Gene-mediated cytotoxic immunotherapy as adjuvant to surgery or chemoradiation for pancreatic adenocarcinoma

Dynamic Tracking of Tumor Microenvironment Modulation Using Kaede Photoconvertible Transgenic Mice Unveils New Biological Properties of Viral Immunotherapy

SIGNIFICANCE

This study utilized a novel photoconvertible mouse tumor model to track immune cell trafficking upon treatment with an investigational viral immunotherapy (CAN-2409), revealing enhanced T-cell responses after viral immunotherapy associated with local proliferation of T cells within tumors that could further enhance antitumor efficacy in combination with immune checkpoint inhibitors. These findings define temporally and spatially distinct interactions of immune cells that could be harnessed by novel therapeutics.

Smart nanocarriers for enzyme-activated prodrug therapy

Exogenous enzyme-activated prodrug therapy (EPT) is a potential cancer treatment strategy that delivers non-human enzymes into or on the surface of the cell and subsequently converts a non-toxic prodrug into an active cytotoxic substance at a specific location and time. The development of several pharmacological pairs based on EPT has been the focus of anticancer research for more than three decades. Numerous of these pharmacological pairs have progressed to clinical trials, and a few have achieved application in specific cancer therapies. The current review highlights the potential of enzyme-activated prodrug therapy as a promising anticancer treatment. Different microbial, plant, or viral enzymes and their corresponding prodrugs that advanced to clinical trials have been listed. Additionally, we discuss new trends in the field of enzyme-activated prodrug nanocarriers, including nanobubbles combined with ultrasound (NB/US), mesoscopic-sized polyion complex vesicles (PICsomes), nanoparticles, and extracellular vesicles (EVs), with special emphasis on smart stimuli-triggered drug release, hybrid nanocarriers, and the main application of nanotechnology in improving prodrugs.

The Current Landscape of Clinical Trials for Immunotherapy in Pancreatic Cancer: A State-of-the-Art Review

BACKGROUND

Pancreatic cancer remains a lethal malignancy with a 5-year survival rate below 6% and about 500,000 deaths annually worldwide. Pancreatic adenocarcinoma, the most prevalent form, is commonly associated with diabetes, chronic pancreatitis, obesity, and smoking, mainly affecting individuals aged 60 to 80 years. This systematic review aims to evaluate the efficacy of immunotherapeutic approaches in the treatment of pancreatic cancer.

METHODS

A systematic search was conducted to identify clinical trials (Phases I-III) assessing immunotherapy in pancreatic cancer in PubMed/Medline, CINAHL, Scopus, and Web of Science, adhering to PRISMA Statement 2020 guidelines. The final search was completed on May 25, 2024. Ongoing trials were sourced from ClinicalTrials.gov and the World Health Organization's International Clinical Trials Registry Platform (ICTRP). Keywords such as "pancreatic," "immunotherapy," "cancer," and "clinical trial" were used across databases. Gray literature was excluded.

RESULTS

Phase I trials, involving 337 patients, reported a median overall survival (OS) of 13.6 months (IQR: 5-62.5 months) and a median progression-free survival (PFS) of 5.1 months (IQR: 1.9-11.7 months). Phase II/III trials pooled in a total of 1463 participants had a median OS of 12.2 months (IQR: 2.5-35.55 months) and a median PFS of 8.8 months (IQR: 1.4-33.51 months).

CONCLUSIONS

Immunotherapy shows potential for extending survival among pancreatic cancer patients, though results vary. The immunosuppressive nature of the tumor microenvironment and diverse patient responses underline the need for further research to optimize these therapeutic strategies.

Therapeutic potential of gene therapy for gastrointestinal diseases: Advancements and future perspectives

Advancements in understanding the pathogenesis mechanisms underlying gastrointestinal diseases, encompassing inflammatory bowel disease, gastrointestinal cancer, and gastroesophageal reflux disease, have led to the identification of numerous novel therapeutic targets. These discoveries have opened up exciting possibilities for developing gene therapy strategies to treat gastrointestinal diseases. These strategies include gene replacement, gene enhancement, gene overexpression, gene function blocking, and transgenic somatic cell transplantation. In this review, we introduce the important gene therapy targets and targeted delivery systems within the field of gastroenterology. Furthermore, we provide a comprehensive overview of recent progress in gene therapy related to gastrointestinal disorders and shed light on the application of innovative gene-editing technologies in treating these conditions. These developments are fueling a revolution in the management of gastrointestinal diseases. Ultimately, we discuss the current challenges (particularly regarding safety, oral efficacy, and cost) and explore potential future directions for implementing gene therapy in the clinical settings for gastrointestinal diseases.

The clinical terrain of immunotherapies in heterogeneous pancreatic cancer: unravelling challenges and opportunities

Pancreatic ductal adenocarcinoma (PDAC) is the most common and aggressive type of pancreatic cancer and has abysmal survival rates. In the past two decades, immunotherapeutic agents with success in other cancer types have gradually been trialled against PDACs at different stages of cancer progression, either as a monotherapy or in combination with chemotherapy. Unfortunately, to this day, chemotherapy still prolongs the survival rates the most and is prescribed in clinics despite the severe side effects in other cancer types. The low success rates of immunotherapy against PDAC have been attributed most frequently to its complex and multi-faceted tumour microenvironment (TME) and low mutational burden. In this review, we give a comprehensive overview of the immunotherapies tested in PDAC clinical trials thus far, their limitations, and potential explanations for their failure. We also discuss the existing classification of heterogenous PDACs into cancer, cancer-associated fibroblast, and immune subtypes and their potential opportunity in patient selection as a form of personalisation of PDAC immunotherapy. © 2023 The Pathological Society of Great Britain and Ireland.

Intrapleural Anticancer Therapy for Malignant Pleural Diseases: Facts or Fiction?

Malignant pleural diseases involves both primary pleural malignancies (e.g., mesothelioma) as well as metastatic disease involving the pleura. The management of primary pleural malignancies remains a challenge, given their limited response to conventional treatments such as surgery, systemic chemotherapy, and immunotherapy. In this article, we aimed to review the management of primary pleural malignancy as well as malignant pleural effusion and assess the current state of intrapleural anticancer therapies. We review the role intrapleural chemotherapy, immunotherapy, and immunogene therapy, as well as oncolytic viral, therapy and intrapleural drug device combination. We further discuss that while the pleural space offers a unique opportunity for local therapy as an adjuvant option to systemic therapy and may help decrease some of the systemic side effects, further patient outcome-oriented research is needed to determine the exact role of these treatments within the armamentarium of currently available options.

