Cancer immunotherapy based on mutation-specific CD4+ T cells in a patient with epithelial cancer

Cancer therapy via neoepitope-specific monoclonal antibody cocktails

Cellular heterogeneity presents a significant challenge to cancer treatment. Antibody therapies targeting individual tumor-associated antigens can be extremely effective but are not suited for all patients and often fail against tumors with heterogeneous expression as tumor cells with low or no antigen expression escape targeting and develop resistance. Simultaneously targeting multiple tumor-specific proteins with multiple antibodies has the potential to overcome this barrier and improve efficacy, but relatively few widely expressed cancer-specific antigens are known. In contrast, neoepitopes, which arise from mutations unique to tumor cells, are considerably more abundant. However, since neoepitopes are not commonly shared between individuals, a patient-customized approach is necessary and motivates efforts to develop an efficient means to identify suitable target mutations and isolate neoepitope-specific monoclonal antibodies. Here, focusing on the latter goal, we use directed evolution in yeast and phage display systems to engineer antibodies from nonimmune, human antibody fragment libraries that are specific for neoepitopes previously reported in the B16F10 melanoma model. We demonstrate proof-of-concept for a pipeline that supports rapid isolation and functional enhancement of multiple neoepitope peptide-targeted monoclonal antibodies and demonstrate their robust binding to B16F10 cells and potent effector functions in vitro. These antibodies were combined and evaluated in vivo for anticancer activity in tumor-bearing mice, where they suppressed B16F10 tumor growth and prolonged survival. These findings emphasize the potential for clinical application of patient-customized antibody cocktails in the treatment of the many cancers poorly addressed by current therapies.

Grain-sized moxibustion activates dendritic cells to enhance the antitumor immunity of cancer vaccines

BACKGROUND

Moxibustion, a traditional Chinese medicine (TCM) therapy, employs thermal stimulation from the combustion of Artemisia argyi H.Lév. & Vaniot at acupoints to treat "deficiency-cold syndromes" (xuhan zheng), historically linked to immune dysfunction and chronic inflammation. Modern pharmacological studies showed that grain-sized moxibustion (gM) enhances innate immune surveillance such as natural killer (NK) cell recruitment. However, its synergy with vaccine-induced adaptive immunity remains unexplored. Guided by the TCM principle of fu zheng qu xie ("fortify the host to dispel pathogens"), this study investigated whether gM augments cancer vaccine efficacy and validate the mechanistic basis of thermal acupoint stimulation in amplifying adaptive antitumor immunity.

METHODS

In tumor-bearing mice model, gM was applied to the ST36 (Zusanli) acupoint. Adjuvant effects on the cancer vaccine were evaluated through flow cytometry, β-adrenergic receptor blockade, and cell depletion.

RESULTS

gM synergized with the cancer vaccine, significantly suppressing tumor growth. Mechanistically, gM inhibited β-adrenergic signaling, driving DC maturation and subsequent coordination of CD4+ T cell, CD8+ T cell and NK cell responses. CD4+ T cells as primary effectors, with NK cells playing a secondary role. Propranolol mirrored gM's effects, further enhancing DC activation and tumor suppression when combined with vaccination.

CONCLUSION

Both gM and β-blockers enhance cancer vaccine efficacy through β-adrenergic suppression and maturation of DC. These findings mechanistically bridge TCM's fu zheng qu xie strategy with modern immunotherapy, positioning β-adrenergic modulation as a convergent target for traditional and pharmacological interventions.

Clinical and Fundamental Research Progressions on Tumor-Infiltrating Lymphocytes Therapy in Cancer

Malignant tumors represent a significant threat to human health. Among the various therapeutic strategies available, cancer immunotherapy-encompassing adoptive cell transfer (ACT) and immune checkpoint blockade therapy-has emerged as a particularly promising approach following surgical resection, radiotherapy, chemotherapy, and molecular targeted therapies. This form of treatment elicits substantial antigen-specific immune responses, enhances or restores anti-tumor immunity, thereby facilitating the control and destruction of tumor cells, and yielding durable responses across a range of cancers, which can lead to the eradication of tumor lesions and the prevention of recurrence. Tumor-infiltrating lymphocytes (TILs), a subset of ACT, are characterized by their heterogeneity and are found within tumor tissues, where they play a crucial role in mediating host antigen-specific immune responses against tumors. This review aims to explore recent advancements in the understanding of TILs biology, their prognostic implications, and their predictive value in therapeutic contexts.

Advances in TIL therapy: Expanding the horizons beyond melanoma

Tumor-infiltrating lymphocyte (TIL) therapy represents a breakthrough in solid tumor treatment, addressing unmet needs for patients with limited options. While its efficacy is established in advanced melanoma, TIL therapy shows early promise in non-small cell lung cancer, breast cancer, gynecological cancers, and head and neck cancers. However, challenges such as reduced T cell infiltration, lower tumor mutational burden (TMB), immunosuppressive tumor microenvironments (TME), and toxicity associated with the TIL therapy regimen hinder its broader application in these patient groups, compared with melanoma. To address these challenges, new approaches focus on the selection of tumor-reactive TIL, optimization of TIL expansion, combination of immune checkpoint inhibitors with TIL therapy to counteract immunosuppressive microenvironments, and genetic modification of TIL to enhance persistence and functionality. Larger clinical trials are essential to validate these innovations and standardize protocols. With continued advancements, TIL therapy has the potential to redefine the treatment landscape for advanced solid cancers.

A phase 2 trial of pembrolizumab for recurrent Lynch-like versus sporadic endometrial cancers with microsatellite instability (NCT02899793): Updated survival and response analyses

OBJECTIVE

Microsatellite instability-high (MSI-H)/mismatch repair deficiency (dMMR) is a biomarker for response to immune checkpoint inhibitors. We report updated results including objective response rate, progression free survival, and overall survival data with 5-year follow-up in recurrent platinum-resistant, MSI-H, endometrial cancer (EC) patients fully sequenced using whole exome sequencing (WES) and treated within a prospective phase II study with pembrolizumab (NCT02899793).

METHODS

Tumors from patients with measurable MSI-H/dMMR endometrial cancer confirmed by immunohistochemistry, polymerase chain reaction, and MLH-1 methylation assays were sequenced using whole exome sequencing and the FoundationOne platform for the identification of Lynch, Lynch-like, and MLH-1 methylated characteristics before receiving pembrolizumab 200 mg every 3 weeks for up to 24 months. The primary endpoint was objective response rate (ORR), and secondary endpoints were progression free survival (PFS), and overall survival (OS).

RESULTS

After almost 97 person-years of follow-up, the Lynch-like subgroup (n = 6) of MSI-H/dMMR patients continues to exhibit better ORR than the methylated (n = 18) subgroup (100 % versus 44 %, Fisher's exact P = 0.024), as well as improved PFS (unreached for Lynch-like versus 14.6 months, Log-Rank P = 0.005) and improved OS (unreached for Lynch-like versus 32.6 months, Log-Rank P = 0.058). Toxicity was manageable in both groups of MSI-H patients.

CONCLUSION

Mature follow-up results continue to suggest the prognostic significance of Lynch-like versus methylated MSI-H/dMMR features in endometrial cancer patients treated with pembrolizumab in terms of ORR, PFS, and OS. Stratification for these translational aspects may be warranted in future clinical trials with immune checkpoint inhibitors in MSI-H/dMMR endometrial cancer patients.

Tumor-specific surface marker-independent targeting of tumors through nanotechnology and bioorthogonal glycochemistry

Biological targeting is crucial for effective cancer treatment with reduced toxicity but is limited by the availability of tumor surface markers. To overcome this, we developed a nanoparticle-based (NP-based), tumor-specific surface marker-independent (TRACER) targeting approach. Utilizing the unique biodistribution properties of NPs, we encapsulated Ac4ManNAz (Maz) to selectively label tumors with azide-reactive groups. Surprisingly, while NP-delivered Maz was cleared by the liver, it did not label macrophages, potentially reducing off-target effects. To exploit this tumor-specific labeling, we functionalized anti-4-1BB Abs with dibenzocyclooctyne to target azide-labeled tumor cells and activate the immune response. In syngeneic B16F10 melanoma and orthotopic 4T1 breast cancer models, TRACER enhanced the therapeutic efficacy of anti-4-1BB, increasing the median survival time. Immunofluorescence analyses revealed increased tumor infiltration of CD8+ T and NK cells with TRACER. Importantly, TRACER reduced the hepatotoxicity associated with anti-4-1BB, resulting in normal serum ALT and AST levels and decreased CD8+ T cell infiltration into the liver. Quantitative analysis confirmed a 4.5-fold higher tumor-to-liver ratio of anti-4-1BB accumulation with TRACER compared with conventional anti-4-1BB Abs. Our work provides a promising approach for developing targeted cancer therapies that circumvent limitations imposed by the paucity of tumor-specific markers, potentially improving efficacy and reducing off-target effects to overcome the liver toxicity associated with anti-4-1BB.

