Adoptive cell therapy for patients with metastatic melanoma: evaluation of intensive myeloablative chemoradiation preparative regimens

Key Factors in Clinical Protocols for Adoptive Cell Therapy in Melanoma

Adoptive cell therapy (ACT) with autologous tumor infiltrating lymphocytes (TIL) has been studied for patients with advanced metastatic cancers (primarily melanoma) for decades and has changed significantly during that period. Treatment with TIL includes ex vivo cell activation and expansion followed by re-infusion of these cells into the patient. After cell infusion, patients receive Interleukin-2 (IL-2). Objective response rates up to 52% have been seen in patients with metastatic melanoma. Efforts to improve TIL therapy include better selection and expansion of tumor-reactive lymphocytes, optimization of IL-2 or other T cell activating cytokine dosing, and, potentially, genetic manipulation of the immune cell product. Here we describe methods involved in the collection, expansion, and treatment with TIL for patients with metastatic melanoma.

Targeting Cancer with Genetically Engineered TCR T Cells

The adoptive cell transfer (ACT) of genetically engineered T cell receptor (TCR) T cells is one of the burgeoning fields of immunotherapy, with promising results in current clinical trials. Presently, clinicaltrials.gov has over 200 active trials involving adoptive cell therapy. The ACT of genetically engineered T cells not only allows the ability to select for TCRs with desired properties such as high-affinity receptors and tumor reactivity but to further enhance those receptors allowing for better targeting and killing of cancer cells in patients. Moreover, the addition of genetic material, including cytokines and cytokine receptors, can increase the survival and persistence of the T cell allowing for complete and sustained remission of cancer targets. The potential for improvement in adoptive cell therapy is limitless, with genetic modifications targeting to improve weaknesses of ACT and to thus enhance receptor affinity and functional avidity of the genetically engineered T cells.

Genetically Modified T-Cell Therapy for Osteosarcoma: Into the Roaring 2020s

T-cell immunotherapy may offer an approach to improve outcomes for patients with osteosarcoma who fail current therapies. In addition, it has the potential to reduce treatment-related complications for all patients. Generating tumor-specific T cells with conventional antigen-presenting cells ex vivo is time-consuming and often results in T-cell products with a low frequency of tumor-specific T cells. Furthermore, the generated T cells remain sensitive to the immunosuppressive tumor microenvironment. Genetic modification of T cells is one strategy to overcome these limitations. For example, T cells can be genetically modified to render them antigen specific, resistant to inhibitory factors, or increase their ability to home to tumor sites. Most genetic modification strategies have only been evaluated in preclinical models; however, early clinical phase trials are in progress. In this chapter, we will review the current status of gene-modified T-cell therapy with special focus on osteosarcoma, highlighting potential antigenic targets, preclinical and clinical studies, and strategies to improve current T-cell therapy approaches.

Trans-endocytosis of intact IL-15Rα-IL-15 complex from presenting cells into NK cells favors signaling for proliferation

Interleukin 15 (IL-15) is an essential cytokine for the survival and proliferation of natural killer (NK) cells. IL-15 activates signaling by the β and common γ (γ_c) chain heterodimer of the IL-2 receptor through trans-presentation by cells expressing IL-15 bound to the α chain of the IL-15 receptor (IL-15Rα). We show here that membrane-associated IL-15Rα-IL-15 complexes are transferred from presenting cells to NK cells through trans-endocytosis and contribute to the phosphorylation of ribosomal protein S6 and NK cell proliferation. NK cell interaction with soluble or surface-bound IL-15Rα-IL-15 complex resulted in Stat5 phosphorylation and NK cell survival at a concentration or density of the complex much lower than required to stimulate S6 phosphorylation. Despite this efficient response, Stat5 phosphorylation was reduced after inhibition of metalloprotease-induced IL-15Rα-IL-15 shedding from trans-presenting cells, whereas S6 phosphorylation was unaffected. Conversely, inhibition of trans-endocytosis by silencing of the small GTPase TC21 or expression of a dominant-negative TC21 reduced S6 phosphorylation but not Stat5 phosphorylation. Thus, trans-endocytosis of membrane-associated IL-15Rα-IL-15 provides a mode of regulating NK cells that is not afforded to IL-2 and is distinct from activation by soluble IL-15. These results may explain the strict IL-15 dependence of NK cells and illustrate how the cellular compartment in which receptor-ligand interaction occurs can influence functional outcome.

Target-Dependent Expression of IL12 by synNotch Receptor-Engineered NK92 Cells Increases the Antitumor Activities of CAR-T Cells

IL12 is an immune-stimulatory cytokine for key immune cells including T cells and NK cells. However, systemic administration of IL12 has serious side effects that limit its clinical application in patients. Recently, synthetic Notch (synNotch) receptors have been developed that induce transcriptional activation and deliver therapeutic payloads in response to the reorganization of specific antigens. NK92 cell is a human natural killer (NK) cell line which has been developed as tools for adjuvant immunotherapy of cancer. Here, we explored the possibility of using synNotch receptor-engineered NK92 cells to selectively secrete IL12 at the tumor site and increase the antitumor activities of chimeric antigen receptor (CAR)-modified T cells. Compared with the nuclear factor of activated T-cells (NFATs) responsive promoter, which is another regulatory element, the synNotch receptor was better at controlling the expression of cytokines. NK92 cells transduced with the GPC3-specific synNotch receptor could produce the proinflammatory cytokine IL12 (GPC3-Syn-IL12-NK92) in response to GPC3 antigen expressed in cancer cells. In vivo GPC3-Syn-IL12-NK92 cells controlling IL12 production could enhance the antitumor ability of GPC3-redirected CAR T cells and increase the infiltration of T cells without inducing toxicity. Taken together, our results demonstrated that IL12 supplementation by synNotch-engineered NK92 cells could secrete IL12 in a target-dependent manner, and promote the antitumor efficiency of CAR-T cells. Local expression of IL12 by synNotch-engineered NK92 cells might be a safe approach to enhance the clinical outcome of CAR-T cell therapy.

PEGylated reduced-graphene oxide hybridized with Fe3O4 nanoparticles for cancer photothermal-immunotherapy

Photoimmunotherapy has attracted much attention recently for the treatment of metastatic tumors. The development of smart nanocomposites for imaging-guided therapies is needed to improve the efficacy of cancer treatment. Herein, a PEGylated nanocomposite was developed for photothermal-immunotherapy. In particular, this nanocomposite was formulated by hybridizing Fe3O4 nanoparticles (FNPs) with reduced-graphene oxide (rGO) through electrostatic interaction, modified by PEG-NH2 on the surface of FNPs/rGO. The FNPs/rGO-PEG nanocomposites are excellent agents for photothermal therapy (PTT) under irradiation by an 805 nm laser. This nanocomposite could promote the activity of the host antitumor immune response efficiently because of the reduction of tumor-associated macrophages by the incorporation of FNPs. In our experiments, we observed FNPs/rGO-PEG based PTT induced immunogenic cell death accompanied by the release of danger-associated molecular patterns. We also found that FNPs/rGO-PEG + laser irradiation of animal tumors could activate dendritic cells (DCs) in tumor draining lymph nodes. In vivo antitumor studies revealed that FNPs/rGO-PEG nanocomposites, when combined with laser irradiation, could result in desirable photothermal effects and destroy primary tumors. Moreover, intratumoral injection of FNPs/rGO-PEG nanocomposites into 4T1 orthotopic mouse breast tumors, in combination with near-infrared laser irradiation, significantly increased the median survival time of tumor-bearing animals. FNPs/rGO-PEG nanocomposites could also be used for magnetic resonance imaging, which may lead to a MRI-guided photothermal-immunotherapy for metastatic cancers. This study could lead to a cancer treatment strategy that combines PTT with immunotherapies using FNPs/rGO-PEG nanocomposites.

