Pre-emptive and therapeutic adoptive immunotherapy for nasopharyngeal carcinoma: Phenotype and effector function of T cells impact on clinical response

Geographic EBV variants confound disease-specific variant interpretation and predict variable immune therapy responses

ABSTRACT

Epstein-Barr virus (EBV) is a potent carcinogen linked to hematologic and solid malignancies and causes significant global morbidity and mortality. Therapy using allogeneic EBV-specific lymphocytes shows promise in certain populations, but the impact of EBV genome variation on these strategies remains unexplored. To address this, we sequenced 217 EBV genomes, including hematologic malignancies from Guatemala, Peru, Malawi, and Taiwan, and analyzed them alongside 1307 publicly available EBV genomes from cancer, nonmalignant diseases, and healthy individuals across Africa, Asia, Europe, North America, and South America. These included, to our knowledge, the first natural killer (NK)/T-cell lymphoma (NKTCL) EBV genomes reported outside of East Asia. Our findings indicate that previously proposed EBV genome variants specific to certain cancer types are more closely tied to geographic origin than to cancer histology. This included variants previously reported to be specific to NKTCL but were prevalent in EBV genomes from other cancer types and healthy individuals in East Asia. After controlling for geographic region, we did identify multiple NKTCL-specific variants associated with a 7.8-fold to 21.9-fold increased risk. We also observed frequent variations in EBV genomes that affected peptide sequences previously reported to bind common major histocompatibility complex alleles. Finally, we found several nonsynonymous variants spanning the coding sequences of current vaccine targets BALF4, BKRF2, BLLF1, BXLF2, BZLF1, and BZLF2. These results highlight the need to consider geographic variation in EBV genomes when devising strategies for exploiting adaptive immune responses against EBV-related cancers, ensuring greater global effectiveness and equity in prevention and treatment.

Immunotherapy for recurrent or metastatic nasopharyngeal carcinoma

Immunotherapy, particularly immune checkpoint inhibitors (ICIs), such as anti-programmed death 1/programmed death-ligand 1 (PD-1/PD-L1) therapy, has emerged as a pivotal treatment modality for solid tumors, including recurrent or metastatic nasopharyngeal carcinoma (R/M-NPC). Despite the advancements in the utilization of ICIs, there is still room for further improving patient outcomes. Another promising approach to immunotherapy for R/M-NPC involves adoptive cell therapy (ACT), which aims to stimulate systemic anti-tumor immunity. However, individual agent therapies targeting dendritic cells (DCs) appear to still be in the clinical trial phase. This current review underscores the potential of immunotherapy as a valuable adjunct to the treatment paradigm for R/M-NPC patients. Further research is warranted to enhance the efficacy of immunotherapy through the implementation of strategies such as combination therapies and overcoming immune suppression. Additionally, the development of a biomarker-based scoring system is essential for identifying suitable candidates for precision immunotherapy.

Efficacy and Safety of Cell-based Immunotherapy in The Treatment of Recurrent or Metastatic Nasopharyngeal Carcinoma - A Systematic Review and Meta-analysis

BACKGROUND

Recurrent/Metastatic Nasopharyngeal Carcinoma (RM-NPC) remains difficult to treat and contributes to considerable mortality. The first-line treatment for RM-NPC is Gemcitabine and Cisplatin and second-line treatment options differ. The endemic variant of NPC is associated with Epstein-Barr Virus (EBV). Therefore, Cell-based Immunotherapy (CBI) targeting EBV-specific RM-NPC may be effective.

METHODS

We systematically searched PubMed, Embase and the Cochrane Library for randomised or observational studies investigating the efficacy and safety of CBI in the treatment of RM-NPC. We performed all meta-analyses using the random-effects model. Studies were further stratified by endemicity, nature of disease and drug type to investigate for potential between-study heterogeneity and additional pre-specified tests were employed to assess for publication bias.

RESULTS

We screened 1,671 studies and included 13 studies with 403 participants in the systematic review, of which nine studies were eligible for meta-analysis. The use of CBI monotherapy as second or subsequent line treatment for EBV-positive RM-NPC revealed an ORR of 10 % (95 %CI = 3 %-29 %), median PFS of 2.37 months (95 %CI = 1.23-3.51) and median OS of 10.16 months (95 %CI = 0.67-19.65). For EBV-specific Cytotoxic T-Lymphocyte monotherapy, the pooled PD rate was 54 % (95 %CI = 9 %-93 %), SD rate was 22 % (95 %CI = 2 %-75 %) and incidence rate of any grade adverse events was 45 %. For Dendritic Cell monotherapy, a PD rate of 80 % (95 % CI = 29 %-98 %), SD rate of 11 % (95 % CI = 0 %-82 %) and incidence rate of any grade adverse events of 29 % was achieved.

CONCLUSION

CBI monotherapy demonstrates some activity in pre-treated RM-NPC. More trials are needed to better understand how to integrate CBI into RM-NPC care.

Efficacy and safety of PD-1 inhibitors in recurrent or metastatic nasopharyngeal carcinoma patients after failure of platinum-containing regimens: a systematic review and meta-analysis

OBJECTIVE

There is a lack of standard salvage treatment options for recurrent or metastatic nasopharyngeal carcinoma (RM-NPC) that has failed platinum-containing regimens. Breakthroughs in immunotherapy have opened up new options for these patients. However, the efficacy and safety of immunotherapy have not been clarified. This study aimed to summarize and assess the efficacy and safety of PD-1 inhibitors in patients with RM-NPC who failed platinum-containing chemotherapy.

METHODS

Up to August 25, 2022, clinical trials of PD-1 inhibitors in RM-NPC patients who failed platinum-containing regimens were searched in the PubMed, Embase, Cochrane, and Web of Science databases. Retrieval subject terms included "nasopharyngeal carcinoma", "metastatic", "recurrence", "PD-1", and "PD-L1". The clinical trials eligible for inclusion were systematically reviewed and meta-analyzed.

