant further evaluation of H101 in clinical settings for treating cervical carcinoma.

Malignant ascites: Current therapy options and treatment prospects

Ascites formation is a common complication of cancer with a significant symptomatic burden for patients. Malignant ascites (MA) is defined by the presence of tumor cells within the ascitic fluid. It does not only cause substantial morbidity, but is also associated with impaired survival. Considering the frequent occurrence of MA, it still represents a clinical challenge for physicians with limited therapy options, mainly comprising of the treatment of the primary tumor and effusion drainage. Particularly the lack of pathophysiological insight limits the development of effective, causative therapies. Causes of MA development such as lymphatic vessel obstruction and the effects of tumor secreted vascular endothelial growth factor (VEGF) have been known for decades. Novel research suggests that the intraperitoneal immune system may also induce and maintain MA accumulation. In this review, we assess current knowledge on the pathophysiology of MA and summarize available evidence of treatment approaches. Also, factors contributing to ascites formation without proof of tumor cells in the peritoneal cavity, defined as paramalignant ascites, with potential treatment strategies are discussed. We further focus on novel findings in the pathophysiology of MA that might lead to treatment improvement in the near future and discussed relevant knowledge gaps in this field.

Effectiveness and safety of human type 5 recombinant adenovirus (H101) in malignant tumor with malignant pleural effusion and ascites: A multicenter, observational, real-world study

BACKGROUND

The aim of this study was to analyze the effectiveness and safety of H101 in Chinese patients with malignant pleural effusion and ascites (MPE/MA) in the real world.

METHODS

This multicenter, observational, real-world study recruited patients with MPE/MA caused by malignant tumor receiving H101-containing treatment between January 2020 and June 2022. Effectiveness was evaluated by overall remission rate (ORR), and safety was evaluated based on adverse events (AEs). Subgroup analysis was performed on patients grouped according to tumor type, the volume of MPE and MA, and dosage of H101.

RESULTS

A total of 643 eligible patients were enrolled, and 467 received H101 monotherapy and 176 received H101 combined with chemotherapy. The ORR of total patients was60.3% with 388 case of PR. In the H101 monotherapy group, the decrease of MPE or MA was achieved in 282 (60.4%, PR) patients, 176 (37.7%, NC) patients showed no change in volume of MPE or MA, and nine (1.9%, PD) patients showed an increase, yielding an ORR of 60.4% (282/467). The ORR for the combination therapy group was 60.2% (106/176), with 106 cases of PR, 69 cases of NC and one case of PD. Subgroup analyses based on tumor type, volume of MPE and MA, and dosage of H101 all showed high ORR, approximately 60%. The main AEs associated with H101-containing regimens were fever, nausea and vomiting. No serious AEs occurred in both groups.

CONCLUSION

Encouraging clinical benefits and manageable toxicity of H101 against MPE/MA were preliminarily observed in the real-world clinical setting, indicating that the H101-containing regimen is reliable, safe, and feasible, providing a novel and effective option for the treatment of this disease.

Malignant ascites in pancreatic cancer: Pathophysiology, diagnosis, molecular characterization, and therapeutic strategies

Malignant ascites is the accumulation of fluid in the peritoneum as a result of advanced cancer and often signifies the terminal phase of the disease. Management of malignant ascites remains a clinical challenge as symptom palliation is the current standard of cure. Previously, studies examining malignant ascites largely focused on ovarian and gastric cancer. In recent years, there has been a significant increase in research on malignant ascites in pancreatic cancer. Malignant ascites is usually diagnosed based on positive cytology, but cytology is not always diagnostic, indicating the need for novel diagnostic tools and biomarkers. This review aims to summarize the current understanding of malignant ascites in pancreatic cancer and the recent advances in the molecular characterization of malignant ascites fluid from patients with pancreatic cancer including analysis of soluble molecules and extracellular vesicles. Current standard of care treatment options such as paracenteses and diuretics are outlined along with new emerging treatment strategies such as immunotherapy and small-molecule based therapies. New potential investigative directions resulting from these studies are also highlighted.

The molecular biology of peritoneal metastatic disease

Peritoneal metastases are a common form of tumor cell dissemination in gastrointestinal malignancies. Peritoneal metastatic disease (PMD) is associated with severe morbidity and resistance to currently employed therapies. Given the distinct route of dissemination compared with distant organ metastases, and the unique microenvironment of the peritoneal cavity, specific tumor cell characteristics are needed for the development of PMD. In this review, we provide an overview of the known histopathological, genomic, and transcriptomic features of PMD. We find that cancers representing the mesenchymal subtype are strongly associated with PMD in various malignancies. Furthermore, we discuss the peritoneal niche in which the metastatic cancer cells reside, including the critical role of the peritoneal immune system. Altogether, we show that PMD should be regarded as a distinct disease entity, that requires tailored treatment strategies.

Establishing a New Platform to Investigate the Efficacy of Oncolytic Virotherapy in a Human Ex Vivo Peritoneal Carcinomatosis Model

Oncolytic virotherapy constitutes a promising treatment option for many solid cancers, including peritoneal carcinomatosis (PC), which still represents a terminal stage of many types of tumors. To date, the in vitro efficacy of oncolytic viruses is mostly tested in 2D-cultured tumor cell lines due to the lack of realistic 3D in vitro tumor models. We have investigated the feasibility of virotherapy as a treatment option for PC in a human ex vivo peritoneum co-culture model. Human HT-29 cancer cells stably expressing marker genes GFP and firefly luciferase (GFP/luc) were cultured on human peritoneum and infected with two prototypic oncolytic viruses (GLV-0b347 and MeV-DsRed). Both viral constructs were able to infect HT-29 cells in patient-derived peritoneum with high tumor specificity. Over time, both GFP signal and luciferase activity decreased substantially, thereby indicating successful virus-induced oncolysis. Furthermore, immunohistochemistry stainings showed specific virotherapeutic infections of HT-29 cells and effective tumor cell lysis in infected co-cultures. Thus, the PC model established here provides a clinically relevant screening platform to evaluate the therapeutic efficacy of virotherapeutic compounds and also to investigate, in an autologous setting, the immunostimulatory potential of oncolytic viruses for PC in a unique human model system superior to standard 2D in vitro models.

Dendritic cells and natural killer cells: The road to a successful oncolytic virotherapy

Every type of cancer tissue is theoretically more vulnerable to viral infection. This natural proclivity has been harnessed as a new anti-cancer therapy by employing oncolytic viruses (OVs) to selectively infect and destroy cancer cells while providing little or no harm with no toxicity to the host. Whereas the primary oncolytic capabilities of OVs initially sparked the greatest concern, the predominant focus of research is on the association between OVs and the host immune system. Numerous OVs are potent causal agents of class I MHC pathway-related chemicals, enabling early tumor/viral immune recognition and cytokine-mediated response. The modified OVs have been studied for their ability to bind to dendritic cells (DCs) by expressing growth factors, chemokines, cytokines, and defensins inside the viral genome. OVs, like reovirus, can directly infect DCs, causing them to release chemokines and cytokines that attract and excite natural killer (NK) cells. In addition, OVs can directly alter cancer cells' sensitivity to NK by altering the expression levels of NK cell activators and inhibitors on cancerous cells. Therefore, NK cells and DCs in modulating the therapeutic response should be considered when developing and improving future OV-based therapeutics, whether modified to express transgenes or used in combination with other drugs/immunotherapies. Concerning the close relationship between NK cells and DCs in the potential of OVs to kill tumor cells, we explore how DCs and NK cells in tumor microenvironment affect oncolytic virotherapy and summarize additional information about the interaction mentioned above in detail in this work.