Specific lymphocyte subsets predict response to adoptive cell therapy using expanded autologous tumor-infiltrating lymphocytes in metastatic melanoma patients

Lymph-directed immunotherapy - Harnessing endogenous lymphatic distribution pathways for enhanced therapeutic outcomes in cancer

The advent of immunotherapy has revolutionised the treatment of some cancers. Harnessing the immune system to improve tumour cell killing is now standard clinical practice and immunotherapy is the first line of defence for many cancers that historically, were difficult to treat. A unifying concept in cancer immunotherapy is the activation of the immune system to mount an attack on malignant cells, allowing the body to recognise, and in some cases, eliminate cancer. However, in spite of a significant proportion of patients that respond well to treatment, there remains a subset who are non-responders and a number of cancers that cannot be treated with these therapies. These limitations highlight the need for targeted delivery of immunomodulators to both tumours and the effector cells of the immune system, the latter being highly concentrated in the lymphatic system. In this context, macromolecular therapies may provide a significant advantage. Macromolecules are too large to easily access blood capillaries and instead typically exhibit preferential uptake via the lymphatic system. In contexts where immune cells are the therapeutic target, particularly in cancer therapy, this may be advantageous. In this review, we examine in brief the current immunotherapy approaches in cancer and how macromolecular and nanomedicine strategies may improve the therapeutic profiles of these drugs. We subsequently discuss how therapeutics directed either by parenteral or mucosal administration, can be taken up by the lymphatics thereby accessing a larger proportion of the body's immune cells. Finally, we detail drug delivery strategies that have been successfully employed to target the lymphatics.

Immune Therapy for Central Nervous System Metastasis

Brain metastases lead to substantial morbidity and mortality among patients with advanced malignancies. Although treatment options have traditionally included largely palliative measures, studies of brain metastasis response to immunotherapy are promising. Immune checkpoint inhibitors have shown efficacy in studies of patients with melanoma, renal cell carcinoma, and lung cancer brain metastases. Patients with brain metastases are more frequently included in clinical trials, ushering in a new era in immunotherapy and management for patients with brain metastases. Gaining an understanding of the molecular determination for response to immunotherapies remains a major challenge and is an active area of future research.

Ovarian granulosa cell tumor characterization identifies FOXL2 as an immunotherapeutic target

Granulosa cell tumors (GCT) are rare ovarian malignancies. Due to the lack of effective treatment in late relapse, there is a clear unmet need for novel therapies. Forkhead Box L2 (FOXL2) is a protein mainly expressed in granulosa cells (GC) and therefore is a rational therapeutic target. Since we identified tumor infiltrating lymphocytes (TILs) as the main immune population within GCT, TILs from 11 GCT patients were expanded, and their phenotypes were interrogated to determine that T cells acquired late antigen-experienced phenotypes and lower levels of PD1 expression. Importantly, TILs maintained their functionality after ex vivo expansion as they vigorously reacted against autologous tumors (100% of patients) and against FOXL2 peptides (57.1% of patients). To validate the relevance of FOXL2 as a target for immune therapy, we developed a plasmid DNA vaccine (FoxL2–tetanus toxin; FoxL2-TT) by fusing Foxl2 cDNA with the immune-enhancing domain of TT. Mice immunization with FoxL2-TT controlled growth of FOXL2-expressing ovarian (BR5) and breast (4T1) cancers in a T cell–mediated manner. Combination of anti–PD-L1 with FoxL2-TT vaccination further reduced tumor progression and improved mouse survival without affecting the female reproductive system and pregnancy. Together, our results suggest that FOXL2 immune targeting can produce substantial long-term clinical benefits. Our study can serve as a foundation for trials testing immunotherapeutic approaches in patients with ovarian GCT.

FOXL2 may serve as a immunotherapeutic target for tumor infiltrating lymphocytes in ovarian granulosa cell tumors.

Chimeric Antigen Receptor Designed to Prevent Ubiquitination and Downregulation Showed Durable Antitumor Efficacy

Clinical evidence suggests that poor persistence of chimeric antigen receptor-T cells (CAR-T) in patients limits therapeutic efficacy. Here, we designed a CAR with recyclable capability to promote in vivo persistence and to sustain antitumor activity. We showed that the engagement of tumor antigens induced rapid ubiquitination of CARs, causing CAR downmodulation followed by lysosomal degradation. Blocking CAR ubiquitination by mutating all lysines in the CAR cytoplasmic domain (CAR^KR) markedly repressed CAR downmodulation by inhibiting lysosomal degradation while enhancing recycling of internalized CARs back to the cell surface. Upon encountering tumor antigens, CAR^KR-T cells ameliorated the loss of surface CARs, which promoted their long-term killing capacity. Moreover, CAR^KR-T cells containing 4-1BB signaling domains displayed elevated endosomal 4-1BB signaling that enhanced oxidative phosphorylation and promoted memory T cell differentiation, leading to superior persistence in vivo. Collectively, our study provides a straightforward strategy to optimize CAR-T antitumor efficacy by redirecting CAR trafficking.

Dual Targeting of Mesothelin and CD19 with Chimeric Antigen Receptor-Modified T Cells in Patients with Metastatic Pancreatic Cancer

B cells infiltrate pancreatic ductal adenocarcinoma (PDAC) and in preclinical cancer models, can suppress T cell immunosurveillance in cancer. Here, we conducted a pilot study to assess the safety and feasibility of administering lentiviral-transduced chimeric antigen receptor (CAR)-modified autologous T cells redirected against mesothelin to target tumor cells along with CART cells redirected against CD19 to deplete B cells. Both CARs contained 4-1BB and CD3ζ signaling domains. Three patients with chemotherapy-refractory PDAC received 1.5 g/m² cyclophosphamide prior to separate infusions of lentiviral-transduced T cells engineered to express chimeric anti-mesothelin immunoreceptor SS1 (CART-Meso, 3 × 10⁷/m²) and chimeric anti-CD19 immunoreceptor (CART-19, 3 × 10⁷/m²). Treatment was well tolerated without dose-limiting toxicities. Best response was stable disease (1 of 3 patients). CART-19 (compared to CART-Meso) cells showed the greatest expansion in the blood, although persistence was transient. B cells were successfully depleted in all subjects, became undetectable by 7-10 days post-infusion, and remained undetectable for at least 28 days. Together, concomitant delivery of CART-Meso and CART-19 cells in patients with PDAC is safe. CART-19 cells deplete normal B cells but at the dose tested in these 3 subjects did not improve CART-Meso cell persistence.

