Cytokine signaling in chimeric antigen receptor T-cell therapy.

Adoptive immunotherapy using chimeric antigen-receptor (CAR)-engineered T cells can induce robust antitumor responses against hematologic malignancies. However, its efficacy is not durable in the majority of the patients, warranting further improvement of T-cell functions. Cytokine signaling is one of the key cascades regulating T-cell survival and effector functions. In addition to cytokines that use the common γ chain as a receptor subunit, multiple cytokines regulate T-cell functions directly or indirectly. Modulating cytokine signaling in CAR-T cells by genetic engineering is one promising strategy to augment their therapeutic efficacy. These strategies include ectopic expression of cytokines, cytokine receptors, and synthetic molecules that mimic endogenous cytokine signaling. Alternatively, autocrine IL-2 signaling can be augmented through reprogramming of CAR-T cell properties through transcriptional and epigenetic modification. On the other hand, cytokine production by CAR-T cells triggers systemic inflammatory responses, which mainly manifest as adverse events such as cytokine-release syndrome (CRS) and neurotoxicity. In addition to inhibiting direct inflammatory mediators such as IL-6 and IL-1 released from activated macrophages, suppression of T-cell-derived cytokines associated with the priming of macrophages can be accomplished through genetic modification of CAR-T cells. In this review, I will outline recently developed synthetic biology approaches to exploit cytokine signaling to enhance CAR-T cell functions. I will also discuss therapeutic target molecules to prevent or alleviate CAR-T cell-related toxicities.

High CD62L expression predicts the generation of chimeric antigen receptor T cells with potent effector functions.

The efficient generation of chimeric antigen receptor (CAR) T cells is highly influenced by the quality of apheresed T cells. Healthy donor-derived T cells usually proliferate better than patients-derived T cells and are precious resources to generate off-the-shelf CAR-T cells. However, relatively little is known about the determinants that affect the efficient generation of CAR-T cells from healthy donor-derived peripheral blood mononuclear cells (PBMCs) compared with those from the patients' own PBMCs. We here examined the efficiency of CAR-T cell generation from multiple healthy donor samples and analyzed its association with the phenotypic features of the starting peripheral blood T cells. We found that CD62L expression levels within CD8+ T cells were significantly correlated with CAR-T cell expansion. Moreover, high CD62L expression within naïve T cells was associated with the efficient expansion of T cells with a stem cell-like memory phenotype, an indicator of high-quality infusion products. Intriguingly, genetic disruption of CD62L significantly impaired CAR-T cell proliferation and cytokine production upon antigen stimulation. Conversely, ectopic expression of a shedding-resistant CD62L mutant augmented CAR-T cell effector functions compared to unmodified CAR-T cells, resulting in improved antitumor activity in vivo. Collectively, we identified the surface expression of CD62L as a concise indicator of potent T-cell proliferation. CD62L expression is also associated with the functional properties of CAR-T cells. These findings are potentially applicable to selecting optimal donors to massively generate CAR-T cell products.

Switchable targeting of solid tumors by BsCAR T cells.

The development of chimeric antigen receptor (CAR) T cell therapy has become a critical milestone in modern oncotherapy. Despite the remarkable in vitro effectiveness, the problem of safety and efficacy of CAR T cell therapy against solid tumors is challenged by the lack of tumor-specific antigens required to avoid on-target off-tumor effects. Spatially separating the cytotoxic function of CAR T cells from tumor antigen recognition provided by protein mediators allows for the precise control of CAR T cell cytotoxicity. Here, the high affinity and capability of the bacterial toxin-antitoxin barnase-barstar system were adopted to guide CAR T cells to solid tumors. The complementary modules based on (1) ankyrin repeat (DARPin)-barnase proteins and (2) barstar-based CAR (BsCAR) were designed to provide switchable targeting to tumor cells. The alteration of the DARPin-barnase switches enabled the targeting of different tumor antigens with a single BsCAR. A gradual increase in cytokine release and tunable BsCAR T cell cytotoxicity was achieved by varying DARPin-barnase loads. Switchable BsCAR T cell therapy was able to eradicate the HER2+ ductal carcinoma in vivo. Guiding BsCAR T cells by DARPin-barnase switches provides a universal approach for a controlled multitargeted adoptive immunotherapy.