MHC2-SCALE enhances identification of immunogenic neoantigens

Recent studies suggest that CD4+ T cells can exert potent anti-tumor effects and improve immunotherapy efficacy by aiding CD8+ T cells. However, characterizing the mechanism of CD4+ T cells' anti-tumor activity has been challenging due to inaccurate major histocompatibility complex class II (MHC-II) peptide prediction algorithms and the lack of high-quality reagents for immune monitoring. To address this, we developed MHC2-substitution of CLIP and analytical LCMS evaluation (MHC2-SCALE), a streamlined approach combining affinity optimized class II-associated invariant chain peptide (CLIP) exchange technology, high throughput 2D-LCMS analysis, and rapid generation of peptide-bound MHC-II monomers for subsequent multimer assembly. We validated MHC-II peptide candidates predicted by the immune epitope database (IEDB) algorithm, as well as uncovered many true and immunogenic MHC-II binders that were not predicted by IEDB. Thus, MHC2-SCALE expands the opportunities for discovering, tracking, and phenotyping antigen-specific CD4+ T cells in preclinical and clinical settings, thereby improving therapies for cancer, autoimmunity, or infectious diseases.

Neoepitope BTLAP267L-specific TCR-T cell immunotherapy unlocks precision treatment for hepatocellular carcinoma

OBJECTIVE

The high heterogeneity of hepatocellular carcinoma (HCC) renders traditional therapies unable to effectively activate the patient's immune system to combat tumors. Patients with advanced HCC and T cell functional deficiencies may benefit more from cellular immunotherapy, especially tumor neoepitope-targeted T cell receptor (TCR)-T cells. Neoepitopes with strong immunogenicity provide precise targets for HCC, further enhancing the efficacy of cellular immunotherapy.

METHODS

A scalable workflow for identifying neoepitopes from 7 HLA-A*02:01-restricted patients with HCC was established based on whole exome sequencing and bioinformatics analyses, followed by identification of neoepitope-specific TCRs through tetramer-based screening and single-cell TCR cloning technology, which were further validated in the JC4 cell model. The cytotoxicity of CD8+ TCR-T cells was evaluated in neoepitope-positive tumor cell lines or NCG mice.

RESULTS

Ten specific neoepitopes were identified, among which neoepitope B and T lymphocyte attenuatorP267L [BTLAP267L (SLNHSVIGL)] exhibited advantageous properties as a potential tumor target. Three TCRs (85-3, 126-5, and 52-3) were confirmed to specifically recognize the neoepitope BTLAP267L, while no cross-recognition of irrelevant or wild-type epitopes was observed. Activated BTLAP267L-specific CD8+ TCR-T cells released extensive perforin, granzyme B, IFN-γ, and TNF-α in vitro, thereby inducing strong cytotoxic effects against BTLAP267L-positive T2 or HCC cell lines. BTLAP267L-specific CD8+ TCR-T cells mediated robust tumor regression due to long-lasting survival and released perforin without causing significant cytotoxic effects on normal organs in murine experiments.

CONCLUSIONS

This preclinical study demonstrated the beneficial effects of neoepitope BTLAP267L-specific TCR-T cell immunotherapy, unlocking a novel strategy for personalized precision therapy in HCC.

Tumor-infiltrating lymphocyte immunotherapy comes of age: a journey of development in the Surgery Branch, NCI

The early development of tumor-infiltrating lymphocytes into an effective clinical strategy was fundamentally the work of hundreds of scientists and clinicians within the Surgery Branch of the National Cancer Institute under the leadership of Steven Rosenberg. That journey brought new insights into the tumor-immune cell interface and ultimately helped create a new first-in-class therapeutic for patients with metastatic cancer.

Abscopal Effects and Immunomodulation in Skin Cancer Therapy

Radiation therapy (RT) is a crucial modality in cancer treatment, functioning through direct DNA damage and immune stimulation. However, RT's effects extend beyond targeted cells, influencing neighboring cells through the bystander effect (ByE) and distant sites via the abscopal effect (AbE). The AbE, first described by Mole in 1953, encompasses biological reactions at sites distant from the irradiation field. While RT can enhance antitumor immune responses, it may also contribute to an immunosuppressive microenvironment. To address this limitation, combining RT with immune checkpoint inhibitors (ICIs) has gained renewed interest, aiming to amplify antitumor immune responses. Evidence of AbEs has been observed in various metastatic or advanced cutaneous cancers, including melanoma, basal cell carcinoma, cutaneous lymphoma, Merkel cell carcinoma, and cutaneous squamous cell carcinoma. Clinical studies suggest combining RT with ICIs targeting CTLA-4 and PD-1/PD-L1 may enhance AbE incidence in these cancers. This review primarily explores the current understanding of AbEs in skin cancers, briefly acknowledging the ByE focusing on combining RT with immunomodulation. It focuses on proposed mechanisms, preclinical and clinical evidence, challenges in clinical translation, and future directions for harnessing AbEs in managing advanced skin malignancies. Alternative modalities for inducing abscopal-like responses are also explored. While promising, challenges remain in consistently reproducing AbEs in clinical practice, necessitating further research to optimize treatment combinations, timing, and patient selection.

Metformin as an immunomodulatory agent in enhancing head and neck squamous cell carcinoma therapies

Head and neck squamous cell carcinoma (HNSCC) remains a significant clinical challenge due to its aggressive behavior and poor prognosis, making the development of novel therapeutics with enhanced efficacy and minimal side effects critical. Metformin, a widely used antidiabetic agent, has recently emerged as a potential adjunctive therapy for HNSCC, exhibiting both direct anti-tumor and immunomodulatory effects. This review comprehensively explores the multifaceted role of metformin in shaping the tumor immune microenvironment within HNSCC. We emphasize its pivotal role in modulating immune cell populations and its potential for synergistic action with immunotherapeutic strategies. Furthermore, we address the current challenges associated with optimizing dosing regimens, identifying predictive biomarkers, and integrating metformin with immunotherapy. By dissecting these aspects, this review aims to pave the way for the development of personalized HNSCC treatment strategies that fully exploit the therapeutic potential of metformin.

Role of genomics in liver transplantation for cholangiocarcinoma

PURPOSE OF REVIEW

The purpose of this review is to summarize the current knowledge of cholangiocarcinoma molecular biology and to suggest a framework for implementation of next-generation sequencing in all stages of liver transplantation. This is timely as recent guidelines recommend increased use of these technologies with promising results.

RECENT FINDINGS

The main themes covered here address germline and somatic genetic alterations recently discovered in cholangiocarcinoma, particularly those associated with prognosis and treatment responses, and nascent efforts to translate these into contemporary practice in the peri-liver transplantation period.

SUMMARY

Early efforts to translate molecular profiling to cholangiocarcinoma care demonstrate a growing number of potentially actionable alterations. Still lacking is a consensus on what biomarkers and technologies to adopt, at what scale and cost, and how to integrate them most effectively into care with the ambition of increasing the number of patients eligible for liver transplantation and improving their long-term outcomes.

Enhancing immunotherapy with tumour-responsive nanomaterials

The targeted delivery of immunotherapies to tumours using tumour-responsive nanomaterials is a promising area of cancer research with the potential to address the limitations of systemic administration such as on-target off-tumour toxicities and a lack of activity owing to the immunosuppressive tumour microenvironment (TME). Attempts to address these challenges include the design and functionalization of nanomaterials capable of releasing their cargoes in response to specific TME characteristics, thus facilitating the targeted delivery of immune-checkpoint inhibitors, cytokines, mRNAs, vaccines and, potentially, chimaeric antigen receptors as well as of agents that modulate the extracellular matrix and induce immunogenic cell death. In this Review, we describe these various research efforts in the context of the dynamic properties of the TME, such as pH, reductive conditions, reactive oxygen species, hypoxia, specific enzymes, high levels of ATP and locoregional aspects, which can be leveraged to enhance the specificity and efficacy of nanomaterial-based immunotherapies. Highlighting preclinical successes and ongoing clinical trials, we evaluate the current landscape and potential of these innovative approaches. We also consider future research directions as well as the most important barriers to successful clinical translation, emphasizing the transformative potential of tumour-responsive nanomaterials in overcoming the barriers that limit the activity of traditional immunotherapies, thus improving patient outcomes.