Combinatorial immunotherapy with gemcitabine and ex vivo-expanded NK cells induces anti-tumor effects in pancreatic cancer

Pancreatic cancer is difficult to diagnose at the initial stage and is often discovered after metastasis to nearby organs. Gemcitabine is currently used as a standard treatment for pancreatic cancer. However, since chemotherapy for pancreatic cancer has not yet reached satisfactory therapeutic results, adjuvant chemotherapy methods are attempted. It can be expected that combining immune cell therapy with existing anticancer drug combination treatment will prevent cancer recurrence and increase survival rates. We isolated natural killer (NK) cells and co-cultured them with strongly activated autologous peripheral blood mononuclear cells (PBMCs) as feeder cells, activated using CD3 antibody, IFN-r, IL-2, and γ-radiation. NK cells expanded in this method showed greater cytotoxicity than resting NK cells, when co-cultured with pancreatic cancer cell lines. Tumor growth was effectively inhibited in a pancreatic cancer mouse xenograft model. Therapeutic efficacy was increased by using gemcitabine and erlotinib in combination. These findings suggest that NK cells cultured by the method proposed here have excellent anti-tumor activity. We demonstrate that activated NK cells can efficiently inhibit pancreatic tumors when used in combination with gemcitabine-based therapy.

Oncolytic virotherapy: basic principles, recent advances and future directions

Oncolytic viruses (OVs) have attracted growing awareness in the twenty-first century, as they are generally considered to have direct oncolysis and cancer immune effects. With the progress in genetic engineering technology, OVs have been adopted as versatile platforms for developing novel antitumor strategies, used alone or in combination with other therapies. Recent studies have yielded eye-catching results that delineate the promising clinical outcomes that OVs would bring about in the future. In this review, we summarized the basic principles of OVs in terms of their classifications, as well as the recent advances in OV-modification strategies based on their characteristics, biofunctions, and cancer hallmarks. Candidate OVs are expected to be designed as "qualified soldiers" first by improving target fidelity and safety, and then equipped with "cold weapons" for a proper cytocidal effect, "hot weapons" capable of activating cancer immunotherapy, or "auxiliary weapons" by harnessing tactics such as anti-angiogenesis, reversed metabolic reprogramming and decomposing extracellular matrix around tumors. Combinations with other cancer therapeutic agents have also been elaborated to show encouraging antitumor effects. Robust results from clinical trials using OV as a treatment congruously suggested its significance in future application directions and challenges in developing OVs as novel weapons for tactical decisions in cancer treatment.

Pancreatic Cancer Cell and Gene Biotherapies: Past, Present, and Future

Solid cancers remain a major health challenge in terms of research, not only due to their structure and organization but also in the molecular and genetic variations present between tumors as well as within the same tumor. When adding on the tumor microenvironment with cancer-associated cells, vasculature, and the body's immune response (or lack of), the weapons used to tackle this disease must also be diverse and intricate. Developing gene-based therapies against tumors contributes to the diverse lines of attack already established for cancers and can potentially overcome certain obstacles encountered with these strategies, the lack of tumor selectivity with chemotherapies, for example. Given the high mortality and relapse rate associated with pancreatic cancer, novel treatments, including gene therapy, are actively being investigated. Even though no gene therapy for pancreatic cancer is currently on the market, a significant amount of clinical trials are underway, especially in active and recruiting or recently completed phases.

An Extensive Review on Preclinical and Clinical Trials of Oncolytic Viruses Therapy for Pancreatic Cancer

Chemotherapy resistance and peculiar tumor microenvironment, which diminish or mitigate the effects of therapies, make pancreatic cancer one of the deadliest malignancies to manage and treat. Advanced immunotherapies are under consideration intending to ameliorate the overall patient survival rate in pancreatic cancer. Oncolytic viruses therapy is a new type of immunotherapy in which a virus after infecting and lysis the cancer cell induces/activates patients’ immune response by releasing tumor antigen in the blood. The current review covers the pathways and molecular ablation that take place in pancreatic cancer cells. It also unfolds the extensive preclinical and clinical trial studies of oncolytic viruses performed and/or undergoing to design an efficacious therapy against pancreatic cancer.

Role of Adenoviruses in Cancer Therapy

Cancer is one of the leading causes of death in the world, which is the second after heart diseases. Adenoviruses (Ads) have become the promise of new therapeutic strategy for cancer treatment. The objective of this review is to discuss current advances in the applications of adenoviral vectors in cancer therapy. Adenoviral vectors can be engineered in different ways so as to change the tumor microenvironment from cold tumor to hot tumor, including; 1. by modifying Ads to deliver transgenes that codes for tumor suppressor gene (p53) and other proteins whose expression result in cell cycle arrest 2. Ads can also be modified to express tumor specific antigens, cytokines, and other immune-modulatory molecules. The other strategy to use Ads in cancer therapy is to use oncolytic adenoviruses, which directly kills tumor cells. Gendicine and Advexin are replication-defective recombinant human p53 adenoviral vectors that have been shown to be effective against several types of cancer. Gendicine was approved for treatment of squamous cell carcinoma of the head and neck by the Chinese Food and Drug Administration (FDA) agency in 2003 as a first-ever gene therapy product. Oncorine and ONYX-015 are oncolytic adenoviral vectors that have been shown to be effective against some types of cancer. The Chiness FDA agency has also approved Oncorin for the treatment of head and neck cancer. Ads that were engineered to express immune-stimulatory cytokines and other immune-modulatory molecules such as TNF-α, IL-2, BiTE, CD40L, 4-1BBL, GM-CSF, and IFN have shown promising outcome in treatment of cancer. Ads can also improve therapeutic efficacy of immune checkpoint inhibitors and adoptive cell therapy (Chimeric Antigen Receptor T Cells). In addition, different replication-deficient adenoviral vectors (Ad5-CEA, Ad5-PSA, Ad-E6E7, ChAdOx1-MVA and Ad-transduced Dendritic cells) that were tested as anticancer vaccines have been demonstrated to induce strong antitumor immune response. However, the use of adenoviral vectors in gene therapy is limited by several factors such as pre-existing immunity to adenoviral vectors and high immunogenicity of the viruses. Thus, innovative strategies must be continually developed so as to overcome the obstacles of using adenoviral vectors in gene therapy.

Trends in patient-reported outcome use in early phase dose-finding oncology trials - an analysis of ClinicalTrials.gov

BACKGROUND

Patient-reported adverse events (AEs) may be a useful adjunct to clinician-assessed AEs for assessing tolerability in early phase, dose-finding oncology trials (DFOTs). We reviewed DFOTs on ClinicalTrials.gov to describe trends in patient-reported outcome (PRO) use.

METHODS

DFOTs commencing 01 January 2007 - 20 January 2020 with 'PROs' or 'quality of life' as an outcome were extracted and inclusion criteria confirmed. Study and PRO characteristics were extracted. Completed trials that reported PRO outcomes and published manuscripts on ClinicalTrials.gov were identified, and PRO reporting details were extracted.

RESULTS

5.3% (548/10 372) DFOTs included PROs as an outcome. 231 (42.2%) were eligible: adult (224, 97%), solid tumour (175, 75.8%), and seamless phase 1/2 (108, 46.8%). PRO endpoints were identified in more trials (2.3 increase/year, 95% CI: 1.6-2.9) from an increasing variety of countries (0.7/year) (95% CI: 0.4-0.9) over time. PROs were typically secondary endpoints (207, 89.6%). 15/77 (19.5%) completed trials reported results on the ClinicalTrials.gov results database, and of those eight included their PRO results. Eighteen trials had published manuscripts available on ClinicalTrials.gov. Three (16.7%) used PROs to confirm the maximum tolerated dose. No trials identified who completed the PROs or how PROs were collected.