CD81 costimulation skews CAR transduction toward naive T cells.

Adoptive cellular therapy using chimeric antigen receptors (CARs) has revolutionized our treatment of relapsed B cell malignancies and is currently being integrated into standard therapy. The impact of selecting specific T cell subsets for CAR transduction remains under investigation. Previous studies demonstrated that effector T cells derived from naive, rather than central memory T cells mediate more potent antitumor effects. Here, we investigate a method to skew CAR transduction toward naive T cells without physical cell sorting. Viral-mediated CAR transduction requires ex vivo T cell activation, traditionally achieved using antibody-mediated strategies. CD81 is a T cell costimulatory molecule that when combined with CD3 and CD28 enhances naive T cell activation. We interrogate the effect of CD81 costimulation on resultant CAR transduction. We identify that upon CD81-mediated activation, naive T cells lose their identifying surface phenotype and switch to a memory phenotype. By prelabeling naive T cells and tracking them through T cell activation and CAR transduction, we document that CD81 costimulation enhanced naive T cell activation and resultantly generated a CAR T cell product enriched with naive-derived CAR T cells.

Melatonin as an immunomodulator in CD19-targeting CAR-T cell therapy: managing cytokine release syndrome.

BACKGROUND: Chimeric antigen receptor CAR-T cell therapies have ushered in a new era of treatment for specific blood cancers, offering unparalleled efficacy in cases of treatment resistance or relapse. However, the emergence of cytokine release syndrome (CRS) as a side effect poses a challenge to the widespread application of CAR-T cell therapies. Melatonin, a natural hormone produced by the pineal gland known for its antioxidant and anti-inflammatory properties, has been explored for its potential immunomodulatory effects. Despite this, its specific role in mitigating CAR-T cell-induced CRS remains poorly understood. METHODS: In this study, our aim was to investigate the potential of melatonin as an immunomodulatory agent in the context of CD19-targeting CAR-T cell therapy and its impact on associated side effects. Using a mouse model, we evaluated the effects of melatonin on CAR-T cell-induced CRS and overall survival. Additionally, we assessed whether melatonin administration had any detrimental effects on the antitumor efficacy and persistence of CD19 CAR-T cells. RESULTS: Our findings demonstrate that melatonin effectively mitigated the severity of CAR-T cell-induced CRS in the mouse model, leading to improved overall survival outcomes. Remarkably, melatonin administration did not compromise the antitumor effectiveness or persistence of CD19 CAR-T cells, indicating its compatibility with therapeutic goals. These results suggest melatonin's potential as an immunomodulatory compound to alleviate CRS without compromising the therapeutic benefits of CAR-T cell therapy. CONCLUSION: The study's outcomes shed light on melatonin's promise as a valuable addition to the existing treatment protocols for CAR-T cell therapies. By attenuating CAR-T cell-induced CRS while preserving the therapeutic impact of CAR-T cells, melatonin offers a potential strategy for optimizing and refining the safety and efficacy profile of CAR-T cell therapy. This research contributes to the evolving understanding of how to harness immunomodulatory agents to enhance the clinical application of innovative cancer treatments.

Abnormal bone marrow findings in patients following treatment with chimeric antigen receptor-T cell therapy.