News on immune checkpoint inhibitors as immunotherapy strategies in adult and pediatric solid tumors

Immune checkpoint inhibitors (ICIs) have shown unprecedented benefits in various adult cancers, and this success has prompted the exploration of ICI therapy even in childhood malignances. Although the use of ICIs as individual agents has achieved disappointing response rates, combinational therapies are likely to promise better results. However, only a subset of patients experienced prolonged clinical effects, thus suggesting the need to identify robust bio-markers that predict individual clinical response or resistance to ICI therapy as the main challenge. In this review, we focus on how the use of ICIs in adult cancers can be translated into pediatric malignances. We discuss the physiological mechanism of action of each IC, including PD-1, PD-L1 and CTLA-4 and the new emerging ones, LAG-3, TIM-3, TIGIT, B7-H3, BTLA and IDO-1, and evaluate their prognostic value in both adult and childhood tumors. Furthermore, we offer an overview of preclinical models and clinical trials currently under investigation to improve the effectiveness of cancer immunotherapies in these patients. Finally, we outline the main predictive factors that influence the efficacy of ICIs, in order to lay the basis for the development of a pan-cancer immunogenomic model, able to direct young patients towards more specific immunotherapy.

Human cancer germline antigen-specific cytotoxic T cell-what can we learn from patient

In this review, we will highlight the importance of cancer germline antigen-specific cytotoxic CD8+ T lymphocytes (CTL) and the factors affecting antitumor CTL responses. In light of cancer immunotherapy, we will emphasis the need to further understand the features, characteristics, and actions of modulatory receptors of human cancer germline-specific CTLs, in order to determine the optimal conditions for antitumor CTL responses.

Neoantigen-Specific Adoptive Cell Therapies for Cancer: Making T-Cell Products More Personal

Mutation-derived neoantigens are taking central stage as a determinant in eliciting effective antitumor immune responses following adoptive T-cell therapies. These mutations are patient-specific, and their targeting calls for highly personalized pipelines. The promising clinical outcomes of tumor-infiltrating lymphocyte (TIL) therapy have spurred interest in generating T-cell infusion products that have been selectively enriched in neoantigen (or autologous tumor) reactivity. The implementation of an isolation step, prior to T-cell in vitro expansion and reinfusion, may provide a way to improve the overall response rates achieved to date by adoptive T-cell therapies in metastatic cancer patients. Here we provide an overview of the main technologies [i.e., peptide major histocompatibility complex (pMHC) multimers, cytokine capture, and activation markers] to enrich infiltrating or circulating T-cells in predefined neoantigen specificities (or tumor reactivity). The unique technical and regulatory challenges faced by such highly specialized and patient-specific manufacturing T-cell platforms are also discussed.

IL6 Fuels Durable Memory for Th17 Cell-Mediated Responses to Tumors

The accessibility of adoptive T-cell transfer therapies (ACT) is hindered by the cost and time required for product development. Here we describe a streamlined ACT protocol using Th17 cells expanded only 4 days ex vivo. While shortening expansion compromised cell yield, this method licensed Th17 cells to eradicate large tumors to a greater extent than cells expanded longer term. Day 4 Th17 cells engrafted, induced release of multiple cytokines including IL6, IL17, MCP-1, and GM-CSF in the tumor-bearing host, and persisted as memory cells. IL6 was a critical component for efficacy of these therapies via its promotion of long-term immunity and resistance to tumor relapse. Mechanistically, IL6 diminished engraftment of FoxP3⁺ donor T cells, corresponding with robust tumor infiltration by donor effector over regulatory cells for the Day 4 Th17 cell product relative to cell products expanded longer durations ex vivo. Collectively, this work describes a method to rapidly generate therapeutic T-cell products for ACT and implicates IL6 in promoting durable immunity of Th17 cells against large, established solid tumors. SIGNIFICANCE: An abbreviated, 4-day ex vivo expansion method licenses Th17 cells to confer long-lived immunity against solid malignancies via induction of systemic IL6 in the host.See related commentary by Fiering and Ho, p. 3795.

Metastatic melanoma: therapeutic agents in preclinical and early clinical development

Introduction: Advanced melanoma historically had a very poor outcome but targeted therapies and immune checkpoint inhibitors (IC) have changed the course of the disease and made durable responses possible. However, most patients will develop progressive disease, so further strategies to overcome treatment resistance are needed. Areas covered: Current treatment strategies and landmark trials are discussed. Novel targeted agents, immune checkpoint inhibitors, and further immune-modulatory drugs, cancer vaccines and tumor infiltrating lymphocytes and their potential role in the treatment of melanoma are described. Current trials investigating these emerging agents and treatment strategies were searched for on ClinicalTrials.gov and are presented on the background of the current literature explaining the rationale for employing these new agents and strategies. Combinations of tumor-directed agents with those causing immune augmentation as well as a new adjuvant and neoadjuvant strategies are discussed. Expert opinion: Questions regarding treatment combination, personalization, and sequence of treatment will become increasingly important and will be guided by new biomarkers. New treatment settings will broaden the patient selection and will highlight the need for further discussions regarding toxicity in long-term survivorship.

Exploration and validation of the effects of robust co-expressed immune-related genes on immune infiltration patterns and prognosis in laryngeal cancer

OBJECTIVES

Laryngeal cancer is a common malignant tumor that originates from the larynx, yet its molecular mechanisms have not been thoroughly explored. The purpose of this study was to identify and evaluate immune-related genes in laryngeal cancer through gene co-expression networks, which may serve as biomarkers for its immunotherapy.

