Explore the vast range of titles available.

A wealth of evidence obtained using mouse models indicates that CD4(+)CD25(+)FOXP3(+) regulatory T cells (Treg) maintain peripheral tolerance to self-antigens and also inhibit anti-tumor immune responses. To date there is limited information about CD4(+) T cell responses in patients with colorectal cancer (CRC). We set out to measure T cell responses to a tumor-associated antigen and examine whether Treg impinge on those anti-tumor immune responses in CRC patients. Treg were identified and characterized as CD4(+)CD25(+)FOXP3(+) using flow cytometry. An increased frequency of Treg was demonstrated in both peripheral blood and mesenteric lymph nodes of patients with colorectal cancer (CRC) compared with either healthy controls or patients with inflammatory bowel disease (IBD). Depletion of Treg from peripheral blood mononuclear cells (PBMC) of CRC patients unmasked CD4(+) T cell responses, as observed by IFNgamma release, to the tumor associated antigen 5T4, whereas no effect was observed in a healthy age-matched control group. Collectively, these data demonstrate that Treg capable of inhibiting tumor associated antigen-specific immune responses are enriched in patients with CRC. These results support a rationale for manipulating Treg to enhance cancer immunotherapy.

BackgroundGene-modified autologous T cells expressing NY-ESO-1c259, an affinity-enhanced T-cell receptor (TCR) reactive against the NY-ESO-1-specific HLA-A*02-restricted peptide SLLMWITQC (NY-ESO-1 SPEAR T-cells; GSK 794), have demonstrated clinical activity in patients with advanced synovial sarcoma (SS). The factors contributing to gene-modified T-cell expansion and the changes within the tumor microenvironment (TME) following T-cell infusion remain unclear. These studies address the immunological mechanisms of response and resistance in patients with SS treated with NY-ESO-1 SPEAR T-cells.MethodsFour cohorts were included to evaluate antigen expression and preconditioning on efficacy. Clinical responses were assessed by RECIST v1.1. Engineered T-cell persistence was determined by qPCR. Serum cytokines were evaluated by immunoassay. Transcriptomic analyses and immunohistochemistry were performed on tumor biopsies from patients before and after T-cell infusion. Gene-modified T-cells were detected within the TME via an RNAish assay.ResultsResponses across cohorts were affected by preconditioning and intra-tumoral NY-ESO-1 expression. Of the 42 patients reported (data cut-off 4June2018), 1 patient had a complete response, 14 patients had partial responses, 24 patients had stable disease, and 3 patients had progressive disease. The magnitude of gene-modified T-cell expansion shortly after infusion was associated with response in patients with high intra-tumoral NY-ESO-1 expression. Patients receiving a fludarabine-containing conditioning regimen experienced increases in serum IL-7 and IL-15. Prior to infusion, the TME exhibited minimal leukocyte infiltration; CD163+ tumor-associated macrophages (TAMs) were the dominant population. Modest increases in intra-tumoral leukocytes (≤5%) were observed in a subset of subjects at approximately 8 weeks. Beyond 8 weeks post infusion, the TME was minimally infiltrated with a TAM-dominant leukocyte infiltrate. Tumor-associated antigens and antigen presentation did not significantly change within the tumor post-T-cell infusion. Finally, NY-ESO-1 SPEAR T cells trafficked to the TME and maintained cytotoxicity in a subset of patients.ConclusionsOur studies elucidate some factors that underpin response and resistance to NY-ESO-1 SPEAR T-cell therapy. From these data, we conclude that a lymphodepletion regimen containing high doses of fludarabine and cyclophosphamide is necessary for SPEAR T-cell persistence and efficacy. Furthermore, these data demonstrate that non-T-cell inflamed tumors, which are resistant to PD-1/PD-L1 inhibitors, can be treated with adoptive T-cell based immunotherapy.Trial registrationClinicalTrials.gov, NCT01343043, Registered 27 April 2011.

Interleukin (IL)-17 is emerging as an important cytokine in vaccine-induced protection against tuberculosis disease in animal models. Here we show that compared to parenteral delivery, BCG delivered mucosally enhances cytokine production, including interferon gamma and IL-17, in the lungs. Furthermore, we find that cholera toxin, delivered mucosally along with BCG, further enhances IL-17 production by CD4(+) T cells over mucosal BCG alone both in the lungs and systemically. This boosting effect of CT is also observed using a vaccine regimen of BCG followed by the candidate vaccine MVA85A. Using a murine Mycobacterium tuberculosis (M.tb) aerosol challenge model, we demonstrate the ability of cholera toxin delivered at the time of a priming BCG vaccination to improve protection against tuberculosis disease in a manner at least partially dependent on the observed increase in IL-17. This observed increase in IL-17 in the lungs has no adverse effect on lung pathology following M.tb challenge, indicating that IL-17 can safely be boosted in murine lungs in a vaccine/M.tb challenge setting.