BACKGROUND: Bone marrow (BM) assessment after CAR-T cell immunotherapy infusion is not routinely performed to monitor adverse events such as cytopenias, hemophagocytic lymphohistiocytosis, or infections. Our institution has performed BM biopsies as part of CAR-T cell treatment protocols, encompassing pre- and post-treatment time points and during long-term follow-up. METHODS: We conducted a systematic retrospective review of BM abnormalities observed in samples from 259 patients following CAR-T cell immunotherapy. We correlated BM pathology findings with mortality, relapse/residual disease, and laboratory values. RESULTS: At a median of 35.5 days post-CAR-T infusion, 25.5% showed severe marrow hypocellularity, and 6.2% showed serous atrophy, and peripheral blood cytopenias corroborated these observations. Marrow features associated with reduced disease burden post-CAR-T infusion include increased lymphocytes seen in 16 patients and an increase of macrophages or granulomatous response seen in 25 patients. However, a 100-day landmark analysis also showed increased marrow histiocytes were associated with lower survival (median OS 6.0 vs. 21.4 months, p = .026), as was grade 2-3 marrow reticulin (18 patients) (median OS 12.5 vs. 24.2 months, p = .034). CONCLUSIONS: These data represent the first systematic observations of BM changes in patients receiving CAR-T cell immunotherapy.

Adenovirus- and cytomegalovirus-specific adoptive T-cell therapy in the context of hematologic cell transplan or HIV infection - A single-center experience.

BACKGROUND: Reactivation of viral infections, in particular cytomegalovirus (CMV) and adenovirus (ADV), cause morbidity and non-relapse-mortality in states of immune deficiency, especially after allogeneic hematopoietic cell transplantation (allo-HCT). Against the background of few available pharmacologic antiviral agents, limited by toxicities and resistance, adoptive transfer of virus-specific T-cells (VST) is a promising therapeutic approach. METHODS: We conducted a single-center retrospective analysis of adult patients treated with ADV- or CMV-specific T-cells in 2012-2022. Information was retrieved by review of electronic health records. Primary outcome was a response to VST by decreasing viral load or clinical improvement. Secondary outcomes included overall survival and safety of VST infusion, in particular association with graft-versus-host disease (GVHD). RESULTS: Ten patients were included, of whom four were treated for ADV, five for CMV, and one for ADV-CMV-coinfection. Cells were derived from stem cell donors (6/10) or third-party donors (4/10). Response criteria were met by six of 10 patients (4/4 ADV, 2/5 CMV, and 0/1 ADV-CMV). Overall survival was 40%. No infusion related adverse events were documented. Aggravation of GVHD after adoptive immunotherapy was observed in two cases, however in temporal association with a conventional donor lymphocyte infusion and a stem cell boost, respectively. CONCLUSION: In this cohort, CMV- and ADV-specific T-cell therapy appear to be safe and effective. We describe the first reported case of virus-specific T-cell therapy for CMV reactivation not associated with transplantation but with advanced HIV infection. This encourages further evaluation of adoptive immunotherapy beyond the context of allo-HCT.

An Assessment of the Effectiveness and Safety of Chimeric Antigen Receptor T-Cell Therapy in Multiple Myeloma Patients with Relapsed or Refractory Disease: A Systematic Review and Meta-Analysis.

Multiple myeloma (MM), the second most common hematologic malignancy, remains incurable, and its incidence is rising. Chimeric Antigen Receptor T-cell (CAR-T cell) therapy has emerged as a novel treatment, with the potential to improve the survival and quality of life of patients with relapsed/refractory multiple myeloma (rrMM). In this systematic review and meta-analysis, conducted in accordance with PRISMA guidelines, we aim to provide a concise overview of the latest developments in CAR-T therapy, assess their potential implications for clinical practice, and evaluate their efficacy and safety outcomes based on the most up-to-date evidence. A literature search conducted from 1 January 2019 to 12 July 2023 on Medline/PubMed, Scopus, and Web of Science identified 2273 articles, of which 29 fulfilled the specified criteria for inclusion. Our results offer robust evidence supporting CAR-T cell therapy's efficacy in rrMM patients, with an encouraging 83.21% overall response rate (ORR). A generally safe profile was observed, with grade ≥ 3 cytokine release syndrome (CRS) at 7.12% and grade ≥ 3 neurotoxicity at 1.37%. A subgroup analysis revealed a significantly increased ORR in patients with fewer antimyeloma regimens, while grade ≥ 3 CRS was more common in those with a higher proportion of high-risk cytogenetics and prior exposure to BCMA therapy.