METHODS

We applied ESTIMATE to evaluate the immune-infiltration landscape of tumor microenvironment. The co-expression networks were constructed by weighted gene co expression network analysis (WGCNA) and compared with the existing human immune related genes (IRGs) to determine the co-expressed IRGs. GSVA combined with CIBERSORT and ssGSEA illustrated the correlation of hub genes and immune infiltration patterns. TIDE algorithm and Subclass mapping evaluated the function of hub genes in predicting immune function and immunotherapeutic sensitivity. The pRRophetic was employed in the sensitivity prediction of chemotherapeutic drugs.

RESULTS

A total of 23 co-expressed IRGs were identified and showed robust expression characteristics. These genes were significantly related to immune infiltration patterns, immune function and sensitivity prediction of immunotherapy and chemotherapeutic drugs for laryngeal cancer patients. Genetic alteration in somatic mutation level and related pathways were also revealed.

CONCLUSION

The 23 co-expressed IRGs may act as immunotherapeutic biomarkers and potential therapeutic targets for laryngeal cancer with certain expression robustness. The molecular mechanisms deserve further investigation, which will guide clinical treatment in the future.

Ex vivo blockade of PI3K gamma or delta signaling enhances the antitumor potency of adoptively transferred CD8+ T cells

Adoptive T cell transfer therapy induces objective responses in patients with advanced malignancies. Despite these results, some individuals do not respond due to the generation of terminally differentiated T cells during the expansion protocol. As the gamma and delta catalytic subunits in the PI3K pathway are abundant in leukocytes and involved in cell activation, we posited that blocking both subunits ex vivo with the inhibitor IPI‐145 would prevent their differentiation, thereby increasing antitumor activity in vivo. However, IPI‐145 treatment generated a product with reduced antitumor activity. Instead, T cells inhibited of PI3Kγ (IPI‐549) or PI3Kδ (CAL‐101 or TGR‐1202) alone were more potent in vivo. While T cells coinhibited of PI3Kγ and PI3Kδ were less differentiated, they were functionally impaired, indicated by reduced production of effector cytokines after antigenic re‐encounter and decreased persistence in vivo. Human CAR T cells expanded with either a PI3Kγ or PI3Kδ inhibitor possessed a central memory phenotype compared to vehicle cohorts. We also found that PI3Kδ‐inhibited CARs lysed human tumors in vitro more effectively than PI3Kγ‐expanded or traditionally expanded CAR T cells. Our data imply that sole blockade of PI3Kγ or PI3Kδ generates T cells with remarkable antitumor properties, a discovery that has substantial clinical implications.

Cytokine IL-36γ improves CAR T-cell functionality and induces endogenous antitumor response

Chimeric antigen receptor (CAR) T cell therapy has shown remarkable responses in B cell malignancies. However, many patients suffer from limited response and tumor relapse due to lack of persisting CAR T cells and immune escape. These clinical challenges have compromised the long-term efficacy of CAR T cell therapy and call for the development of novel CAR designs. We demonstrated that CAR T cells secreting a cytokine interleukin-36γ (IL-36γ) showed significantly improved CAR T cell expansion and persistence, and resulted in superior tumor eradication compared to conventional CAR T cells. The enhanced cellular function by IL-36γ was mediated through an autocrine manner. In addition, activation of endogenous antigen-presenting cells (APCs) and T cells by IL-36γ aided the formation of a secondary anti-tumor response which delayed the progression of antigen-negative tumor challenge. Together, our data provide preclinical evidence to support the translation of this design for an improved CAR T cell–mediated anti-tumor response.

Adoptive cell transfer (ACT) of autologous tumor-infiltrating lymphocytes (TILs) to treat malignant melanoma: the dawn of a chimeric antigen receptor T (CAR-T) cell therapy from autologous donor

BACKGROUND

Tumor-infiltrating lymphocytes (TILs) are B, T-helper, and T-cytotoxic lymphocytes migrated from the blood or lymph stream toward a tumor with the aim to infiltrate and destroy it. They can be histologically graded as brisk, nonbrisk, or absent. Malignant melanoma has been the first malignancy found to be correlated with TILs status, being brisk TILs associated with better clinical outcomes. By the terminology of "adoptive cell transfer" (ACT), the medical oncology refers to the transfer of cells in a tumor-bearing patient from the same recipient or a healthy donor.

METHODS

A PubMed literature search on the topic has been performed. Additional documents known to the authors and identified from the reference list of cited publications have been included.

RESULTS

In the past, autologous TILs ACT was successfully tested for the treatment of malignant melanoma and, today, it is a standardized procedure in several centers around the world. It represents the first research step toward the bioengineered chimeric antigen receptor T (CAR-T) cell therapy from autologous donor.

CONCLUSIONS

Both autologous TILs ACT and CAR-T cell therapy from autologous donor exploit the anticancer power of targeted self-lymphocytes, but CAR-T cell technology also virtually allows treatment of those melanomas devoid of TILs or with so few cytotoxic TILs that are difficult to identify.

Targeting the 4-1BB costimulatory molecule through single chain antibodies promotes the human T-cell response

Background

Adoptive T-cell therapy (ACT) using autologous tumor-reactive T lymphocytes has considerable potential for cancer immunotherapy. In ACT, T cells are isolated from cancer patients and then stimulated and expanded in vitro by cytokines and costimulatory molecules. 4-1BB is an important costimulatory protein belonging to the TNF receptor superfamily. It is involved in T-cell survival, proliferation and activation. Agonistic anti-4-1BB monoclonal antibodies have been introduced as appropriate tools for ACT.

Methods

Here, various single-chain fragment variable (scFv) antibodies were used to activate T cells isolated from peripheral blood via immune magnetic isolation. The T cells were stimulated with IL-2 and anti-CD-3 mAb and then treated with agonistic anti-4-1BB scFvs. The results showed the remarkable effects of anti-41BB scFvs on the functional properties of T cells, including their activation, proliferation and cytokine production. The flow cytometry analysis revealed a considerable increase in the expression of the T-cell activation marker CD69. Moreover, T-cell proliferation was evidenced in treated cells by CFSE labeling compared to the control groups.