RESULTS

A total of 9 studies including 842 patients with RM-NPC were included in this meta-analysis. The results showed that PD-1 inhibitors had promising efficacy in patients with RM-NPC who failed platinum-containing regimens: objective response rate (ORR) was 24% (95% confidence interval [CI] 21-26%), disease control rate (DCR) was 52% (95% CI 45-58%), 1-year progression-free survival (PFS) rate was 25% (95% CI 18-32%), and 1-year overall survival (OS) rate was 53% (95% CI 37-68%). In terms of treatment-related adverse events (AEs), the incidence of grade ≥ 3 treatment-related AEs was 19% (95% CI 13-24%). In addition, we found that PD-1 inhibitors were more effective in patients with PD-L1 positive than in patients with PD-L1 negative nasopharyngeal carcinoma who had failed platinum-containing regimens (ORR 31% (95%CI 26-35%) vs. 21% (95% CI 17-25%)).

CONCLUSION

PD-1 inhibitors may provide a survival benefit for patients with RM-NPC who have failed platinum-containing regimens and have the advantage of a good safety profile, making them a promising treatment option.

Immunoinformatic Execution and Design of an Anti-Epstein-Barr Virus Vaccine with Multiple Epitopes Triggering Innate and Adaptive Immune Responses

One of the most important breakthroughs in healthcare is the development of vaccines. The life cycle and its gene expression in the numerous virus-associated disorders must be considered when choosing the target vaccine antigen for Epstein-Barr virus (EBV). The vaccine candidate used in the current study will also be effective against all other herpesvirus strains, based on the conservancy study, which verified that the protein is present in all herpesviruses. From the screening, two B-cell epitopes, four MHC-I, and five MHC-II restricted epitopes were chosen for further study. The refined epitopes indicated 70.59% coverage of the population in Malaysia and 93.98% worldwide. After removing the one toxin (PADRE) from the original vaccine design, it was projected that the new vaccine would not be similar to the human host and would instead be antigenic, immunogenic, non-allergenic, and non-toxic. The vaccine construct was stable, thermostable, soluble, and hydrophilic. The immunological simulation projected that the vaccine candidate would be subject to a long-lasting active adaptive response and a short-lived active innate response. With IgM concentrations of up to 450 cells per mm3 and active B-cell concentrations of up to 400 cells per mm3, the B-cells remain active for a considerable time. The construct also discovered other conformational epitopes, improving its ability to stimulate an immune response. This suggests that, upon injection, the epitope will target the B-cell surface receptors and elicit a potent immune response. Furthermore, the discotope analysis confirmed that our conformational B-cell epitope was not displaced during the design. Lastly, the docking complex was stable and exhibited little deformability under heat pressure. These computational results are very encouraging for future testing of our proposed vaccine, which may potentially help in the management and prevention of EBV infections worldwide.

Recurrent/Metastatic Nasopharyngeal Carcinoma Treatment from Present to Future: Where Are We and Where Are We Heading?

OPINION STATEMENT

Nasopharyngeal carcinoma (NPC) is distinct in its anatomic location and biology from other epithelial head and neck cancer (HNC). There are 3 WHO subtypes, which considers the presence of Epstein-Barr virus (EBV) and other histopathology features. Despite the survival benefit obtained from modern treatment modalities and techniques specifically in the local and locally advanced setting, a number of patients with this disease will recur and subsequently die of distant metastasis, locoregional relapse, or both. In the recurrent setting, the ideal therapy approach continues to be a topic of discussion and current recommendations are platinum-based combination chemotherapy. Phase III clinical trials which led to the approval of pembrolizumab or nivolumab for head and neck squamous cell carcinoma (HNSCC) specifically excluded NPC. No immune checkpoint inhibitor therapy, to date, has been approved by the FDA to treat NPC although the National Comprehensive Cancer Network (NCCN) recommendations do include use of these agents. Hence, this remains the major challenge for treatment options. Nasopharyngeal carcinoma is challenging as it is really 3 different diseases, and much research is required to determine best options and sequencing of those options. This article is going to address the data to date and discuss ongoing research in EBV + and EBV - inoperable recurrent/metastatic NPC patients.

Characteristics of immunotherapy trials for nasopharyngeal carcinoma over a 15-year period

Background

Immunotherapy has been a hotspot in nasopharyngeal carcinoma (NPC) in recent years. This study aimed to provide a comprehensive landscape of the characteristics of immunotherapy clinical trials in NPC and to determine whether contemporary studies are of sufficient quality to demonstrate therapeutic value.

Methods

This is a cross-sectional analysis of NPC trials registered on ClinicalTrials.gov in the last 15 years (Jan 1, 2008-Nov 20, 2022). Only interventional trials with a primary purpose of treatment were included in the final analysis. Characteristics of immunotherapy trials were compared with those of other NPC trials. Chronological shifts in NPC immunotherapy trials were also analyzed.

Results

Of the 440 NPC studies selected, 161 (36.6%) were immunotherapy trials and 279 (63.4%) were other NPC trials. NPC immunotherapy trials were more likely than other NPC trials to be phase 1-2 (82.6% vs. 66.7%, P < 0.001), single-arm (51.3% vs. 39.6%, P = 0.020), non-randomized (64.8% vs. 44.4%, P < 0.001), and enroll fewer than 50 participants (46.3% vs. 34.4%, P = 0.015). Blinding was used in 8.8% of NPC immunotherapy trials. Also, 90.7% of NPC immunotherapy trials were recruited nationally and 82.6% were Asia-centric. Although academic institutions and governments (72.7%) were the major sponsors of NPC trials, immunotherapy trials were more likely to be industry-funded than other NPC trials (34.2% vs. 11.5%, P < 0.001). The number of NPC immunotherapy trials increased exponentially after 2017, attributed to the exploration of immune checkpoint inhibitors. Immunotherapy combined with chemotherapy was the most commonly investigated regimen.

Conclusion

NPC immunotherapy trials over a 15-year period were predominantly exploratory. To generate high-quality evidence and advance the clinical application of immunotherapy in NPC, more attention and concerted efforts are needed.