Regulatory T cells (Tregs) can control excessive or undesirable immune responses toward autoantigens, alloantigens, and pathogens. In transplantation, host immune responses against the allograft are suppressed through the use of immunosuppressive drugs, however this often results in life-threatening side effects including nephrotoxicity and an increased incidence of cancer and opportunistic infections. Tregs can control graft-vs.-host disease and transplant rejection in experimental models, providing impetus for the use of Tregs as a cellular therapy in clinical transplantation. One of the major barriers to the widespread use of Treg cellular therapy is the requirement to expand cells to large numbers in order to alter the overall balance between regulatory and effector cells. Methods that enhance suppressive capacity thereby reducing the need for expansion are therefore of interest. Here, we have compared the function of freshly-isolated and -manipulated human Tregs in a pre-clinical humanized mouse model of skin transplantation. Sorted human CD127 CD25 CD4 Tregs were assessed in three different conditions: freshly-isolated, following transient activation with antiCD3/antiCD28 beads or after -expansion for 2 weeks in the presence of antiCD3/antiCD28 beads and recombinant human IL2. While -expansion of human Tregs increased their suppressive function moderately, transient -activation of freshly isolated Tregs resulted in a powerful enhancement of Treg activity sufficient to promote long-term graft survival of all transplants . In order to investigate the mechanisms responsible for these effects, we measured the expression of Treg-associated markers and susceptibility to apoptosis in activated Tregs. Transiently activated Tregs displayed enhanced survival and proliferation and . On a molecular level, Treg activation resulted in an increased expression of anti-apoptotic (encoding BCL-XL) which may be at least partially responsible for the observed enhancement in function. Our results suggest that activation of human Tregs arms them with superior proliferative and survival abilities, enabling them to more effectively control alloresponses. Importantly, this transient activation results in a rapid functional enhancement of freshly-isolated Tregs, thereby providing an opportunity to eliminate the need for expansion in select circumstances. A protocol employing this technique would therefore benefit from a reduced requirement for large cell numbers for effective therapy.

The Bacillus Calmette - Guerin (BCG) vaccine provides a critical but limited defense against Mycobacterium tuberculosis (M.tb). More than 60 years after the widespread introduction of BCG, there is an urgent need for a better vaccine. A large body of pre-clinical research continues to support ongoing clinical trials to assess whether viral vectors expressing M.tb antigens that are shared by BCG and M.tb, can be used alongside BCG to enhance protection. A major focus involves using multiple unique viral vectors to limit anti-vector immunity and thereby enhance responses to the insert antigen delivered. The successful introduction of viral vector vaccines to target M.tb and other pathogens will be reliant on reducing the costs when using multiple vectors and inhibiting the development of unwanted anti-vector responses that interfere with the response to insert antigen. This study examines methods to reduce the logistical costs of vaccination by mixing different viral vectors that share the same insert antigen in one vaccine; and whether combining different viral vectors reduces anti-vector immunity to improve immunogenicity to the insert antigen. Here we show that a homologous prime-boost regimen with a mixture of MVA (Modified Vaccinia virus Ankara) and Ad5 (human adenovirus type 5) vectors both expressing Ag85A in a single vaccine preparation is able to reduce anti-vector immunity, compared with a homologous prime-boost regimen with either vector alone. However, the level of immunogenicity induced by the homologous mixture remained comparable to that induced with single viral vectors and was less immunogenic than a heterologous Ad5 prime-MVA-boost regimen. These findings advance the understanding of how anti-vector immunity maybe reduced in viral vector vaccination regimens. Furthermore, an insight is provided to the impact on vaccine immunogenicity from altering vaccination methods to reduce the logistical demands of using separate vaccine preparations in the field.