Result

Anti-4-1BB scFvs significantly increased IFN-γ and IL-2 mRNA and protein expression in T cells, but exhibited no stimulatory effect on IL-4 expression. These findings show that anti-4-1BB scFvs could evoke a Type I immune response.

Conclusions

Our results demonstrate that targeting the 4-1BB molecule using agonistic scFvs could be an effective strategy for T-cell stimulation as part of an ACT approach to cancer treatment.

The Outcome of Ex Vivo TIL Expansion Is Highly Influenced by Spatial Heterogeneity of the Tumor T-Cell Repertoire and Differences in Intrinsic In Vitro Growth Capacity between T-Cell Clones

PURPOSE

During our efforts to develop tumor-infiltrating lymphocyte (TIL) therapy to counter the devastating recurrence rate in patients with primary resectable pancreatic ductal adenocarcinoma (PDA), we found that PDA TILs can readily be expanded in vitro and that the majority of resulting TIL cultures show reactivity against the autologous tumor. However, the fraction of tumor-reactive T cells is low. We investigated to which extent this was related to the in vitro expansion.

EXPERIMENTAL DESIGN

We compared the clonal composition of TIL preparations before and after in vitro expansion using T-cell receptor (TCR) deep sequencing. Our findings for PDA were benchmarked to experiments with melanoma TILs.

RESULTS

We found that the TIL TCR repertoire changes dramatically during in vitro expansion, leading to loss of tumor- dominant T-cell clones and overgrowth by newly emerging T-cell clones that are barely detectable in the tumor. These changes are primarily driven by differences in the intrinsic in vitro expansion capacity of T-cell clones. Single-cell experiments showed an association between poor proliferative capacity and expression of markers related to antigen experience and dysfunction. Furthermore, we found that spatial heterogeneity of the TIL repertoire resulted in TCR repertoires that are greatly divergent between TIL cultures derived from distant tumor samples of the same patient.

CONCLUSIONS

Culture-induced changes in clonal composition are likely to affect tumor reactivity of TIL preparations. TCR deep sequencing provides important insights into the factors that govern the outcome of in vitro TIL expansion and thereby a path toward optimization of the production of TIL preparations with high therapeutic efficacy.See related commentary by Lozano-Rabella and Gros, p. 4177.

Overproduction of IL-2 by Cbl-b deficient CD4+ T cells provides resistance against regulatory T cells

Regulatory T cells are integral to the regulation of autoimmune and anti-tumor immune responses. However, several studies have suggested that changes in T cell signaling networks can result in T cells that are resistant to the suppressive effects of regulatory T cells. Here, we investigated the role of Cbl-b, an E3 ubiquitin ligase, in establishing resistance to Treg-mediated suppression. We found that the absence of Cbl-b, a negative regulator of multiple TCR signaling pathways, rendered T cells impartial to Treg suppression by regulating cytokine networks leading to improved anti-tumor immunity despite the presence of Treg cells in the tumor. Specifically, Cbl-b KO CD4⁺FoxP3⁻ T cells hyper-produced IL-2 and together with IL-2 Rα upregulation served as an essential mechanism to escape suppression by Treg cells. Furthermore, we report that IL-2 serves as the central molecule required for cytokine-induced Treg resistance. Collectively our data emphasize the role of IL-2 as a key mechanism that renders CD4⁺ T cells resistant to the inhibitory effects of Treg cells.

Cytotoxic T Lymphocytes Regenerated from iPS Cells Have Therapeutic Efficacy in a Patient-Derived Xenograft Solid Tumor Model

Current adoptive T cell therapies conducted in an autologous setting are costly, time consuming, and depend on the quality of the patient's T cells. To address these issues, we developed a strategy in which cytotoxic T lymphocytes (CTLs) are regenerated from iPSCs that were originally derived from T cells and succeeded in regenerating CTLs specific for the WT1 antigen, which exhibited therapeutic efficacy in a xenograft model of leukemia. In this study, we extended our strategy to solid tumors. The regenerated WT1-specific CTLs had a strong therapeutic effect in orthotopic xenograft model using a renal cell carcinoma (RCC) cell line. To make our method more generally applicable, we developed an allogeneic approach by transducing HLA-haplotype homozygous iPSCs with WT1-specific TCR α/β genes that had been tested clinically. The regenerated CTLs antigen-specifically suppressed tumor growth in a patient-derived xenograft model of RCC, demonstrating the feasibility of our strategy against solid tumors.

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Patient-derived xenograft of renal cell carcinoma was used in a cell-therapy model

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Cytotoxic T lymphocytes (CTLs) that target WT1-antigen were used as effector cells

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CTLs produced from iPSCs transduced with WT1-TCR genes showed efficacy in the model

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The present results demonstrate the feasibility of our strategy against solid tumors

And Now for Something Completely Different: Immunotherapy Beyond Checkpoints in Melanoma

Advances in the understanding of biology and therapy of melanoma have occurred at an astonishing pace over the past approximately 15 years, and successful melanoma therapy has led the way for similar advances in many other solid tumors that are continuing to improve outcomes for all patients with cancer. Although the 2018 Nobel Prize was awarded to two investigators who discovered that therapeutic targeting of immune checkpoints held the key to major patient benefits, there are many additional immunotherapeutic strategies that warrant further study and discussion at scientific and medical meetings. This article provides the newest information on three areas of immunotherapy that have been successfully applied to melanoma and continue to pave the way for new developments: cytokines, adoptive cell therapies (ADTs), and intratumoral injection of immunomodulatory agents.

Harnessing neoantigen specific CD4 T cells for cancer immunotherapy

The goal of precision immunotherapy is to direct a patient's T cell response against the immunogenic mutations expressed on their tumors. Most immunotherapy approaches to-date have focused on MHC class I-restricted peptide epitopes by which cytotoxic CD8+ T lymphocytes (CTL) can directly recognize tumor cells. This strategy largely overlooks the critical role of MHC class II-restricted CD4+ T cells as both positive regulators of CTL and other effector cell types, and as direct effectors of antitumor immunity. In this review, we will discuss the role of neoantigen specific CD4+ T cells in cancer immunotherapy and how existing treatment modalities may be leveraged to engage this important T cell subset.