CONCLUSIONS

PRO use in DFOT has increased but remains limited. Future work should explore the role of PROs in DFOT and determine what guidelines are needed to standardise PRO use.

Quality of Life Instruments and Trajectories After Pancreatic Cancer Resection: A Systematic Review

ABSTRACT

This systematic review aimed to investigate the instruments available to measure quality of life (QOL) after pancreatic cancer surgery and to describe short- and long-term QOL outcomes. A comprehensive literature search was completed using PubMed, Embase, and Medline from inception to March 2019. Studies investigating QOL outcomes in patients undergoing pancreatic cancer surgery who were 18 years or older were included. The main outcomes of interest were QOL instruments and short (≤6 months) and long term (>6 months) QOL outcomes. The overarching domains of physical, psychosocial, overall QOL, symptoms, and other were used to summarize QOL outcomes. Thirty-five studies reporting on 3573 patients were included. Fifteen unique QOL instruments were identified, of which 4 were disease-specific instruments. Most of the included studies reported no changes in QOL at short- and long-term follow-ups for the overarching domains. No difference in QOL outcomes was reported between different surgical approaches, except laparoscopic versus open distal pancreatectomy, and pancreaticoduodenectomy versus distal pancreatectomy. There are a wide range of instruments available to measure QOL outcomes in pancreatic cancer surgical patients, although only few are disease-specific. Most of the included studies reported no significant changes in QOL outcomes at short- or long-term follow-ups.

Pancreatic Cancer and Immunotherapy: A Clinical Overview

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease with high mortality. The vast majority of patients present with unresectable, advanced stage disease, for whom standard of care chemo(radio)therapy may improve survival by several months. Immunotherapy has led to a fundamental shift in the treatment of several advanced cancers. However, its efficacy in PDAC in terms of clinical benefit is limited, possibly owing to the immunosuppressive, inaccessible tumor microenvironment. Still, various immunotherapies have demonstrated the capacity to initiate local and systemic immune responses, suggesting an immune potentiating effect. In this review, we address PDAC's immunosuppressive tumor microenvironment and immune evasion methods and discuss a wide range of immunotherapies, including immunomodulators (i.e., immune checkpoint inhibitors, immune stimulatory agonists, cytokines and adjuvants), oncolytic viruses, adoptive cell therapies (i.e., T cells and natural killer cells) and cancer vaccines. We provide a general introduction to their working mechanism as well as evidence of their clinical efficacy and immune potentiating abilities in PDAC. The key to successful implementation of immunotherapy in this disease may rely on exploitation of synergistic effects between treatment combinations. Accordingly, future treatment approaches should aim to incorporate diverse and novel immunotherapeutic strategies coupled with cytotoxic drugs and/or local ablative treatment, targeting a wide array of tumor-induced immune escape mechanisms.

Nonreplicating Adenoviral Vectors: Improving Tropism and Delivery of Cancer Gene Therapy

Recent preclinical and clinical studies have used viral vectors in gene therapy research, especially nonreplicating adenovirus encoding strategic therapeutic genes for cancer treatment. Adenoviruses were the first DNA viruses to go into therapeutic development, mainly due to well-known biological features: stability in vivo, ease of manufacture, and efficient gene delivery to dividing and nondividing cells. However, there are some limitations for gene therapy using adenoviral vectors, such as nonspecific transduction of normal cells and liver sequestration and neutralization by antibodies, especially when administered systemically. On the other hand, adenoviral vectors are amenable to strategies for the modification of their biological structures, including genetic manipulation of viral proteins, pseudotyping, and conjugation with polymers or biological membranes. Such modifications provide greater specificity to the target cell and better safety in systemic administration; thus, a reduction of antiviral host responses would favor the use of adenoviral vectors in cancer immunotherapy. In this review, we describe the structural and molecular features of nonreplicating adenoviral vectors, the current limitations to their use, and strategies to modify adenoviral tropism, highlighting the approaches that may allow for the systemic administration of gene therapy.

Neoadjuvant Gene-Mediated Cytotoxic Immunotherapy for Non-Small-Cell Lung Cancer: Safety and Immunologic Activity

Gene-mediated cytotoxic immunotherapy (GMCI) is an immuno-oncology approach involving local delivery of a replication-deficient adenovirus expressing herpes simplex thymidine kinase (AdV-tk) followed by anti-herpetic prodrug activation that promotes immunogenic tumor cell death, antigen-presenting cell activation, and T cell stimulation. This phase I dose-escalation pilot trial assessed bronchoscopic delivery of AdV-tk in patients with suspected lung cancer who were candidates for surgery. A single intra-tumoral AdV-tk injection in three dose cohorts (maximum 1012 viral particles) was performed during diagnostic staging, followed by a 14-day course of the prodrug valacyclovir, and subsequent surgery 1 week later. Twelve patients participated after appropriate informed consent. Vector-related adverse events were minimal. Immune biomarkers were evaluated in tumor and blood before and after GMCI. Significantly increased infiltration of CD8+ T cells was found in resected tumors. Expression of activation, inhibitory, and proliferation markers, such as human leukocyte antigen (HLA)-DR, CD38, Ki67, PD-1, CD39, and CTLA-4, were significantly increased in both the tumor and peripheral CD8+ T cells. Thus, intratumoral AdV-tk injection into non-small-cell lung cancer (NSCLC) proved safe and feasible, and it effectively induced CD8+ T cell activation. These data provide a foundation for additional clinical trials of GMCI for lung cancer patients with potential benefit if combined with other immune therapies.

The Present Status of Immuno-Oncolytic Viruses in the Treatment of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is the fifth leading cause of cancer-related death in Western countries. The incidence of PDAC has increased over the last 40 years and is projected to be the second leading cause of cancer death by 2030. Despite aggressive treatment regimens, prognosis for patients diagnosed with PDAC is very poor; PDAC has the lowest 5-year survival rate for any form of cancer in the United States (US). PDAC is very rarely detected in early stages when surgical resection can be performed. Only 20% of cases are suitable for surgical resection; this remains the only curative treatment when combined with adjuvant chemotherapy. Treatment regimens excluding surgical intervention such as chemotherapeutic treatments are associated with adverse effects and genetherapy strategies also struggle with lack of specificity and/or efficacy. The lack of effective treatments for this disease highlights the necessity for innovation in treatment options for patients diagnosed with early- to late-phase PDAC and immuno-oncolytic viruses (OVs) have been of particular interest since 2006 when the first oncolytic virus was approved as a therapy for nasopharyngeal cancers in China. Interest resurged in 2015 when T-Vec, an oncolytic herpes simplex virus, was approved in the United States for treatment of advanced melanoma. While many vectors have been explored, few show promise as treatment for pancreatic cancer, and fewer still have progressed to clinical trial evaluation. This review outlines recent strategies in the development of OVs targeting treatment of PDAC, current state of preclinical and clinical investigation and application.

