T-Cell Therapy for Lymphoma Using Nonengineered Multiantigen-Targeted T Cells Is Safe and Produces Durable Clinical Effects

Photothermal Prussian blue nanoparticles generate potent multi-targeted tumor-specific T cells as an adoptive cell therapy

Prussian blue nanoparticle-based photothermal therapy (PBNP-PTT) is an effective tumor treatment capable of eliciting an antitumor immune response. Motivated by the ability of PBNP-PTT to potentiate endogenous immune responses, we recently demonstrated that PBNP-PTT could be used ex vivo to generate tumor-specific T cells against glioblastoma (GBM) cell lines as an adoptive T cell therapy (ATCT). In this study, we further developed this promising T cell development platform. First, we assessed the phenotype and function of T cells generated using PBNP-PTT. We observed that PBNP-PTT facilitated CD8+ T cell expansion from healthy donor PBMCs that secreted IFNγ and TNFα and upregulated CD107a in response to engagement with target U87 cells, suggesting specific antitumor T cell activation and degranulation. Further, CD8+ effector and effector memory T cell populations significantly expanded after co-culture with U87 cells, consistent with tumor-specific effector responses. In orthotopically implanted U87 GBM tumors in vivo, PBNP-PTT-derived T cells effectively reduced U87 tumor growth and generated long-term survival in >80% of tumor-bearing mice by Day 100, compared to 0% of mice treated with PBS, non-specific T cells, or T cells expanded from lysed U87 cells, demonstrating an enhanced antitumor efficacy of this ATCT platform. Finally, we tested the generalizability of our approach by generating T cells targeting medulloblastoma (D556), breast cancer (MDA-MB-231), neuroblastoma (SH-SY5Y), and acute monocytic leukemia (THP-1) cell lines. The resulting T cells secreted IFNγ and exerted increased tumor-specific cytolytic function relative to controls, demonstrating the versatility of PBNP-PTT in generating tumor-specific T cells for ATCT.

Targeting IDH2R140Q and other neoantigens in acute myeloid leukemia

ABSTRACT

For patients with high-risk or relapsed/refractory acute myeloid leukemia (AML), allogeneic stem cell transplantation (allo-HSCT) and the graft-versus-leukemia effect mediated by donor T cells, offer the best chance of long-term remission. However, the concurrent transfer of alloreactive T cells can lead to graft-versus-host disease that is associated with transplant-related morbidity and mortality. Furthermore, ∼60% of patients will ultimately relapse after allo-HSCT, thus, underscoring the need for novel therapeutic strategies that are safe and effective. In this study, we explored the feasibility of immunotherapeutically targeting neoantigens, which arise from recurrent nonsynonymous mutations in AML and thus represent attractive targets because they are exclusively present on the tumor. Focusing on 14 recurrent driver mutations across 8 genes found in AML, we investigated their immunogenicity in 23 individuals with diverse HLA profiles. We demonstrate the immunogenicity of AML neoantigens, with 17 of 23 (74%) reactive donors screened mounting a response. The most immunodominant neoantigens were IDH2R140Q (n = 11 of 17 responders), IDH1R132H (n = 7 of 17), and FLT3D835Y (n = 6 of 17). In-depth studies of IDH2R140Q-specific T cells revealed the presence of reactive CD4+ and CD8+ T cells capable of recognizing distinct mutant-specific epitopes restricted to different HLA alleles. These neo-T cells could selectively recognize and kill HLA-matched AML targets endogenously expressing IDH2R140Q both in vitro and in vivo. Overall, our findings support the clinical translation of neoantigen-specific T cells to treat relapsed/refractory AML.

Cancer testis antigens: Emerging therapeutic targets leveraging genomic instability in cancer

Cancer care has witnessed remarkable progress in recent decades, with a wide array of targeted therapies and immune-based interventions being added to the traditional treatment options such as surgery, chemotherapy, and radiotherapy. However, despite these advancements, the challenge of achieving high tumor specificity while minimizing adverse side effects continues to dictate the benefit-risk balance of cancer therapy, guiding clinical decision making. As such, the targeting of cancer testis antigens (CTAs) offers exciting new opportunities for therapeutic intervention of cancer since they display highly tumor specific expression patterns, natural immunogenicity and play pivotal roles in various biological processes that are critical for tumor cellular fitness. In this review, we delve deeper into how CTAs contribute to the regulation and maintenance of genomic integrity in cancer, and how these mechanisms can be exploited to specifically target and eradicate tumor cells. We review the current clinical trials targeting aforementioned CTAs, highlight promising pre-clinical data and discuss current challenges and future perspectives for future development of CTA-based strategies that exploit tumor genomic instability.

Classic Hodgkin Lymphoma in Adolescents and Young Adults

Hodgkin lymphoma (HL) represents one of the more common cancers occurring in adolescent and young adults (AYAs) age 15-39 years. Despite a generally high cure rate, age-related differences in HL biology and the optimal therapeutic approaches including supportive care and risks for long-term adverse effects in the AYA population remain understudied. After an overview of HL epidemiology and biology in the AYA population, this review will cover frontline pediatric and adult treatment approaches. Recently completed and ongoing studies will foster harmonization of risk group definition and trial eligibility criteria across the AYA spectrum, enabling more rapid progress. In addition to treatment approaches, an evolving holistic care approach to AYA HL will result in enhanced understanding of unique challenges, and continued improved short- and long-term outcome for these patients.