T cell immune profiling of respiratory syncytial virus for the development of a targeted immunotherapy.

Respiratory syncytial virus (RSV)-associated viral infections are a major public health problem affecting the immunologically naïve/compromised populations. Given the RSV-associated morbidity and the limited treatment options, we sought to characterize the cellular immune response to RSV to develop a targeted T cell therapy for off-the-shelf administration to immunocompromised individuals. Here we report on the immunological profiling, as well as manufacturing, characterization and antiviral properties of these RSV-targeted T cells. A randomized, phase 1/2 clinical trial evaluating their safety and activity in haematopoietic stem cell transplant recipients as an off-the-shelf multi-respiratory virus-directed product is currently underway (NCT04933968, https://clinicaltrials.gov).

Phase 1 trial of 4-1BB-based adoptive T-cell therapy targeting human telomerase reverse transcriptase in patients with advanced refractory solid tumors.

BACKGROUND AIMS: Human telomerase reverse transcriptase (hTERT) is an attractive target for anti-cancer therapies. We developed an effective method for generating hTERT-specific CD8+ T cells (hTERT-induced natural T cells [TERTiNTs]) using peripheral blood mononuclear cells (PBMCs) from patients with solid cancers and investigated their feasibility and safety. METHODS: This was a single-center phase 1 trial using a 3 + 3 dose escalation design to evaluate six dose levels of TERTiNTs. PBMCs from each patient were screened using an hTERT peptide panel to select those that stimulated CD8+ T cells. The four most stimulatory peptides were used to produce autologous CD8+ T cells from patients refractory or intolerant to standard therapies. Eligible patients received a single intravenous infusion of TERTiNTs at different dose levels (4 × 108 cells/m2, 8 × 108 cells/m2 and 16 × 108 cells/m2). Pre-conditioning chemotherapy, including cyclophosphamide alone or in combination with fludarabine, was administered to induce lymphodepletion. RESULTS: From January 2014 to October 2019, a total of 24 patients with a median of three prior lines of therapy were enrolled. The most common adverse events were lymphopenia (79.2%), nausea (58.3%) and neutropenia (54.2%), mostly caused by pre-conditioning chemotherapy. The TERTiNT infusion was well tolerated, and dose-limiting toxicities were not observed. None of the patients showed objective responses. Seven patients (30.4%) achieved stable disease with a median progression-free survival of 3.9 months (range, 3.2-11.3). At the highest dose level (16 × 108 cells/m2), four of five patients showed disease stabilization. CONCLUSIONS: The generation of TERTiNTs was feasible and safe and provided an interesting disease control rate in heavily pre-treated cancer patients.

Generation of induced pluripotent stem cell (iPSC) from NY-ESO-I-specific cytotoxic T cells isolated from the melanoma patient with minor HLAs: The practical pilot study for the adoptive immunotherapy for melanoma using iPSC technology.

Melanoma is one of the most severe skin cancers, derived from melanocytes. Among various therapies for melanoma, adoptive immunotherapy using tumor-infiltrating lymphocytes/chimeric antigen receptor-T cells (TCs) is advanced in recent years; however, the efficacy is still limited, and major challenges remain in terms of safety and cell supply. To solve the issues of adoptive immunotherapy, we utilized induced pluripotent stem cells (iPSCs), which have an unlimited proliferative ability and various differentiation capability. First, we monoclonally isolated CD8+ TCs specifically reactive with NY-ESO-1, one of tumor antigens, from the melanoma patient's monocytes after stimulated with NY-ESO-1 peptide by manual procedure, and cultured NY-ESO-1-specific TCs until proliferated and formed colonies. iPSCs were consequently generated from colony-forming TCs by exogenous expression of reprogramming factors using Sendai virus vector. After the RAG2 gene in TC-derived iPSCs (T-iPSCs) was knocked out for preventing T-cell receptor (TCR) rearrangement, T-iPSCs were re-differentiated into rejuvenated cytotoxic TCs. We confirmed that TCR of T-iPSC-derived TC was maintained as the same of original TCs. In conclusion, T-iPSCs have a potential to be an unlimited cell source for providing cytotoxic TCs. Our study could be a "touchstone" to develop iPSC-based adoptive immunotherapy for the treatment of melanoma for the future clinical use.