Lymph node targeted multi-epitope subunit vaccine promotes effective immunity to EBV in HLA-expressing mice

The recent emergence of a causal link between Epstein-Barr virus (EBV) and multiple sclerosis has generated considerable interest in the development of an effective vaccine against EBV. Here we describe a vaccine formulation based on a lymph node targeting Amphiphile vaccine adjuvant, Amphiphile-CpG, admixed with EBV gp350 glycoprotein and an engineered EBV polyepitope protein that includes 20 CD8+ T cell epitopes from EBV latent and lytic antigens. Potent gp350-specific IgG responses are induced in mice with titers >100,000 in Amphiphile-CpG vaccinated mice. Immunization including Amphiphile-CpG also induces high frequencies of polyfunctional gp350-specific CD4+ T cells and EBV-specific CD8+ T cells that are 2-fold greater than soluble CpG and are maintained for >7 months post immunization. This combination of broad humoral and cellular immunity against multiple viral determinants is likely to provide better protection against primary infection and control of latently infected B cells leading to protection against the development of EBV-associated diseases.

Virus-Specific T-Cell Therapy for Viral Infections of the Central Nervous System: A Review

Opportunistic viral infections of the central nervous system represent a significant cause of morbidity and mortality among an increasing number of immunocompromised patients. Since antiviral treatments are usually poorly effective, the prognosis generally relies on the ability to achieve timely immune reconstitution. Hence, strategies aimed at reinvigorating antiviral immune activity have recently emerged. Among these, virus-specific T-cells are increasingly perceived as a principled and valuable tool to treat opportunistic viral infections. Here we briefly discuss how to develop and select virus-specific T-cells, then review their main indications in central nervous system infections, including progressive multifocal leukoencephalopathy, CMV infection, and adenovirus infection. We also discuss their potential interest in the treatment of progressive multiple sclerosis, or EBV-associated central nervous system inflammatory disease. We finish with the key future milestones of this promising treatment strategy.

The role of Epstein-Barr virus in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a metastasis-prone malignancy closely associated with the Epstein-Barr virus (EBV). Despite ubiquitous infection of EBV worldwide, NPC incidences displayed predominance in certain ethnic groups and endemic regions. The majority of NPC patients are diagnosed with advanced-stage disease, as a result of anatomical isolation and non-specific clinical manifestation. Over the decades, researchers have gained insights into the molecular mechanisms underlying NPC pathogenesis as a result of the interplay of EBV infection with several environmental and genetic factors. EBV-associated biomarkers were also used for mass population screening for the early detection of NPC. EBV and its encoded products also serve as potential targets for the development of therapeutic strategies and tumour-specific drug delivery. This review will discuss the pathogenic role of EBV in NPC and efforts in exploiting the potential of EBV-associated molecules as biomarkers and therapeutic targets. The current knowledge on the role of EBV and its associated products in NPC tumorigenesis, development and progression will offer a new outlook and potential intervention strategy against this EBV-associated malignancy.

Immunotherapeutic approaches in EBV-associated nasopharyngeal carcinoma

Epstein-Barr virus (EBV) was the first tumor virus in humans. Nasopharyngeal carcinoma (NPC) accounts for approximately 60% of the 200,000 new tumor cases caused by EBV infection worldwide each year. NPC has an insidious onset and is highly malignant, with more than 70% of patients having intermediate to advanced disease at the time of initial diagnosis, and is strongly implicated in epithelial cancers as well as malignant lymphoid and natural killer/T cell lymphomas. Over 90% of patients with confirmed undifferentiated NPC are infected with EBV. In recent decades, much progress has been made in understanding the molecular mechanisms of NPC and developing therapeutic approaches. Radiotherapy and chemotherapy are the main treatment options for NPC; however, they have a limited efficacy in patients with locally advanced or distant metastatic tumors. Tumor immunotherapy, including vaccination, adoptive cell therapy, and immune checkpoint blockade, represents a promising therapeutic approach for NPC. Significant breakthroughs have recently been made in the application of immunotherapy for patients with recurrent or metastatic NPC (RM-NPC), indicating a broad prospect for NPC immunotherapy. Here, we review important research findings regarding immunotherapy for NPC patients and provide insights for future research.

Pathogen-specific T Cells: Targeting Old Enemies and New Invaders in Transplantation and Beyond

Adoptive immunotherapy with virus-specific cytotoxic T cells (VSTs) has evolved over the last three decades as a strategy to rapidly restore virus-specific immunity to prevent or treat viral diseases after solid organ or allogeneic hematopoietic cell-transplantation (allo-HCT). Since the early proof-of-principle studies demonstrating that seropositive donor-derived T cells, specific for the commonest pathogens post transplantation, namely cytomegalovirus or Epstein-Barr virus (EBV) and generated by time- and labor-intensive protocols, could effectively control viral infections, major breakthroughs have then streamlined the manufacturing process of pathogen-specific T cells (pSTs), broadened the breadth of target recognition to even include novel emerging pathogens and enabled off-the-shelf administration or pathogen-naive donor pST production. We herein review the journey of evolution of adoptive immunotherapy with nonengineered, natural pSTs against infections and virus-associated malignancies in the transplant setting and briefly touch upon recent achievements using pSTs outside this context.

Updates on Epstein-Barr Virus (EBV)-Associated Nasopharyngeal Carcinoma: Emphasis on the Latent Gene Products of EBV

Nasopharyngeal carcinoma (NPC) is an uncommon type of malignancy/cancer worldwide. However, NPC is an endemic disease in southeast Asia and southern China and the reasons behind the underlying for such changes are unclear. Even though the Epstein-Barr infection (EBV) has been suggested as an important reason for undistinguishable NPC, the EBV itself is not adequate to source this type of cancer. The risk factors, for example, genetic susceptibility, and environmental factors might be associated with EBV to undertake a part in the NPC carcinogenesis. Normal healthy people have a memory B cell pool where the EBV persists, and any disturbance of this connection leads to virus-associated B cell malignancies. Less is known about the relationship between EBV and epithelial cell tumors, especially the EBV-associated nasopharyngeal carcinoma (EBVaNPC) and EBV-associated gastric carcinoma (EBVaGC). Currently, it is believed that premalignant genetic changes in epithelial cells contribute to the aberrant establishment of viral latency in these tumors. The early and late phases of NPC patients' survival rates vary significantly. The presence of EBV in all tumor cells presents prospects for the development of innovative therapeutic and diagnostic techniques, despite the fact that the virus's exact involvement in the carcinogenic process is presently not very well known. EBV research continues to shed light on the carcinogenic process, which is important for a more comprehensive knowledge of tumor etiology and the development of targeted cancer therapeutics. In order to screen for NPC, EBV-related biomarkers have been widely used in a few high-incidence locations because of their close associations with the risks of NPC. The current review highlights the scientific importance of EBV and its possible association with NPC.