The power and the promise of CAR-mediated cell immunotherapy for clinical application in pancreatic cancer

BACKGROUND

Pancreatic cancer, referred to as the "monarch of malignancies," is a neoplastic growth mostly arising from the epithelial cells of the pancreatic duct and acinar cells. This particular neoplasm has a highly unfavorable prognosis due to its marked malignancy, inconspicuous initial manifestation, challenging early detection, rapid advancement, and limited survival duration. Cellular immunotherapy is the ex vivo culture and expansion of immune effector cells, granting them the capacity to selectively target malignant cells using specialized techniques. Subsequently, these modified cells are reintroduced into the patient's organism with the purpose of eradicating tumor cells and providing therapeutic intervention for cancer.

PRESENT SITUATION

Presently, the primary cellular therapeutic modalities employed in the treatment of pancreatic cancer encompass CAR T-cell therapy, TCR T-cell therapy, NK-cell therapy, and CAR NK-cell therapy.

AIM OF REVIEW

This review provides a concise overview of the mechanisms and primary targets associated with various cell therapies. Additionally, we will explore the prospective outlook of cell therapy in the context of treating pancreatic cancer.

The optimal management of relapsed and refractory Hodgkin lymphoma: post-brentuximab and checkpoint inhibitor failure

The treatment landscape of classical Hodgkin lymphoma has changed dramatically over the past decade. Relapsed and refractory mainstay therapeutics such as brentuximab vedotin (BV) and checkpoint inhibitors (CPIs) are being moved to earlier lines of therapy. However, the treatment of patients who progress after BV and CPI remains a challenge. Allogeneic stem cell transplantation still plays an important role in this patient population as the only current treatment approach with curative potential. Unfortunately, not all patients are transplant candidates, and many will still relapse afterward. Cytotoxic chemotherapy and radiation may be used for symptom palliation or as a bridge to transplant. Targeted therapies, including the antibody drug conjugate, camidanlumab tesirine, and transcriptional agents such mammalian target of rapamycin and histone deacetylase inhibitors have shown some potential in patients with refractory disease. In addition, combination therapies with CPIs and novel agents may help overcome resistance to therapy. Clinical trials with cellular therapies, including chimeric antigen receptor T cells targeting CD30 and allogeneic natural killer cells combined with AFM13, a CD30/CD16a-bispecific antibody, have shown promising results. The availability of more therapeutic options for this patient population is eagerly awaited.

CAR-T Cell Therapy for Classical Hodgkin Lymphoma

Classical Hodgkin lymphoma (cHL) is a malignancy characterized by the presence of Hodgkin and Reed-Sternberg (HRS) cells within a complex tumor microenvironment (TME). Despite advances in conventional therapies, a subset of cHL patients experience relapse or refractory disease, necessitating the exploration of novel treatment strategies. Chimeric antigen receptor T cell (CAR-T cell) therapy has emerged as a promising approach for the management of cHL, harnessing the power of genetically modified T cells to recognize and eliminate tumor cells. In this article, we provide an overview of the pathogenesis of cHL, highlighting the key molecular and cellular mechanisms involved. Additionally, we discuss the rationale for the development of CAR-T cell therapy in cHL, focusing on the identification of suitable targets on HRS cells (such as CD30, CD123, LMP1, and LMP2A), clonotypic lymphoma initiating B cells (CD19, CD20), and cells within the TME (CD123, CD19, CD20) for CAR-T cell design. Furthermore, we explore various strategies employed to enhance the efficacy and safety of CAR-T cell therapies in the treatment of cHL. Finally, we present an overview of the results obtained from clinical trials evaluating the efficacy of CAR-T cell therapies in cHL, highlighting their potential as a promising therapeutic option. Collectively, this article provides a comprehensive review of the current understanding of cHL pathogenesis and the rationale for CAR-T cell therapy development, offering insights into the future directions of this rapidly evolving field.

PRAME Expression: A Target for Cancer Immunotherapy and a Prognostic Factor in Uveal Melanoma

Purpose

Uveal melanoma (UM) is a rare disease with a high mortality, and new therapeutic options are being investigated. Preferentially Expressed Antigen in Melanoma (PRAME) is a cancer testis antigen, expressed in the testis, but also in cancers, including uveal melanoma. PRAME is considered a target for immune therapy in several cancers, and PRAME-specific T cell clones have been shown to kill UM cells.

Methods

We studied the literature on PRAME expression in hematological and solid malignancies, including UM, and its role as a target for immunotherapy. The distribution of tumor features was compared between PRAME-high and PRAME-low UM in a 64-patient cohort from the Leiden University Medical Center (LUMC) and in the Cancer Genome Atlas (TCGA) cohort of 80 cases and differential gene expression analysis was performed in the LUMC cohort.