PEGylated reduced-graphene oxide hybridized with Fe3O4 nanoparticles for cancer photothermal-immunotherapy

Photoimmunotherapy has attracted much attention recently for the treatment of metastatic tumors. The development of smart nanocomposites for imaging-guided therapies is needed to improve the efficacy of cancer treatment. Herein, a PEGylated nanocomposite was developed for photothermal-immunotherapy. In particular, this nanocomposite was formulated by hybridizing Fe₃O₄ nanoparticles (FNPs) with reduced-graphene oxide (rGO) through electrostatic interaction, modified by PEG-NH₂ on the surface of FNPs/rGO. The FNPs/rGO-PEG nanocomposites are excellent agents for photothermal therapy (PTT) under irradiation by an 805 nm laser. This nanocomposite could promote the activity of the host antitumor immune response efficiently because of the reduction of tumor-associated macrophages by the incorporation of FNPs. In our experiments, we observed FNPs/rGO-PEG based PTT induced immunogenic cell death accompanied by the release of danger-associated molecular patterns. We also found that FNPs/rGO-PEG + laser irradiation of animal tumors could activate dendritic cells (DCs) in tumor draining lymph nodes. In vivo antitumor studies revealed that FNPs/rGO-PEG nanocomposites, when combined with laser irradiation, could result in desirable photothermal effects and destroy primary tumors. Moreover, intratumoral injection of FNPs/rGO-PEG nanocomposites into 4T1 orthotopic mouse breast tumors, in combination with near-infrared laser irradiation, significantly increased the median survival time of tumor-bearing animals. FNPs/rGO-PEG nanocomposites could also be used for magnetic resonance imaging, which may lead to a MRI-guided photothermal-immunotherapy for metastatic cancers. This study could lead to a cancer treatment strategy that combines PTT with immunotherapies using FNPs/rGO-PEG nanocomposites.

Expression of lymphocyte immunoregulatory biomarkers in bone and soft-tissue sarcomas

Despite advances in our understanding of the underlying molecular drivers of sarcomas, few treatments are available with proven benefit for advanced metastatic sarcomas. Immunotherapy has value in this setting for some types of cancers, but sarcomas, with their multiplicity of rare types, have not been characterized in detail for their expression of targetable immune biomarkers. This study provides the most systematic evaluation to date of tumor-infiltrating lymphocytes and immune checkpoint biomarker expression in sarcomas. We examined by morphology and immunohistochemistry 1072 sarcoma specimens representing 22 types, in addition to 236 benign bone and soft-tissue tumors. Genomically-complex sarcoma types-those driven by mutations and/or copy-number alterations-had much higher numbers of tumor-infiltrating lymphocytes than translocation-associated sarcomas. Prior exposure to radiotherapy was associated with increased immune infiltrates. Higher lymphocytic infiltration was associated with better overall survival among the non-translocation-associated sarcomas. Expression of PD-1 and CD56 were associated with worse overall survival. LAG-3 and TIM-3, two emerging immune checkpoints, were frequently expressed in most sarcoma types. Indeed, most cases positive for PD-(L)1 coexpressed one or both of these novel biomarkers, providing a potential rationale in support for trials targeting LAG-3 and/or TIM-3 in conjunction with PD-1 inhibition.

Gene Therapy for Liver Cancers: Current Status from Basic to Clinics

The liver is a key organ for metabolism, protein synthesis, detoxification, and endocrine function, and among liver diseases, including hepatitis, cirrhosis, malignant tumors, and congenital disease, liver cancer is one of the leading causes of cancer-related deaths worldwide. Conventional therapeutic options such as embolization and chemotherapy are not effective against advanced-stage liver cancer; therefore, continuous efforts focus on the development of novel therapeutic options, including molecular targeted agents and gene therapy. In this review, we will summarize the progress toward the development of gene therapies for liver cancer, with an emphasis on recent clinical trials and preclinical studies.

Development of adaptive immune effector therapies in solid tumors

State-of-the-art treatment strategies have drastically ameliorated the outcome of patients affected by cancer. However, resistant and recurrent solid tumors are generally nonresponsive to conventional therapies. A central factor in the sequence of events that lead to cancer is an alteration in antitumor immune surveillance, which results in failure to recognize and eliminate the transformed tumor cell. A greater understanding of the dysregulation and evasion of the immune system in the evolution and progression of cancer provides the basis for improved therapies. Targeted strategies, such as T-cell therapy, not only generally spare normal tissues, but also use alternative antineoplastic mechanisms that synergize with other therapeutics. Despite encouraging success in hematologic malignancies, adaptive cellular therapies for solid tumors face unique challenges because of the immunosuppressive tumor microenvironment, and the hurdle of T-cell trafficking within scarcely accessible tumor sites. This review provides a brief overview of current cellular therapeutic strategies for solid tumors, research carried out to increase efficacy and safety, and results from ongoing clinical trials.

Expansion processes for cell-based therapies

Living cells are emerging as therapeutic entities for the treatment of patients affected with severe and chronic diseases where no conventional drug can provide a definitive cure. At the same time, the promise of cell-based therapies comes with several biological, regulatory, economic, logistical, safety and engineering challenges that need to be addressed before translating into clinical practice. Among the complex operations required for their manufacturing, cell expansion occupies a significant part of the entire process and largely determines the number, the phenotype and several other critical quality attributes of the final cell therapy products (CTPs). This review aims at characterizing the main culture systems and expansion processes used for CTP production, highlighting the need to implement scalable, cost-efficient technologies together with process optimization strategies to bridge the gap between basic scientific research and commercially available therapies.

Potential clinical application of tumor-infiltrating lymphocyte therapy for ovarian epithelial cancer prior or post-resistance to chemotherapy

BACKGROUND

Immunotherapy has become a powerful treatment option for several solid tumor types. The presence of tumor-infiltrating lymphocytes (TIL) is correlated with better prognosis in ovarian cancer, pointing at the possibility to benefit from harnessing their anti-tumor activity. This preclinical study explores the feasibility of adoptive cell therapy (ACT) with TIL using an improved culture method.

METHODS

TIL from high-grade serous ovarian cancer were cultured using a combination of IL-2 with agonistic antibodies targeting 4-1BB and CD3. The cells were phenotyped using flow cytometry in the fresh tissue and after expansion. Tumor reactivity was assessed against HLA-matched ovarian cancer cell lines via IFN-γ ELISPOT.

RESULTS

Ovarian cancer is highly infiltrated with CD8⁺ TIL that are preferentially and robustly expanded with the addition of the agonistic antibodies. With a 95% success rate, the TIL are grown to ≥ 100 × 10⁶ cells in 2-3 weeks without over differentiation. In addition, the CD8⁺ TIL grown with this method showed HLA-restricted tumor recognition.

CONCLUSIONS

These results indicate the viability of TIL ACT for refractory ovarian cancer by allowing for the large expansion of anti-tumor TIL in a short time and consistent manner.