The impact of neoadjuvant and adjuvant immunotherapy on the survival of pancreatic cancer patients: a retrospective analysis

Background

Immunotherapy has become an essential part of cancer treatment after showing great efficacy in various malignancies. However, its effectiveness in pancreatic ductal adenocarcinoma (PDAC), especially in resectable pancreatic cancer, has not been studied. The primary objective of this study is to compare the OS impact of immunotherapy between PDAC patients who receive neoadjuvant immunotherapy and patients who receive adjuvant immunotherapy. The secondary objective is to investigate the impact of neoadjuvant and adjuvant immunotherapy in combination with chemotherapy and chemoradiation by performing subset analyses of these two groups.

Methods

Patients diagnosed with PDAC between 2004 and 2016 were identified from the National Cancer Database (NCDB). Multivariable Cox proportional hazard analysis was performed to examine the effect of neoadjuvant and adjuvant immunotherapy in combination with chemotherapy and chemoradiation on the OS of the patients. The multivariable analysis was adjusted for essential factors such as the age at diagnosis, sex, race, education, income, place of living insurance status, hospital type, comorbidity score, and year of diagnosis.

Results

Overall, 526 patients received immunotherapy. Among whom, 408/526 (77.57%) received neoadjuvant immunotherapy, and the remaining 118/526 (22.43%) received adjuvant immunotherapy. There was no significant difference in OS between neoadjuvant and adjuvant immunotherapy (HR: 1.06, CI: 0.79–1.41; p < 0.714) in the multivariable analysis. In the univariate neoadjuvant treatment subset analysis, immunotherapy was associated with significantly improved OS compared to no immunotherapy (HR: 0.88, CI: 0.78–0.98; p < 0.026). This benefit disappeared in the multivariable analysis. However, after patients were stratified by educational level, the multivariable Cox regression analysis revealed that neoadjuvant immunotherapy was associated with significantly improved OS (HR: 0.86, CI: 0.74–0.99; p < 0.04) compared to no immunotherapy only in patients with high-level of education, but not in patients with low-level of education.

Conclusion

In this study, no difference in the OS between patients who received neoadjuvant immunotherapy and patients who received adjuvant immunotherapy was noticed. Future studies comparing neoadjuvant adjuvant immunotherapy combined with chemotherapy, radiation therapy, and chemoradiation are needed.

The impact of immunotherapy on the survival of pancreatic adenocarcinoma patients who received definitive surgery of the pancreatic tumor: a retrospective analysis of the National Cancer Database

BACKGROUND

Immunotherapy has paved the way for new therapeutic opportunities in cancer but has failed to show any efficacy in Pancreatic Adenocarcinoma (PDAC), and its therapeutic role remains unclear. The objective of this study is to examine the impact of immunotherapy in combination with chemotherapy, RT, and chemoradiation on the overall survival (OS) of PDAC patients who received definitive surgery of the tumor using the National Cancer Database (NCDB).

METHODS

Patients with PDAC who received definitive surgery of the pancreatic tumor and were diagnosed between 2004 and 2016 from the NCDB were identified. Cox proportional hazard analysis was used to assess the survival difference between patients who received chemotherapy plus immunotherapy and chemoradiation therapy plus immunotherapy and their counterparts who only receive these treatments without immunotherapy. The multivariable analysis was adjusted for age of diagnosis, race, sex, place of living, income, education, treatment facility type, insurance status, year of diagnosis, and treatment types such as chemotherapy and radiation therapy.

RESULTS

In total, 63,154 PDAC patients who received definitive surgery of the tumor were included in the analysis. Among the 63,154 patients, 636 (1.01%) received immunotherapy. Among patients who received chemotherapy (21,355), and chemoradiation (21,875), 157/21,355 (0.74%) received chemotherapy plus immunotherapy, and 451/21,875 (2.06%) received chemoradiation plus immunotherapy. Patients who received chemoradiation plus immunotherapy had significantly improved median OS compared to patients who only received chemoradiation with an absolute median OS benefit of 5.7 [29.31 vs. 23.66, p < 0.0001] months. In the multivariable analysis, patients who received immunotherapy had significantly improved OS compared to patients who did not receive immunotherapy (HR: 0.900; CI: 0.814-0.995; P < 0.039). Patients who received chemoradiation plus immunotherapy had significantly improved OS compared to their counterparts who only received chemoradiation without immunotherapy (HR: 0.852 CI: 0.757-0.958; P < 0.008).

CONCLUSIONS

In this study, the addition of immunotherapy to chemoradiation therapy was associated with significantly improved OS in PDAC patients who received definitive surgery. The study warrants further future clinical trials of immunotherapy in PDAC.

Phase I study of gene-mediated cytotoxic immunotherapy with AdV-tk as adjuvant to surgery and radiation for pediatric malignant glioma and recurrent ependymoma

BACKGROUND

Gene-mediated cytotoxic immunotherapy (GMCI) is a tumor-specific immune stimulatory strategy implemented through local delivery of aglatimagene besadenovec (AdV-tk) followed by anti-herpetic prodrug. GMCI induces T-cell dependent tumor immunity and synergizes with radiotherapy. Clinical trials in adult malignant gliomas demonstrated safety and potential efficacy. This is the first trial of GMCI in pediatric brain tumors.

METHODS

This phase I dose escalation study was conducted to evaluate GMCI in patients 3 years of age or older with malignant glioma or recurrent ependymoma. AdV-tk at doses of 1 × 1011 and 3 × 1011 vector particles (vp) was injected into the tumor bed at the time of surgery followed by 14 days of valacyclovir. Radiation started within 8 days of surgery, and if indicated, chemotherapy began after completion of valacyclovir.

RESULTS

Eight patients (6 glioblastoma, 1 anaplastic astrocytoma, 1 recurrent ependymoma) were enrolled and completed therapy: 3 on dose level 1 and 5 on dose level 2. Median age was 12.5 years (range 7-17) and Lansky/Karnofsky performance scores were 60-100. Five patients had multifocal/extensive tumors that could not be resected completely and 3 had gross total resection. There were no dose-limiting toxicities. The most common possibly GMCI-related adverse events included Common Terminology Criteria for Adverse Events grade 1-2 fever, fatigue, and nausea/vomiting. Three patients, in dose level 2, lived more than 24 months, with 2 alive without progression 37.3 and 47.7 months after AdV-tk injection.

CONCLUSIONS

GMCI can be safely combined with radiation therapy with or without temozolomide in pediatric patients with brain tumors and the present results strongly support further investigation.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov NCT00634231.