Results

PRAME is expressed in many malignancies, it is frequently associated with a negative prognosis, and can be the target of T cell receptor (TCR)-transduced T cells, a promising treatment option with high avidity and safety. In UM, PRAME is expressed in 26% to 45% of cases and is correlated with a worse prognosis. In the LUMC and the TCGA cohorts, high PRAME expression was associated with larger diameter, higher Tumor-Node-Metastasis (TNM) stage, more frequent gain of chromosome 8q, and an inflammatory phenotype.

Conclusions

We confirm that PRAME is associated with poor prognosis in UM and has a strong connection with extra copies of 8q. We show that PRAME-specific immunotherapy in an adjuvant setting is promising in treatment of malignancies, including UM.

Multi-tiered approach to detect autoimmune cross-reactivity of therapeutic T cell receptors

T cell receptor (TCR)-engineered T cell therapy using high-affinity TCRs is a promising treatment modality for cancer. Discovery of high-affinity TCRs especially against self-antigens can require approaches that circumvent central tolerance, which may increase the risk of cross-reactivity. Despite the potential for toxicity, no standardized approach to screen cross-reactivity has been established in the context of preclinical safety evaluation. Here, we describe a practical framework to prospectively detect clinically prohibitive cross-reactivity of therapeutic TCR candidates. Cross-reactivity screening consisted of multifaceted series of assays including assessment of p-MHC tetramer binding, cell line recognition, and reactivity against candidate peptide libraries. Peptide libraries were generated using conventional contact residue motif-guided search, amino acid substitution matrix-based search unguided by motif information, and combinatorial peptide library scan-guided search. We demonstrate the additive nature of a layered approach, which efficiently identifies unsafe cross-reactivity including one undetected by conventional motif-guided search. These findings have important implications for the safe development of TCR-based therapies.

Naive T cells inhibit the outgrowth of intractable antigen-activated memory T cells: implications for T-cell immunotherapy

BACKGROUND

The wider application of T cells targeting viral tumor-antigens via their native receptors is hampered by the failure to expand potent tumor-specific T cells from patients. Here, we examine reasons for and solutions to this failure, taking as our model the preparation of Epstein-Barr virus (EBV)-specific T cells (EBVSTs) for the treatment of EBV-positive lymphoma. EBVSTs could not be manufactured from almost one-third of patients, either because they failed to expand, or they expanded, but lacked EBV specificity. We identified an underlying cause of this problem and established a clinically feasible approach to overcome it.

METHODS

CD45RO+CD45RA- memory compartment residing antigen-specific T cells were enriched by depleting CD45RA positive (+) peripheral blood mononuclear cells (PBMCs) that include naïve T cells, among other subsets, prior to EBV antigen stimulation. We then compared the phenotype, specificity, function and T-cell receptor (TCR) Vβ repertoire of EBVSTs expanded from unfractionated whole (W)-PBMCs and CD45RA-depleted (RAD)-PBMCs on day 16. To identify the CD45RA component that inhibited EBVST outgrowth, isolated CD45RA+ subsets were added back to RAD-PBMCs followed by expansion and characterization. The in vivo potency of W-EBVSTs and RAD-EBVSTs was compared in a murine xenograft model of autologous EBV+ lymphoma.

RESULTS

Depletion of CD45RA+ PBMCs before antigen stimulation increased EBVST expansion, antigen-specificity and potency in vitro and in vivo. TCR sequencing revealed a selective outgrowth in RAD-EBVSTs of clonotypes that expanded poorly in W-EBVSTs. Inhibition of antigen-stimulated T cells by CD45RA+ PBMCs could be reproduced only by the naïve T-cell fraction, while CD45RA+ regulatory T cells, natural killer cells, stem cell memory and effector memory subsets lacked inhibitory activity. Crucially, CD45RA depletion of PBMCs from patients with lymphoma enabled the outgrowth of EBVSTs that failed to expand from W-PBMCs. This enhanced specificity extended to T cells specific for other viruses.

CONCLUSION

Our findings suggest that naïve T cells inhibit the outgrowth of antigen-stimulated memory T cells, highlighting the profound effects of intra-T-cell subset interactions. Having overcome our inability to generate EBVSTs from many patients with lymphoma, we have introduced CD45RA depletion into three clinical trials: NCT01555892 and NCT04288726 using autologous and allogeneic EBVSTs to treat lymphoma and NCT04013802 using multivirus-specific T cells to treat viral infections after hematopoietic stem cell transplantation.

A perspective of immunotherapy for acute myeloid leukemia: Current advances and challenges

During the last decade, the underlying pathogenic mechanisms of acute myeloid leukemia (AML) have been the subject of extensive study which has considerably increased our understanding of the disease. However, both resistance to chemotherapy and disease relapse remain the principal obstacles to successful treatment. Because of acute and chronic undesirable effects frequently associated with conventional cytotoxic chemotherapy, consolidation chemotherapy is not feasible, especially for elderly patients, which has attracted a growing body of research to attempt to tackle this problem. Immunotherapies for acute myeloid leukemia, including immune checkpoint inhibitors, monoclonal antibodies, dendritic cell (DC) vaccines, together with T-cell therapy based on engineered antigen receptor have been developed recently. Our review presents the recent progress in immunotherapy for the treatment of AML and discusses effective therapies that have the most potential and major challenges.