Developing neoantigen-targeted T cell-based treatments for solid tumors

Stimulating an immune response against cancer through adoptive transfer of tumor-targeting lymphocytes has shown great promise in hematological malignancies, but clinical efficacy against many common solid epithelial cancers remains low. Targeting 'neoantigens'-the somatic mutations expressed only by tumor cells-might enable tumor destruction without causing undue damage to vital healthy tissues. Major challenges to targeting neoantigens with T cells include heterogeneity and variability in antigen processing and presentation of targets by tumors, and an incomplete understanding of which T cell qualities are essential for clinically effective therapies. Finally, the prospect of targeting somatic tumor mutations to promote T cell destruction of cancer must contend with the biology that not all tumor-expressed 'neoepitopes' actually generate neoantigens that can be functionally recognized and provoke an effective immune response. In this Review, we discuss the promise, progress and challenges for improving neoantigen-targeted T cell-based immunotherapies for cancer.

Primary Bone Tumors: Challenges and Opportunities for CAR-T Therapies

Primary malignant bone tumors are rare, occur in all age groups, and include distinct entities such as osteosarcoma, Ewing sarcoma, and chondrosarcoma. Traditional treatment with some combination of chemotherapy, surgery, and radiation has reached the limit of efficacy, with substantial room for improvement in patient outcome. Furthermore, genomic characterization of these tumors reveals a paucity of actionable molecular targets. Against this backdrop, recent advances in cancer immunotherapy represent a silver lining in the treatment of primary bone cancer. Major strategies in cancer immunotherapy include stimulating naturally occurring anti-tumor T cells and adoptive transfer of tumor-specific cytotoxic T cells. Chimeric antigen receptor T cells (CAR-T cells) belong to the latter strategy and are an impressive application of both insights into T cell biology and advances in genetic engineering. In this review, we briefly describe the CAR-T approach and discuss its applications in primary bone tumors. © 2019 American Society for Bone and Mineral Research.

Application Of Adoptive Immunotherapy In Ovarian Cancer

Ovarian cancer (OC) has been the most fatal gynecological disease that threatens women's health. Surgery and platinum-based chemotherapy are the basic ovarian cancer treatments that can improve survival, but the five-year survival rate has not improved because of delayed diagnosis, drug resistance, and recurrence. Novel treatments are needed to improve the prognosis and survival rate of ovarian cancer patients. In recent years, adoptive cell therapy (ACT) has received increasing attention as an emerging therapeutic strategy in the treatment of solid tumors including OC. ACT has shown promising results in many preclinical and clinical trials of OC. The application of ACT depends on different effector cells, such as lymphokine-activated killer (LAK) cells, tumor-infiltrating lymphocytes (TILs), and genetically modified T cells. In this review, we focus on adoptive immunotherapies in ovarian cancer and summarize completed and ongoing preclinical/clinical trials. The future development directions and obstacles for ACT in OC treatment are discussed.

T-Cell Receptor Stimulation Enhances the Expansion and Function of CD19 Chimeric Antigen Receptor-Expressing T Cells

PURPOSE

Current protocols for CD19 chimeric antigen receptor-expressing T cells (CD19.CAR-T cells) require recipients to tolerate preinfusion cytoreductive chemotherapy, and the presence of sufficient target antigen on normal or malignant B cells.

PATIENTS AND METHODS

We investigated whether additional stimulation of CD19.CAR-T cells through their native receptors can substitute for cytoreductive chemotherapy, inducing expansion and functional persistence of CD19.CAR-T even in patients in remission of B-cell acute lymphocytic leukemia. We infused a low dose of CD19.CAR-modified virus-specific T cells (CD19.CAR-VST) without prior cytoreductive chemotherapy into 8 patients after allogeneic stem cell transplant.

RESULTS

Absent virus reactivation, we saw no CD19.CAR-VST expansion. In contrast, in patients with viral reactivation, up to 30,000-fold expansion of CD19.CAR-VSTs was observed, with depletion of CD19⁺ B cells. Five patients remain in remission at 42-60+ months.

CONCLUSIONS

Dual T-cell receptor and CAR stimulation can thus potentiate effector cell expansion and CAR-target cell killing, even when infusing low numbers of effector cells without cytoreduction.

Genetically engineered T cells for cancer immunotherapy

T cells in the immune system protect the human body from infection by pathogens and clear mutant cells through specific recognition by T cell receptors (TCRs). Cancer immunotherapy, by relying on this basic recognition method, boosts the antitumor efficacy of T cells by unleashing the inhibition of immune checkpoints and expands adaptive immunity by facilitating the adoptive transfer of genetically engineered T cells. T cells genetically equipped with chimeric antigen receptors (CARs) or TCRs have shown remarkable effectiveness in treating some hematological malignancies, although the efficacy of engineered T cells in treating solid tumors is far from satisfactory. In this review, we summarize the development of genetically engineered T cells, outline the most recent studies investigating genetically engineered T cells for cancer immunotherapy, and discuss strategies for improving the performance of these T cells in fighting cancers.

Dendritic Cell-Based and Other Vaccination Strategies for Pediatric Cancer

Dendritic cell-based and other vaccination strategies that use the patient’s own immune system for the treatment of cancer are gaining momentum. Most studies of therapeutic cancer vaccination have been performed in adults. However, since cancer is one of the leading causes of death among children past infancy in the Western world, the hope is that this form of active specific immunotherapy can play an important role in the pediatric population as well. Since children have more vigorous and adaptable immune systems than adults, therapeutic cancer vaccines are expected to have a better chance of creating protective immunity and preventing cancer recurrence in pediatric patients. Moreover, in contrast to conventional cancer treatments such as chemotherapy, therapeutic cancer vaccines are designed to specifically target tumor cells and not healthy cells or tissues. This reduces the likelihood of side effects, which is an important asset in this vulnerable patient population. In this review, we present an overview of the different therapeutic cancer vaccines that have been studied in the pediatric population, with a main focus on dendritic cell-based strategies. In addition, new approaches that are currently being investigated in clinical trials are discussed to provide guidance for further improvement and optimization of pediatric cancer vaccines.

Is it true that gut microbiota is considered as panacea in cancer therapy?

Recent studies demonstrated that a combination of the gut microbiome has the vital effect on the efficacy of anticancer immune therapies. Regulatory effects of microbiota have been shown in different types of cancer therapies such as chemotherapy and immunotherapy. Immune-checkpoint-blocked therapies are the recent efficient cancer immunotherapy strategies. The target of immune-checkpoint blocking is cytotoxic T lymphocyte protein-4 (CTLA-4) or blockade of programmed death-1 (PD-1) protein and its ligand programmed death ligand 1 (PD-L1) that they have been considered as cancer immunotherapy in recent years. In the latest studies, it have been demonstrated that several gut bacteria such as Akkermansia muciniphila, Bifidobacterium spp., Faecalibacterium spp., and Bacteroides fragilis have the regulatory effects on PD-1, PD-L1, and CTLA-4 blocked anticancer therapy outcome.