Adenovirus infection in allogeneic hematopoietic cell transplantation.

Adenovirus (AdV) infection occurs in 0-20% of patients in the first 3-4 months after allogeneic hematopoietic cell transplantation (HCT), being higher in pediatric than in adult patients. About 50% of AdV infections involve the blood, which in turn, correlates with an increased risk developing AdV diseases, end-organ damage, and 6-month overall mortality. The main risk factors for AdV infection are T-cell depletion of the graft by ex vivo selection procedures or in vivo use of alemtuzumab or antithymocyte serum, development of graft versus host disease (GVHD) grade III-IV, donor type (haploidentical or human leucocyte antigen mismatched related donor > cord blood> unrelated matched donor) and severe lymphopenia (<0.2 × 109 /L). The prevention of AdV disease relies on early diagnosis of increasing viral replication in blood or stool and the pre-emptive start of cidofovir as viral load exceeds the threshold of ≥102-3 copies/mL in blood and/or 106 copies/g stool in the stool. Cidofovir (CDV), a cytosine monophosphate nucleotide analog, is currently the only antiviral recommended for AdV infection despite limited efficacy and moderate risk of nephrotoxicity. Brincidofovir, a lipid derivative of CDV with more favorable pharmacokinetics properties and superior efficacy, is not available and currently is being investigated for other viral infections. The enhancement of virus-specific T-cell immunity in the first few months post-HCT by the administration of donor-derived or third-party-donor-derived virus-specific T-cells represents an innovative and promising modality of intervention and data of efficacy and safety of the ongoing prospective randomized studies are eagerly awaited.

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.

A qualitative service evaluation of patient and caregiver experiences of CAR-T therapy: Recommendations for service development and implications for palliative care teams.

BACKGROUND: Chimeric Antigen-Receptor-T-cell (CAR-T) therapy is a potentially life-saving treatment for refractory haematological malignancies. Internationally, CAR-T services are undergoing rapid development. Despite this, research on the lived experiences of patients receiving novel immunotherapies is limited. Little is known about their supportive care needs. Consequently, dedicated palliative and supportive care services may not be considered. AIM: To explore the patient and caregiver experience of CAR-T therapy and identify unmet needs to inform service development. DESIGN: A qualitative longitudinal service evaluation. Sixteen interviews were conducted between December 2020 and March 2021 with patients (n = 10) and family caregivers (n = 4). Thematic analysis was underpinned by a constructivist approach. SETTING/PARTICIPANTS: All patients and caregivers attending one UK centre for CAR-T therapy were eligible. Semi-structured interviews were conducted at specific time points: prior to infusion, one month after infusion and follow-up post-treatment (5-18 months). RESULTS: Identified themes described the unique challenges of CAR-T therapy. From the point of referral patients had a wide range of supportive care needs. Initially, this was attributed to prior receipt of multiple failed treatments. Subsequently, CAR-T side-effects impacted on quality-of-life and physical function. Significant psychological morbidity from prognostic uncertainty was described throughout. Patients and caregivers reported that a dedicated nurse specialist - an expert, consistent point of contact - was essential. CONCLUSION: Patients and caregivers would benefit from early and ongoing support from palliative care, allied-health professionals and psychology. As indications for CAR-T therapy expand, there is an urgent need for multi-centre studies incorporating patient-reported outcome data to ensure patient-centred service delivery.

Lactate dehydrogenase inhibition synergizes with IL-21 to promote CD8+ T cell stemness and antitumor immunity.