Neoantigen-specific tumor-infiltrating lymphocytes in gastrointestinal cancers: a phase 2 trial

Adoptive transfer of unselected autologous tumor-infiltrating lymphocytes (TILs) has mediated meaningful clinical responses in patients with metastatic melanoma but not in cancers of gastrointestinal epithelial origin. In an evolving single-arm phase 2 trial design, TILs were derived from and administered to 91 patients with treatment-refractory mismatch repair proficient metastatic gastrointestinal cancers in a schema with lymphodepleting chemotherapy and high-dose interleukin-2 (three cohorts of an ongoing trial). The primary endpoint of this study was the objective response rate as measured using Response Evaluation Criteria in Solid Tumors 1.0; safety was a descriptive secondary endpoint. In the pilot phase, no clinical responses were observed in 18 patients to bulk, unselected TILs; however, when TILs were screened and selected for neoantigen recognition (SEL-TIL), three responses were seen in 39 patients (7.7% (95% confidence interval (CI): 2.7-20.3)). Based on the high levels of programmed cell death protein 1 in the infused TILs, pembrolizumab was added to the regimen (SEL-TIL + P), and eight objective responses were seen in 34 patients (23.5% (95% CI: 12.4-40.0)). All patients experienced transient severe hematologic toxicities from chemotherapy. Seven (10%) patients required critical care support. Exploratory analyses for laboratory and clinical correlates of response were performed for the SEL-TIL and SEL-TIL + P treatment arms. Response was associated with recognition of an increased number of targeted neoantigens and an increased number of administered CD4+ neoantigen-reactive TILs. The current strategy (SEL-TIL + P) exceeded the parameters of the trial design for patients with colorectal cancer, and an expansion phase is accruing. These results could potentially provide a cell-based treatment in a population not traditionally expected to respond to immunotherapy. ClinicalTrials.gov identifier: NCT01174121 .

Optical-magnetic Imaging for Optimizing Lymphodepletion-TIL Combination Therapy in Breast Cancer

PURPOSE

Lymphodepletion before tumor-infiltrating lymphocytes (TIL) infusion can activate the immune system, enhance the release of homeostatic cytokines, and decrease the number of immunosuppressive cells. This process is crucial for improving the therapeutic efficacy of TIL therapy. However, the challenge of in vivo assessing TILs targeting tumors limits the optimization of lymphodepleting conditioning regimen (LDC).

PROCEDURES

This study aims to employ magnetic particle imaging (MPI) and fluorescence molecular imaging (FMI) to monitor TIL biodistribution in vivo and optimize LDC in triple-negative breast cancer TIL therapy. MPI provides quantitative imaging capabilities without depth limitations, effectively complementing the high sensitivity of FMI. The efficacy of different LDCs in enhancing TIL therapy was assessed using FMI, and MPI quantified the number of TILs accumulated in the 4T1 tumor.

RESULTS

TILs preserved viability, phenotypes, and anti-tumor efficacy after being labeled with superparamagnetic iron oxide and fluorescence dye DiR. The dual-modality imaging system effectively discerned variations in LDC treatments that enhanced TIL therapy. Compared to TIL monotherapy, lymphodepletion with TIL therapy improves tumor dual-modality imaging signal intensity, increases the expression of monocyte chemotactic protein-1 in serum and tumor tissue, and enhances the therapeutic effect of TILs.

CONCLUSION

Our results confirm the utility of optical-magnetic dual-modality imaging for tracking the biodistribution of TILs in vivo. With the help of optical-magnetic dual-modality imaging, we successfully optimize TIL combination therapy. Optical-magnetic dual-modality imaging provides a new approach to develop personalized immunotherapy strategies and mine potential therapeutic mechanisms for TIL.

Adoptively transferred tumor-specific IL-9-producing cytotoxic CD8+ T cells activate host CD4+ T cells to control tumors with antigen loss

Host effector CD4+ T cells emerge as critical mediators for tumor regression but whether they can be activated by adoptively transferred CD8+ T cells remains unknown. We previously reported that adoptive transfer of interleukin 9 (IL-9)-producing cytotoxic CD8+ T (Tc9) cells achieved long-term control of tumor growth. Here, we demonstrate that murine tumor-specific Tc9 cells control the outgrowth of antigen-loss relapsed tumors by recruiting and activating host effector CD4+ T cells. Tc9 cells secreted IL-24 and recruited CCR7-expressing conventional type 2 dendritic cells (cDC2 cells) into tumor-draining lymph nodes to prime host CD4+ T cells against relapsed tumors. Host CD4+ T cell or cDC2 deficiency impaired the ability of Tc9 cells to control relapsed tumor outgrowth. Additionally, intratumoral IL24 expression correlates with cDC2 and CD4+ T cell gene signatures in human cancers and their expression is associated with better patient survival. This study reports a mechanism for activation of tumor-specific CD4+ T cells in vivo.

Predicting MHC-I ligands across alleles and species: how far can we go?

BACKGROUND

CD8+ T-cell activation is initiated by the recognition of epitopes presented on class I major histocompatibility complex (MHC-I) molecules. Identifying such epitopes is useful for molecular understanding of cellular immune responses and can guide the development of personalized vaccines for various diseases including cancer. For a few hundred common human and mouse MHC-I alleles, large datasets of ligands are available and machine learning MHC-I ligand predictors trained on such data reach high prediction accuracy. However, for the vast majority of other MHC-I alleles, no ligand is known.

METHODS

We capitalize on an expanded architecture of our MHC-I ligand predictor (MixMHCpred3.0) to systematically assess the extent to which predictions of MHC-I ligands can be applied to MHC-I alleles that currently lack known ligand data.

RESULTS

Our results reveal high prediction accuracy for most MHC-I alleles in human and in laboratory mouse strains, but significantly lower accuracy in other species. Our work further outlines some of the molecular determinants of MHC-I ligand prediction accuracy across alleles and species. Robust benchmarking on external data shows that our MHC-I ligand predictor demonstrates competitive performance relative to other state-of-the-art MHC-I ligand predictors and can be used for CD8+ T-cell epitope predictions.

CONCLUSIONS

Our work provides a valuable tool for predicting antigen presentation across all human and mouse MHC-I alleles. MixMHCpred3.0 tool is available at https://github.com/GfellerLab/MixMHCpred .

Neoantigens: new hope for cancer therapy

As research into tumour immunotherapy continues to accelerate, new frontiers are being revealed in the field of cancer treatment. A significant focus has been drawn to neoantigen-based personalised tumour vaccines, a pioneering immunotherapy. This approach involves the use of genetic mutations that are unique to tumor cells to custom-design personalized tumor vaccines. These vaccines elicit an immune response that is specifically directed at targeting and eliminating cancer cells. The incorporation of neoantigens, arising from mutations within tumor cells, confers a distinct advantage to personalized tumor vaccines in terms of precision and the mitigation of adverse effects. However, the intricate pathways from antigen presentation to the activation of tumor immunogenicity remain to be elucidated. This paper primarily delves into the origins and characteristics of neoantigens, and also neoantigen prediction, highlights existing screening methods, and addresses the limitations of current approaches. It is hoped that this review will act as a catalyst, accelerating the understanding of relevant knowledge and illuminating research hotspots for scientists poised to venture into neoantigen research.

Individualized Neoantigen-Directed Melanoma Therapy

Individualized neoantigen-directed therapy represents a groundbreaking approach in melanoma treatment that leverages the patient's own immune system to target cancer cells. This innovative strategy involves the identification of unique immunogenic neoantigens (mutated proteins specific to an individual's tumor) and the development of therapeutic vaccines that either consist of peptide sequences or RNA encoding these neoantigens. The goal of these therapies is to induce neoantigen-specific immune responses, enabling the immune system to recognize and destroy cancer cells presenting the targeted neoantigens. This individualized approach is particularly advantageous given the genetic heterogeneity of melanoma, which exhibits distinct mutations among different patients. In contrast to traditional therapies, neoantigen-directed therapy offers a tailored treatment that potentially reduces off-target side effects and enhances therapeutic efficacy. Recent advances in neoantigen prediction and vaccine development have facilitated clinical trials exploring the combination of neoantigen vaccines with immune checkpoint inhibitors. These trials have shown promising clinical outcomes, underscoring the potential of this personalized approach. This review provides an overview of the rationale behind neoantigen-directed therapies and summarizes the current state of knowledge regarding personalized neoantigen vaccines in melanoma treatment.