Blocking Formation of the Stable HIV Reservoir: A New Perspective for HIV-1 Cure

Recent studies demonstrate that the stable HIV-1 reservoir in resting CD4+ T cells is mostly formed from viruses circulating when combination antiretroviral therapy (ART) is initiated. Here we explore the immunological basis for these observations. Untreated HIV-1 infection is characterized by a progressive depletion of memory CD4+ T cells which mostly express CD127, the α chain of the IL-7 receptor (IL-7R). Depletion results from both direct infection and bystander loss of memory CD4+ T cells in part attributed to dysregulated IL-7/IL-7R signaling. While IL-7/IL7R signaling is not essential for the generation of effector CD4+ T cells from naïve cells, it is essential for the further transition of effectors to memory CD4+ T cells and their subsequent homeostatic maintenance. HIV-1 infection therefore limits the transition of CD4+ T cells from an effector to long-lived memory state. With the onset of ART, virus load (VL) levels rapidly decrease and the frequency of CD127+ CD4+ memory T cells increases, indicating restoration of effector to memory transition in CD4+ T cells. Collectively these data suggest that following ART initiation, HIV-1 infected effector CD4+ T cells transition to long-lived, CD127+ CD4+ T cells forming the majority of the stable HIV-1 reservoir. We propose that combining ART initiation with inhibition of IL-7/IL-7R signaling to block CD4+ T cell memory formation will limit the generation of long-lived HIV-infected CD4+ T cells and reduce the overall size of the stable HIV-1 reservoir.

CD19 CAR T cells following autologous transplantation in poor-risk relapsed and refractory B-cell non-Hodgkin lymphoma

High-dose chemotherapy and autologous stem cell transplantation (HDT-ASCT) is the standard of care for relapsed or primary refractory (rel/ref) chemorefractory diffuse large B-cell lymphoma. Only 50% of patients are cured with this approach. We investigated safety and efficacy of CD19-specific chimeric antigen receptor (CAR) T cells administered following HDT-ASCT. Eligibility for this study includes poor-risk rel/ref aggressive B-cell non-Hodgkin lymphoma chemosensitive to salvage therapy with: (1) positron emission tomography-positive disease or (2) bone marrow involvement. Patients underwent standard HDT-ASCT followed by 19-28z CAR T cells on days +2 and +3. Of 15 subjects treated on study, dose-limiting toxicity was observed at both dose levels (5 × 106 and 1 × 107 19-28z CAR T per kilogram). Ten of 15 subjects experienced CAR T-cell-induced neurotoxicity and/or cytokine release syndrome (CRS), which were associated with greater CAR T-cell persistence (P = .05) but not peak CAR T-cell expansion. Serum interferon-γ elevation (P < .001) and possibly interleukin-10 (P = .07) were associated with toxicity. The 2-year progression-free survival (PFS) is 30% (95% confidence interval, 20% to 70%).  Subjects given decreased naive-like (CD45RA+CCR7+) CD4+ and CD8+ CAR T cells experienced superior PFS (P = .02 and .04, respectively). There was no association between CAR T-cell peak expansion, persistence, or cytokine changes and PFS. 19-28z CAR T cells following HDT-ASCT were associated with a high incidence of reversible neurotoxicity and CRS. Following HDT-ASCT, effector CD4+ and CD8+ immunophenotypes may improve disease control. This trial was registered at www.clinicaltrials.gov as #NCT01840566.

Human CD4+ T Cells Specific for Merkel Cell Polyomavirus Localize to Merkel Cell Carcinomas and Target a Required Oncogenic Domain

Although CD4⁺ T cells likely play key roles in antitumor immune responses, most immuno-oncology studies have been limited to CD8⁺ T-cell responses due to multiple technical barriers and a lack of shared antigens across patients. Merkel cell carcinoma (MCC) is an aggressive skin cancer caused by Merkel cell polyomavirus (MCPyV) oncoproteins in 80% of cases. Because MCPyV oncoproteins are shared across most patients with MCC, it is unusually feasible to identify, characterize, and potentially augment tumor-specific CD4⁺ T cells. Here, we report the identification of CD4⁺ T-cell responses against six MCPyV epitopes, one of which included a conserved, essential viral oncogenic domain that binds/disables the cellular retinoblastoma (Rb) tumor suppressor. We found that this epitope (WED_LT209-228) could be presented by three population-prevalent HLA class II alleles, making it a relevant target in 64% of virus-positive MCC patients. Cellular staining with a WED_LT209-228-HLA-DRB1*0401 tetramer indicated that specific CD4⁺ T cells were detectable in 78% (14 of 18) of evaluable MCC patients, were 250-fold enriched within MCC tumors relative to peripheral blood, and had diverse T-cell receptor sequences. We also identified a modification of this domain that still allowed recognition by these CD4⁺ T cells but disabled binding to the Rb tumor suppressor, a key step in the detoxification of a possible therapeutic vaccine. The use of these new tools for deeper study of MCPyV-specific CD4⁺ T cells may provide broader insight into cancer-specific CD4⁺ T-cell responses.

Chimeric antigen receptor T-cell therapy for cancer: a basic research-oriented perspective

Chimeric antigen receptor (CAR) T cells have outstanding therapeutic potential for treating blood cancers. The prospects for this technology have accelerated basic research, clinical translation and Big Pharma's investment in the field of T-cell therapeutics. This interest has led to the discovery of key factors that affect CAR T-cell efficacy and play pivotal roles in T-cell immunology. Herein, we introduce advances in adoptive immunotherapy and the birth of CAR T cells, and review CAR T-cell studies that focus on three important features: CAR constructs, target antigens and T-cell phenotypes. At last, we highlight novel strategies that overcome the tumor microenvironment and circumvent CAR T-cell side effects, and consider the future direction of CAR T-cell development.

Low mutational load in pediatric medulloblastoma still translates into neoantigens as targets for specific T-cell immunotherapy

BACKGROUND

Medulloblastoma is the most common malignant brain tumor in childhood and adolescence. Although some patients present with distinct genetic alterations, such as mutated TP53 or MYC amplification, pediatric medulloblastoma is a tumor entity with minimal mutational load and low immunogenicity.

METHODS

We identified tumor-specific mutations using next-generation sequencing of medulloblastoma DNA and RNA derived from primary tumor samples from pediatric patients. Tumor-specific mutations were confirmed using deep sequencing and in silico analyses predicted high binding affinity of the neoantigen-derived peptides to the patients' human leukocyte antigen molecules. Tumor-specific peptides were synthesized and used to induce a de novo T-cell response characterized by interferon gamma and tumor necrosis factor alpha release of CD8⁺ cytotoxic T cells in vitro.

RESULTS

Despite low mutational tumor burden, at least two immunogenic tumor-specific peptides were identified in each patient. T cells showed a balanced CD4/CD8 ratio and mostly effector memory phenotype. Induction of a CD8-specific T-cell response was achieved for the neoepitopes derived from Histidine Ammonia-Lyase (HAL), Neuraminidase 2 (NEU2), Proprotein Convertase Subtilisin (PCSK9), Programmed Cell Death 10 (PDCD10), Supervillin (SVIL) and tRNA Splicing Endonuclease Subunit 54 (TSEN54) variants.

CONCLUSION

Detection of patient-specific, tumor-derived neoantigens confirms that even in tumors with low mutational load a molecular design of targets for specific T-cell immunotherapy is possible. The identified neoantigens may guide future approaches of adoptive T-cell transfer, transgenic T-cell receptor transfer or tumor vaccination.