Landscape of Health-Related Quality of Life in Patients With Early-Stage Pancreatic Cancer Receiving Adjuvant or Neoadjuvant Chemotherapy: A Systematic Literature Review

OBJECTIVES

Pancreatic resection is associated with postoperative morbidity and reduced quality of life (QoL). A systematic literature review was conducted to understand the patient-reported outcome measure (PROM) landscape in early-stage pancreatic cancer (PC).

METHODS

Databases/registries (through January 24, 2019) and conference abstracts (2014-2017) were searched. Study quality was assessed using the Newcastle-Ottawa Scale/Cochrane risk-of-bias tool. Searches were for general (resectable PC, adjuvant/neoadjuvant, QoL) and supplemental studies (resectable PC, European Organisation for Research and Treatment of Cancer QoL Questionnaire [QLQ] - Pancreatic Cancer [PAN26]).

RESULTS

Of 750 studies identified, 39 (general, 22; supplemental, 17) were eligible: 32 used QLQ Core 30 (C30) and/or QLQ-PAN26, and 15 used other PROMs. Baseline QLQ-C30 global health status/QoL scores in early-stage PC were similar to all-stage PC reference values but lower than all-stage-all-cancer values. The QoL declined after surgery, recovered to baseline in 3 to 6 months, and then generally stabilized. A minimally important difference (MID) of 10 was commonly used for QLQ-C30 but was not established for QLQ-PAN26.

CONCLUSIONS

In early-stage PC, QLQ-C30 and QLQ-PAN26 are the most commonly used PROMs. Baseline QLQ-C30 global health status/QoL scores suggested a high humanistic burden. Immediately after surgery, QoL declined but seemed stable over the longer term. The QLQ-C30 MID may elucidate the clinical impact of treatment on QoL; MID for QLQ-PAN26 needs to be established.

Alpha-Herpesvirus Thymidine Kinase Genes Mediate Viral Virulence and Are Potential Therapeutic Targets

Alpha-herpesvirus thymidine kinase (TK) genes are virulence-related genes and are nonessential for viral replication; they are often preferred target genes for the construction of gene-deleted attenuated vaccines and genetically engineered vectors for inserting and expressing foreign genes. The enzymes encoded by TK genes are key kinases in the nucleoside salvage pathway and have significant substrate diversity, especially the herpes simplex virus 1 (HSV-1) TK enzyme, which phosphorylates four nucleosides and various nucleoside analogues. Hence, the HSV-1 TK gene is exploited for the treatment of viral infections, as a suicide gene in antitumor therapy, and even for the regulation of stem cell transplantation and treatment of parasitic infection. This review introduces the effects of α-herpesvirus TK genes on viral virulence and infection in the host and classifies and summarizes the current main application domains and potential uses of these genes. In particular, mechanisms of action, clinical limitations, and antiviral and antitumor therapy development strategies are discussed.

Intrapleural immunotherapy: An update on emerging treatment strategies for pleural malignancy

OBJECTIVES

Malignant pleural mesothelioma and malignant pleural effusions are a major therapeutic challenge, and are associated with impairment in quality of life and increased mortality. Advances in systemic therapies of malignant pleural mesothelioma have demonstrated limited clinical benefit and there is ongoing interest in intrapleural immunotherapies which have been demonstrated to be well tolerated overall with variable clinical responses. We have reviewed the literature to provide a comprehensive summary of novel intrapleural immunotherapeutic paradigms, including oncolytic virus therapy, gene-mediated cytotoxic immunotherapy, direct cytokine-mediated immunotherapies, innate immunomodulators and adoptive transfer of intrapleural chimeric antigen receptor T-cell therapy.

DATA SOURCES

A review of PubMed for original manuscripts and conference reports published between 1998 and 2018 pertaining to intrapleural immunotherapy, as well as examination of reference lists from reviewed manuscripts.

STUDY SELECTION

Human clinical trials on intrapleural immunotherapies in subjects with malignant pleural mesothelioma or malignant pleural effusion were included in this review, including some relevant preclinical studies and anticipated ongoing trials reported on Clinicaltrials.gov.

RESULTS

Twenty-six clinical trials were identified, in addition to three trials currently in progress.

CONCLUSION

Intrapleural immunotherapies for pleural malignancy have demonstrated promise with regard to generating durable tumor-specific immune responses with possible clinical benefits which merit further investigation as part of multimodal chemotherapeutic and immunotherapeutic regimens.

Synergistic effect of immunotherapy and radiotherapy in non-small cell lung cancer: current clinical trials and prospective challenges

Lately, the success of ICIs has drastically changed the landscape of cancer treatment, and several immune checkpoint inhibitors (ICIs) have been approved by the US Food and Drug Administration (FDA) for advanced non-small cell lung cancer (NSCLC). However, numerous patients are resistant to ICIs and require additional procedures for better efficacy results. Thus, combination therapy is urgently needed to strengthen the anti-tumor immunity. A variety of preclinical and clinical studies combining ICIs with radiotherapy (RT) have demonstrated that the combination could induce synergistic effects, as RT overcomes the resistance to ICIs. However, the underlying mechanism of the synergistic effect and the optimal arrangement of the combination therapy are indecisive now. Hence, this review was conducted to provide an update on the current clinical trial results and highlighted the ongoing trials. We also discussed the optimal parameters in clinical trials, including radiation dose, radiation fractionation, radiation target field, and sequencing of combination therapy. In this review, we found that combination therapy showed stronger anti-tumor immunity with tolerable toxicities in clinical trials. However, the best combination mode and potential biomarkers for the target patients in combination therapy are still unclear.

Impact of Immunotherapy after Resection of Pancreatic Cancer

BACKGROUND

Adjuvant immunotherapy has improved outcomes in patients with advanced melanoma; however, the potential benefit for patients with pancreatic ductal adenocarcinoma (PDAC) remains unknown. The aim of this study was to determine the impact of adjuvant chemotherapy and immunotherapy (CTx-IT) compared with CTx alone on patient survival after resection of PDAC.

STUDY DESIGN

Patients who underwent resection of PDAC from 2004 to 2015 were identified from the National Cancer Database. Univariate and multivariate Cox proportional hazards models were used to determine predictors of overall survival (OS) based on the type of adjuvant therapy received. Patients who received adjuvant immunotherapy were compared with those who received adjuvant CTx alone by propensity score matching.

RESULTS

Of 21,313 patients who received curative-intent resection for PDAC followed by adjuvant systemic therapy, 269 (1.3%) patients were treated with adjuvant CTx-IT. Propensity score matching resulted in a cohort of 477 patients: (229 CTx only and 248 CTx-IT). The 5-year OS was higher in the CTx-IT group compared with CTx alone (29.2% vs 18.3%; p = 0.0045). On multivariate analysis, the addition of adjuvant immunotherapy was associated was improved overall survival (hazard ratio 0.74; p = 0.007).

CONCLUSIONS

The addition of adjuvant immunotherapy to chemotherapy is associated with improved survival compared with chemotherapy alone after curative-intent resection of pancreatic adenocarcinoma. Future research is warranted to match specific immunotherapy agents with susceptible patient populations to improve outcomes for this aggressive disease.