Current status and advances of immunotherapy in nasopharyngeal carcinoma

The general immune landscape of nasopharyngeal carcinoma (NPC) renders immunotherapy suitable for patients with NPC. Immune checkpoint inhibitors (ICIs) based on programmed death-1/programmed death ligand-1 (PD-1/PD-L1) blockade have made a breakthrough with the approval of PD-1 inhibitor for refractory recurrence and/or metastatic (R/M NPC) and the approval of PD-1 inhibitor in combination with gemcitabine and cisplatin as first line for R/M NPC in 2021 in China. The incorporation of ICIs into the treatment paradigms of NPC has become a clinical hot spot and many prospective clinical studies are ongoing. In this review, we provide a comprehensive overview of the rationale for immunotherapy in NPC and current status, advances and challenges of immunotherapy in NPC based on published clinical data, and ongoing trials. We focus on the clinical application and advances of PD-1 inhibitor monotherapy and its combination with chemotherapy and summarize the clinical explorations of other immunotherapy approaches, for example, combination of PD-1/PD-L1 inhibitors with antiangiogenic inhibitor with molecular targeted agents, cancer vaccines, adaptive immunotherapy, and new ICI agents beyond PD-1/PD-L1 inhibitors in R/M NPC. We also describe the clinical studies’ status and challenges of ICIs-based immunomodulatory strategies in local advanced NPC and pay attention to the biomarker application for personalized immunotherapy of NPC in the hope to provide insights for clinical practice and future clinical studies.

SARS-CoV-2-specific T cells generated for adoptive immunotherapy are capable of recognizing multiple SARS-CoV-2 variants

Adoptive T-cell immunotherapy has provided promising results in the treatment of viral complications in humans, particularly in the context of immunocompromised patients who have exhausted all other clinical options. The capacity to expand T cells from healthy immune individuals is providing a new approach to anti-viral immunotherapy, offering rapid off-the-shelf treatment with tailor-made human leukocyte antigen (HLA)-matched T cells. While most of this research has focused on the treatment of latent viral infections, emerging evidence that SARS-CoV-2-specific T cells play an important role in protection against COVID-19 suggests that the transfer of HLA-matched allogeneic off-the-shelf virus-specific T cells could provide a treatment option for patients with active COVID-19 or at risk of developing COVID-19. We initially screened 60 convalescent individuals and based on HLA typing and T-cell response profile, 12 individuals were selected for the development of a SARS-CoV-2-specific T-cell bank. We demonstrate that these T cells are specific for up to four SARS-CoV-2 antigens presented by a broad range of both HLA class I and class II alleles. These T cells show consistent functional and phenotypic properties, display cytotoxic potential against HLA-matched targets and can recognize HLA-matched cells infected with different SARS-CoV-2 variants. These observations demonstrate a robust approach for the production of SARS-CoV-2-specific T cells and provide the impetus for the development of a T-cell repository for clinical assessment.

Since the emergence of SARS-CoV-2 variants that reduce the effectiveness of vaccines, it is evident that other interventional strategies will be needed to treat COVID-19, particularly in patients with a compromised immune system who are at an increased risk of developing severe COVID-19. Off-the-shelf T-cell immunotherapy is proving to be a powerful tool to treat viral disease in patients with a compromised immune system. Here, we report here that a small number of SARS-CoV-2 exposed individuals can be used generate a bank of specific T cells that provide broad population coverage. Importantly, we demonstrate that most of the epitopes recognized by these T cells remain unchanged in different variants and that the T cells can recognize cells infected with three different variants of SARS-CoV-2. We believe these observations provide critical proof-of-concept that T-cell based immunotherapy may offer an option for the future treatment of immunocompromised patients who remain susceptible to the severe complications associated with COVID-19.

Nasopharyngeal carcinoma: an evolving paradigm

The past three decades have borne witness to many advances in the understanding of the molecular biology and treatment of nasopharyngeal carcinoma (NPC), an Epstein-Barr virus (EBV)-associated cancer endemic to southern China, southeast Asia and north Africa. In this Review, we provide a comprehensive, interdisciplinary overview of key research findings regarding NPC pathogenesis, treatment, screening and biomarker development. We describe how technological advances have led to the advent of proton therapy and other contemporary radiotherapy approaches, and emphasize the relentless efforts to identify the optimal sequencing of chemotherapy with radiotherapy through decades of clinical trials. Basic research into the pathogenic role of EBV and the genomic, epigenomic and immune landscape of NPC has laid the foundations of translational research. The latter, in turn, has led to the development of new biomarkers and therapeutic targets and of improved approaches for individualizing immunotherapy and targeted therapies for patients with NPC. We provide historical context to illustrate the effect of these advances on treatment outcomes at present. We describe current preclinical and clinical challenges and controversies in the hope of providing insights for future investigation.

Epstein Barr Virus: Development of Vaccines and Immune Cell Therapy for EBV-Associated Diseases