BackgroundThe ongoing SURPASS trial (NCT04044859) evaluates safety and efficacy of next-generation ADP-A2M4CD8 SPEAR T-cells co-expressing the CD8α co-receptor with the engineered MAGE-A4c1032T cell receptor (TCR).MethodsFirst-in-human trial in HLA-A*02 positive patients (pts) with advanced cancers expressing MAGE-A4 antigen by immunohistochemistry. Eligible pts undergo apheresis, T-cells are isolated, transduced with a Lentiviral vector containing the MAGE-A4c1032 TCR and CD8α co receptor, and expanded. Expansion, transduction level, cellular composition and function of the manufactured product (MP) are assessed in vitro. Prior to infusion, pts receive lymphodepletion with fludarabine 30 mg/m2/day for 4 days and cyclophosphamide 600 mg/m2/day for 3 days.ResultsAs of 16 July 2020, 5 pts (1 with MRCLS, 2 with esophagogastric junction [EGJ] cancers, 1 with ovarian cancer, and 1 with head and neck cancer) were treated with ADP-A2M4 CD8 (range ~1 to 5.7 billion transduced cells). No DLTs or SAEs have been reported. To date, 1 pt with EGJ cancer had a partial response (PR per RECIST) and has had progression-free survival >6 months. One pt with head and neck cancer also had a PR. All other pts have had best overall response of stable disease.MP expanded by an average of 15.3 fold during manufacturing (range 5.9 to 25.6-fold). On average, 43% of T-cells in the MP expressed the TCR (range 23 to 63%). The fraction of CD4+ cells in the final MP varied (range 45 to 84%). Co-expression of the MAGE-A4 TCR and CD8α in CD4+ T-cells in the patient MP enabled CD4+ T-cells to kill tumor target cells directly in vitro. MAGE-A4 expression in tumor biopsies varied (H-score range 55 to 300). Transduced T-cells were detected in peripheral blood of all pts. IFN-gamma increased transiently in the serum of 1 pt who responded.ConclusionsADP-A2M4CD8 SPEAR T-cells have shown an acceptable safety profile and pts with EGJ cancer and head and neck cancer have demonstrated evidence of antitumor activity. Translational data and early clinical results indicate that co-expression of the CD8α co-receptor on CD4+ SPEAR T-cells may increase the potency of the product by conferring additional killing activity to the helper T-cell subset. This dose escalation trial is ongoing and updated clinical and translational data will be presented.Trial RegistrationNCT04044859Ethics ApprovalThe trial was conducted in accordance with the principles of the Declaration of Helsinki and the International Conference on Harmonization Good Clinical Practice guidelines and was approved by local authorities. An independent ethics committee or institutional review board approved the clinical protocol at each participating center. All the patients provided written informed consent before study entry.

Affinity-optimized T cell receptors can enhance the potency of adoptive T cell therapy. Afamitresgene autoleucel (afami-cel) is a human leukocyte antigen-restricted autologous T cell therapy targeting melanoma-associated antigen A4 (MAGE-A4), a cancer/testis antigen expressed at varying levels in multiple solid tumors. We conducted a multicenter, dose-escalation, phase 1 trial in patients with relapsed/refractory metastatic solid tumors expressing MAGE-A4, including synovial sarcoma (SS), ovarian cancer and head and neck cancer ( NCT03132922 ). The primary endpoint was safety, and the secondary efficacy endpoints included overall response rate (ORR) and duration of response. All patients ( N  = 38, nine tumor types) experienced Grade ≥3 hematologic toxicities; 55% of patients (90% Grade ≤2) experienced cytokine release syndrome. ORR (all partial response) was 24% (9/38), 7/16 (44%) for SS and 2/22 (9%) for all other cancers. Median duration of response was 25.6 weeks (95% confidence interval (CI): 12.286, not reached) and 28.1 weeks (95% CI: 12.286, not reached) overall and for SS, respectively. Exploratory analyses showed that afami-cel infiltrates tumors, has an interferon-γ-driven mechanism of action and triggers adaptive immune responses. In addition, afami-cel has an acceptable benefit–risk profile, with early and durable responses, especially in patients with metastatic SS. Although the small trial size limits conclusions that can be drawn, the results warrant further testing in larger studies. In a phase 1 dose-escalation trial in patients with nine different types of solid tumors, MAGE-A4-specific T cells had an acceptable safety profile and exhibited an encouraging overall response rate in patients with synovial sarcoma.

BackgroundThere is indirect evidence that T cell responses can control the metastatic spread of colorectal cancer (CRC). However, an enrichment of CD4+Foxp3+ regulatory T cells (Tregs) has also been documented.ObjectiveTo evaluate whether CRC promotes Treg activity and how this influences anti-tumour immune responses and disease progression.MethodsA longitudinal study of Treg activity on a cohort of patients was performed before and after tumour resection. Specific CD4+ T cell responses were also measured to the tumour associated antigens carcinoembryonic antigen (CEA) and 5T4.ResultsTregs from 62 preoperative CRC patients expressed a highly significant increase in levels of Foxp3 compared to healthy age-matched controls (p=0.007), which returned to normal after surgery (p=0.0075). CD4+ T cell responses to one or both of the tumour associated antigens, CEA and 5T4, were observed in approximately two-thirds of patients and one third of these responses were suppressed by Tregs. Strikingly, in all patients with tumour recurrence at 12 months, significant preoperative suppression was observed of tumour-specific (p=0.003) but not control CD4+ T cell responses.ConclusionThese findings demonstrate that the presence of CRC drives the activity of Tregs and accompanying suppression of CD4+ T cell responses to tumour-associated antigens. Suppression is associated with recurrence of tumour at 12 months, implying that Tregs contribute to disease progression. These findings offer a rationale for the manipulation of Tregs for therapeutic intervention.