Preclinical investigation of combined gene-mediated cytotoxic immunotherapy and immune checkpoint blockade in glioblastoma

Background

Combined immunotherapy approaches are promising cancer treatments. We evaluated anti-programmed cell death protein 1 (PD-1) treatment combined with gene-mediated cytotoxic immunotherapy (GMCI) performed by intratumoral injection of a prodrug metabolizing nonreplicating adenovirus (AdV-tk), providing in situ chemotherapy and immune stimulation.

Methods

The effects of GMCI on PD ligand 1 (PD-L1) expression in glioblastoma were investigated in vitro and in vivo. The efficacy of the combination was investigated in 2 syngeneic mouse glioblastoma models (GL261 and CT-2A). Immune infiltrates were analyzed by flow cytometry.

Results

GMCI upregulated PD-L1 expression in vitro and in vivo. Both GMCI and anti-PD-1 increased intratumoral T-cell infiltration. A higher percentage of long-term survivors was observed in mice treated with combined GMCI/anti-PD-1 relative to single treatments. Long-term survivors were protected from tumor rechallenge, demonstrating durable memory antitumor immunity. GMCI led to elevated interferon gamma positive T cells and a lower proportion of exhausted double positive PD1+TIM+CD8+ T cells. GMCI also increased PD-L1 levels on tumor cells and infiltrating macrophages/microglia. Our data suggest that anti-PD-1 treatment improves the effectiveness of GMCI by overcoming interferon-induced PD-L1-mediated inhibitory signals, and GMCI improves anti-PD-1 efficacy by increasing tumor-infiltrating T-cell activation.

Conclusions

Our data show that the GMCI/anti-PD-1 combination is well tolerated and effective in glioblastoma mouse models. These results support evaluation of this combination in glioblastoma patients.

Engineered Thymidine-Active Deoxycytidine Kinase for Bystander Killing of Malignant Cells

Suicide transgenes encode proteins that are either capable of activating specific prodrugs into cytotoxic antimetabolites that can trigger cancer cell apoptosis or are capable of directly inducing apoptosis. Suicide gene therapy of cancer (SGTC) involves the targeted or localized delivery of suicide transgene sequences into tumor cells by means of various gene delivery vehicles. SGTC that operates via the potentiation of small-molecule pharmacologic agents can elicit the elimination of cancer cells within a tumor beyond only those cells successfully transduced. Such "bystander effects ", typically mediated by the spread of activated cytotoxic antimetabolites from the transduced cells expressing the suicide transgene to adjacent cells in the tumor, can lead to a significant reduction of the tumor mass without the requirement of transduction of a high percentage of cells within the tumor. The spread of activated cytotoxic molecules to adjacent cells is mediated primarily by diffusion and normally involves gap junctional intercellular communications (GJIC). We have developed a novel SGTC system based on viral vector-mediated delivery of an engineered variant of human deoxycytidine kinase (dCK), which is capable of phosphorylating uridine- and thymidine-based nucleoside analogues that are not substrates for wild-type dCK, such as bromovinyl deoxyuridine (BVdU) and L-deoxythymidine (LdT). Since our dCK-based SGTC system is capable of mediating strong bystander cell killing, it holds promise for clinical translation. In this chapter, we detail the key procedures for the preparation of recombinant lentivectors for the delivery of engineered dCK, transduction of tumor cells, and evaluation of bystander cell killing effects in vitro and in vivo.

An Antibody Designed to Improve Adoptive NK-Cell Therapy Inhibits Pancreatic Cancer Progression in a Murine Model

Natural killer (NK) cells are primary immune cells that target cancer cells and can be used as a therapeutic agent against pancreatic cancer. Despite the usefulness of NK cells, NK-cell therapy is limited by tumor cell inhibition of NK-cell homing to tumor sites, thereby preventing a sustained antitumor immune response. One approach to successful cancer immunotherapy is to increase trafficking of NK cells to tumor tissues. Here, we developed an antibody-based NK-cell-homing protein, named NK-cell-recruiting protein-conjugated antibody (NRP-body). The effect of NRP-body on infiltration of NK cells into primary and metastatic pancreatic cancer was evaluated in vitro and in murine pancreatic ductal adenocarcinoma models. The NRP-body increased NK-cell infiltration of tumors along a CXCL16 gradient (CXCL16 is cleaved from the NRP-body by furin expressed on the surface of pancreatic cancer cells). CXCL16 induced NK-cell infiltration by activating RhoA via the ERK signaling cascade. Administration of the NRP-body to pancreatic cancer model mice increased tumor tissue infiltration of transferred NK cells and reduced the tumor burden compared with that in controls. Overall survival of NRP-body-treated mice (even the metastasis models) was higher than that of mice receiving NK cells alone. In conclusion, increasing NK-cell infiltration into tumor tissues improved response to this cancer immunotherapy. The combination of an NRP-body with NK-cell therapy might be useful for treating pancreatic cancer.

Gene Therapy for Pancreatic Diseases: Current Status

The pancreas is a key organ involved in digestion and endocrine functions in the body. The major diseases of the pancreas include pancreatitis, pancreatic cancer, cystic diseases, pancreatic divisum, islet cell tumors, endocrine tumors, diabetes mellitus, and pancreatic pain induced by these diseases. While various therapeutic methodologies have been established to date, however, the improvement of conventional treatments and establishment of novel therapies are essential to improve the efficacy. For example, conventional therapeutic options, including chemotherapy, are not effective against pancreatic cancer, and despite improvements in the last decade, the mortality rate has not declined and is estimated to become the second cause of cancer-related deaths by 2030. Therefore, continuous efforts focus on the development of novel therapeutic options. In this review, we will summarize the progress toward the development of gene therapies for pancreatic diseases, with an emphasis on recent preclinical studies and clinical trials. We aim to identify new areas for improvement of the current methodologies and new strategies that will lead to safe and effective gene therapeutic approaches in pancreatic diseases.

Advances in oncolytic adenovirus therapy for pancreatic cancer

Survival rates for pancreatic cancer patients have remained unchanged for the last four decades. The most aggressive, and most common, type of pancreatic cancer is pancreatic ductal adenocarcinoma (PDAC), which has the lowest 5-year survival rate of all cancers globally. The poor prognosis is typically due to late presentation of often non-specific symptoms and rapid development of resistance to all current therapeutics, including the standard-of-care cytotoxic drug gemcitabine. While early surgical intervention can significantly prolong patient survival, there are few treatment options for late-stage non-resectable metastatic disease, resulting in mostly palliative care. In addition, a defining feature of pancreatic cancer is the immunosuppressive and impenetrable desmoplastic stroma that blocks access to tumour cells by therapeutic drugs. The limited effectiveness of conventional chemotherapeutics reveals an urgent need to develop novel therapies with different mechanisms of action for this malignancy. An emerging alternative to current therapeutics is oncolytic adenoviruses; these engineered biological agents have proven efficacy and tumour-selectivity in preclinical pancreatic cancer models, including models of drug-resistant cancer. Safety of oncolytic adenoviral mutants has been extensively assessed in clinical trials with only limited toxicity to normal healthy tissue being reported. Promising efficacy in combination with gemcitabine was demonstrated in preclinical and clinical studies. A recent surge in novel adenoviral mutants entering clinical trials for pancreatic cancer indicates improved efficacy through activation of the host anti-tumour responses. The potential for adenoviruses to synergise with chemotherapeutics, activate anti-tumour immune responses, and contribute to stromal dissemination render these mutants highly attractive candidates for improved patient outcomes. Currently, momentum is gathering towards the development of systemically-deliverable mutants that are able to overcome anti-viral host immune responses, erythrocyte binding and hepatic uptake, to promote elimination of primary and metastatic lesions. This review will cover the key components of pancreatic cancer oncogenesis; novel oncolytic adenoviruses; clinical trials; and the current progress in overcoming the challenges of systemic delivery.