A systematic review of economic evaluations of advanced therapy medicinal products

Aims

Advanced therapy medicinal products (ATMPs) represent a new category of medicinal products with a potential for transformative improvements in health outcomes but at exceptionally high prices. Routine adoption of ATMPs requires robust evidence of their cost‐effectiveness.

Methods

A systematic literature review of economic evaluations of ATMPs, including gene therapies, somatic cell therapies and tissue‐engineered products, was conducted. Literature was searched using MedLine, Embase, PubMed, Cochrane Register, the NHS Economic Evaluation Database and the grey literature of health technology assessment organisations with search terms relating to ATMPs and economic evaluations. Titles were screened independently by 2 reviewers. Articles deemed to meet the inclusion criteria were screened independently on abstract, and full texts reviewed. Study findings were appraised critically.

Results

4514 articles were identified, of which 23 met the inclusion criteria. There was some evidence supporting the cost‐effectiveness of: chimeric antigen receptor T‐cell therapy axicabtagene–ciloleucel (Yescarta), embryonic neural stem cells, tumour infiltrating lymphocytes, in vitro expanded myoblast, autologous chondrocyte implantation, ex vivo gene therapy (Strimvelis) and voretigene neparvovec (Luxturna). However, estimates of cost‐effectiveness were associated with significant uncertainty and high likelihood of bias, resulting from largely unknown long‐term outcomes, a paucity of evidence on health state utilities and extensive modelling assumptions.

Conclusion

There are critical limitations to the economic evidence for ATMPs, most notably in relation to evidence on the durability of treatment effect, and the reliability of opinion‐based assumptions necessary when evidence is absent.

Adoptive Cell Therapy-Harnessing Antigen-Specific T Cells to Target Solid Tumours

In recent years, much research has been focused on the field of adoptive cell therapies (ACT) that use native or genetically modified T cells as therapeutic tools. Immunotherapy with T cells expressing chimeric antigen receptors (CARs) demonstrated great success in the treatment of haematologic malignancies, whereas adoptive transfer of autologous tumour infiltrating lymphocytes (TILs) proved to be highly effective in metastatic melanoma. These encouraging results initiated many studies where ACT was tested as a treatment for various solid tumours. In this review, we provide an overview of the challenges of T cell-based immunotherapies of solid tumours. We describe alternative approaches for choosing the most efficient T cells for cancer treatment in terms of their tumour-specificity and phenotype. Finally, we present strategies for improvement of anti-tumour potential of T cells, including combination therapies.

CTLA-4 blockade boosts the expansion of tumor-reactive CD8+ tumor-infiltrating lymphocytes in ovarian cancer

Adoptive cell therapy (ACT) with autologous tumor-infiltrating lymphocytes (TILs) can induce durable complete tumor regression in patients with advanced melanoma. Efforts are currently underway to expand this treatment modality to other cancer types. In the microenvironment of ovarian cancer, the engagement of co-inhibitory immune checkpoint molecules such as CTLA-4 can lead to the inactivation of TILs. Thus, approaches that directly manipulate co-inhibitory pathways within the tumor microenvironment might improve the expansion of tumor-reactive TILs. The initial expansion of TILs for ACT from tumor fragments provides a window of opportunity to manipulate an intact tumor microenvironment and improve CD8⁺ T-cell output and TIL tumor reactivity. To exploit this, we used a CTLA-4-blocking antibody, added during the initial TIL culture, and found that the blockade of CTLA-4 favored the propagation of CD8⁺ TILs from ovarian tumor fragments. Interestingly, adding the CTLA-4 blocking antibody in the initial phase of the TIL culture resulted in more potent anti-tumor TILs in comparison to standard TIL cultures. This phenotype was preserved during the rapid expansion phase. Thus, targeting CTLA-4 within the intact tumor microenvironment of tumor fragments enriches tumor-reactive TILs and may improve clinical outcome of TIL-based ACT in ovarian cancer.

Mutated RAS: Targeting the "Untargetable" with T Cells

The RAS family of proteins is at the apex of several pathways implicated in a multitude of epithelial cancers but has remained stubbornly resistant to the wave of targeted small molecules and antibodies that have revolutionized clinical oncology. KRAS, the most commonly mutated of the isoforms, represents an attractive target for treatment, given its ubiquity, central role as a driver mutation, and association with poor prognosis. This review is a comprehensive summary of the existing approaches to targeting KRAS spanning small-molecule inhibitors, cancer vaccines, and with a focus on trials in adoptive cell therapy. Here we explain how the limitations of existing drugs and nonspecific immune-based therapies are circumvented with techniques in modern immunotherapy. The successes outlined represent the most promising path to finally targeting the prototypical "undruggable" RAS oncogene family.

Adoptive Cell Therapy: A Novel and Potential Immunotherapy for Glioblastoma

Glioblastoma multiforme (GBM) is the most common primary brain tumor in adults with very poor prognosis and few advances in its treatment. Recently, fast-growing cancer immunotherapy provides a glimmer of hope for GBM treatment. Adoptive cell therapy (ACT) aims at infusing immune cells with direct anti-tumor activity, including tumor-infiltrating lymphocyte (TIL) transfer and genetically engineered T cells transfer. For example, complete regressions in patients with melanoma and refractory lymphoma have been shown by using naturally tumor-reactive T cells and genetically engineered T cells expressing the chimeric anti-CD19 receptor, respectively. Recently, the administration of ACT showed therapeutic potentials for GBM treatment as well. In this review, we summarize the success of ACT in the treatment of cancer and provide approaches to overcome some challenges of ACT to allow its adoption for GBM treatment.

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.