Cancer Immunotherapy Beyond Checkpoint Blockade: JACC: CardioOncology State-of-the-Art Review

Avoidance of immune destruction is recognized as one of the hallmarks of cancer development. Although first predicted as a potential antitumor treatment modality more than 50 years ago, the widespread clinical use of cancer immunotherapies has only recently become a reality. Cancer immunotherapy works by reactivation of a stalled pre-existing immune response or by eliciting a de novo immune response, and its toolkit comprises antibodies, vaccines, cytokines, and cell-based therapies. The treatment paradigm in some malignancies has completely changed over the past 10 to 15 years. Massive efforts in preclinical development have led to a surge of clinical trials testing innovative therapeutic approaches as monotherapy and, increasingly, in combination. Here we provide an overview of approved and emerging antitumor immune therapies, focusing on the rich landscape of therapeutic approaches beyond those that block the canonical PD-1/PD-L1 and CTLA-4 axes and placing them in the context of the latest understanding of tumor immunology.

Immune responses against shared antigens are common in esophago-gastric cancer and can be enhanced using CD40-activated B cells

BACKGROUND

Specific immune response is a hallmark of cancer immunotherapy and shared tumor-associated antigens (TAAs) are important targets. Recent advances using combined cellular therapy against multiple TAAs renewed the interest in this class of antigens. Our study aims to determine the role of TAAs in esophago-gastric adenocarcinoma (EGA).

METHODS

RNA expression was assessed by NanoString in tumor samples of 41 treatment-naïve EGA patients. Endogenous T cell and antibody responses against the 10 most relevant TAAs were determined by FluoroSpot and protein-bound bead assays. Digital image analysis was used to evaluate the correlation of TAAs and T-cell abundance. T-cell receptor sequencing, in vitro expansion with autologous CD40-activated B cells (CD40Bs) and in vitro cytotoxicity assays were applied to determine specific expansion, clonality and cytotoxic activity of expanded T cells.

RESULTS

68.3% of patients expressed ≥5 TAAs simultaneously with coregulated clusters, which were similar to data from The Cancer Genome Atlas (n=505). Endogenous cellular or humoral responses against ≥1 TAA were detectable in 75.0% and 53.7% of patients, respectively. We found a correlation of T-cell abundance and the expression of TAAs and genes related to antigen presentation. TAA-specific T-cell responses were polyclonal, could be induced or enhanced using autologous CD40Bs and were cytotoxic in vitro. Despite the frequent expression of TAAs co-occurrence with immune responses was rare.

CONCLUSIONS

We identified the most relevant TAAs in EGA for monitoring of clinical trials and as therapeutic targets. Antigen-escape rather than missing immune response should be considered as mechanism underlying immunotherapy resistance of EGA.

T-Cell-Based Cellular Immunotherapy of Multiple Myeloma: Current Developments

Simple Summary

Over the past two decades, there has been significant progress in the treatment of multiple myeloma. Starting with the approval of bortezomib and lenalidomide, followed by newer agents in the same classes, monoclonal antibodies, and most recently idecabtagene vicleucel and ciltacabtagene autoleucel, which are genetically engineered autologous T-cell-based therapies, our view of this disease has changed from incurable to controllable and potentially curable. In addition to multiple myeloma and B-cell lymphomas, T-cell-based therapies are also actively investigated in various types of hematological and non-hematological malignancies and are considered one of the most impactful evolutions in cancer therapeutics. This review aims to summarize existing data regarding the efficacy, toxicity, and management of unique adverse events in T-cell-based therapies that are both clinically available and under investigation. We will also address undergoing efforts to improve the survival outcomes of multiple myeloma patients through this treatment modality.

Abstract

T-cell-based cellular therapy was first approved in lymphoid malignancies (B-cell acute lymphoblastic leukemia and large B-cell lymphoma) and expanding its investigation and application both in hematological and non-hematological malignancies. Two anti-BCMA (B cell maturation antigen) CAR (Chimeric Antigen Receptor) T-cell therapies have been recently approved for relapsed and refractory multiple myeloma with excellent efficacy even in the heavily pre-treated patient population. This new therapeutic approach significantly changes our practice; however, there is still room for further investigation to optimize antigen receptor engineering, cell harvest/selection, treatment sequence, etc. They are also associated with unique adverse events, especially CRS (cytokine release syndrome) and ICANS (immune effector cell-associated neurotoxicity syndrome), which are not seen with other anti-myeloma therapies and require expertise for management and prevention. Other T-cell based therapies such as TCR (T Cell Receptor) engineered T-cells and non-genetically engineered adoptive T-cell transfers (Vγ9 Vδ2 T-cells and Marrow infiltrating lymphocytes) are also actively studied and worth attention. They can potentially overcome therapeutic challenges after the failure of CAR T-cell therapy through different mechanisms of action. This review aims to provide readers clinical data of T-cell-based therapies for multiple myeloma, management of unique toxicities and ongoing investigation in both clinical and pre-clinical settings.