Rapid parallel reconstruction and specificity screening of hundreds of T cell receptors

The ability to screen the reactivity of T cell receptors (TCRs) is essential to understanding how antigen-specific T cells drive productive or dysfunctional immune responses during infections, cancer and autoimmune diseases. Methods to profile large numbers of TCRs are critical for characterizing immune responses sustained by diverse T cell clones. Here we provide a medium-throughput approach to reconstruct dozens to hundreds of TCRs in parallel, which can be simultaneously screened against primary human tissues and broad curated panels of antigenic targets. Using Gibson assembly and miniaturized lentiviral transduction, individual TCRs are rapidly cloned and expressed in T cells; before screening, TCR cell lines undergo combinatorial labeling with dilutions of three fluorescent dyes, which allows retrieval of the identity of individual T cell effectors when they are organized and tested in pools using flow cytometry. Upon incubation with target cells, we measure the upregulation of CD137 on T cells as a readout of TCR activation. This approach is scalable and simultaneously captures the reactivity of pooled TCR cell lines, whose activation can be deconvoluted in real time, thus providing a path for screening the reactivity of dozens of TCRs against broad panels of synthetic antigens or against cellular targets, such as human tumor cells. We applied this pipeline to systematically deconvolute the antitumoral and antiviral reactivity and antigenic specificity of TCRs from human tumor-infiltrating lymphocytes. This protocol takes ~2 months, from experimental design to data analysis, and requires standard expertise in cloning, cell culture and flow cytometry.

Tumor-Infiltrating Lymphocyte Therapy for Melanoma and Other Solid Tumors: Looking Back, Yet Moving Forward

Lifileucel, the first solid tumor adoptive tumor infiltrating lymphocyte (TIL) therapy product to receive regulatory approval in advanced melanoma, represents a critical achievement in the pursuit of improving outcomes using cellular therapies in patients with solid tumors. This review traces the development of adoptive TIL therapy from the initial human studies in melanoma, through recent advances in studies of other solid tumors, and previews ongoing and future areas for preclinical and clinical advances to improve upon this novel therapeutic strategy.

Development of CAR-T Therapies and Personalized Vaccines for the Treatment of Cholangiocarcinoma: Current Progress, Mechanisms of Action, and Challenges

Cholangiocarcinoma (CCA) is a highly fatal malignancy with an increasing prevalence, a high mortality rate, poor overall survival, and limited responsiveness to conventional chemoradiotherapy. Targeted therapies addressing specific gene mutations have expanded treatment options for some patient populations. The introduction of chimeric antigen receptor-modified T-cell (CAR-T) immunotherapy and personalized vaccines have opened up a new avenue for managing various cancers. Considerable efforts have been dedicated to preclinical research and ongoing clinical trials of immunotherapeutic approaches including CAR-T therapy, vaccines, and antibody-based therapies such as antibody drug conjugates. However, the potential of CAR-T therapy and vaccines in treating advanced unresectable/metastatic cholangiocarcinoma remains largely unexplored. This article offers an overview of the current landscape of antibody-based immunotherapy, particularly CAR-T therapy and vaccines in the context of cholangiocarcinoma treatment. It outlines a framework for selecting CAR-T and vaccine targets and delves into the biology of promising targetable antigens, as well as potential future therapeutic targets.

Personalized, autologous neoantigen-specific T cell therapy in metastatic melanoma: a phase 1 trial

New treatment approaches are warranted for patients with advanced melanoma refractory to immune checkpoint blockade (ICB) or BRAF-targeted therapy. We designed BNT221, a personalized, neoantigen-specific autologous T cell product derived from peripheral blood, and tested this in a 3 + 3 dose-finding study with two dose levels (DLs) in patients with locally advanced or metastatic melanoma, disease progression after ICB, measurable disease (Response Evaluation Criteria in Solid Tumors version 1.1) and, where appropriate, BRAF-targeted therapy. Primary and secondary objectives were evaluation of safety, highest tolerated dose and anti-tumor activity. We report here the non-pre-specified, final results of the completed monotherapy arm consisting of nine patients: three at DL1 (1 × 108-1 × 109 cells) and six at DL2 (2 × 109-1 × 1010 cells). Drug products (DPs) were generated for all enrolled patients. BNT221 was well tolerated across both DLs, with no dose-limiting toxicities of grade 3 or higher attributed to the T cell product observed. Specifically, no cytokine release, immune effector cell-associated neurotoxicity or macrophage activation syndromes were reported. A dose of 5.0 × 108-1.0 × 1010 cells was identified for further study conduct. Six patients showed stable disease as best overall response, and tumor reductions (≤20%) were reported for four of these patients. In exploratory analyses, multiple mutant-specific CD4+ and CD8+ T cell responses were generated in each DP. These were cytotoxic, polyfunctional and expressed T cell receptors with broad functional avidities. Neoantigen-specific clonotypes were detected after treatment in blood and tumor. Our results provide key insights into this neoantigen-specific adoptive T cell therapy and demonstrate proof of concept for this new therapeutic approach. ClinicalTrials.gov registration: NCT04625205 .

Preclinical data and design of a phase I clinical trial of neoantigen-reactive TILs for advanced epithelial or ICB-resistant solid cancers

Background

Adoptive cell therapy (ACT) of ex vivo expanded tumor-infiltrating lymphocytes (TILs) can mediate objective tumor regression in 28%-49% of metastatic melanoma patients. However, the efficacy of TIL therapy in most epithelial cancers remains limited. We present the design of a phase I clinical study that aims to assess the safety and efficacy of NEXTGEN-TIL, a TIL product selected based on ex vivo neoantigen recognition, in patients with advanced epithelial tumors and immune checkpoint blockade (ICB)-resistant solid tumors.

Materials and methods

Pre-rapid expansion protocol (REP) TIL cultures expanded in high-dose interleukin 2 (HD-IL-2) from patients with metastatic solid tumors were screened for recognition of autologous tumor cell lines (TCLs) and/or neoantigens. Six good manufacturing practice (GMP)-grade validations of pre-REP TIL expansion were carried out and TIL cultures from these six intermediate products were selected to carry out the clinical-scale GMP validation of the REP.

Results

TILs expanded in 82% of patient-derived tumor biopsies across different cancer types and these frequently contained tumor- and neoantigen-reactive T cells. During GMP validations, a variable number of TIL cultures expanded, constituting the intermediate products (pre-REP). Three finished products were manufactured using a REP which reached cell doses ranging from 4.3e9 to 1.1e11 and met the established specifications. The NEXTGEN-TIL clinical trial entails a first expansion of TILs from tumor fragments in HD-IL-2 followed by TIL screening for neoantigen recognition and REP of selected neoantigen-reactive TIL cultures. Treatment involves a classical non-myeloablative lymphodepleting chemotherapy followed by NEXTGEN-TIL product administration together with HD-IL-2.

Conclusions

NEXTGEN-TIL exploits ex vivo expanded neoantigen-reactive TIL to potentially improve efficacy in patients with epithelial and ICB-resistant tumors, with a safety profile like traditional TILs.

Vax-Innate: improving therapeutic cancer vaccines by modulating T cells and the tumour microenvironment

T cells have a critical role in mediating antitumour immunity. The success of immune checkpoint inhibitors (ICIs) for cancer treatment highlights how enhancing endogenous T cell responses can mediate tumour regression. However, mortality remains high for many cancers, especially in the metastatic setting. Based on advances in the genetic characterization of tumours and identification of tumour-specific antigens, individualized therapeutic cancer vaccines targeting mutated tumour antigens (neoantigens) are being developed to generate tumour-specific T cells for improved therapeutic responses. Early clinical trials using individualized neoantigen vaccines for patients with advanced disease had limited clinical efficacy despite demonstrated induction of T cell responses. Therefore, enhancing T cell activity by improving the magnitude, quality and breadth of T cell responses following vaccination is one current goal for improving outcome against metastatic tumours. Another major consideration is how T cells can be further optimized to function within the tumour microenvironment (TME). In this Perspective, we focus on neoantigen vaccines and propose a new approach, termed Vax-Innate, in which vaccination through intravenous delivery or in combination with tumour-targeting immune modulators may improve antitumour efficacy by simultaneously increasing the magnitude, quality and breadth of T cells while transforming the TME into a largely immunostimulatory environment for T cells.

Tumor-Infiltrating Lymphocytes, CAR-, and T-Cell Receptor-Modified T Cells in Solid Cancer Oncology

BACKGROUND

Adoptive cellular therapy (ACT) is a promising treatment approach aiming at enhancing T-cell antitumor immune response. ACT includes tumor-infiltrating lymphocytes, chimeric antigen receptor (CAR) and T-cell receptor gene-modified T cells. Despite a milestone achievement with CAR-T cells in hematopoietic malignancies, ACT has shown modest clinical responses in refractory solid cancers and durable responses remain limited to a minor fraction of patients.

SUMMARY

In this review, we highlight major advances, limitations and current developments of T-cell therapies for solid cancers. We discuss emerging promising strategies as next-generation ACT, exploring local delivery routes to maximize efficacy and improve safety, integrating predictive biomarkers to optimize selection of patients who most likely would benefit from ACT, using combination therapy to overcome the immunosuppressive tumor microenvironment, targeting multiple tumor antigen to avoid tumor antigen escape, selection of the most potent T-cell product to overcome T-cell dysfunction, and incorporating cutting-edge new technologies, such as gene-editing to further improve antitumor T-cell functions and reduce therapy-related toxicity.