Immunological Targets for Immunotherapy: Inhibitory T Cell Receptors

Tumor development is characterized by the accumulation of mutational and epigenetic changes that transform normal cells and survival pathways into self-sustaining cells capable of untrammeled growth. Although multiple modalities including surgery, radiation, and chemotherapy are available for the treatment of cancer, the benefits conferred are often limited. The immune system is capable of specific, durable, and adaptable responses. However, cancers hijack immune mechanisms such as negative regulatory checkpoints that have evolved to limit inflammatory and immune responses to thwart effective antitumor immunity. The development of monoclonal antibodies against inhibitory receptors expressed by immune cells has produced durable responses in a broad array of advanced malignancies and heralded a new dawn in the cancer armamentarium. However, these remarkable responses are limited to a minority of patients and indications, highlighting the need for more effective and novel approaches. Preclinical and clinical studies with immune checkpoint blockade are exploring the therapeutic potential antibody-based therapy targeting multiple inhibitory receptors. In this chapter, we discuss the current understanding of the structure, ligand specificities, function, and signaling activities of various inhibitory receptors. Additionally, we discuss the current development status of various immune checkpoint inhibitors targeting these negative immune receptors and highlight conceptual gaps in knowledge.

Overview of Current Immunotherapies Targeting Mutated KRAS Cancers

The occurrence of somatic substitution mutations of the KRAS proto-oncogene is highly prevalent in certain cancer types, which often leads to constant activation of proliferative pathways and subsequent neoplastic transformation. It is often seen as a gateway mutation in carcinogenesis and has been commonly deemed as a predictive biomarker for poor prognosis and relapse when conventional chemotherapeutics are employed. Additionally, its mutational status also renders EGFR targeted therapies ineffective owing to its downstream location. Efforts to discover new approaches targeting this menacing culprit have been ongoing for years without much success, and with incidences of KRAS positive cancer patients being on the rise, researchers are now turning towards immunotherapies as the way forward. In this scoping review, recent immunotherapeutic developments and advances in both preclinical and clinical studies targeting K-ras directly or indirectly via its downstream signal transduction machinery will be discussed. Additionally, some of the challenges and limitations of various K-ras targeting immunotherapeutic approaches such as vaccines, adoptive T cell therapies, and checkpoint inhibitors against KRAS positive cancers will be deliberated.

Efficacy of adoptive therapy with tumor-infiltrating lymphocytes and recombinant interleukin-2 in advanced cutaneous melanoma: a systematic review and meta-analysis

Adoptive cell therapy (ACT) using autologous tumor-infiltrating lymphocytes (TIL) has been tested in advanced melanoma patients at various centers. We conducted a systematic review and meta-analysis to assess its efficacy on previously treated advanced metastatic cutaneous melanoma. The PubMed electronic database was searched from inception to 17 December 2018 to identify studies administering TIL-ACT and recombinant interleukin-2 (IL-2) following non-myeloablative chemotherapy in previously treated metastatic melanoma patients. Objective response rate (ORR) was the primary end point. Secondary end points were complete response rate (CRR), overall survival (OS), duration of response (DOR) and toxicity. Pooled estimates were derived from fixed or random effect models, depending on the amount of heterogeneity detected. Analysis was carried out separately for high dose (HD) and low dose (LD) IL-2. Sensitivity analyses were carried out. Among 1211 records screened, 13 studies (published 1988 - 2016) were eligible for meta-analysis. Among 410 heavily pretreated patients (some with brain metastasis), 332 received HD-IL-2 and 78 LD-IL-2. The pooled overall ORR estimate was 41% [95% confidence interval (CI) 35% to 48%], and the overall CRR was 12% (95% CI 7% to 16%). For the HD-IL-2 group, the ORR was 43% (95% CI 36% to 50%), while for the LD-IL-2 it was 35% (95% CI 25% to 45%). Corresponding pooled estimates for CRR were 14% (95% CI 7% to 20%) and 7% (95% CI 1% to 12%). The majority of HD-IL-2 complete responders (27/28) remained in remission during the extent of follow-up after CR (median 40 months). Sensitivity analyses yielded similar results. Higher number of infused cells was associated with a favorable response. The ORR for HD-IL-2 compared favorably with the nivolumab/ipilimumab combination following anti-PD-1 failure. TIL-ACT therapy, especially when combined with HD-IL-2, achieves durable clinical benefit and warrants further investigation. We discuss the current position of TIL-ACT in the therapy of advanced melanoma, particularly in the era of immune checkpoint blockade therapy, and review future opportunities for improvement of this approach.

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.

Tumor-infiltrating lymphocytes from human prostate tumors reveal anti-tumor reactivity and potential for adoptive cell therapy

Advanced prostate cancer remains incurable and is the second leading cause of mortality in men. Immunotherapy based on the adoptive transfer of tumor-infiltrating lymphocytes (TIL) has demonstrated promising clinical results in patients with metastatic melanoma and lately also in other solid tumors. However, the ability to obtain TIL from patients with prostate cancer, considered poorly immunogenic, remains unknown. In this study, we investigate the feasibility of isolating and expanding TIL from primary prostate tumors. We collected tumor specimens from eight patients with diagnosed prostate adenocarcinoma undergoing radical prostatectomy and were able to successfully expand multiple autologous TIL cultures from all patients. Twenty-eight prostate-TIL cultures were further expanded using a standard rapid expansion procedure under Good Manufacturing Practice conditions. TIL cultures were phenotypically characterized for T cell subset composition, differentiation status and co-inhibitory/stimulatory markers such as PD-1, TIM-3, LAG-3, and CD28 and were found to have in general similarity to TIL obtained from patients with melanoma and lung carcinoma previously treated at our center. All analyzed TIL cultures were functional as determined by the capability to produce high level of IFNγ upon stimuli. Most importantly, co-culture assays of prostate-TIL with autologous tumors demonstrated anti-tumor reactivity. In conclusion, these findings demonstrate that functional and anti-tumor reactive TIL can be obtained, despite the immunosuppressive microenvironment of the cancer, thus this study supports the development of TIL therapy for prostate cancer patients.

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.