Epstein-Barr virus (EBV) is the first human tumor virus discovered and is strongly implicated in the etiology of multiple lymphoid and epithelial cancers. Each year EBV associated cancers account for over 200,000 new cases of cancer and cause 150,000 deaths world-wide. EBV is also the primary cause of infectious mononucleosis, and up to 70% of adolescents and young adults in developed countries suffer from infectious mononucleosis. In addition, EBV has been shown to play a critical role in the pathogenesis of multiple sclerosis. An EBV prophylactic vaccine that induces neutralizing antibodies holds great promise for prevention of EBV associated diseases. EBV envelope proteins including gH/gL, gB and gp350 play key roles in EBV entry and infection of target cells, and neutralizing antibodies elicited by each of these proteins have shown to prevent EBV infection of target cells and markedly decrease EBV titers in the peripheral blood of humanized mice challenged with lethal dose EBV. Recent studies demonstrated that immunization with the combination of gH/gL, gB and/or gp350 induced markedly increased synergistic EBV neutralizing activity compared to immunization with individual proteins. As previous clinical trials focused on gp350 alone were partially successful, the inclusion of gH/gL and gB in a vaccine formulation with gp350 represents a promising approach of EBV prophylactic vaccine development. Therapeutic EBV vaccines have also been tested clinically with encouraging results. Immunization with various vaccine platforms expressing the EBV latent proteins EBNA1, LMP1, and/or LMP2 promoted specific CD4+ and CD8+ cytotoxic responses with anti-tumor activity. The addition of EBV envelope proteins gH/gL, gB and gp350 has the potential to increase the efficacy of a therapeutic EBV vaccine. The immune system plays a critical role in the control of tumors, and immune cell therapy has emerged as a promising treatment of cancers. Adoptive T-cell therapy has been successfully used in the prevention and treatment of post-transplant lymphoproliferative disorder. Chimeric antigen receptor T cell therapy and T cell receptor engineered T cell therapy targeting EBV latent proteins LMP1, LMP2 and/or EBNA1 have been in development, with the goal to increase the specificity and efficacy of treatment of EBV associated cancers.

The emergence of tumor-infiltrating lymphocytes in nasopharyngeal carcinoma: Predictive value and immunotherapy implications

The clinical study of nasopharyngeal carcinoma (NPC) often reveals a large number of lymphocytes infiltrating the primary tumor site. As an important part of the tumor microenvironment, tumor-infiltrating lymphocytes (TILs) do not exist alone but as a complex multicellular population with high heterogeneity. TILs play an extremely significant role in the occurrence, development, invasion and metastasis of NPC. The latest research shows that they participate in tumorigenesis and treatment, and the composition, quantity, functional status and distribution of TILs subsets have good predictive value for the prognosis of NPC patients. TILs are an independent prognostic factor for TNM stage and significantly correlated with better prognosis. Additionally, adoptive immunotherapy using anti-tumor TILs has achieved good results in a variety of solid tumors including NPC. This review evaluates recent clinical and preclinical studies of NPC, summarizes the role of TILs in promoting and inhibiting tumor growth, evaluates the predictive value of TILs, and explores the potential benefits of TILs-based immunotherapy in the treatment of NPC.

Virus-specific T cells for malignancies - then, now and where to?

Purpose of Review

Virus-associated malignancies are a global health burden, constituting 10-12% of cancers worldwide. As these tumors express foreign viral antigens that can elicit specific T cell responses, virus-directed immunotherapies are a promising treatment strategy. Specifically, adoptive cell transfer of virus-specific T cells (VSTs) has demonstrated the potential to eradicate cancers associated with certain viruses.

Recent Findings

Initial studies in 1990s first showed that VSTs specific for the Epstein-Barr virus (EBVSTs) can induce complete remissions in patients with post-transplant lymphoproliferative disease. Since then, studies have validated the specificity and safety of VSTs in multiple lymphomas and solid malignancies. However, challenges remain to optimize this platform for widespread use, including enhancing potency and persistence, overcoming the immunosuppressive tumor microenvironment, and streamlining manufacturing processes that comply with regulatory requirements.

Summary

This review focuses on data from clinical trials evaluating VSTs directed against three viruses (EBV, HPV and MCPyV), as well as recent preclinical and clinical advances, and potential future directions.

Complete response to PD-1 blockade following EBV-specific T-cell therapy in metastatic nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is an Epstein–Barr virus (EBV)-associated heterogeneous disease and is characterized by peritumoral immune infiltrate. Adoptive T-cell therapy (ACT) has emerged as a potential therapeutic strategy for NPC. However, the tumor microenvironment remains a major roadblock for the successful implementation of ACT in clinical settings. Expression of checkpoint molecules by malignant cells can inhibit the effector function of adoptively transferred EBV-specific T cells. Here we present a novel case report of a patient with metastatic NPC who was successfully treated with a combination of EBV-specific ACT and programmed cell death-1 blockade therapy. Following combination immunotherapy, the patient showed complete resolution of metastatic disease with no evidence of disease relapse for 22 months. Follow-up immunological analysis revealed dramatic restructuring of the global T-cell repertoire that was coincident with the clinical response. This case report provides an important platform for translating these findings to a larger cohort of NPC patients.

'Off-the-shelf' allogeneic antigen-specific adoptive T-cell therapy for the treatment of multiple EBV-associated malignancies

Background

Epstein-Barr virus (EBV), an oncogenic human gammaherpesvirus, is associated with a wide range of human malignancies of epithelial and B-cell origin. Recent studies have demonstrated promising safety and clinical efficacy of allogeneic ‘off-the-shelf’ virus-specific T-cell therapies for post-transplant viral complications.

Methods

Taking a clue from these studies, we developed a highly efficient EBV-specific T-cell expansion process using a replication-deficient AdE1-LMPpoly vector that specifically targets EBV-encoded nuclear antigen 1 (EBNA1) and latent membrane proteins 1 and 2 (LMP1 and LMP2), expressed in latency II malignancies.

Results

These allogeneic EBV-specific T cells efficiently recognized human leukocyte antigen (HLA)-matched EBNA1-expressing and/or LMP1 and LMP2-expressing malignant cells and demonstrated therapeutic potential in a number of in vivo models, including EBV lymphomas that emerged spontaneously in humanized mice following EBV infection. Interestingly, we were able to override resistance to T-cell therapy in vivo using a ‘restriction-switching’ approach, through sequential infusion of two different allogeneic T-cell therapies restricted through different HLA alleles. Furthermore, we have shown that inhibition of the programmed cell death protein-1/programmed death-ligand 1 axis in combination with EBV-specific T-cell therapy significantly improved overall survival of tumor-bearing mice when compared with monotherapy.

Conclusion

These findings suggest that restriction switching by sequential infusion of allogeneic T-cell therapies that target EBV through distinct HLA alleles may improve clinical response.