KEY MESSAGES

Advances made in ACT trials have move the field of immunotherapy for refractory solid cancers to a new stage, by constantly incorporating new strategies to develop next-generation therapies designed to enhance efficacy and improve safety and to allow a broaden access to a large numbers of patients.

Mapping naturally presented T cell antigens in medulloblastoma based on integrative multi-omics

Medulloblastoma is the most frequent malignant primary brain tumor in children. Despite recent advances in integrated genomics, the prognosis in children with high-risk medulloblastoma remains devastating, and new tumor-specific therapeutic approaches are needed. Here, we present an atlas of naturally presented T cell antigens in medulloblastoma. We map the human leukocyte antigen (HLA)-presented peptidomes of 28 tumors and perform comparative immunopeptidome profiling against an in-house benign database. Medulloblastoma is shown to be a rich source of tumor-associated antigens, naturally presented on HLA class I and II molecules. Remarkably, most tumor-associated peptides and proteins are subgroup-specific, whereas shared presentation among all subgroups of medulloblastoma (WNT, SHH, Group 3 and Group 4) is rare. Functional testing of top-ranking novel candidate antigens demonstrates the induction of peptide-specific T cell responses, supporting their potential for T cell immunotherapy. This study is an in-depth mapping of naturally presented T cell antigens in medulloblastoma. Integration of immunopeptidomics, transcriptomics, and epigenetic data leads to the identification of a large set of actionable targets that can be further used for the translation into the clinical setting by facilitating the informed design of immunotherapeutic approaches to children with medulloblastoma.

Identification and Phenotypic Characterization of Neoantigen-Specific Cytotoxic CD4+ T Cells in Endometrial Cancer

Tumor-reactive CD4+ T cells often accumulate in the tumor microenvironment (TME) in human cancer, but their functions and roles in antitumor responses remain elusive. Here, we investigated the immunopeptidome of HLA class II-positive (HLA-II+) endometrial cancer with an inflamed TME using a proteogenomic approach. We identified HLA-II neoantigens, one of which induced polyclonal CD4+ tumor-infiltrating lymphocyte responses. We then experimentally demonstrated that neoantigen-specific CD4+ tumor-infiltrating lymphocytes lyse target cells in an HLA-II-dependent manner. Single-cell transcriptomic analysis of the TME coupled with T-cell receptor sequencing revealed the presence of CD4+ T-cell clusters characterized by CXCL13 expression. The CXCL13+ clusters contained two subclusters with distinct cytotoxic gene expression patterns. The identified neoantigen-specific CD4+ T cells were found exclusively in one of the CXCL13+ subclusters characterized by granzyme B and CCL5 expression. These results demonstrate the involvement of tumor-reactive CD4+ T cells with cytotoxic function in immune surveillance of endometrial cancer and reveal their transcriptomic signature.

Discovery of tumor-reactive T cell receptors by massively parallel library synthesis and screening

T cell receptor (TCR) gene therapy is a potent form of cellular immunotherapy in which patient T cells are genetically engineered to express TCRs with defined tumor reactivity. However, the isolation of therapeutic TCRs is complicated by both the general scarcity of tumor-specific T cells among patient T cell repertoires and the patient-specific nature of T cell epitopes expressed on tumors. Here we describe a high-throughput, personalized TCR discovery pipeline that enables the assembly of complex synthetic TCR libraries in a one-pot reaction, followed by pooled expression in reporter T cells and functional genetic screening against patient-derived tumor or antigen-presenting cells. We applied the method to screen thousands of tumor-infiltrating lymphocyte (TIL)-derived TCRs from multiple patients and identified dozens of CD4+ and CD8+ T-cell-derived TCRs with potent tumor reactivity, including TCRs that recognized patient-specific neoantigens.

Unlocking novel T cell-based immunotherapy for hepatocellular carcinoma through neoantigen-driven T cell receptor isolation

BACKGROUND

Tumour-infiltrating T cells can mediate both antitumour immunity and promote tumour progression by creating an immunosuppressive environment. This dual role is especially relevant in hepatocellular carcinoma (HCC), characterised by a unique microenvironment and limited success with current immunotherapy.

OBJECTIVE

We evaluated T cell responses in patients with advanced HCC by analysing tumours, liver flushes and liver-draining lymph nodes, to understand whether reactive T cell populations could be identified despite the immunosuppressive environment.

DESIGN

T cells isolated from clinical samples were tested for reactivity against predicted neoantigens. Single-cell RNA sequencing was employed to evaluate the transcriptomic and proteomic profiles of antigen-experienced T cells. Neoantigen-reactive T cells expressing 4-1BB were isolated and characterised through T-cell receptor (TCR)-sequencing.

RESULTS

Bioinformatic analysis identified 542 candidate neoantigens from seven patients. Of these, 78 neoantigens, along with 11 hotspot targets from HCC driver oncogenes, were selected for ex vivo T cell stimulation. Reactivity was confirmed in co-culture assays for 14 targets, with most reactive T cells derived from liver flushes and lymph nodes. Liver flush-derived T cells exhibited central memory and effector memory CD4+ with cytotoxic effector profiles. In contrast, tissue-resident memory CD4+ and CD8+ T cells with an exhausted profile were primarily identified in the draining lymph nodes.

CONCLUSION

These findings offer valuable insights into the functional profiles of neoantigen-reactive T cells within and surrounding the HCC microenvironment. T cells isolated from liver flushes and tumour-draining lymph nodes may serve as a promising source of reactive T cells and TCRs for further use in immunotherapy for HCC.

Identification and validation of a T cell receptor targeting KRAS G12V in HLA-A*11:01 pancreatic cancer patients

T cells targeting a KRAS mutation can induce durable tumor regression in some patients with metastatic epithelial cancer. It is unknown whether T cells targeting mutant KRAS that are capable of killing tumor cells can be identified from peripheral blood of patients with pancreatic cancer. We developed an in vitro stimulation approach and identified HLA-A*11:01-restricted KRAS G12V-reactive CD8+ T cells and HLA-DRB1*15:01-restricted KRAS G12V-reactive CD4+ T cells from peripheral blood of 2 out of 6 HLA-A*11:01-positive patients with pancreatic cancer whose tumors expressed KRAS G12V. The HLA-A*11:01-restricted KRAS G12V-reactive T cell receptor (TCR) was isolated and validated to specifically recognize the KRAS G12V8-16 neoepitope. While T cells engineered to express this TCR specifically recognized all 5 tested human HLA-A*11:01+ and KRAS G12V+ pancreatic cancer organoids, the recognition was often modest, and tumor cell killing was observed in only 2 out of 5 organoids. IFN-γ priming of the organoids enhanced the recognition and killing by the TCR-engineered T cells. The TCR-engineered T cells could significantly slow the growth of an established organoid-derived xenograft in immunodeficient mice. Our data suggest that this TCR has potential for use in TCR-gene therapy, but additional strategies that enhance tumor recognition by the TCR-engineered T cells likely will be required to increase clinical activity.

Art of TIL immunotherapy: SITC's perspective on demystifying a complex treatment

In a first for solid cancers, cellular immunotherapy has entered standard of care in the treatment of patients with metastatic melanoma. The infusion of autologous tumor-infiltrating T lymphocytes (TIL) is capable of mediating durable tumor regression and is now Food and Drug Administration-approved for patients with disease refractory to immune checkpoint inhibitors. Since the advent of chimeric antigen receptor (CAR) T cells for patients with hematological malignancies, a growing network of centers capable of delivering effector T cell products to patients has developed. Administration of TIL can be layered onto that institutional framework, but there are many complex and unique aspects to TIL immunotherapy. The highly multidisciplinary clinical expertise and coordination required to successfully and safely deliver TIL to patients began within the National Cancer Institute Surgery Branch and have been subsequently adopted worldwide. The general steps, most of which require hospital inpatient resources, include a surgical procedure to harvest sufficient tumor for TIL manufacturing, admission for non-myeloablative lymphodepleting chemotherapy followed by TIL, and intravenous interleukin-2 (IL-2, aldesleukin). Here, we provide the principles, practice, and required resources underlying the efficient and safe delivery of TIL immunotherapy derived from the clinical expertise of high-volume centers around the world. This article enhances published clinical practice guidelines by providing underlying clinical rationale and data-driven examples to demystify TIL immunotherapy in order to facilitate uptake and improve patient access to this promising treatment modality in clinical and research settings.

Utilization of primary tumor samples for cancer neoantigen discovery

BACKGROUND

The use of tumor-infiltrating T lymphocytes (TIL) that recognize cancer neoantigens has led to lasting remissions in metastatic melanoma and certain cases of metastatic epithelial cancer. For the treatment of the latter, selecting cells for therapy typically involves laborious screening of TIL for recognition of autologous tumor-specific mutations, detected through next-generation sequencing of freshly resected metastatic tumors. Our study explored the feasibility of using archived formalin-fixed, paraffin-embedded (FFPE) primary tumor samples for cancer neoantigen discovery, to potentially expedite this process and reduce the need for resections normally required for tumor sequencing.