T cell engineering for adoptive T cell therapy: safety and receptor avidity

Since the first bone marrow transplantation, adoptive T cell therapy (ACT) has developed over the last 80 years to a highly efficient and specific therapy for infections and cancer. Genetic engineering of T cells with antigen-specific receptors now provides the possibility of generating highly defined and efficacious T cell products. The high sensitivity of engineered T cells towards their targets, however, also bears the risk of severe off-target toxicities. Therefore, different safety strategies for engineered T cells have been developed that enable removal of the transferred cells in case of adverse events, control of T cell activity or improvement of target selectivity. Receptor avidity is a crucial component in the balance between safety and efficacy of T cell products. In clinical trials, T cells equipped with high avidity T cell receptor (TCR)/chimeric antigen receptor (CAR) have been mostly used so far because of their faster and better response to antigen recognition. However, over-activation can trigger T cell exhaustion/death as well as side effects due to excessive cytokine production. Low avidity T cells, on the other hand, are less susceptible to over-activation and could possess better selectivity in case of tumor antigens shared with healthy tissues, but complete tumor eradication may not be guaranteed. In this review we describe how 'optimal' TCR/CAR affinity can increase the safety/efficacy balance of engineered T cells, and discuss simultaneous or sequential infusion of high and low avidity receptors as further options for efficacious but safe T cell therapy.

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.

Proteomics of Melanoma Response to Immunotherapy Reveals Mitochondrial Dependence

Immunotherapy has revolutionized cancer treatment, yet most patients do not respond. Here, we investigated mechanisms of response by profiling the proteome of clinical samples from advanced stage melanoma patients undergoing either tumor infiltrating lymphocyte (TIL)-based or anti- programmed death 1 (PD1) immunotherapy. Using high-resolution mass spectrometry, we quantified over 10,300 proteins in total and ∼4,500 proteins across most samples in each dataset. Statistical analyses revealed higher oxidative phosphorylation and lipid metabolism in responders than in non-responders in both treatments. To elucidate the effects of the metabolic state on the immune response, we examined melanoma cells upon metabolic perturbations or CRISPR-Cas9 knockouts. These experiments indicated lipid metabolism as a regulatory mechanism that increases melanoma immunogenicity by elevating antigen presentation, thereby increasing sensitivity to T cell mediated killing both in vitro and in vivo. Altogether, our proteomic analyses revealed association between the melanoma metabolic state and the response to immunotherapy, which can be the basis for future improvement of therapeutic response.

Utilizing T-cell Activation Signals 1, 2, and 3 for Tumor-infiltrating Lymphocytes (TIL) Expansion: The Advantage Over the Sole Use of Interleukin-2 in Cutaneous and Uveal Melanoma

In this study, we address one of the major critiques for tumor-infiltrating lymphocyte (TIL) therapy-the time needed for proper expansion of a suitable product. We postulated that T-cell receptor activation in the first phase of expansion combined with an agonistic stimulation of CD137/4-1BB and interleukin-2 would favor preferential expansion of CD8 TIL. Indeed, this novel 3-signal approach for optimal T-cell activation resulted in faster and more consistent expansion of CD8CD3 TIL. This new method allowed for successful expansion of TIL from cutaneous and uveal melanoma tumors in 100% of the cultures in <3 weeks. Finally, providing the 3 signals attributed to optimal T-cell activation led to expansion of TIL capable of recognizing their tumor counterpart in cutaneous and uveal melanoma. This new methodology for the initial phase of TIL expansion brings a new opportunity for translation of TIL therapy in challenging malignancies such as uveal melanoma.

Low Avidity T Cells Do Not Hinder High Avidity T Cell Responses Against Melanoma

The efficacy of T cells depends on their functional avidity, i. e., the strength of T cell interaction with cells presenting cognate antigen. The overall T cell response is composed of multiple T cell clonotypes, involving different T cell receptors and variable levels of functional avidity. Recently, it has been proposed that the presence of low avidity tumor antigen-specific CD8 T cells hinder their high avidity counterparts to protect from tumor growth. Here we analyzed human cytotoxic CD8 T cells specific for the melanoma antigen Melan-A/MART-1. We found that the presence of low avidity T cells did not result in reduced cytotoxicity of tumor cells, nor reduced cytokine production, by high avidity T cells. In vivo in NSG-HLA-A2 mice, the anti-tumor effect of high avidity T cells was similar in presence or absence of low avidity T cells. These data indicate that low avidity T cells are not hindering anti-tumor T cell responses, a finding that is reassuring because low avidity T cells are an integrated part of natural T cell responses.

Tumor infiltrating lymphocytes expanded from pediatric neuroblastoma display heterogeneity of phenotype and function

Adoptive transfer of ex vivo expanded tumor infiltrating lymphocytes (TILs) has led to clinical benefit in some patients with melanoma but has not demonstrated convincing efficacy in other solid cancers. Whilst the presence of TILs in many types of cancer is often associated with better clinical prognosis, their function has not been systematically evaluated across cancer types. Responses to immunological checkpoint inhibitors in a wide range of cancers, including those for which adoptive transfer of expanded TILs has not shown clinical benefit, has clearly delineated a number of tumor type associated with tumor-reactive lymphocytes capable of effecting tumor remissions. Neuroblastoma is an aggressive childhood solid cancer in which immunotherapy with GD2-directed antibodies confers a proven survival advantage through incompletely understood mechanisms. We therefore evaluated the feasibility of ex vivo expansion of TILs from freshly resected neuroblastoma tumors and the potential therapeutic utility of TIL expansions. TILs were successfully expanded from both tumor biopsies or resections. Significant numbers of NKT and γδT cells were identified alongside the mixed population of cytotoxic (CD8⁺) and helper (CD4⁺) T cells of both effector and central memory phenotypes. Isolated TILs were broadly non-reactive against autologous tumor and neuroblastoma cell lines, so enhancement of neuroblastoma killing was attained by transducing TILs with a second-generation chimeric antigen receptor (CAR) targeting GD2. CAR-TILs demonstrated antigen-specific cytotoxicity against tumor cell lines. This study is the first to show reproducible expansion of TILs from pediatric neuroblastoma, the high proportion of innate-like lymphocytes, and the feasibility to use CAR-TILs therapeutically.