Monocytic Myeloid-Derived Suppressor Cells Underpin Resistance to Adoptive T Cell Therapy in Nasopharyngeal Carcinoma

Advanced, late-stage Epstein-Barr virus (EBV)-positive nasopharyngeal carcinoma (NPC) is incurable, and its treatment remains a clinical and therapeutic challenge. Results from a phase II clinical trial in advanced NPC patients employing a combined chemotherapy and EBV-specific T cell (EBVST) immunotherapy regimen showed a response rate of 71.4%. Longitudinal analysis of patient samples showed that an increase in EBV DNA plasma concentrations and the peripheral monocyte-to-lymphocyte ratio negatively correlated with overall survival. These parameters were combined into a multivariate analysis to stratify patients according to risk of death. Immunophenotyping at serial time points showed that low-risk individuals displayed significantly decreased amounts of monocytic myeloid-derived suppressor cells postchemotherapy, which subsequently influenced successful cytotoxic T-lymphocyte (CTL) immunotherapy. Examination of the low-risk group, 2 weeks post-EBVST infusion, showed that individuals with a greater overall survival possessed an increased frequency of CD8 central and effector memory T cells, together with higher levels of plasma interferon (IFN)-γ, and cytotoxic lymphocyte-associated transcripts. These results highlight the importance of the rational selection of chemotherapeutic agents and consideration of their impact on both systemic immune responses and downstream cellular immunotherapy outcomes.

Chapter XX Antiviral Treatment and Cancer Control

Hepatitis B virus (HBV), hepatitis C virus (HCV), human papilloma virus (HPV), Epstein-Barr virus (EBV), human T-cell lymphotropic virus type 1 (HTLV-1), Kaposi's sarcoma-associated herpesvirus (KSHV), and Merkel cell polyomavirus (MCV) contribute to about 10-15% global burden of human cancers. Conventional chemotherapy or molecular target therapies have been used to treat virus-associated cancers. However, a more proactive approach would be the use of antiviral treatment to suppress or eliminate viral infections to prevent the occurrence of cancer in the first place. Antiviral treatments against chronic HBV and HCV infection have achieved this goal, with significant reduction in the incidence of hepatocellular carcinoma in treated patients. Antiviral treatments for EBV, KSHV, and HTLV-1 had limited success in treating refractory EBV-associated lymphoma and post-transplant lymphoproliferative disorder, KSHV-associated Kaposi's sarcoma in AIDS patients, and HTLV-1-associated acute, chronic, and smoldering subtypes of adult T-cell lymphoma, respectively. Therapeutic HPV vaccine and RNA interference-based therapies for treating HPV-associated infection or cervical cancers also showed some encouraging results. Taken together, antiviral therapies have yielded promising results in cancer prevention and treatment. More large-scale studies in a real-world setting are necessary to confirm the efficacy of antiviral therapy. Further investigation for more effective and convenient antiviral regimens warrants more attention.

Treatment Deescalation Strategies for Nasopharyngeal Cancer: A Review

IMPORTANCE

Since the advent of modern radiotherapy techniques and incorporation of systemic chemotherapy for nasopharyngeal cancer, locoregional control has been excellent. However, the rate of treatment-related complications, many of which are irreversible, remains high. New approaches are being explored to determine whether the toxic effects of treatment can be relieved while maintaining disease control. This review presents the current state of deescalation strategies for nasopharyngeal cancer.

OBSERVATIONS

A review of the literature shows that deescalation approaches can be generally categorized into deescalating systemic therapy vs deescalating radiotherapy. This review discusses studies that have explored sparing chemotherapy in selected patients with stage II cancer as well as altering the chemotherapy scheduling, dosing, and agent from the current standard of care, cisplatin. Deescalating radiotherapy has involved decreasing the dose and the treatment volume. In many cases, these approaches are being guided by measuring Epstein-Barr virus DNA levels, which is a robust biomarker for screening, treatment monitoring, and surveillance. Ongoing work with various imaging modalities, such as fluorodeoxyglucose positron emission tomography and dynamic contrast-enhanced or diffusion-weighted magnetic resonance imaging sequences, have shown promise as another biomarker to safely guide practitioners toward deescalation.

CONCLUSIONS AND RELEVANCE

Various strategies to deescalate treatment in nasopharyngeal cancer have been explored, and outcomes have remained excellent in most approaches. Patient selection remains key, and long-term outcomes and late complications are still to be determined. Continued investigation with prospective, multi-institutional studies are needed to better elucidate how treatment for nasopharyngeal carcinoma can best be individualized and deescalated.

Joining Forces: Improving Clinical Response to Cellular Immunotherapies with Small-Molecule Inhibitors

Adoptive T cell therapy (ACT) has emerged as a powerful therapeutic tool against both hematological and virus-associated cancers. However, extension of this success to solid cancers has been challenging owing to intratumoral mechanisms that induce a hostile immunosuppressive tumor microenvironment (TME). Delineating the impact of tumor-intrinsic adaptive resistance mechanisms on immune-based therapies is essential to improve long-term efficacy. We discuss the different tumor-intrinsic factors that lead to resistance to ACT. We highlight the potential of repurposing molecular targeted therapies to modulate immune responses and override intratumor resistance to ACT. Finally, we discuss the potential of combining targeted therapy and ACT as a new paradigm to improve the clinical efficacy of cancer therapeutics.

Adoptive T-cell therapy for pediatric cytomegalovirus-associated retinitis

TCRαβ+/CD19+-depleted haploidentical HSCT was used to restore immunity in a pediatric patient with combined immunodeficiency syndrome. Posttransplant drug-resistant CMV retinitis was successfully treated with T cells expanded from a haploidentical HSCT donor.