Phase I Study of Intrapleural Gene-Mediated Cytotoxic Immunotherapy in Patients with Malignant Pleural Effusion

Gene-mediated cytotoxic immunotherapy (GMCI) is an immune strategy implemented through local delivery of an adenovirus-based vector expressing the thymidine kinase gene (aglatimagene besadenovec, AdV-tk) followed by anti-herpetic prodrug valacyclovir. A phase I dose escalation trial of GMCI followed by chemotherapy was conducted in patients with malignant pleural effusion (MPE). AdV-tk was administered intrapleurally (IP) in three cohorts at a dose of 1 × 10¹² to 10¹³ vector particles. Primary endpoint was safety; secondary endpoints included response rate, progression-free survival, and overall survival. Nineteen patients were enrolled: median age 67 years; 14 with malignant mesothelioma, 4 non-small-cell lung cancer (NSCLC), and 1 breast cancer. There were no dose limiting toxicities. All 3 patients in cohort 2 experienced transient cytokine release syndrome (CRS). Addition of celecoxib in cohort 3 reduced the incidence and severity of CRS (none > grade 2). Three patients are alive (23-33 months after GMCI), and 3 of 4 NSCLC patients had prolonged disease stabilization; one is alive 29 months after GMCI, 3.6 years after initial diagnosis. GMCI was safe and well tolerated in combination with chemotherapy in patients with MPE and showed encouraging response. Further studies are warranted to determine efficacy.

Immunotherapy and gene therapy as novel treatments for cancer

The immune system interacts closely with tumors during the disease development and progression to metastasis. The complex communication between the immune system and the tumor cells can prevent or promote tumor growth. New therapeutic approaches harnessing protective immunological mechanisms have recently shown very promising results. This is performed by blocking inhibitory signals or by activating immunological effector cells directly. Immune checkpoint blockade with monoclonal antibodies directed against the inhibitory immune receptors CTLA-4 and PD-1 has emerged as a successful treatment approach for patients with advanced melanoma. Ipilimumab is an anti-CTLA-4 antibody which demonstrated good results when administered to patients with melanoma. Gene therapy has also shown promising results in clinical trials. Particularly, Herpes simplex virus (HSV)-mediated delivery of the HSV thymidine kinase (TK) gene to tumor cells in combination with ganciclovir (GCV) may provide an effective suicide gene therapy for destruction of glioblastomas, prostate tumors and other neoplasias by recruiting tumor-infiltrating lymphocytes into the tumor. The development of new treatment strategies or combination of available innovative therapies to improve cell cytotoxic T lymphocytes trafficking into the tumor mass and the production of inhibitory molecules blocking tumor tissue immune-tolerance are crucial to improve the efficacy of cancer therapy.

Gene Therapy for Pancreatic Cancer: Specificity, Issues and Hopes

A recent death projection has placed pancreatic ductal adenocarcinoma as the second cause of death by cancer in 2030. The prognosis for pancreatic cancer is very poor and there is a great need for new treatments that can change this poor outcome. Developments of therapeutic innovations in combination with conventional chemotherapy are needed urgently. Among innovative treatments the gene therapy offers a promising avenue. The present review gives an overview of the general strategy of gene therapy as well as the limitations and stakes of the different experimental in vivo models, expression vectors (synthetic and viral), molecular tools (interference RNA, genome editing) and therapeutic genes (tumor suppressor genes, antiangiogenic and pro-apoptotic genes, suicide genes). The latest developments in pancreatic carcinoma gene therapy are described including gene-based tumor cell sensitization to chemotherapy, vaccination and adoptive immunotherapy (chimeric antigen receptor T-cells strategy). Nowadays, there is a specific development of oncolytic virus therapies including oncolytic adenoviruses, herpes virus, parvovirus or reovirus. A summary of all published and on-going phase-1 trials is given. Most of them associate gene therapy and chemotherapy or radiochemotherapy. The first results are encouraging for most of the trials but remain to be confirmed in phase 2 trials.

Immunotherapy for patients with advanced pancreatic carcinoma: a promising treatment

There are limited data on the safety and efficacy of immunotherapy for patients with advanced pancreatic cancer (APC). A meta-analysis of single-arm trials is proposed to assess the efficacy and safety of immunotherapy for APC. Eighteen relevant studies involving 527 patients were identified. The pooled disease control rate (DCR), overall survival (OS), progression free survival (PFS), and 1-year survival rate were estimated as 59.32%, 7.90 months, 4.25 months, and 30.12%, respectively. Subgroup analysis showed that the pooled OS, PFS, and 1-year survival rate were significantly higher for autologous activated lymphocyte therapy compared with peptide-based vaccine therapy (OS: 8.28 months vs. 7.40 months; PFS: 6.04 months vs. 3.86 months; 1-year survival rate: 37.17% vs. 19.74%). Another subgroup analysis demonstrated that the pooled endpoints were estimated as obviously higher for immunotherapy plus chemotherapy compared with immunotherapy alone (DCR: 62.51% vs. 47.63%; OS: 8.67 months vs. 4.91 months; PFS: 4.91 months vs. 3.34 months; 1-year survival rate: 32.32% vs. 21.43%). Of the included trials, seven trials reported no treatment related adverse events , five trials reported (16.6 ± 3.9) % grade 3 adverse events and no grade 4 adverse events. In conclusion, immunotherapy is safe and effective in the treatment of APC.

Second pancreatectomy for recurrent pancreatic ductal adenocarcinoma in the remnant pancreas: A pooled analysis

OBJECTIVES

The aim of this study was to examine the outcomes of second pancreatectomy for the treatment of recurrent pancreatic ductal adenocarcinoma (PDAC) in the remnant pancreas.

METHOD

Search of the PubMed database was undertaken to identify relevant English language studies. Pooled individually data were examined for clinical outcomes after second pancreatectomy for recurrent PDAC.