Interleukin (IL)-2 and IL-21 dichotomously shape CD8+ T cell differentiation. IL-2 drives terminal differentiation, generating cells that are poorly effective against tumors, whereas IL-21 promotes stem cell memory T cells (TSCM) and antitumor responses. Here we investigated the role of metabolic programming in the developmental differences induced by these cytokines. IL-2 promoted effector-like metabolism and aerobic glycolysis, robustly inducing lactate dehydrogenase (LDH) and lactate production, whereas IL-21 maintained a metabolically quiescent state dependent on oxidative phosphorylation. LDH inhibition rewired IL-2-induced effects, promoting pyruvate entry into the tricarboxylic acid cycle and inhibiting terminal effector and exhaustion programs, including mRNA expression of members of the NR4A family of nuclear receptors, as well as Prdm1 and Xbp1 While deletion of Ldha prevented development of cells with antitumor effector function, transient LDH inhibition enhanced the generation of memory cells capable of triggering robust antitumor responses after adoptive transfer. LDH inhibition did not significantly affect IL-21-induced metabolism but caused major transcriptomic changes, including the suppression of IL-21-induced exhaustion markers LAG3, PD1, 2B4, and TIM3. LDH inhibition combined with IL-21 increased the formation of TSCM cells, resulting in more profound antitumor responses and prolonged host survival. These findings indicate a pivotal role for LDH in modulating cytokine-mediated T cell differentiation and underscore the therapeutic potential of transiently inhibiting LDH during adoptive T cell-based immunotherapy, with an unanticipated cooperative antitumor effect of LDH inhibition and IL-21.

GTS-21 Enhances Regulatory T Cell Development from T Cell Receptor-Activated Human CD4+ T Cells Exhibiting Varied Levels of CHRNA7 and CHRFAM7A Expression.

Immune cells such as T cells and macrophages express α7 nicotinic acetylcholine receptors (α7 nAChRs), which contribute to the regulation of immune and inflammatory responses. Earlier findings suggest α7 nAChR activation promotes the development of regulatory T cells (Tregs) in mice. Using human CD4+ T cells, we investigated the mRNA expression of the α7 subunit and the human-specific dupα7 nAChR subunit, which functions as a dominant-negative regulator of ion channel function, under resting conditions and T cell receptor (TCR)-activation. We then explored the effects of the selective α7 nAChR agonist GTS-21 on proliferation of TCR-activated T cells and Treg development. Varied levels of mRNA for both the α7 and dupα7 nAChR subunits were detected in resting human CD4+ T cells. mRNA expression of the α7 nAChR subunit was profoundly suppressed on days 4 and 7 of TCR-activation as compared to day 1, whereas mRNA expression of the dupα7 nAChR subunit remained nearly constant. GTS-21 did not alter CD4+ T cell proliferation but significantly promoted Treg development. These results suggest the potential ex vivo utility of GTS-21 for preparing Tregs for adoptive immunotherapy, even with high expression of the dupα7 subunit.

Cellular therapy: Adoptive immunotherapy with expanded natural killer cells.

Adoptive immunotherapy with natural killer cells was pioneered 30 years ago in human clinical trials with the development of cytokine-induced killer cells-unfractionated peripheral blood mononuclear cell (PBMC) populations activated overnight with IL-2. Higher doses were subsequently made possible through the advent of steady-state apheresis, allowing the collection of PBMC numbers equivalent to an entire adult blood volume, and increased purity made feasible through magnetic CD3-depletion and/or CD56-selection methods. Still, these approaches rarely achieved clinical dosing above a single infusion of 108 NK cells/kg, except with substantial donor-recipient size mismatch (eg, parents donating cells to children). To address this shortcoming, leukemia cell lines with NK cell-like function or ex vivo expansion approaches centered on the homeostatic cytokine IL-15 were developed. Here, we describe the development of an ex vivo expansion system based on a feeder cell expressing membrane-bound IL-21 that enables log-phase growth of primary NK cells for many weeks without inducing senescence, and describe the biology, correlative science, and translation to clinical trials for patients with leukemia, brain tumors, and solid tumors.

T cell receptor-based cancer immunotherapy: Emerging efficacy and pathways of resistance.