Induced pluripotent stem cells display a distinct set of MHC I-associated peptides shared by human cancers

Previous reports showed that mouse vaccination with pluripotent stem cells (PSCs) induces durable anti-tumor immune responses via T cell recognition of some elusive oncofetal epitopes. We characterize the MHC I-associated peptide (MAP) repertoire of human induced PSCs (iPSCs) using proteogenomics. Our analyses reveal a set of 46 pluripotency-associated MAPs (paMAPs) absent from the transcriptome of normal tissues and adult stem cells but expressed in PSCs and multiple adult cancers. These paMAPs derive from coding and allegedly non-coding (48%) transcripts involved in pluripotency maintenance, and their expression in The Cancer Genome Atlas samples correlates with source gene hypomethylation and genomic aberrations common across cancer types. We find that several of these paMAPs were immunogenic. However, paMAP expression in tumors coincides with activation of pathways instrumental in immune evasion (WNT, TGF-β, and CDK4/6). We propose that currently available inhibitors of these pathways could synergize with immune targeting of paMAPs for the treatment of poorly differentiated cancers.

Immunotherapy of Neuroblastoma: Facts and Hopes

While the adoption of multimodal therapy including surgery, radiation, and aggressive combination chemotherapy has improved outcomes for many children with high-risk neuroblastoma, we appear to have reached a plateau in what can be achieved with cytotoxic therapies alone. Most children with cancer, including high-risk neuroblastoma, do not benefit from treatment with immune checkpoint inhibitors (ICI) that have revolutionized the treatment of many highly immunogenic adult solid tumors. This likely reflects the low tumor mutation burden as well as the downregulated MHC-I that characterizes most high-risk neuroblastomas. For these reasons, neuroblastoma represents an immunotherapeutic challenge that may be a model for the creation of effective immunotherapy for other "cold" tumors in children and adults that do not respond to ICI. The identification of strong expression of the disialoganglioside GD2 on the surface of nearly all neuroblastoma cells provided a target for immune recognition by anti-GD2 mAbs that recruit Fc receptor-expressing innate immune cells that mediate cytotoxicity or phagocytosis. Adoption of anti-GD2 antibodies into both upfront and relapse treatment protocols has dramatically increased survival rates and altered the landscape for children with high-risk neuroblastoma. This review describes how these approaches have been expanded to additional combinations and forms of immunotherapy that have already demonstrated clear clinical benefit. We also describe the efforts to identify additional immune targets for neuroblastoma. Finally, we summarize newer approaches being pursued that may well help both innate and adaptive immune cells, endogenous or genetically engineered, to more effectively destroy neuroblastoma cells, to better induce complete remission and prevent recurrence.

Multi-antigen-targeted T-cell therapy to treat patients with relapsed/refractory breast cancer

Purpose

Adoptively transferred, ex vivo expanded multi-antigen-targeted T cells (multiTAA-T) represent a new, potentially effective, and nontoxic therapeutic approach for patients with breast cancer (BC). In this first-in-human trial, we investigated the safety and clinical effects of administering multiTAA T cells targeting the tumor-expressed antigens, Survivin, NY-ESO-1, MAGE-A4, SSX2, and PRAME, to patients with relapsed/refractory/metastatic BC.

Materials and methods

MultiTAA T-cell products were generated from the peripheral blood of heavily pre-treated patients with metastatic or locally recurrent unresectable BC of all subtypes and infused at a fixed dose level of 2 × 107/m2. Patients received two infusions of cells 4 weeks apart and safety and clinical activity were determined. Cells were administered in an outpatient setting and without prior lymphodepleting chemotherapy.

Results

All patients had estrogen receptor/progesterone receptor positive BC, with one patient also having human epidermal growth factor receptor 2-positive. There were no treatment-related toxicities and the infusions were well tolerated. Of the 10 heavily pre-treated patients enrolled and infused with multiTAA T cells, nine had disease progression while one patient with 10 lines of prior therapies experienced prolonged (5 months) disease stabilization that was associated with the in vivo expansion and persistence of T cells directed against the targeted antigens. Furthermore, antigen spreading and the endogenous activation of T cells directed against a spectrum of non-targeted tumor antigens were observed in 7/10 patients post-multiTAA infusion.

Conclusion

MultiTAA T cells were well tolerated and induced disease stabilization in a patient with refractory BC. This was associated with in vivo T-cell expansion, persistence, and antigen spreading. Future directions of this approach may include additional strategies to enhance the therapeutic benefit of multiTAA T cells in patients with BC.

Kita-Kyushu Lung Cancer Antigen-1 (KK-LC-1): A Promising Cancer Testis Antigen

Cancer has always been a huge problem in the field of human health, and its early diagnosis and treatment are the key to solving this problem. Cancer testis antigens (CTAs) are a family of multifunctional proteins that are specifically expressed in male spermatozoa and tumor cells but not in healthy somatic cells. Studies have found that CTAs are involved in the occurrence and development of tumors, and some CTAs trigger immunogenicity, which suggests a possibility of tumor immunotherapy. The differential expression and function of CTAs in normal tissues and tumor cells can promote the screening of tumor markers and the development of new immunotherapies. This article introduces the expression of Kita-Kyushu lung cancer antigen-1 (KK-LC-1), a new member of the CTA family, in different types of tumors and its role in immunotherapy.