METHOD

Whole-exome sequencing was conducted on matched primary and metastatic colorectal cancer samples from 22 patients. The distribution of metastatic tumor mutations that were confirmed as neoantigens through cognate TIL screening was evaluated in the corresponding primary tumors. Mutations unique to primary tumors were screened for recognition by metastasis-derived TIL and circulating T lymphocytes.

RESULTS

We found that 25 (65.8%) of the 38 validated neoantigens identified in metastatic tumors from 18 patients with colorectal cancer were also present in matched primary tumor samples. This included all 12 neoantigens encoded by putative cancer driver genes, which are generally regarded as superior targets for adoptive cell therapy. The detection rate for other neoantigens, representing mutations without an established role in cancer biology, was 50% (13/26). Gene products encoding neoantigens detected in the primary tumors were not more likely to be clonal or broadly distributed among the analyzed metastatic lesions compared with those undetected in the primary tumors. Additionally, we found that mutations detected only in primary tumor samples did not elicit recognition by metastatic tumor-derived TIL but could elicit specific recognition by the autologous circulating memory T cells.

CONCLUSIONS

Our findings indicate that primary FFPE tumor-derived screening libraries could be used to discover most neoantigens present in metastatic tumors requiring treatment. Furthermore, this approach can reveal additional neoantigens not present in resected metastatic tumors, prompting further research to understand their clinical relevance as potential therapeutic targets.

Modifications to rhesus macaque TCR constant regions improve TCR cell surface expression

T cell immunotherapy success is dependent on effective levels of antigen receptor expressed at the surface of engineered cells. Efforts to optimize surface expression in T cell receptor (TCR)-based therapeutic approaches include optimization of cellular engineering methods and coding sequences, and reducing the likelihood of exogenous TCR α and β chains mispairing with the endogenous TCR chains. Approaches to promote correct human TCR chain pairing include constant region mutations to create an additional disulfide bond between the two chains, full murinization of the constant region of the TCR α and β sequences, and a minimal set of murine mutations to the TCR α and β constant regions. Preclinical animal models are valuable tools to optimize engineering designs and methods, and to evaluate the potential for off-target tissue injury. To further develop rhesus macaque models for TCR based cellular immunotherapy, we tested methods for improving cell surface expression of rhesus macaque TCR in rhesus macaque primary cells by generating five alternative TCRαβ constant region constructs in the context of a SIV Gag-specific TCR: 1. human codon optimized rhesus macaque (RH); 2. RH TCR with an additional disulfide linkage; 3. rhesus macaque constant sequences with minimal murine amino acid substitutions; 4. murinized constant sequences; and 5. murinized constant sequences with a portion of the exposed FG loop in the β constant sequence replaced with rhesus macaque sequence to reduce potential immunogencity. Murinization or mutation of a minimal set of amino acids to the corresponding murine sequence of the constant region resulted in the greatest increase in rhesus macaque TCR surface expression relative to wild type. All novel TCR constructs retained the ability to induce production of cytokines in response to cognate peptide antigen specific stimulation. This work can inform the design of TCRs selected for use in rhesus macaque models of TCR-based cellular immunotherapy.

Level of Expression of MHCI-Presented Neoepitopes Influences Tumor Rejection by Neoantigen-Specific CD8+ T Cells

Neoantigen-targeted therapy holds an array of benefits for cancer immunotherapy, but the identification of peptide targets with tumor rejection capacity remains a limitation. To better define the criteria dictating tumor rejection potential, we examined the capacity of high-magnitude T-cell responses induced toward several distinct neoantigen targets to regress MC38 tumors. Despite their demonstrated immunogenicity, vaccine-induced T-cell responses were unable to regress established MC38 tumors or prevent tumor engraftment in a prophylactic setting. Although unable to kill tumor cells, T cells showed robust killing capacity toward neoantigen peptide-loaded cells. Tumor-cell killing was rescued by saturation of target peptide-loaded MHCs on the cell surface. Overall, this study demonstrates a pivotal role for target protein expression levels in modulating the tumor rejection capacity of neoantigens. Thus, inclusion of this metric, in addition to immunogenicity analysis, may benefit antigen prediction techniques to ensure the full antitumor effect of cancer vaccines.

Infiltrating T lymphocytes and tumor microenvironment within cholangiocarcinoma: immune heterogeneity, intercellular communication, immune checkpoints

Cholangiocarcinoma is the second most common primary liver cancer, and its global incidence has increased in recent years. Radical surgical resection and systemic chemotherapy have traditionally been the standard treatment options. However, the complexity of cholangiocarcinoma subtypes often presents a challenge for early diagnosis. Additionally, high recurrence rates following radical treatment and resistance to late-stage chemotherapy limit the benefits for patients. Immunotherapy has emerged as an effective strategy for treating various types of cancer, and has shown efficacy when combined with chemotherapy for cholangiocarcinoma. Current immunotherapies targeting cholangiocarcinoma have predominantly focused on T lymphocytes within the tumor microenvironment, and new immunotherapies have yielded unsatisfactory results in clinical trials. Therefore, it is essential to achieve a comprehensive understanding of the unique tumor microenvironment of cholangiocarcinoma and the pivotal role of T lymphocytes within it. In this review, we describe the heterogeneous immune landscape and intercellular communication in cholangiocarcinoma and summarize the specific distribution of T lymphocytes. Finally, we review potential immune checkpoints in cholangiocarcinoma.

The global trends and distribution in tumor-infiltrating lymphocytes over the past 49 years: bibliometric and visualized analysis

Background

The body of research on tumor-infiltrating lymphocytes (TILs) is expanding rapidly; yet, a comprehensive analysis of related publications has been notably absent.

Objective

This study utilizes bibliometric methodologies to identify emerging research hotspots and to map the distribution of tumor-infiltrating lymphocyte research.

Methods

Literature from the Web of Science database was analyzed and visualized using VOSviewer, CiteSpace, Scimago Graphica, R-bibliometrix, and R packages.

Results

Research on tumor-infiltrating lymphocytes began in 1975 and has experienced significant growth, particularly after 2015. Leading contributors include the United States, the National Cancer Institute, the journal Cancer Immunology Immunotherapy, and researcher Steven A. Rosenberg. Other prominent contributors include China, the National Institutes of Health, researcher Roberto Salgado, and the Journal of Immunology. Prominent institutions in the USA and Europe occupy central roles within collaborative networks. Financial support plays a pivotal role in driving research advancements. Keyword clustering analysis reveals four primary knowledge domains: adoptive cell therapy; the prognostic value of TILs; PD-1/PD-L1 and TILs; and prognostic studies of TILs across various cancers. Keyword and reference analyses further indicate that "adoptive cell therapy," "the prognostic value of TILs," and "immune checkpoint inhibitors and TILs" are central themes in current and future research. Combination therapies; tumor neoantigens; gene editing; dominant population selection of TILs therapy; TILs in Tumor microenvironment; emerging predictive biomarkers; TILs in predicting the efficacy of neoadjuvant chemotherapy and immunotherapy; the relationship between TILs and PD-L1; TIL-based patient stratification; tertiary lymphoid structures; and TIL evaluation through digital pathology and artificial intelligence are identified as key areas of interest.

Conclusions

This analysis highlights the increasing academic focus on tumor-infiltrating lymphocyte research and identifies key recent themes in the field such as prognostic value of TILs, personalized treatments, and combination therapies.

Cell-Based Therapies in GI Cancers: Current Landscape and Future Directions

Cell-based therapies have become integral to the routine clinical management of hematologic malignancies. Tumor-infiltrating lymphocyte (TIL) therapy has demonstrated efficacy in immunogenic solid tumors, such as melanoma. However, in the GI field, evidence supporting the clinical success of cell-based therapies is still awaited. CLDN18.2, a key tight junction molecule in stomach epithelium, has emerged as a promising target for gastric cancer (GC) treatment. Because of its lineage-specific expression, significant efforts have been made to develop chimeric antigen receptor T-cell (CAR-T) therapies targeting CLDN18.2. These therapies have shown encouraging tumor shrinkage in patients with heavily pretreated GC. However, durable responses remain uncommon. CAR-T exhaustion driven by immune-suppressive cells in the tumor microenvironment, along with the heterogeneous expression of target molecules, poses significant challenges. In addition, managing on-target, off-tumor toxicities remains a critical issue in therapies targeting tissue-associated antigens. Next-generation CARs are expected to address these resistance mechanisms. Furthermore, adoptive macrophage and natural killer cell therapies hold promise for not only their efficacy but also for the ease off-the-shelf production. Advanced neoantigen prediction and identification of optimal T-cell activation targets could facilitate the clinical application of TIL and T-cell receptor-T therapies in GI cancers. Cell-based therapies might have the potential to transform the treatment landscape for GI cancers.