Adoptive cell transfer (ACT) using chimeric antigen receptor (CAR)-modified T cells can induce durable remissions in patients with refractory B-lymphoid cancers. By contrast, results applying CAR-modified T cells to solid malignancies have been comparatively modest. Alternative strategies to redirect T cell specificity and cytolytic function are therefore necessary if ACT is to serve a greater role in human cancer treatments. T cell receptors (TCRs) are antigen recognition structures physiologically expressed by all T cells that have complementary, and in some cases superior, properties to CARs. Unlike CARs, TCRs confer recognition to epitopes derived from proteins residing within any subcellular compartment, including the membrane, cytoplasm and nucleus. This enables TCRs to detect a broad universe of targets, such as neoantigens, cancer germline antigens, and viral oncoproteins. Moreover, because TCRs have evolved to efficiently detect and amplify antigenic signals, these receptors respond to epitope densities many fold smaller than required for CAR-signaling. Herein, we summarize recent clinical data demonstrating that TCR-based immunotherapies can mediate regression of solid malignancies, including immune-checkpoint inhibitor refractory cancers. These trials simultaneously highlight emerging mechanisms of TCR resistance. We conclude by discussing how TCR-based immunotherapies can achieve broader dissemination through innovations in cell manufacturing and non-viral genome integration techniques.

Clinical grade production of IL-15 stimulated NK cells for early infusion in adult AML patients undergoing haploidentical stem cell transplantation with post-transplant cyclophosphamide.

BACKGROUND: Allogeneic stem cell transplantation is the treatment of choice for acute myeloid leukemia (AML) patients. Unmanipulated haploidentical transplantation (Haplo-HSCT) is commonly used for those AML patients who need a timely transplant and do not have a suitable matched donor, but relapse rates are still high, and improvements are needed. Adoptive immunotherapy using natural killer cells (NK cells) could be a promising tool to improved Haplo-HSCT but, to date, no optimal infusion and manufacturing protocols have been developed. STUDY DESIGN AND METHODS: In this study, we describe a quick and reproducible protocol for clinical-grade production of haploidentical donor NK cells using double immunomagnetic depletion and enrichment protocol and overnight IL-15 stimulation. RESULTS: Thus, we have obtained 8 viable and functional NK cell products that have been safely infused to five AML patients undergoing unmanipulated Haplo-HSCT. DISCUSSION: Our results demonstrate the safety and feasibility of manufactured NK IL15 cells obtained from an adult allogeneic donor in the setting of haploidentical transplantation for AML patients.

Adoptive NK-cell transfer as a potential treatment paradigm for Wilms tumor: A preclinical study.

BACKGROUND: Natural killer (NK) cell therapy has been shown to be effective in the treatment of some cancers. However, the effects of this adoptive immunotherapy have not been investigated for Wilms tumor (WT). In this study, the effects of adoptive NK-cell transfer on a patient-derived xenograft (PDX) model of anaplastic WT were evaluated, and the impacts of cell source and ex vivo activation strategy on the therapeutic efficacy of NK-cell product were appraised. METHODS: NK cells were isolated from human peripheral blood mononuclear cells (NKPB ) and human cord blood (NKCB ), and were expanded and activated using a cytokine cocktail. Another group of NK cells (NKET ) was produced through activation with the exosomes extracted from previously challenged NKPB cells with WT. PDX-bearing mice were treated with clinically relevant doses of NKPB , NKCB , NKET , standard chemotherapy, and placebo (phosphate-buffered saline). RESULTS: PDX models treated with NKCB showed a better survival rate, though the difference among the study groups was not significant. Compared with the placebo control group, NKCB significantly improved the histopathologic response, NKPB significantly inhibited the proliferation of neoplastic cells, and NKET led to a significant decrease in the metastasis score (all p-values <.05). Standard chemotherapy provided the greatest tumor growth inhibition and the lowest mitotic count, though it did not show any significant advantage over NK-cell therapies in any of the outcome parameters in two-by-two comparisons. CONCLUSIONS: This study spotlights the efficacy of adoptive NK-cell transfer as a potential treatment candidate for high-risk WT.