HydrAd: A Helper-Dependent Adenovirus Targeting Multiple Immune Pathways for Cancer Immunotherapy

Simple Summary

Solid tumors are highly immunosuppressive and develop multiple inhibitory mechanisms that must be targeted simultaneously for successful cancer immunotherapy. Adenoviral vectors are promising cancer gene therapy vectors due to their inherent ability to stimulate multiple immune pathways. Adenoviruses are well characterized, and their genomes are easily manipulated, allowing for therapeutic transgene expression. Oncolytic adenoviruses are engineered to replicate specifically in malignant cells, resulting in cancer cell lysis. However, oncolytic adenoviral vectors have limited transgene capacity. Helper-dependent adenoviral vectors have been developed with the capability of expressing multiple transgenes through removal of all viral coding sequences. We have developed a helper-dependent platform for cancer immunotherapy and demonstrate expression of up to four functional transgenes. This platform allows us to target tumors with specific inhibitory pathways using our library of immunomodulatory transgenes in a mix-and-match approach for a synchronized cancer immunotherapy strategy.

Abstract

For decades, Adenoviruses (Ads) have been staple cancer gene therapy vectors. Ads are highly immunogenic, making them effective adjuvants. These viruses have well characterized genomes, allowing for substantial modifications including capsid chimerism and therapeutic transgene insertion. Multiple generations of Ad vectors have been generated with reduced or enhanced immunogenicity, depending on their intended purpose, and with increased transgene capacity. The latest-generation Ad vector is the Helper-dependent Ad (HDAd), in which all viral coding sequences are removed from the genome, leaving only the cis-acting ITRs and packaging sequences, providing up to 34 kb of transgene capacity. Although HDAds are replication incompetent, their innate immunogenicity remains intact. Therefore, the HDAd is an ideal cancer gene therapy vector as its infection results in anti-viral immune stimulation that can be enhanced or redirected towards the tumor via transgene expression. Co-infection of tumor cells with an oncolytic Ad and an HDAd results in tumor cell lysis and amplification of HDAd-encoded transgene expression. Here, we describe an HDAd-based cancer gene therapy expressing multiple classes of immunomodulatory molecules to simultaneously stimulate multiple axes of immune pathways: the HydrAd. Overall, the HydrAd platform represents a promising cancer immunotherapy agent against complex solid tumors.

The generation and application of antigen-specific T cell therapies for cancer and viral-associated disease

Immunotherapy with antigen-specific T cells is a promising, targeted therapeutic option for patients with cancer as well as for immunocompromised patients with virus infections. In this review, we characterize and compare current manufacturing protocols for the generation of T cells specific to viral and non-viral tumor-associated antigens. Specifically, we discuss: (1) the different methodologies to expand virus-specific T cell and non-viral tumor-associated antigen-specific T cell products, (2) an overview of the immunological principles involved when developing such manufacturing protocols, and (3) proposed standardized methodologies for the generation of polyclonal, polyfunctional antigen-specific T cells irrespective of donor source. Ex vivo expanded cells have been safely administered to treat numerous patients with virus-associated malignancies, hematologic malignancies, and solid tumors. Hence, we have performed a comprehensive review of the clinical trial results evaluating the safety, feasibility, and efficacy of these products in the clinic. In summary, this review seeks to provide new insights regarding antigen-specific T cell technology to benefit a rapidly expanding T cell therapy field.

Allogeneic Tumor Antigen-Specific T Cells for Broadly Applicable Adoptive Cell Therapy of Cancer

T cells specific for major histocompatibility complex (MHC)-presented tumor antigens are capable of inducing durable remissions when adoptively transferred to patients with refractory cancers presenting such antigens. When such T cells are derived from healthy donors, they can be banked for off-the-shelf administration in appropriately tissue matched patients. Therefore, tumor antigen-specific, donor-derived T cells are expected to be a mainstay in the cancer immunotherapy armamentarium. In this chapter, we analyze clinical evidence that tumor antigen-specific donor-derived T cells can induce tumor regressions when administered to appropriately matched patients whose tumors are refractory to standard therapy. We also delineate the landscape of MHC-presented and unconventional tumor antigens recognized by T cells in healthy individuals that have been targeted for adoptive T cell therapy, as well as emerging antigens for which mounting evidence suggests their utility as targets for adoptive T cell therapy. We discuss the growing technological advancements that have facilitated sequence identification of such antigens and their cognate T cells, and applicability of such technologies in the pre-clinical and clinical settings.

Cancer Therapy With TCR-Engineered T Cells: Current Strategies, Challenges, and Prospects

To redirect T cells against tumor cells, T cells can be engineered ex vivo to express cancer-antigen specific T cell receptors (TCRs), generating products known as TCR-engineered T cells (TCR T). Unlike chimeric antigen receptors (CARs), TCRs recognize HLA-presented peptides derived from proteins of all cellular compartments. The use of TCR T cells for adoptive cellular therapies (ACT) has gained increased attention, especially as efforts to treat solid cancers with ACTs have intensified. In this review, we describe the differing mechanisms of T cell antigen recognition and signal transduction mediated through CARs and TCRs. We describe the classes of cancer antigens recognized by current TCR T therapies and discuss both classical and emerging pre-clinical strategies for antigen-specific TCR discovery, enhancement, and validation. Finally, we review the current landscape of clinical trials for TCR T therapy and discuss what these current results indicate for the development of future engineered TCR approaches.