Apatinib, a novel VEGFR-2 tyrosine kinase inhibitor, for relapsed and refractory nasopharyngeal carcinoma: data from an open-label, single-arm, exploratory study

Purpose Apatinib, a new tyrosine kinase inhibitor targeting vascular endothelial growth factor receptor-2, has shown promising efficacy against several solid cancers, but evidence of its efficacy against relapsed and refractory nasopharyngeal carcinoma is limited. We investigated the efficacy and safety of apatinib for relapsed and refractory nasopharyngeal carcinoma in an open-label, single-arm, phase II clinical trial. Fifty-one patients with relapsed and refractory nasopharyngeal carcinoma in the First Affiliated Hospital, Zhengzhou University, who met the inclusion criteria were enrolled in the study. All patients received apatinib at an initial dose of 500 mg daily (1 cycle = 28 days). The primary and secondary endpoints were overall response rate, progression-free survival, and overall survival. We evaluated treatment effects and recorded apatinib-related adverse events by performing regular follow-ups and workup. The overall response rate (complete and partial responses) was 31.37% (16/51). The median overall survival and progression-free survival were 16 (95% CI, 9.32–22.68) and 9 months (95% CI, 5.24–12.76), respectively. Most patients tolerated treatment-related adverse events of grades 1 and 2; hypertension (29, 56.86%), proteinuria (25, 49.02%), and hand–foot syndrome (27, 52.94%) were the most common adverse events. There were no treatment-related deaths. Apatinib showed good efficacy and safety in patients with relapsed and refractory NPC.

Translational genomics of nasopharyngeal cancer

Nasopharyngeal carcinoma (NPC), also named the Cantonese cancer, is a unique cancer with strong etiological association with infection of the Epstein-Barr virus (EBV). With particularly high prevalence in Southeast Asia, the involvement of EBV and genetic aberrations contributive to NPC tumorigenesis have remained unclear for decades. Recently, genomic analysis of NPC has defined it as a genetically homogeneous cancer, driven largely by NF-κB signaling caused by either somatic aberrations of NF-κB negative regulators or by overexpression of the latent membrane protein 1 (LMP1), an EBV viral oncoprotein. This represents a landmark finding of the NPC genome. Exome and RNA sequencing data from new EBV-positive NPC models also highlight the importance of PI3K pathway aberrations in NPC. We also realize for the first time that NPC mutational burden, mutational signatures, MAPK/PI3K aberrations, and MHC Class I gene aberrations, are prognostic for patient outcome. Together, these multiple genomic discoveries begin to shape the focus of NPC therapy development. Given the challenge of NF-κB targeting in human cancers, more innovative drug discovery approaches should be explored to target the unique atypical NF-κB activation feature of NPC. Our next decade of NPC research should focus on further identification of the -omic landscapes of recurrent and metastatic NPC, development of gene-based precision medicines, as well as large-scale drug screening with the newly developed and well-characterized EBV-positive NPC models. Focused preclinical and clinical investigations on these major directions may identify new and effective targeting strategies to further improve survival of NPC patients.

Immunotherapeutic approaches in nasopharyngeal carcinoma

Introduction: Nasopharyngeal carcinoma (NPC) is endemic in Southern China and Southeast Asia. Epstein-Barr virus (EBV) represents a unique etiological culprit in the poorly differentiated nonkeratinizing and undifferentiated subtypes. EBV antigens are expressed on tumor cells albeit in a restricted manner. Treatment options for recurrent or metastatic disease are limited. Nevertheless, emerging data from immunotherapy studies in NPC have shed light into their potential antitumor efficacy. Areas covered: This article reviews existing clinical evidence for different immunotherapeutic approaches for NPC, including adoptive cellular therapy, therapeutic cancer vaccines, and immune checkpoint inhibitors. Expert opinion: There is a growing understanding on EBV virology and the immune evasion mechanisms in NPC. Immunotherapeutic strategies leveraging these properties have shown encouraging efficacy and safety results in early-phase clinical studies. Moving forward, areas to be addressed include appropriate patient selection, optimal incorporation into standard treatment paradigms, biomarker identification, as well as the development of scalable and reproducible immune product generation processes.

Interferon β and Anti-PD-1/PD-L1 Checkpoint Blockade Cooperate in NK Cell-Mediated Killing of Nasopharyngeal Carcinoma Cells

Nasopharyngeal carcinoma (NPC) is a highly malignant epithelial cancer linked to EBV infection. Addition of interferon-β (IFNβ) to chemo- and radiochemotherapy has led to survival rates >90% in children and adolescents. As NPC cells are sensitive to apoptosis via tumor necrosis factor-related apoptosis inducing ligand (TRAIL), we explored the role of TRAIL and IFNβ in the killing of NPC cells by natural killer (NK) cells. NPC cells, including cells of a patient-derived xenograft were exposed to NK cells in the presence or absence of IFNβ. NK cells killed NPC- but not nasoepithelial cells and killing was predominately mediated via TRAIL. Incubation of NK cells with IFNβ increased cytotoxicity against NPC cells. Concomitant incubation of NK- and NPC cells with IFNβ before coculture reduced cytotoxicity and could be overcome by blocking the PD-1/PD-L1 axis leading to the release of intracellular TRAIL from NK cells. In conclusion, combination of IFNβ and anti-PD-1, augmenting cytotoxicity of NK cells against NPC cells, could be a strategy to improve NPC-directed therapy and warrants further evaluation in vivo.

Current Treatment Landscape of Nasopharyngeal Carcinoma and Potential Trials Evaluating the Value of Immunotherapy

Nasopharyngeal carcinoma (NPC) is a type of head and neck cancer with a distinctive regional and racial prevalence. It is associated with Epstein-Barr virus infection and has a high propensity for regional and distant metastases, while it is very sensitive to radiation and chemotherapy. A common feature of Epstein-Barr virus-positive NPC is the dense infiltration of lymphocytes in the tumor stroma and positive programmed death-ligand 1 expression in tumor cells, making it an attractive target for immunotherapy, especially immune checkpoint inhibitors. As new immunotherapeutic agents are being rapidly adopted in many cancers, including head and neck cancer, the National Cancer Institute sponsored a clinical trial planning meeting to identify opportunities for developing phase II and III trials testing immunotherapy in different stages of NPC. The meeting started with the summary of the biology of the disease, current standards of care, and evidence of immunotherapy in this cancer. Three subcommittees were tasked to develop clinical trials: loco regionally advanced, nonmetastatic NPC; widely metastatic NPC; and either local recurrence after initial treatment or presenting with oligometastatic disease. This article summarizes the proceedings of this clinical trial planning meeting and provides a road map for future trials incorporating immune checkpoint inhibitors for therapeutic management of NPC. This road map, though specific for NPC, may also be applicable to other virally driven cancers that have similar ability to evade the host's immune system.