RESULTS

A total of 19 articles involving 55 patients were eligible for inclusion. The median disease-free interval after initial resection was 33 (range 7-143) months. Of the 55 patients reported, 52 (94.5%) patients underwent completion total pancreatectomy in the second operation for recurrences, including 15 patients who developed recurrences more than 5 years after the initial operation. There was no perioperative death. The 1-, 3- and 5-year overall survival rate after the second pancreatectomy was 82.2%, 49.2% and 40.6% respectively.

CONCLUSION

Second pancreatectomy for recurrent PDAC can be performed safely with long-term survival in selected patients.

Enzyme/Prodrug Systems for Cancer Gene Therapy

The use of enzyme/prodrug system has gained attention because it could help improve the efficacy and safety of conventional cancer chemotherapies. In this approach, cancer cells are first transfected with a gene that can express an enzyme with ability to convert a non-toxic prodrug into its active cytotoxic form. As a result, the activated prodrug could kill the transfected cancer cells. Despite the significant progress of different suicide gene therapy protocols in preclinical studies and early clinical trials, none has reached the clinic due to several shortcomings. These include slow prodrug-drug conversion rate, low transfection/transduction efficiency of the vectors and nonspecific toxicity/immunogenicity related to the delivery systems, plasmid DNA, enzymes and/or prodrugs. This mini review aims at providing an overview of the most widely used enzyme/prodrug systems with emphasis on reporting the results of the recent preclinical and clinical studies.

Current clinical trials testing the combination of immunotherapy with radiotherapy

Increasing evidence demonstrates that radiation acts as an immune stimulus, recruiting immune mediators that enable anti-tumor responses within and outside the radiation field. There has been a rapid expansion in the number of clinical trials harnessing radiation to enhance antitumor immunity. If positive, results of these trials will lead to a paradigm shift in the use of radiotherapy. In this review, we discuss the rationale for trials combining radiation with various immunotherapies, provide an update of recent clinical trial results and highlight trials currently in progress. We also address issues pertaining to the optimal incorporation of immunotherapy with radiation, including sequencing of treatment, radiation dosing and evaluation of clinical trial endpoints.

Surgical immune interventions for solid malignancies

BACKGROUND

The purpose of this study was to systematically review clinically translatable immunotherapeutic agents that are delivered regionally for solid malignancies.

DATA SOURCES

PubMed and ClinicalTrials.gov were searched for published and registered clinical trials, respectively. The search yielded 334 relevant publications, of which 116 articles were included for review after exclusion criteria were applied.

CONCLUSIONS

There has been an increase in the regional administration of cell-based and viral vector-based clinical trials over the last 5 years. Surgical interventions have been developed for intrapleural, intracranial, intraperitoneal, and intratumoral routes of access to enhance the local delivery of these therapies. Multimodality therapies that combine regional immunotherapy with other local and systemic therapies are demonstrating continued growth as the field of immunotherapy continues to expand.

Coinhibitory Pathways in Immunotherapy for Cancer

The immune system is capable of recognizing tumors and eliminates many early malignant cells. However, tumors evolve to evade immune attack, and the tumor microenvironment is immunosuppressive. Immune responses are regulated by a number of immunological checkpoints that promote protective immunity and maintain tolerance. T cell coinhibitory pathways restrict the strength and duration of immune responses, thereby limiting immune-mediated tissue damage, controlling resolution of inflammation, and maintaining tolerance to prevent autoimmunity. Tumors exploit these coinhibitory pathways to evade immune eradication. Blockade of the PD-1 and CTLA-4 checkpoints is proving to be an effective and durable cancer immunotherapy in a subset of patients with a variety of tumor types, and additional combinations are further improving response rates. In this review we discuss the immunoregulatory functions of coinhibitory pathways and their translation to effective immunotherapies for cancer.

Phase II multicenter study of gene-mediated cytotoxic immunotherapy as adjuvant to surgical resection for newly diagnosed malignant glioma

BACKGROUND

Despite aggressive standard of care (SOC) treatment, survival of malignant gliomas remains very poor. This Phase II, prospective, matched controlled, multicenter trial was conducted to assess the safety and efficacy of aglatimagene besadenovec (AdV-tk) plus valacyclovir (gene-mediated cytotoxic immunotherapy [GMCI]) in combination with SOC for newly diagnosed malignant glioma patients.

METHODS

Treatment cohort patients received SOC + GMCI and were enrolled at 4 institutions from 2006 to 2010. The preplanned, matched-control cohort included all concurrent patients meeting protocol criteria and SOC at a fifth institution. AdV-tk was administered at surgery followed by SOC radiation and temozolomide. Subset analyses were preplanned, based on prognostic factors: pathological diagnosis (glioblastoma vs others) and extent of resection.

RESULTS

Forty-eight patients completed SOC + GMCI, and 134 met control cohort criteria. Median overall survival (OS) was 17.1 months for GMCI + SOC versus 13.5 months for SOC alone (P = .0417). Survival at 1, 2, and 3 years was 67%, 35%, and 19% versus 57%, 22%, and 8%, respectively. The greatest benefit was observed in gross total resection patients: median OS of 25 versus 16.9 months (P = .0492); 1, 2, and 3-year survival of 90%, 53%, and 32% versus 64%, 28% and 6%, respectively. There were no dose-limiting toxicities; fever, fatigue, and headache were the most common GMCI-related symptoms.

CONCLUSIONS

GMCI can be safely combined with SOC in newly diagnosed malignant gliomas. Survival outcomes were most notably improved in patients with minimal residual disease after gross total resection. These data should help guide future immunotherapy studies and strongly support further evaluation of GMCI for malignant gliomas.

CLINICAL TRIAL REGISTRY

ClinicalTrials.gov NCT00589875.

Improving the safety of cell therapy with the TK-suicide gene

While opening new frontiers for the cure of malignant and non-malignant diseases, the increasing use of cell therapy poses also several new challenges related to the safety of a living drug. The most effective and consolidated cell therapy approach is allogeneic hematopoietic stem cell transplantation (HSCT), the only cure for several patients with high-risk hematological malignancies. The potential of allogeneic HSCT is strictly dependent on the donor immune system, particularly on alloreactive T lymphocytes, that promote the beneficial graft-versus-tumor effect (GvT), but may also trigger the detrimental graft-versus-host-disease (GvHD). Gene transfer technologies allow to manipulate donor T-cells to enforce GvT and foster immune reconstitution, while avoiding or controlling GvHD. The suicide gene approach is based on the transfer of a suicide gene into donor lymphocytes, for a safe infusion of a wide T-cell repertoire, that might be selectively controlled in vivo in case of GvHD. The herpes simplex virus thymidine kinase (HSV-TK) is the suicide gene most extensively tested in humans. Expression of HSV-TK in donor lymphocytes confers lethal sensitivity to the anti-herpes drug, ganciclovir. Progressive improvements in suicide genes, vector technology and transduction protocols have allowed to overcome the toxicity of GvHD while preserving the antitumor efficacy of allogeneic HSCT. Several phase I-II clinical trials in the last 20 years document the safety and the efficacy of HSV-TK approach, able to maintain its clear value over the last decades, in the rapidly progressing horizon of cancer cellular therapy.