Phase 1 Clinical Trial Evaluating the Safety and Anti-Tumor Activity of ADP-A2M10 SPEAR T-Cells in Patients With MAGE-A10+ Head and Neck, Melanoma, or Urothelial Tumors

Background

ADP-A2M10 specific peptide enhanced affinity receptor (SPEAR) T-cells are genetically engineered autologous T-cells that express a high-affinity melanoma-associated antigen (MAGE)-A10-specific T-cell receptor (TCR) targeting MAGE-A10-positive tumors in the context of human leukocyte antigen (HLA)-A*02. ADP-0022-004 is a phase 1, dose-escalation trial to evaluate the safety and anti-tumor activity of ADP-A2M10 in three malignancies (https://clinicaltrials.gov: NCT02989064).

Methods

Eligible patients were HLA-A*02 positive with advanced head and neck squamous cell carcinoma (HNSCC), melanoma, or urothelial carcinoma (UC) expressing MAGE-A10. Patients underwent apheresis; T-cells were isolated, transduced with a lentiviral vector containing the MAGE-A10 TCR, and expanded. Patients underwent lymphodepletion with fludarabine and cyclophosphamide prior to receiving ADP-A2M10. ADP-A2M10 was administered in two dose groups receiving 0.1×10⁹ and >1.2 to 6×10⁹ transduced cells, respectively, and an expansion group receiving 1.2 to 15×10⁹ transduced cells.

Results

Ten patients (eight male and two female) with HNSCC (four), melanoma (three), and UC (three) were treated. Three patients were treated in each of the two dose groups, and four patients were treated in the expansion group. The most frequently reported adverse events grade ≥3 were leukopenia (10), lymphopenia (10), neutropenia (10), anemia (nine), and thrombocytopenia (five). Two patients reported cytokine release syndrome (one each with grade 1 and grade 3), with resolution. Best response included stable disease in four patients, progressive disease in five patients, and not evaluable in one patient. ADP-A2M10 cells were detectable in peripheral blood from patients in each dose group and the expansion group and in tumor tissues from patients in the higher dose group and the expansion group. Peak persistence was greater in patients from the higher dose group and the expansion group compared with the lower dose group.

Conclusions

ADP-A2M10 has shown an acceptable safety profile with no evidence of toxicity related to off-target binding or alloreactivity in these malignancies. Persistence of ADP-A2M10 in the peripheral blood and trafficking of ADP-A2M10 into the tumor was demonstrated. Because MAGE-A10 expression frequently overlaps with MAGE-A4 expression in tumors and responses were observed in the MAGE-A4 trial (NCT03132922), this clinical program closed, and trials with SPEAR T-cells targeting the MAGE-A4 antigen are ongoing.

Rituximab as adjunctive therapy to BEAM conditioning for autologous stem cell transplantation in Hodgkin lymphoma

While high-dose chemotherapy followed by autologous stem cell transplantation (ASCT) leads to improved disease-free survival (DFS) for children and adults with relapsed/refractory Hodgkin lymphoma (HL), relapse remains the most frequent cause of mortality post-transplant. Rituximab has been successfully incorporated into regimens for other B-cell lymphomas, yet there have been limited studies of rituximab in HL patients. We hypothesized that adding rituximab to BEAM (carmustine, etoposide, cytarabine, melphalan) conditioning would reduce relapse risk in HL patients post-transplant. Here, we retrospectively review the outcomes of patients with relapsed/refractory HL who received rituximab in addition to BEAM. The primary outcome was DFS. Our cohort included 96 patients with a median age of 28 years (range, 6-76). Majority of patients (57%) were diagnosed with advanced (Stage III-IV) disease, and 62% were PET negative pre-transplant. DFS was 91.5% at 1 year [95% CI 86-98%], and 78% at 3 years [95% CI 68-88%]. NRM was 0% and 3.5% at 1-year [95% CI 0-3%] and 3-years [95% CI 0-8.5%], respectively. 25% of patients developed delayed neutropenia, with 7% requiring infection-related hospitalizations, and one death. We have demonstrated excellent outcomes for patients receiving rituximab with BEAM conditioning for relapsed/refractory HL. Future comparative studies are needed to better determine whether rituximab augments outcomes post-transplant.

Phase I clinical trial evaluating the safety and efficacy of ADP-A2M10 SPEAR T cells in patients with MAGE-A10+ advanced non-small cell lung cancer

Background

ADP-A2M10 specific peptide enhanced affinity receptor (SPEAR) T cells (ADP-A2M10) are genetically engineered autologous T cells that express a high-affinity melanoma-associated antigen A10 (MAGE-A10)-specific T-cell receptor (TCR) targeting MAGE-A10⁺ tumors in the context of human leukocyte antigen (HLA)-A*02. ADP-0022-003 was a phase I dose-escalation trial that aimed to evaluate the safety and antitumor activity of ADP-A2M10 in non-small cell lung cancer (NSCLC) (NCT02592577).