Immunotherapy for skin cancer

Among all tumor types, skin cancers are profoundly sensitive to immunotherapy. Indeed, the recently reported response rates for anti-PD-1 (anti-programmed-death 1) therapy for cutaneous malignant melanomas (MM), Merkel cell carcinomas, basal cell carcinomas, cutaneous squamous cell carcinomas and Kaposi sarcomas are all above 40%. This unique immunogenicity renders skin cancers as a paradigm for tumor-immune interactions and is driven by high mutational burdens, over-expressed tumor antigens and/or viral antigens. However, despite the clear demonstration of immunologic cure of skin cancer in some patients, most tumors develop either early (primary) or late (adaptive) resistance to immunotherapy. Resistance mechanisms are complex, and include contributions of tumor cell-intrinsic, T cell and microenvironment factors that have been recently further elucidated with the advent of single-cell technologies. This review will focus on the exciting progress with immunotherapy for skin cancers to date, and also our current understanding of the mechanisms of resistance to immunotherapy.

Gene editing: Towards the third generation of adoptive T-cell transfer therapies

First-generation adoptive T-cell transfer (ACT) administering tumor-infiltrating lymphocytes (TILs), and second-generation ACT using autologous T cells genetically modified to express tumor-specific T-cell receptors (TCRs) or chimeric antigen receptors (CARs) have both shown promise for the treatment of several cancers, including melanoma, leukemia and lymphoma. However, these treatments require labor-intensive manufacturing of the cell product for each patient, frequently utilize lentiviral or retroviral vectors to genetically modify the T cells, and have limited antitumor efficacy in solid tumors. Gene editing is revolutionizing the field of gene therapy, and ACT is at the forefront of this revolution. Gene-editing technologies can be used to re-engineer the phenotype of T cells to increase their antitumor potency, to generate off-the-shelf ACT products, and to replace endogenous TCRs with tumor-specific TCRs or CARs using homology-directed repair (HDR) donor templates. Adeno-associated viral vectors or linear DNA have been used as HDR donor templates. Of note, non-viral delivery substantially reduces the time required to generate clinical-grade reagents for manufacture of T-cell products—a critical step for the translation of personalized T-cell therapies. These technological advances in the field using gene editing open the door to the third generation of ACT therapies.

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CRISPR-Cas9 allows the generation of tumor-specific T cells for adoptive T-cell transfer (ACT).

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Gene editing allows generation of off-the-shelf ACT products.

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Gene editing can tailor T-cell phenotype and increase antitumor potency.

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Non-viral gene editing is a requirement for personalized ACT.

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Personalized third-generation ACT: gene-edited neoantigen-specific T cells.

The Impact of Intratumoral and Gastrointestinal Microbiota on Systemic Cancer Therapy

The human microbiome is a complex aggregate of microorganisms, and their genomes exert a number of influences crucial to the metabolic, immunologic, hormonal, and homeostatic function of the host. Recent work, both in preclinical mouse models and human studies, has shed light on the impact of gut and tumor microbiota on responses to systemic anticancer therapeutics. In light of this, strategies to target the microbiome to improve therapeutic responses are underway, including efforts to target gut and intratumoral microbes. Here, we discuss mechanisms by which microbiota may impact systemic and antitumor immunity, in addition to outstanding questions in the field. A deeper understanding of these is critical as we devise putative strategies to target the microbiome.

A good start of immunotherapy in esophageal cancer

Considering the benefits of immunotherapy in advanced melanoma, non–small cell lung cancer, renal cell carcinoma, bladder cancers, and refractory Hodgkin lymphoma, we begin to consider whether immunotherapy is effective for esophageal cancer, which is extremely malignant and has a poor prognosis. There are a large number of clinical trials to study the application of immunotherapy such as immune checkpoint inhibitors, peptide vaccine, adoptive T cell transfer and oncolytic virus in esophageal cancer. Some already have preliminary results and show the advantages of immunotherapy in esophageal cancer, while others are still in progress. This review aims to introduce the feasibility and current status of immunotherapy in esophageal cancer.

Aging, Cancer and Immunity

Cancers are being frequently diagnosed in the elderly. Immunosenescence which refers to the gradual deterioration of the immune system brought on by natural age advancement, has been the key cross center in the increasing frequency and severity of cancer, aging and immunity. Monoclonal antibodies targeting immune checkpoint molecules CTLA-4, PD-1 or PD-L1 are the promising anticancer therapeutics in multiple cancer subtypes generating remarkable and long-lasting clinical responses. These immune checkpoint blockers (ICBs)have already obtained approval for the treatment of patients with metastatic melanoma, advanced/refractory non-small cell lung cancer and renal cell cancer. ICBs can not only enhance immune responses against cancer cells but can also lead to inflammatory side effects called immune-related adverse events (irAEs). As none or only a small number of older patients were enrolled in most ICBs studies, it remains difficult to confirm the impacts of ICBs on the elderly. We could expect that clinical specificity of older patients (co-medications, comorbidities and reduced functional reserve) and immunosenescence may affect the efficacy of ICBs and tolerance in this population. However, the results from meta-analysis on the efficacy of ICBs are very encouraging and suggesting that the older patients will benefit from the ICBs revolution in oncology without increased toxicity.

New Developments in Imaging Cell-Based Therapy

Cancer immunotherapy is now established as a central therapeutic pillar in hematologic oncology. Cell-based therapies, with or without genetic modification ex vivo, have reached the clinic as the standard of care in limited indications and remain the subject of intense preclinical and translational development. Expanding on this, related therapeutic approaches are in development for solid-tumor and nonmalignant indications, broadening the scope of this technology. It has long been recognized that in vivo tracking of infused cellular therapies would provide unique opportunities to optimize their efficacy and aid in the assessment and management of toxicity. Recently, we have witnessed the introduction of novel tracers for passive labeling of cell products and advances in the introduction and use of reporter genes to enable longitudinal imaging. This review highlights the key developments over the last 5 y.

Can Immunogenic Chemotherapies Relieve Cancer Cell Resistance to Immune Checkpoint Inhibitors?

The unprecedented clinical activity of checkpoint blockade in several types of cancers has formally demonstrated that anti-tumor immune responses are crucial in cancer therapy. Durable responses seen in patients treated with immune checkpoint inhibitors (ICI) show that they can trigger the establishment of long-lasting immunologic memory. This beneficial outcome is however achieved for a limited number of patients. In addition, late relapses are emerging suggesting the development of acquired resistances that compromise the anticancer efficacy of ICI. How can this be prevented through combination therapies? We here review the functions of immune checkpoints, the successes of ICI in treating cancer and their therapeutic limits. We discuss how conventional cancer therapies can be properly selected to set up combinatorial approaches with ICI leading to treatment improvement. We finally summarize clinical data showing the ongoing progress in cancer treatment involving ICI and chemotherapy combination strategies.

Radiation therapy and immunotherapy: what is the optimal timing or sequencing?

Radiotherapy is a component of the standard of care for many patients with locally advanced nonmetastatic tumors and increasingly those with oligometastatic tumors. Despite encouraging advances in local control and progression-free and overall survival outcomes, continued manifestation of tumor progression or recurrence leaves room for improvement in therapeutic efficacy. Novel combinations of radiation with immunotherapy have shown promise in improving outcomes and reducing recurrences by overcoming tumor immune tolerance and evasion mechanisms via boosting the immune system's ability to recognize and eradicate tumor cells. In this review, we discuss preclinical and early clinical evidence that radiotherapy and immunotherapy can improve treatment outcomes for locally advanced and metastatic tumors, elucidate underlying molecular mechanisms and address strategies to optimize timing and sequencing of combination therapy for maximal synergy.