Prophylactic and therapeutic strategies for Epstein-Barr virus-associated diseases: emerging strategies for clinical development

INTRODUCTION

Epstein-Barr virus (EBV) infects more than 95% of the world's population and is associated with infectious mononucleosis as well as a number of cancers in various geographical locations. Despite its significant health burden, no licenced prophylactic or therapeutic vaccines are available. Areas covered: Over the last two decades, our understanding of the role of EBV infection in the pathogenesis and immune regulation of EBV-associated diseases has provided new lines of research to conceptualize various novel prophylactic and therapeutic approaches to control EBV-associated disease. In this review, we evaluate the prophylactic and therapeutic vaccine approaches against EBV and various immunotherapeutic strategies against a number of EBV-associated malignancies. This review also describes the existing and future prospects of improved EBV-targeted therapeutic strategies. Expert opinion: It is anticipated that these emerging strategies will provide answers for the major challenges in EBV vaccine development and help improve the efficacy of novel therapeutic strategies.

Viral-Targeted Strategies Against EBV-Associated Lymphoproliferative Diseases

Epstein-Barr virus (EBV) is strongly associated with a spectrum of EBV-associated lymphoproliferative diseases (EBV-LPDs) ranging from post-transplant lymphoproliferative disorder, B cell lymphomas (e.g., endemic Burkitt lymphoma, Hodgkin lymphoma, and diffuse large B cell lymphoma) to NK or T cell lymphoma (e.g., nasal NK/T-cell lymphoma). The virus expresses a number of latent viral proteins which are able to manipulate cell cycle and cell death processes to promote survival of the tumor cells. Several FDA-approved drugs or novel compounds have been shown to induce killing of some of the EBV-LPDs by inhibiting the function of latent viral proteins or activating the viral lytic cycle from latency. Here, we aim to provide an overview on the mechanisms by which EBV employs to drive the pathogenesis of various EBV-LPDs and to maintain the survival of the tumor cells followed by a discussion on the development of viral-targeted strategies based on the understanding of the patho-mechanisms.

Immune-based therapeutic approaches to virus-associated cancers

It is estimated that 60-70% of cancers associated with infectious agents are linked to viral infections. Both RNA and DNA viruses that can establish persistent infection exploit various mechanisms including host cell immortalization through genomic instability, chronic inflammation and immune escape, to promote oncogenic transformation of human cells. Expression of selected viral proteins in malignant cells provides a unique opportunity to employ targeted therapies that can disrupt the cellular proliferation and prevent collateral damage caused by standard clinical therapies. While vaccination can be used to prevent infection before malignant transformation, immune-based therapies based on adoptive transfer of T cells and/or antibodies have emerged as powerful tools for the treatment of virus-associated cancers. Here we discuss recent advances and future prospects of immune-based therapies for virus-associated cancers.

Identifying neoantigens for use in immunotherapy

This review focuses on the types of cancer antigens that can be recognised by the immune system and form due to alterations in the cancer genome, including cancer testis, overexpressed and neoantigens. Specifically, neoantigens can form when cancer cell-specific mutations occur that result in alterations of the protein from ‘self’. This type of antigen can result in an immune response sufficient to clear tumour cells when activated. Furthermore, studies have reported that the likelihood of successful immunotherapeutic targeting of cancer by many different methods was reliant on immune response to neoantigens. The recent resurgence of interest in the immune response to tumour cells, in conjunction with technological advances, has resulted in a large increase in the predicted, identified and functionally confirmed neoantigens. This growth in identified neoantigen sequences has increased the contents of training sets for algorithms, which in turn improves the prediction of which genetic mutations may form neoantigens. Additionally, algorithms predicting how proteins will be processed into peptide epitopes by the proteasome and which peptides bind to the transporter complex are also improving with this research. Now that large screens of all the tumour-specific protein altering mutations are possible, the emerging data from assessment of the immunogenicity of neoantigens suggest that only a minority of variants will form targetable epitopes. The potential for immunotherapeutic targeting of neoantigens will therefore be greater in cancers with a higher frequency of protein altering somatic variants. There is considerable potential in the use of neoantigens to treat patients, either alone or in combination with other immunotherapies and with continued advancements, these potentials will be realised.

Role of Epstein-Barr Virus in the Pathogenesis of Head and Neck Cancers and Its Potential as an Immunotherapeutic Target

The role of Epstein-Barr virus (EBV) infection in the development and progression of tumor cells has been described in various cancers. Etiologically, EBV is a causative agent in certain variants of head and neck cancers such as nasopharyngeal cancer. Proteins expressed by the EVB genome are involved in invoking and perpetuating the oncogenic properties of the virus. However, these protein products were also identified as important targets for therapeutic research in the past decades, particularly within the context of immunotherapy. The adoptive transfer of EBV-targeted T-cells as well as the development of EBV vaccines has opened newer lines of research to conceptualize novel therapeutic approaches toward the disease. This review addresses the most important aspects of the association of EBV with head and neck cancers from an immunological perspective. It also aims to highlight the current and future prospects of enhanced EBV-targeted immunotherapies.

Epstein-Barr Virus as a Promising Immunotherapeutic Target for Nasopharyngeal Carcinoma Treatment

Epstein-Barr virus (EBV) is a pathogen that infects more than 90% of global human population. EBV primarily targets B-lymphocytes and epithelial cells while some of them infect monocyte/macrophage, T-lymphocytes, and dendritic cells (DCs). EBV infection does not cause death by itself but the infection has been persistently associated with certain type of cancers such as nasopharyngeal carcinoma (NPC), Burkitt's lymphoma (BL), and Hodgkin's lymphoma (HL). Recent findings have shown promise on targeting EBV proteins for cancer therapy by immunotherapeutic approach. Some studies have also shown the success of adopting EBV-based therapeutic vaccines for the prevention of EBV-associated cancer particularly on NPC. In-depth investigations are in progress to refine the current therapeutic and vaccination strategies. In present review, we discuss the highly potential EBV targets for NPC immunotherapy and therapeutic vaccine development as well as addressing the underlying challenges in the process of bringing the therapy and vaccination from the bench to bedside.