Management of neoplastic pericardial disease

At present, there is no accurate and effective method for treating neoplastic pericardial effusion. This study analyzed the current literature on the treatment of neoplastic pericardial effusion to provide advice and guidance for clinical treatment. Surgical treatments include pericardial puncture, extension of catheter drainage, pericardial window, and surgical pericardiotomy. Each surgical procedure has a corresponding indication, and the best treatment is selected according to the patient's specific conditions. Systemic chemotherapy is effective in lymphoma and small cell lung cancer that are sensitive to chemotherapeutic drugs. Although pericardial injection of drugs is effective for pericardial tamponade and recurrent pericardial effusion, these methods can only temporarily relieve symptoms and cannot prolong the life of patients. In recent years, immunotherapy, especially adoptive immunotherapy, has achieved good results in the treatment of neoplastic pericardial effusion, thus providing a novel treatment option for neoplastic pericardial effusion.

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.

BRAF Inhibition: Bridge or Boost to T-cell Therapy?

The concept of treatment-refractory disease has evolved as checkpoint modulation has changed the therapeutic landscape for patients with metastatic melanoma. Developing meaningful salvage strategies will involve the exploration of combination therapies and new immunotherapeutics, including adoptive transfer of tumor-infiltrating lymphocytes or other T-cell-based therapy.See related article by Atay et al., p. 2783.

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.).

CAR-T with License to Kill Solid Tumors in Search of a Winning Strategy

Artificial receptors designed for adoptive immune therapies need to absolve dual functions: antigen recognition and abilities to trigger the lytic machinery of reprogrammed effector T lymphocytes. In this way, CAR-T cells deliver their cytotoxic hit to cancer cells expressing targeted tumor antigens, bypassing the limitation of HLA-restricted antigen recognition. Expanding technologies have proposed a wide repertoire of soluble and cellular "immunological weapons" to kill tumor cells; they include monoclonal antibodies recognizing tumor associated antigens on tumor cells and immune cell checkpoint inhibition receptors expressed on tumor specific T cells. Moreover, a wide range of formidable chimeric antigen receptors diversely conceived to sustain quality, strength and duration of signals delivered by engineered T cells have been designed to specifically target tumor cells while minimize off-target toxicities. The latter immunological weapons have shown distinct efficacy and outstanding palmarès in curing leukemia, but limited and durable effects for solid tumors. General experience with checkpoint inhibitors and CAR-T cell immunotherapy has identified a series of variables, weaknesses and strengths, influencing the clinical outcome of the oncologic illness. These aspects will be shortly outlined with the intent of identifying the still "missing strategy" to combat epithelial cancers.

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.

Current Immunotherapy Practices in Melanoma

Immunotherapy has revolutionized the treatment of melanoma, with implications for the surgical management of this disease. Surgeons must be aware of the impact of various immunotherapies on patients with resectable and unresectable disease, and how surgical decision-making should progress as a result. We expect that current and developing immunotherapies will increase surgeon involvement for resection of metastatic melanoma, whether for tumor harvests to generate autologous lymphocytes or for consolidating control of disease beyond what immunotherapies alone can achieve. Despite remarkable advancements in the field, significant work is needed to optimize the immuno-modulation that targets cancers while minimizing toxicity for patients.

Immune-enrichment of non-small cell lung cancer baseline biopsies for multiplex profiling define prognostic immune checkpoint combinations for patient stratification

Background

Permanence of front-line management of lung cancer by immunotherapies requires predictive companion diagnostics identifying immune-checkpoints at baseline, challenged by the size and heterogeneity of biopsy specimens.

Methods

An innovative, tumor heterogeneity reducing, immune-enriched tissue microarray was constructed from baseline biopsies, and multiplex immunofluorescence was used to profile 25 immune-checkpoints and immune-antigens.

Results

Multiple immune-checkpoints were ranked, correlated with antigen presenting and cytotoxic effector lymphocyte activity, and were reduced with advancing disease. Immune-checkpoint combinations on TILs were associated with a marked survival advantage. Conserved combinations validated on more than 11,000 lung, breast, gastric and ovarian cancer patients demonstrate the feasibility of pan-cancer companion diagnostics.

Conclusions

In this hypothesis-generating study, deepening our understanding of immune-checkpoint biology, comprehensive protein-protein interaction and pathway mapping revealed that redundant immune-checkpoint interactors associate with positive outcomes, providing new avenues for the deciphering of molecular mechanisms behind effects of immunotherapeutic agents targeting immune-checkpoints analyzed.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0544-x) contains supplementary material, which is available to authorized users.

Th17 Cells Paradoxical Roles in Melanoma and Potential Application in Immunotherapy

The progressive infiltration of immune cells is associated with the progression of melanoma. Specifically, Th17 cells in melanoma microenvironment have both antitumor and protumor effects. It is now necessary to understand the contradictory data associated with how Th17 cells play a role in melanoma. This review will summarize the current knowledge regarding the potential mechanisms that may be involved in the effects of Th17 cells in melanoma progression. Currently, since adoptive transferring Th17 cells has been successful in eradicating melanoma in mice, it offers promise for next-generation adoptive cell transfer, as ex vivo expanded stemness-like memory Th17 cells which are induced by distinct cytokines or pharmacologic reagents may be infused into melanoma patients to potentiate treatment outcome.

Combined Immune Checkpoint Blockade and Stereotactic Ablative Radiotherapy Can Stimulate Response to Immunotherapy in Metastatic Melanoma: A Case Report

Skin cancer is the most commonly diagnosed malignancy in the United States, and invasive cutaneous melanoma is responsible for the vast majority of skin cancer-related deaths. Treatment options for patients with regional nodal disease, in-transit metastases, or locally advanced or distant metastatic disease are challenging. Historically survival rates in this patient population are dismal. Improved systemic control is possible using targeted agents and checkpoint inhibitors have redefined treatment outcomes. Furthermore, multi-modal therapy incorporating radiation may improve survival outcomes by priming the immune system for antigen release and help in reversing T-cell exhaustion. Herein, we describe a patient with widespread metastatic melanoma with progressive systemic disease while receiving checkpoint inhibition therapy that was reversed after combined immunoradiotherapy. The patient is now more than 41 months from diagnosis with durable, stable systemic disease.