MicroRNA-155 Expression Is Enhanced by T-cell Receptor Stimulation Strength and Correlates with Improved Tumor Control in Melanoma

microRNAs are short noncoding RNAs that regulate protein expression posttranscriptionally. We previously showed that miR-155 promotes effector CD8⁺ T-cell responses. However, little is known about the regulation of miR-155 expression. Here, we report that antigen affinity and dose determine miR-155 expression in CD8⁺ T cells. In B16 tumors expressing a low-affinity antigen ligand, tumor-specific infiltrating CD8⁺ T cells showed variable miR-155 expression, whereby high miR-155 expression was associated with more cytokine-producing cells and tumor control. Moreover, anti-PD-1 treatment led to both increased miR-155 expression and tumor control by specific CD8⁺ T cells. In addition, miR-155 overexpression enhanced exhausted CD8⁺ T-cell persistence in the LCMV cl13 chronic viral infection model. In agreement with these observations in mouse models, miR-155 expression in human effector memory CD8⁺ T cells positively correlated with their frequencies in tumor-infiltrated lymph nodes of melanoma patients. Low miR-155 target gene signature in tumors was associated with prolonged overall survival in melanoma patients. Altogether, these results raise the possibility that high miR-155 expression in CD8⁺ tumor-infiltrating T cells may be a surrogate marker of the relative potency of in situ antigen-specific CD8⁺ T-cell responses.

Phase II clinical trial of adoptive cell therapy for patients with metastatic melanoma with autologous tumor-infiltrating lymphocytes and low-dose interleukin-2

Adoptive cell therapy using autologous tumor-infiltrating lymphocytes (TIL) has shown significant clinical benefit, but is limited by toxicities due to a requirement for post-infusion interleukin-2 (IL-2), for which high dose is standard. To assess a modified TIL protocol using lower dose IL-2, we performed a single institution phase II protocol in unresectable, metastatic melanoma. The primary endpoint was response rate. Secondary endpoints were safety and assessment of immune correlates following TIL infusion. Twelve metastatic melanoma patients were treated with non-myeloablative lymphodepleting chemotherapy, TIL, and low-dose subcutaneous IL-2 (125,000 IU/kg/day, maximum 9-10 doses over 2 weeks). All but one patient had previously progressed after treatment with immune checkpoint inhibitors. No unexpected adverse events were observed, and patients received an average of 6.8 doses of IL-2. By RECIST v1.1, two patients experienced a partial response, one patient had an unconfirmed partial response, and six had stable disease. Biomarker assessment confirmed an increase in IL-15 levels following lymphodepleting chemotherapy as expected and a lack of peripheral regulatory T-cell expansion following protocol treatment. Interrogation of the TIL infusion product and monitoring of the peripheral blood following infusion suggested engraftment of TIL. In one responding patient, a population of T cells expressing a T-cell receptor Vβ chain that was dominant in the infusion product was present at a high percentage in peripheral blood more than 2 years after TIL infusion. This study shows that this protocol of low-dose IL-2 following adoptive cell transfer of TIL is feasible and clinically active. (ClinicalTrials.gov identifier NCT01883323.).

Immunotherapy and targeted therapies in older patients with advanced melanoma; Young International Society of Geriatric Oncology review paper

Malignant melanoma is an aggressive cancer associated with a poor prognosis in patients with metastatic disease. As in many other cancers, the incidence of melanoma rises with age; and combined with the longer life expectancy, this led to an increasing prevalence of melanoma in the older population. Recently, immune checkpoint inhibitors significantly improved the treatment of melanoma given their efficacy and tolerability profile. Two major classes of agents include the anti-cytotoxic T lymphocyte-associated protein 4 (CTLA-4) inhibitors, such as ipilimumab, and the anti-programmed death-ligand 1 (PD-1) inhibitors, such as nivolumab and pembrolizumab. Treatment of metastatic disease with immune checkpoint inhibitors demonstrated improved efficacy and better safety profiles compared to cytotoxic drugs and appears to be an attractive treatment option. Nevertheless, there is a need for tools designed to better predict which older patients will benefit from its use and who will experience toxicities related to the treatment. Current data do not show a major increase in toxicity rates in older patients. However, patients above 75 are often under-represented and those who are included are not representative of the general population of older patients, thereby also stressing the need for real-life data. Ongoing research is aiming at maximizing the potential treatment efficacy and developing novel immune-targeting modalities. Future studies should include older patients and assess geriatric domains in these older patients to better guide decision-making. This review discusses published clinical trials and where known, the efficacy and toxicity in older patients. Moreover, the clinical implications and future perspectives are discussed, with current recommendations for older patients, management of toxicities, and a proposal for an initial approach to the treatment of older patients with metastatic melanoma.

BCMA CAR T cells: the winding path to success

Chimeric antigen receptor (CAR) T cells have been shown to successfully treat some hematopoietic malignancies. Recognition of a relevant target on malignant cells and the proper costimulatory molecule are essential for CAR T cell efficacy. In this issue of the JCI, Cohen et al. conducted an early phase trial to evaluate B cell maturation antigen-targeting (BCMA-targeting) CAR T cells in patients with refractory multiple myeloma. Patients who received the highest dose of BCMA-targeting CAR T cells in combination with lymphodepletion had the greatest response. The results of the study provide further support for the use of BCMA-targeting CAR T cells for myeloma, and reiterate the importance of space and cell dose for CAR T cell success.

Impact of the microbiome on cancer progression and response to anti-cancer therapies

Humans are a colonized with trillions of commensal microorganisms which exert a profound effect on normal host physiology and immune function through an abundance of genetic and metabolic by-products. Although the commensal microbiome has beneficial functions to host physiology, perturbations of the composition of the commensal microbiome or the homeostatic mucosal environment can lead to the induction of immune pathology and systemic inflammation. In the context of cancer progression or response to immune therapy, this inflammation can be detrimental, resulting in tumor growth and the promotion of immune suppression. On the other hand, significant associations have been identified whereby certain commensal microorganisms are able to enhance T cell function or are required for tumor control in cancer patients treated with certain immune therapies and chemotherapies. The focus of this chapter is to highlight the role of the commensal microbiome during tumor progression and in response to immune therapies.

Turning the Tide Against Regulatory T Cells

Regulatory T (Treg) cells play crucial roles in health and disease through their immunosuppressive properties against various immune cells. In this review we will focus on the inhibitory role of Treg cells in anti-tumor immunity. We outline how Treg cells restrict T cell function based on our understanding of T cell biology, and how we can shift the equilibrium against regulatory T cells. To date, numerous strategies have been proposed to limit the suppressive effects of Treg cells, including Treg cell neutralization, destabilizing Treg cells and rendering T cells resistant to Treg cells. Here, we focus on key mechanisms which render T cells resistant to the suppressive effects of Treg cells. Lastly, we also examine current limitations and caveats of overcoming the inhibitory activity of Treg cells, and briefly discuss the potential to target Treg cell resistance in the context of anti-tumor immunity.

Indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders: current practice in Europe, 2019

This is the seventh special EBMT report on the indications for haematopoietic stem cell transplantation for haematological diseases, solid tumours and immune disorders. Our aim is to provide general guidance on transplant indications according to prevailing clinical practice in EBMT countries and centres. In order to inform patient decisions, these recommendations must be considered together with the risk of the disease, the risk of the transplant procedure and the results of non-transplant strategies. In over two decades since the first report, the EBMT indications manuscripts have incorporated changes in transplant practice coming from scientific and technical developments in the field. In this same period, the establishment of JACIE accreditation has promoted high quality and led to improved outcomes of patient and donor care and laboratory performance in transplantation and cellular therapy. An updated report with operating definitions, revised indications and an additional set of data with overall survival at 1 year and non-relapse mortality at day 100 after transplant in the commonest standard-of-care indications is presented. Additional efforts are currently underway to enable EBMT member centres to benchmark their risk-adapted outcomes as part of the Registry upgrade Project 2020 against national and/or international outcome data.

Emerging CRISPR/Cas9 applications for T-cell gene editing

Gene editing tools are being rapidly developed, accelerating many areas of cell and gene therapy research. Each successive gene editing technology promises increased efficacy, improved specificity, reduced manufacturing cost and design complexity; all of which are currently epitomised by the clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein (Cas9) platform. Since its conceptualisation, CRISPR-based gene editing has been applied to existing methodologies and has further allowed the exploration of novel avenues of research. Implementation of CRISPR/Cas9 has been instrumental to recent progress in the treatment of cancer, primary immunodeficiency, and infectious diseases. To this end, T-cell therapies have attempted to harness and redirect antigen recognition function, and through gene editing, broaden T-cell targeting capabilities and enhance their potency. The purpose of this review is to provide insights into emerging applications of CRISPR/Cas9 in T-cell therapies, to briefly address concerns surrounding CRISPR-mediated indel formation, and to introduce CRISPR/Cas9 base editing technologies that hold vast potential for future research and clinical translation.

B cell maturation antigen-specific CAR T cells are clinically active in multiple myeloma

BACKGROUND

Chimeric antigen receptor (CAR) T cells are a promising therapy for hematologic malignancies. B-cell maturation antigen (BCMA) is a rational target in multiple myeloma (MM).

METHODS

We conducted a phase I study of autologous T cells lentivirally-transduced with a fully-human, BCMA-specific CAR containing CD3ζ and 4-1BB signaling domains (CART-BCMA), in subjects with relapsed/refractory MM. Twenty-five subjects were treated in 3 cohorts: 1) 1-5 x 108 CART-BCMA cells alone; 2) Cyclophosphamide (Cy) 1.5 g/m2 + 1-5 x 107 CART-BCMA cells; and 3) Cy 1.5 g/m2 + 1-5 x 108 CART-BCMA cells. No pre-specified BCMA expression level was required.

RESULTS

CART-BCMA cells were manufactured and expanded in all subjects. Toxicities included cytokine release syndrome and neurotoxicity, which were grade 3-4 in 8 (32%) and 3 (12%) subjects, respectively, and reversible. One subject died at day 24 from candidemia and progressive myeloma, following treatment for severe CRS and encephalopathy. Responses (based on treated subjects) were seen in 4/9 (44%) in cohort 1, 1/5 (20%) in cohort 2, and 7/11 (64%) in cohort 3, including 5 partial, 5 very good partial, and 2 complete responses, 3 of which were ongoing at 11, 14, and 32 months. Decreased BCMA expression on residual MM cells was noted in responders; expression increased at progression in most. Responses and CART-BCMA expansion were associated with CD4:CD8 T cell ratio and frequency of CD45RO-CD27+CD8+ T cells in the pre-manufacturing leukapheresis product.

CONCLUSION

CART-BCMA infusions with or without lymphodepleting chemotherapy are clinically active in heavily-pretreated MM patients.

TRIAL REGISTRATION

NCT02546167.

FUNDING

University of Pennsylvania-Novartis Alliance and NIH.

Immunotherapy Approaches Beyond PD-1 Inhibition: the Future of Cellular Therapy for Head and Neck Squamous Cell Carcinoma

OPINION STATEMENT

In a span of a few years, the surprising early successes of programmed cell death 1 (PD-1) inhibitors across a vast range of tumor types have transformed our understanding of cancer immunogenicity and provided proof of principle that T cells, if manipulated, can mediate meaningful tumor regression. In head and neck cancer, only a minority of patients respond to PD-1 therapy, but these small outcomes have fueled the enthusiasm for the next generation of immunotherapy-adoptive cell therapy-which employs recent advances in genetic engineering and cell culturing methods to generate T cells with enhanced anti-tumor efficacy for infusion back into the patient. Head and neck cancer is comprised of biologically distinct cancers, HPV-positive and HPV-negative, and the clinical responses to PD-1 inhibitors in both HPV-positive and HPV-negative head and neck patients have showcased better than any other cancer type that there are distinct pathways to immunogenicity that may lend themselves to different therapeutic approaches. Thus, head and neck cancer is uniquely poised to benefit from the personalized approach of adoptive cell therapy as well as provide a valuable platform to explore contrasting T cell modalities. In this article, we will review the growing portfolio of trials of adoptive cell therapies in head and neck cancer and discuss the future directions of this emerging new field.

The Duplex Interaction of Microbiome with Chemoradiation and Immunotherapy: Potential Implications for Colorectal Cancer

Purpose of review

Gut microbiota has the ability to modify the metabolism of wide array of therapeutic drugs. Current treatment modalities used in colorectal cancer have a narrow therapeutic index with a side effects profile that decreases tolerance to these treatments and adversely affects treatment outcome. Harnessing the gut microbiota ability to modify oncotherapeutic drugs metabolism and hence efficacy, could be potentially used to improve treatment outcomes in colorectal cancer patients. This review will shed lights on important findings from recent microbiome interaction studies which would hopefully serve as a useful tool to guide future translative colorectal cancer research.

Recent findings

Recent advances in microbiome studies have revealed an interesting aspect of gut microbes carcinogenic properties in dysbiotic gut environment. Microbiota niche in colorectal cancer can also modify efficacy and toxicity profile of different oncotherapeutic treatment modalities from chemoradiotherapy to immunotherapy. Conversely, each of these treatment modalities has numerous effects on the gastrointestinal flora, causing changes in the gut microbial community that affects host morbidity and mortality.

Summary

Symbiotic gut microbiota is an incredible functioning organ that maintains essential aspects of our homeostasis and immunity. According to the recent body of literature, they also can modify efficacy of many therapeutic drugs including oncotherapy. Considering that unexplainable variable treatment outcomes as well as variable tolerance to treatment have been observed in colorectal cancer patients, studying gut microbiota modulatory effects on oncotherapy might be a feasible approach to explain this phenomenon.

Evaluating in vivo efficacy - toxicity profile of TEG001 in humanized mice xenografts against primary human AML disease and healthy hematopoietic cells

BACKGROUND

γ9δ2T cells, which express Vγ9 and Vδ2 chains of the T cell receptor (TCR), mediate cancer immune surveillance by sensing early metabolic changes in malignant leukemic blast and not their healthy hematopoietic stem counterparts via the γ9δ2TCR targeting joined conformational and spatial changes of CD277 at the cell membrane (CD277J). This concept led to the development of next generation CAR-T cells, so-called TEGs: αβT cells Engineered to express a defined γδTCR. The high affinity γ9δ2TCR clone 5 has recently been selected within the TEG format as a clinical candidate (TEG001). However, exploring safety and efficacy against a target, which reflects an early metabolic change in tumor cells, remains challenging given the lack of appropriate tools. Therefore, we tested whether TEG001 is able to eliminate established leukemia in a primary disease model, without harming other parts of the healthy hematopoiesis in vivo.