Circulating Immune Cells Predict Prognosis and Clinical Response to Chemotherapy in Cholangiocarcinoma

BACKGROUND

The immune system is linked to the prognosis and response to treatment of patients with cancer. However, the clinical implication of peripheral blood immune cells in cholangiocarcinoma (CCA) remains vague. Thus, we aimed to assess whether peripheral circulating immune cells could be used as an indicator for prognosis and chemotherapeutic efficacy in CCA.

METHODS

The distributions of immune subsets were analyzed in peripheral blood samples from 141 patients with CCA and 131 healthy volunteers by using flow cytometry. The variation in the subset distribution in the two groups and the relationship between clinicopathological features and the subpopulations were investigated. Meanwhile, we assessed the implications of lymphocyte subsets as predictors of chemotherapy outcomes and overall survival (OS).

RESULTS

The proportion of total lymphocytes decreased, while the percentages of activated T cells as well as CD4+CD25+ regulatory T cells (Tregs) increased in CCA. Notably, lymphocyte proportion decreased in patients with regional lymph node (N) (p=0.016) and distant metastasis (M) (p= 0.001). Furthermore, our study showed that peripheral blood lymphocyte subsets were significantly correlated with chemotherapy efficacy, with increased proportions of CD3+ cells (p=0.021) and CD4+ cells (p=0.016) in the effective group. Finally, the Kaplan-Meier analysis indicated that patients with high natural killer (NK) cell proportion might have prolonged OS (p = 0.028).

CONCLUSION

The relationship between circulating immune cells with prognosis and chemotherapy response in patients with CCA highlights their potential application as an indicator of CCA prognosis and stratification of chemotherapy response.

Clinical trials, challenges, and changes in TCR-based therapeutics for hematologic malignancies

INTRODUCTION

T cells engineered to express antigen-specific T cell receptors (TCR; TCR-T) are a promising class of immunotherapeutic for patients with hematologic malignancies. Like chimeric antigen receptor-engineered T cells (CAR-T), TCR-T are cell products with defined specificity and composition. Unlike CAR-T, TCR-T can recognize targets arising both from intracellular and cell surface proteins and leverage the sensitivity of natural TCR signaling machinery. A growing number of TCR-T targeting various antigens in different hematologic malignancies are in early-phase clinical trials, and more are in preclinical development.

AREAS COVERED

This review covers results from early-phase TCR-T clinical trials for hematologic malignancies. Challenges in the field are reviewed, including identifying optimal targets, engaging CD4+ help for CD8+ T cells, and overcoming tumor-induced suppression; recent innovations to overcome these challenges are also highlighted.

EXPERT OPINION

In the future, TCR-T's promise for hematologic malignancies will be borne out in later-phase clinical trials and approvals for clinical use. Improved antigen discovery methods will help build the toolbox of targets needed for broadly applicable TCR-T. Rationally designed TCR-T modifications including incorporation of accessory receptors and gene editing will enhance TCR-T function. New hybrid receptors combining features of TCR and CAR will enter the clinic.

HLA class II neoantigen presentation for CD4+ T cell surveillance in HLA class II-negative colorectal cancer

Neoantigen-reactive CD4+ T cells play a key role in the anti-tumor immune response. However, the majority of epithelial tumors are negative for HLA class II (HLA-II) surface expression, and less is known about the processing of HLA-II antigens. Here, we directly identified naturally presented HLA-II neoantigens in HLA-II negative colorectal cancer (CRC) tissue using a proteogenomic approach. The neoantigens were immunogenic and induced patient CD4+ T cells with a Th1-like memory phenotype that produced IFN-γ, IL2 and TNF-α. Multiplex immunohistochemistry (IHC) demonstrated an interaction between Th cells and HLA-II-positive antigen-presenting cells (APCs) at the invasive margin and within the tertiary lymphoid structures (TLS). In our CRC cohort, the density of stromal APCs was associated with HLA-II antigen presentation in the tumor microenvironment (TME), and the number of TLS was positively correlated with the number of somatic mutations in the tumors. These results demonstrate the presence of neoantigen-specific CD4+ surveillance in HLA-II-negative CRC and suggest a potential role for macrophages and dendritic cells (DCs) at the invasive margin and in TLS for antigen presentation. Stromal APCs in the TME can potentially be used as a source for HLA-II neoantigen identification.

Relevance of mutation-derived neoantigens and non-classical antigens for anticancer therapies

Efficacy of cancer immunotherapies relies on correct recognition of tumor antigens by lymphocytes, eliciting thus functional responses capable of eliminating tumor cells. Therefore, important efforts have been carried out in antigen identification, with the aim of understanding mechanisms of response to immunotherapy and to design safer and more efficient strategies. In addition to classical tumor-associated antigens identified during the last decades, implementation of next-generation sequencing methodologies is enabling the identification of neoantigens (neoAgs) arising from mutations, leading to the development of new neoAg-directed therapies. Moreover, there are numerous non-classical tumor antigens originated from other sources and identified by new methodologies. Here, we review the relevance of neoAgs in different immunotherapies and the results obtained by applying neoAg-based strategies. In addition, the different types of non-classical tumor antigens and the best approaches for their identification are described. This will help to increase the spectrum of targetable molecules useful in cancer immunotherapies.

Recent progress in mRNA cancer vaccines

The research and development of messenger RNA (mRNA) cancer vaccines have gradually overcome numerous challenges through the application of personalized cancer antigens, structural optimization of mRNA, and the development of alternative RNA-based vectors and efficient targeted delivery vectors. Clinical trials are currently underway for various cancer vaccines that encode tumor-associated antigens (TAAs), tumor-specific antigens (TSAs), or immunomodulators. In this paper, we summarize the optimization of mRNA and the emergence of RNA-based expression vectors in cancer vaccines. We begin by reviewing the advancement and utilization of state-of-the-art targeted lipid nanoparticles (LNPs), followed by presenting the primary classifications and clinical applications of mRNA cancer vaccines. Collectively, mRNA vaccines are emerging as a central focus in cancer immunotherapy, offering the potential to address multiple challenges in cancer treatment, either as standalone therapies or in combination with current cancer treatments.

Recombinant ClearColi™-derived outer membrane vesicles as an effective carrier for development of neoepitope-based vaccine candidate against colon carcinoma

BACKGROUND

Colorectal carcinoma (CRC) is the third most common cancer worldwide, with high clonal heterogeneity due to somatic mutations. Poly neoepitope vaccines can inhibit the tumor's escape from the immune system. However, they have rapid clearance and low immunogenicity. Bacteria-derived recombinant outer membrane vesicles (OMVs) have gained increased attention as ideal cancer vaccine candidates due to their unique adjuvant properties and ability to carry antigens. Herein, the benefits of OMV-based and polyneoepitope-based vaccines were combined to obtain a functional individualized cancer vaccine.

METHODS

OMVs and rOMVs displaying CT26 polytopes were isolated from ClearColi™ and recombinant ClearColi™ containing pET-22b (ClyA-CT26 polytope) by the AS (70 %) + UDF method. BALB/c mice were immunized with OMVs (40 µg) and rOMVs (20 and 40 µg) and subcutaneously challenged with CT26 cells. Then, IgG1 and IgG2a antibodies specific for CT26 M90 and CT26 polytope, the stimulated IFN-γ, TNF-α, and IL-10 cytokines and the stimulated CTL responses by measuring granzyme B were evaluated. To investigate whether pooled sera and pooled splenocytes are indicators of individual responses, pooled and individual methods for determining the elicited immunity were compared. Additionally, the ability of OMVs and rOMVs (20 and 40 µg) to prevent tumor growth against the CT26 challenge was investigated.

RESULTS

Immunization with rOMVs displaying CT26 polytopes induced a higher titer of CT26 polytope- and CT26 M90 peptide-specific IgG2a than IgG1 antibodies in a dose-dependent manner, thus directing immunity to Th1. The antibody responses determined by pooled sera can be used as indicators of individual responses. In addition, both OMVs and rOMVs displaying CT26 polytopes could induce tumor-suppressing cytokines (IFN-γ and TNF-α). The ability of rOMVs displaying CT26 polytopes to induce these cytokines was higher than OMVs in a dose-dependent way. The results of the granzyme B assay were also in agreement with the cytokine assay. The survival of mice after the CT26 challenge was 100 % in the OMVs and rOMVs groups, and inhibition of tumor growth was significantly higher by rOMVs (40 µg) compared to OMVs.