Methods

Eligible patients were HLA-A*02 positive with advanced NSCLC expressing MAGE-A10. Patients underwent apheresis; T cells were isolated, transduced with a lentiviral vector containing the TCR targeting MAGE-A10, and expanded. Patients underwent lymphodepletion with varying doses/schedules of fludarabine and cyclophosphamide prior to receiving ADP-A2M10. ADP-A2M10 were administered at 0.08–0.12×10⁹ (dose group 1), 0.5–1.2×10⁹ (dose group 2), and 1.2–15×10⁹ (dose group 3/expansion) transduced cells.

Results

Eleven patients (male, n=6; female, n=5) with NSCLC (adenocarcinoma, n=8; squamous cell carcinoma, n=3) were treated. Five, three, and three patients received cells in dose group 1, dose group 2, and dose group 3/expansion, respectively. The most frequently reported grade ≥3 adverse events were lymphopenia (n=11), leukopenia (n=10), neutropenia (n=8), anemia (n=6), thrombocytopenia (n=5), and hyponatremia (n=5). Three patients presented with cytokine release syndrome (grades 1, 2, and 4, respectively). One patient received the highest dose of lymphodepletion (fludarabine 30 mg/m² on days –5 to –2 and cyclophosphamide 1800 mg/m² on days −5 to −4) prior to a second infusion of ADP-A2M10 and had a partial response, subsequently complicated by aplastic anemia and death. Responses included: partial response (after second infusion; one patient), stable disease (four patients), clinical or radiographic progressive disease (five patients), and not evaluable (one patient). ADP-A2M10 were detectable in peripheral blood and in tumor tissue. Peak persistence was higher in patients who received higher doses of ADP-A2M10.

Conclusions

ADP-A2M10 demonstrated an acceptable safety profile and no evidence of toxicity related to off-target binding or alloreactivity. There was persistence of ADP-A2M10 in peripheral blood as well as ADP-A2M10 trafficking into the tumor. Given the discovery that MAGE-A10 and MAGE-A4 expression frequently overlap, this clinical program closed as trials with SPEAR T cells targeting MAGE-A4 are ongoing.

Tumor-associated antigen-specific T cells with nivolumab are safe and persist in vivo in relapsed/refractory Hodgkin lymphoma

Hodgkin lymphoma (HL) Reed Sternberg cells express tumor-associated antigens (TAA) that are potential targets for cellular therapies. We recently demonstrated that TAA-specific T cells (TAA-Ts) targeting WT1, PRAME, and Survivin were safe and associated with prolonged time to progression in solid tumors. Hence, we evaluated whether TAA-Ts when given alone or with nivolumab were safe and could elicit antitumor effects in vivo in patients with relapsed/refractory (r/r) HL. Ten patients were infused with TAA-Ts (8 autologous and 2 allogeneic) for active HL (n = 8) or as adjuvant therapy after hematopoietic stem cell transplant (n = 2). Six patients received nivolumab priming before TAA-Ts and continued until disease progression or unacceptable toxicity. All 10 products recognized 1 or more TAAs and were polyfunctional. Patients were monitored for safety for 6 weeks after the TAA-Ts and for response until disease progression. The infusions were safe with no clear dose-limiting toxicities. Patients receiving TAA-Ts as adjuvant therapy remain in continued remission at 3+ years. Of the 8 patients with active disease, 1 patient had a complete response and 7 had stable disease at 3 months, 3 of whom remain with stable disease at 1 year. Antigen spreading and long-term persistence of TAA-Ts in vivo were observed in responding patients. Nivolumab priming impacted TAA-T recognition and persistence. In conclusion, treatment of patients with r/r HL with TAA-Ts alone or in combination with nivolumab was safe and produced promising results. This trial was registered at www.clinicaltrials.gov as #NCT022039303 and #NCT03843294.

Reverted exhaustion phenotype of circulating lymphocytes as immune correlate of anti-PD1 first-line treatment in Hodgkin lymphoma

While classical Hodgkin lymphoma (HL) is highly susceptible to anti-programmed death protein 1 (PD1) antibodies, the exact modes of action remain controversial. To elucidate the circulating lymphocyte phenotype and systemic effects during anti-PD1 1st-line HL treatment we applied multicolor flow cytometry, FluoroSpot and NanoString to sequential samples of 81 HL patients from the NIVAHL trial (NCT03004833) compared to healthy controls. HL patients showed a decreased CD4 T-cell fraction, a higher percentage of effector-memory T cells and higher expression of activation markers at baseline. Strikingly, and in contrast to solid cancers, expression for 10 out of 16 analyzed co-inhibitory molecules on T cells (e.g., PD1, LAG3, Tim3) was higher in HL. Overall, we observed a sustained decrease of the exhausted T-cell phenotype during anti-PD1 treatment. FluoroSpot of 42.3% of patients revealed T-cell responses against ≥1 of five analyzed tumor-associated antigens. Importantly, these responses were more frequently observed in samples from patients with early excellent response to anti-PD1 therapy. In summary, an initially exhausted lymphocyte phenotype rapidly reverted during anti-PD1 1st-line treatment. The frequently observed IFN-y responses against shared tumor-associated antigens indicate T-cell-mediated cytotoxicity and could represent an important resource for immune monitoring and cellular therapy of HL.