BackgroundAfamitresgene autoleucel (afami-cel) is an engineered T-cell receptor (TCR) T-cell therapy targeting tumors expressing melanoma-associated antigen (MAGE) A4 and is the first such therapy with advanced FDA approval for a solid tumor. In the Phase 2 SPEARHEAD-1 trial in patients with advanced synovial sarcoma or myxoid (with/without round cell) liposarcoma, greater long-term afami-cel pharmacokinetic exposure was associated with clinical benefit.1 We explored gene expression profiles and functional characteristics of afami-cel manufactured product (MP, i.e., before infusion into patients) associated with long-term persistence.MethodsAfami-cel MP were flow sorted into transduced (t)CD4+ and tCD8+ subpopulations. Single-cell RNA sequencing was performed on afami-cel tCD4+ and tCD8+ MP subpopulations from 22 and 23 patients, respectively, using 10X Genomics single-cell 5’ technology. In vitro cytotoxicity assays measured killing of a target HLA-A2/MAGE-A4-expressing tumor cell line over 125 hours co-culture with afami-cel MP subpopulations. qPCR specific to the engineered TCR measured afami-cel persistence in patient peripheral blood, with pharmacokinetic exposure calculated as area under the curve over 0–6 months after infusion.ResultsWe saw distinct gene expression profiles associated with greater pharmacokinetic exposure in patients. In tCD8+ MP samples, this was characterized by an effector function and long-lived memory formation expression profile, whereas expression of genes involved in T-cell dysfunction was associated with lower pharmacokinetic exposure. In tCD4+ MP samples, higher exposure was associated with expression of T-cell activation genes and lower exposure was associated with pro-apoptotic, anti-proliferative gene expression, including genes shared with the tCD8+ T-cell dysfunction-like profile. Afami-cel tCD8+ MP samples demonstrated strong cytotoxicity in vitro and sustained cytotoxic activity was associated with greater long-term pharmacokinetic exposure. Loss of initial cytotoxic activity was associated with a higher percentage of cells expressing a T-cell dysfunction-like gene profile. Afami-cel tCD4+ MP samples also displayed in vitro cytotoxic activity, and greater in vitro cytotoxicity of afami-cel tCD4+ T-cells was associated with CD4+ T-cell activation and effector gene expression.ConclusionsWe hypothesize that MP with T-cell subsets poised for sustained effector function and long-lived memory formation are capable of longer post-infusion persistence, sustaining higher afami-cel pharmacokinetic exposure, and will discuss the gene expression programs underlying these different cellular potentials.AcknowledgementsThis study was sponsored by Adaptimmune. Writing/editorial support by Christine Ingleby, DPhil, CMPP, Envision Pharma Inc. (Glasgow, UK) funded by Adaptimmune. The authors would like to thank the patients, their families, caregivers, and the teams involved in the SPEARHEAD-1 trial.Trial RegistrationSPEARHEAD-1 is registered at ClinicalTrials.gov with ID NCT04044768.ReferenceD’Angelo SP, Araujo DM, Abdul Razak AR, et al. Afamitresgene autoleucel for advanced synovial sarcoma and myxoid round cell liposarcoma (SPEARHEAD-1): an international, open-label, phase 2 trial. Lancet. 2024; 403: 1460–1471.Ethics ApprovalSPEARHEAD-1 was approved by local or independent institutional review boards or ethics committees at each participating site and all patients provided written informed consent.

A wealth of evidence obtained using mouse models indicates that CD4.sup.+ CD25.sup.+ FOXP3.sup.+ regulatory T cells (Treg) maintain peripheral tolerance to self-antigens and also inhibit anti-tumor immune responses. To date there is limited information about CD4.sup.+ T cell responses in patients with colorectal cancer (CRC). We set out to measure T cell responses to a tumor-associated antigen and examine whether Treg impinge on those anti-tumor immune responses in CRC patients. Treg were identified and characterized as CD4.sup.+ CD25.sup.+ FOXP3.sup.+ using flow cytometry. An increased frequency of Treg was demonstrated in both peripheral blood and mesenteric lymph nodes of patients with colorectal cancer (CRC) compared with either healthy controls or patients with inflammatory bowel disease (IBD). Depletion of Treg from peripheral blood mononuclear cells (PBMC) of CRC patients unmasked CD4.sup.+ T cell responses, as observed by IFN[gamma] release, to the tumor associated antigen 5T4, whereas no effect was observed in a healthy age-matched control group. Collectively, these data demonstrate that Treg capable of inhibiting tumor associated antigen-specific immune responses are enriched in patients with CRC. These results support a rationale for manipulating Treg to enhance cancer immunotherapy.