CONCLUSION

The bioengineered OMVs displaying CT26 neoepitopes have the potential for the development of personalized tumor vaccines. Our results can provide new insights for developing rOMV-based vaccines displaying polytopes against diseases containing highly variable antigens.

Preclinical model for evaluating human TCRs against chimeric syngeneic tumors

BACKGROUND

The adoptive cell transfer (ACT) of T cell receptor (TCR)-engineered T cells targeting the HLA-A2-restricted epitope NY-ESO-1157-165 (A2/NY) has yielded important clinical responses against several cancers. A variety of approaches are being taken to augment tumor control by ACT including TCR affinity-optimization and T-cell coengineering strategies to address the suppressive tumor microenvironment (TME). Most TCRs of clinical interest are evaluated in immunocompromised mice to enable human T-cell engraftment and do not recapitulate the dynamic interplay that occurs with endogenous immunity in a treated patient. A variety of humanized mouse models have been described but they have limitations in immune reconstitution and are technically challenging to implement. Here, we have developed a chimeric syngeneic tumor model in which A2Kb transgenic C57BL/6 mice are engrafted with B16 expressing A2Kb:NY as a single chain trimer (SCT) and treated by ACT with murine T cells expressing A2/NY TCRs comprising human variable fused to mouse constant regions.

METHODS

We compared the function of a supraphysiological affinity A2/NY TCR (wtc51m), a computationally designed TCR in an optimal affinity range (DMβ), and a near non-binding TCR (V49I), engineered in both primary human and murine T cells by lentiviral and retroviral transduction, respectively. We evaluated a variety of strategies to stably express A2Kb:NY on the surface of mouse tumor cell lines including B16 melanoma, ultimately achieving success with an SCT comprising human β2m fused by GS linkers to both the NY-peptide and to α1 of the HLA complex. ACT studies were performed in B16-A2Kb:NY tumor-bearing, non-preconditioned immune-competent HLA-A*0201/H-2Kb (A2Kb) transgenic C57BL/6 mice and tumors characterized post-transfer.

RESULTS

We observed significantly improved function of DMβ-T cells as well as superior infiltration and tumor control upon ACT as compared to the control TCR-T cells. Moreover, with our chimeric syngeneic tumor model, we were able to track dynamic and favorable changes in the TME upon DMβ-T cell transfer.

CONCLUSIONS

We have developed a robust, simple, and inexpensive preclinical strategy for evaluating human TCRs in the context of a fully competent murine immune system that can aid in the development of coengineered TCR-T cells and combination treatments translated to the clinic.

CAR-T cell therapy for the treatment of adult high-grade gliomas

Treatment for malignant primary brain tumors, including glioblastoma, remains a significant challenge despite advances in therapy. CAR-T cell immunotherapy represents a promising alternative to conventional treatments. This review discusses the landscape of clinical trials for CAR-T cell therapy targeting brain tumors, highlighting key advancements like novel target antigens and combinatorial strategies designed to address tumor heterogeneity and immunosuppression, with the goal of improving outcomes for patients with these aggressive cancers.

Genetically Engineered T Cells and Recombinant Antibodies to Target Intracellular Neoantigens: Current Status and Future Directions

Recombinant antibodies and, more recently, T cell receptor (TCR)-engineered T cell therapies represent two immunological strategies that have come to the forefront of clinical interest for targeting intracellular neoantigens in benign and malignant diseases. T cell-based therapies targeting neoantigens use T cells expressing a recombinant complete TCR (TCR-T cell), a chimeric antigen receptor (CAR) with the variable domains of a neoepitope-reactive TCR as a binding domain (TCR-CAR-T cell) or a TCR-like antibody as a binding domain (TCR-like CAR-T cell). Furthermore, the synthetic T cell receptor and antigen receptor (STAR) and heterodimeric TCR-like CAR (T-CAR) are designed as a double-chain TCRαβ-based receptor with variable regions of immunoglobulin heavy and light chains (VH and VL) fused to TCR-Cα and TCR-Cβ, respectively, resulting in TCR signaling. In contrast to the use of recombinant T cells, anti-neopeptide MHC (pMHC) antibodies and intrabodies neutralizing intracellular neoantigens can be more easily applied to cancer patients. However, different limitations should be considered, such as the loss of neoantigens, the modification of antigen peptide presentation, tumor heterogenicity, and the immunosuppressive activity of the tumor environment. The simultaneous application of immune checkpoint blocking antibodies and of CRISPR/Cas9-based genome editing tools to engineer different recombinant T cells with enhanced therapeutic functions could make T cell therapies more efficient and could pave the way for its routine clinical application.

Retrospective Analysis of HLA Class II-Restricted Neoantigen Peptide-Pulsed Dendritic Cell Vaccine for Breast Cancer

Background/Objectives: Neoantigens have attracted attention as ideal therapeutic targets for anti-tumour immunotherapy because the T cells that respond to neoantigens are not affected by central immune tolerance. Recent findings have revealed that the activation of CD4-positive T cells plays a central role in antitumor immunity, and thus targeting human leukocyte antigen (HLA) class II-restricted neoantigens, which are targets of CD4-positive T cells, is of significance. However, there are very few detailed reports of neoantigen vaccine therapies that use an HLA class II-restricted long peptide. In the present study, we retrospectively analysed the ability of HLA class II-restricted neoantigen-pulsed dendritic cell vaccines to induce immune response in five breast cancer patients. Methods: We performed whole exome and RNA sequencing of breast cancer tissues and neoantigen prediction using an in silico pipeline. We then administered dendritic cells pulsed with synthesized an HLA class II-restricted long peptide containing an epitope with high affinity to HLA class I in the lymph node. Results: ELISPOT analysis confirmed that a T-cell response specific for the HLA class II-restricted neoantigen was induced in all cases. TCR repertoire analysis of peripheral blood mononuclear cells before and after treatment in three patients showed increases of specific T-cell clones in two of the three patients. Importantly, no recurrence was observed in all patients. Conclusions: Our analysis demonstrated the immunological efficacy of the HLA class II-restricted neoantigen peptide dendritic cell vaccine against breast cancer and provides useful information for the development of neoantigen vaccine therapy for breast cancer.

Novel tri-specific T-cell engager targeting IL-13Rα2 and EGFRvIII provides long-term survival in heterogeneous GBM challenge and promotes antitumor cytotoxicity with patient immune cells

BACKGROUND

Glioblastoma multiforme (GBM) is known for its high antigenic heterogeneity, which undermines the effectiveness of monospecific immunotherapies. Multivalent immunotherapeutic strategies that target multiple tumor antigens simultaneously could enhance clinical outcomes by preventing antigen-driven tumor escape mechanisms.

METHODS

We describe novel trivalent antibodies, DNA-encoded tri-specific T-cell engagers (DTriTEs), targeting two GBM antigens, epidermal growth factor receptor variant III (EGFRvIII) and IL-13Rα2, and engaging T cells through CD3. We engineered three DTriTE constructs, each with a unique arrangement of the antigen-binding fragments within a single-chain sequence. We assessed the binding efficiency and cytotoxic activity of these DTriTEs in vitro on target cells expressing relevant antigens. In vivo efficacy was tested in immunocompromised mice, including a longitudinal expression study post-administration and a survival analysis in an NOD scid gamma (NSG)-K mouse model under a heterogeneous tumor burden. RNA sequencing of DTriTE-activated T cells was employed to identify the molecular pathways influenced by the treatment. The antitumor cytotoxicity of patient-derived immune cells was evaluated following stimulation by DTriTE to assess its potential effectiveness in a clinical setting.

RESULTS

All DTriTE constructs demonstrated strong binding to EGFRvIII and IL-13Rα2-expressing cells, induced significant T cell-mediated cytotoxicity, and enhanced cytokine production (interferon-γ, tumor necrosis factor (TNF)-α, and interleukin(IL)-2). The lead construct, DT2035, sustained expression for over 105 days in vivo and exhibited elimination of tumor burden in a heterogeneous intracranial GBM model, outperforming monospecific antibody controls. In extended survival studies using the NSG-K model, DT2035 achieved a 67% survival rate over 120 days. RNA sequencing of DTriTE-activated T cells showed that DT2035 enhances genes linked to cytotoxicity, proliferation, and immunomodulation, reflecting potent immune activation. Finally, DT2035 effectively induced target-specific cytotoxicity in post-treatment peripheral blood mononuclear cells from patients with GBM, highlighting its potential for clinical effectiveness.

CONCLUSIONS

DTriTEs exhibit potent anti-tumor effects and durable in vivo activity, offering promising therapeutic potential against GBM. These findings support further development of such multivalent therapeutic strategies to improve treatment outcomes in GBM and potentially other antigenically heterogeneous tumors. The opportunity to advance such important therapies either through biologic delivery or direct in vivo nucleic acid production is compelling.