METHODS

Separate sets of NSG mice were respectively injected with primary human acute myeloid leukemia (AML) blasts and cord blood-derived human progenitor cells from healthy donors. These mice were then treated with TEG001 and mock cells. Tumor burden and human cells engraftment were measured in peripheral blood and followed up over time by quantifying for absolute cell number by flow cytometry. Statistical analysis was performed using non-parametric 2-tailed Mann-Whitney t-test.

RESULTS

We successfully engrafted primary AML blasts and healthy hematopoietic cells after 6-8 weeks. Here we report that metabolic cancer targeting through TEG001 eradicated established primary leukemic blasts in vivo, while healthy hematopoietic compartments derived from human cord-blood remained unharmed in spite of TEGs persistence up to 50 days after infusion. No additional signs of off-target toxicity were observed in any other tissues.

CONCLUSION

Within the limitations of humanized PD-X models, targeting CD277J by TEG001 is safe and efficient. Therefore, we have initiated clinical testing of TEG001 in a phase I first-in-human clinical trial (NTR6541; date of registration 25 July 2017).

Impact of microbiota on central nervous system and neurological diseases: the gut-brain axis

Development of central nervous system (CNS) is regulated by both intrinsic and peripheral signals. Previous studies have suggested that environmental factors affect neurological activities under both physiological and pathological conditions. Although there is anatomical separation, emerging evidence has indicated the existence of bidirectional interaction between gut microbiota, i.e., (diverse microorganisms colonizing human intestine), and brain. The cross-talk between gut microbiota and brain may have crucial impact during basic neurogenerative processes, in neurodegenerative disorders and tumors of CNS. In this review, we discuss the biological interplay between gut-brain axis, and further explore how this communication may be dysregulated in neurological diseases. Further, we highlight new insights in modification of gut microbiota composition, which may emerge as a promising therapeutic approach to treat CNS disorders.

Genetic Redirection of T Cells for the Treatment of Pancreatic Cancer

Conventional treatments for pancreatic cancer are largely ineffective, and the prognosis for the vast majority of patients is poor. Clearly, new treatment options are desperately needed. Immunotherapy offers hope for the development of treatments for pancreatic cancer. A central requirement for the efficacy of this approach is the existence of cancer antigen-specific T cells, but these are often not present or difficult to isolate for most pancreatic tumors. Nevertheless, specific T cells can be generated using genetic modification to express chimeric antigen receptors (CAR), which can enable T cell responses against pancreatic tumor cells. CAR T cells can be produced ex vivo and expanded in vitro for infusion into patients. Remarkable responses have been documented using CAR T cells against several malignancies, including leukemias and lymphomas. Based on these successes, the extension of CAR T cell therapy for pancreatic cancer holds great promise. However, there are a number of challenges that limit the full potential of CAR T cell therapies for pancreatic cancer, including the highly immunosuppressive tumor microenvironment (TME). In this article, we will review the recent progress in using CAR T cells in pancreatic cancer preclinical and clinical settings, discuss hurdles for utilizing the full potential of CAR T cell therapy and propose research strategies and future perspectives. Research into the use of CAR T cell therapy in pancreatic cancer setting is rapidly gaining momentum and understanding strategies to overcome the current challenges in the pancreatic cancer setting will allow the development of effective CAR T cell therapies, either alone or in combination with other treatments to benefit pancreatic cancer patients.

Combination immunotherapies implementing adoptive T-cell transfer for advanced-stage melanoma

Immunotherapy is a promising method of treatment for a number of cancers. Many of the curative results have been seen specifically in advanced-stage melanoma. Despite this, single-agent therapies are only successful in a small percentage of patients, and relapse is very common. As chemotherapy is becoming a thing of the past for treatment of melanoma, the combination of cellular therapies with immunotherapies appears to be on the rise in in-vivo models and in clinical trials. These forms of therapies include tumor-infiltrating lymphocytes, T-cell receptor, or chimeric antigen receptor-modified T cells, cytokines [interleukin (IL-2), IL-15, IL-12, granulocyte-macrophage colony stimulating factor, tumor necrosis factor-α, interferon-α, interferon-γ], antibodies (αPD-1, αPD-L1, αTIM-3, αOX40, αCTLA-4, αLAG-3), dendritic cell-based vaccines, and chemokines (CXCR2). There are a substantial number of ongoing clinical trials using two or more of these combination therapies. Preliminary results indicate that these combination therapies are a promising area to focus on for cancer treatments, especially melanoma. The main challenges with the combination of cellular and immunotherapies are adverse events due to toxicities and autoimmunity. Identifying mechanisms for reducing or eliminating these adverse events remains a critical area of research. Many important questions still need to be elucidated in regard to combination cellular therapies and immunotherapies, but with the number of ongoing clinical trials, the future of curative melanoma therapies is promising.

Unleash the power of the mighty T cells-basis of adoptive cellular therapy

Adoptive cellular therapy (ACT) is an immunotherapy which involves the passive transfer of lymphocytes into a lymphodepleted host after ex vivo stimulation and expansion. Tumor-infiltrating lymphocytes (TILs) have shown objective tumor responses mainly restricted to melanoma and rely on a laborious manufacturing process. These limitations led to emergence of engineered cells, where normal peripheral blood lymphocytes are modified to express T cell receptors (TCRs) or chimeric antigen receptors (CARs) specific for tumor-associated antigens (TAAs). To date, CD19-targeted chimeric antigen receptor T (CAR T) cells have been the most extensively studied, showing complete and durable responses in B-cell malignancies. Antitumor responses with engineered T cells have often been accompanied by undesired toxicities in clinical trials including cytokine release syndrome (CRS) and neurotoxicity. In this review, we provide an overview of adoptive cellular strategies, early and ongoing clinical trials, adverse events and strategies to mitigate side effects and overcome limitations.

Scaling up the Manufacturing Process of Adoptive T Cell Immunotherapy

Adoptive T cell immunotherapy, involving the reprogramming of immune cells to target specific cancer or virus-infected cells, has been recognized as a promising novel approach for the treatment of complex diseases. The impressive global momentum of this therapeutic approach has highlighted the urgent need for establishing it as an effective and standardized onco-therapeutic approach in a large manufacturing scale. However, given its heterogeneity and uncertainty in nature, adoptive T cell immunotherapy is associated with a high failure rate that restricts its manufacturing to a limited number of institutions worldwide. It is undoubted that quite a few major challenges must be met before engineered T cells can be considered as a reliable, safe, and effective remedy for a broad range of diseases with global-wise patient benefits. Here, the fundamental challenges that as yet remain unsolved in the manufacturing process before adoptive T cell therapy can be considered as a key element in the next generation of precision medicine is reviewed. It is proposed that it is necessary to adopt a closed system, automation, cost-effective manufacturing model, and quality-by-design (QbD) strategy to enable scaled up manufacturing of adoptive T cell immunotherapy; and it is challenging to choose appropriate bioreactors, parameters, and infrastructure in this process.