Immunoreceptor Tyrosine-based Inhibitory Motif Domain Research Articles

AdvanTIG-202: A phase 2 study investigating anti-TIGIT monoclonal antibody ociperlimab plus anti-PD-1 monoclonal antibody tislelizumab in patients with previously treated recurrent or metastatic cervical cancer.

TPS5595 Background: Women with recurrent/metastatic cervical cancer represent a poor prognostic group with high unmet clinical needs. T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT) is a co-inhibitory, immune checkpoint receptor expressed on immune cells and upregulated on T-cells and natural killer cells in multiple solid tumors, inhibiting anticancer immune responses. Ociperlimab (BGB-A1217) is a novel, humanized, monoclonal antibody that binds TIGIT with high specificity and affinity, blocking the interaction with its ligands on tumor cells. Tislelizumab is an anti-PD-1 antibody engineered to minimize binding to FcγR on macrophages to abrogate antibody-dependent phagocytosis, a mechanism of T-cell clearance and potential resistance to anti-PD-1 therapy. Preclinical and clinical studies suggest that dual targeting with anti-TIGIT and anti-PD-1 antibodies produces synergistic immune cell activation and enhanced antitumor activity. Methods: AdvanTIG-202 is a Phase 2, randomized, multicenter, open-label study (NCT04693234). Approximately 167 pts with cervical squamous cell or adenosquamous carcinoma or adenocarcinoma, recruited from 100 centers, whose disease progressed on or after ≥ 1 prior line of chemotherapy for recurrent/metastatic disease will be included in this 2-Part study. In Part 1, approximately 80 pts will be randomized (1:1) to either ociperlimab 900 mg intravenously (IV) in combination with tislelizumab 200 mg IV every 3 weeks (Q3W) (Arm 1), or tislelizumab monotherapy 200 mg IV Q3W (Arm 2), until disease progression, unacceptable toxicity, or withdrawal of consent. In Part 2, Arm 1 will be expanded by approximately 87 additional pts whose tumors are evaluable for PD-L1 expression. The primary endpoint is overall response rate (ORR) (RECIST v1.1) assessed by Independent Review Committee (IRC) in Arm 1. Secondary endpoints are investigator-assessed ORR in Arm 2, IRC-assessed and investigator-assessed ORR in Arm 1, IRC-assessed and investigator-assessed duration of response, progression-free survival, time to response, disease control rate, clinical benefit rate and overall survival, cancer-specific health-related quality of life (HRQoL), safety, pharmacokinetics and immunogenicity in Arms 1 and 2. Exploratory endpoints are generic HRQoL and the association of biomarkers with patient prognosis, response or resistance. Clinical trial information: NCT04693234.

AdvanTIG-203: A randomized phase 2 study comparing anti-TIGIT ociperlimab plus tislelizumab versus tislelizumab plus placebo as second-line treatment in patients with advanced or recurrent esophageal squamous cell carcinoma (ESCC) expressing programmed death-ligand 1 (PD-L1).

TPS4150 Background: The programmed death-1 (PD-1)/PD-L1 pathway plays an important role in tumor induced immunosuppression. PD-L1 overexpression is observed in approximately 30–60% of esophageal cancers and is associated with poor prognosis. Anti-PD-1 agents demonstrate moderate efficacy in PD-L1-positive esophageal cancer in terms of response rate and overall survival, however, long-term outcomes remain poor due to primary and secondary resistance driven by tumor immune escape. The T-cell immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain (TIGIT) is upregulated on T-cells and natural killer cells in multiple solid tumors, which can inhibit anticancer immune responses. Ociperlimab (BGB-A1217) is a novel, humanized, monoclonal antibody that binds TIGIT with high specificity and affinity, blocking the interaction with its ligands on tumor cells. Preclinical and clinical studies suggest that dual targeting with anti-TIGIT and anti-PD-1 antibodies produces synergistic immune cell activation and enhanced antitumor activity. Methods: AdvanTIG-203 is a phase 2, global, randomized, double-blind, placebo-controlled study (NCT04732494) of patients with unresectable, locally advanced, recurrent or metastatic ESCC, who progressed on or after 1st line systemic therapy and whose tumors express PD-L1 (visually estimated combined positive score ≥10%). After stratification by Eastern Cooperative Oncology Group performance status (0 or 1), number of metastatic sites (≤1 or ≥2) and region (Asian or non-Asian), 280 patients will be randomized (1:1) to either ociperlimab 900 mg intravenous (IV) plus tislelizumab 200 mg IV every 3 weeks (Q3W), or tislelizumab plus placebo Q3W, until disease progression (per RECIST v1.1), unacceptable toxicity, death or withdrawal of consent. Co-primary endpoints are investigator-assessed overall response rate (ORR) and overall survival (OS) in the intention-to-treat population. A sample size of 280 patients was estimated to provide approximately 94.8% power to detect a 20% difference in ORR at a one-sided significance level of 0.025. With 198 deaths, the study was estimated to provide approximately 86% power to detect a hazard ratio of 0.65 for OS. Secondary endpoints are ORR by independent review, progression-free survival, duration of response, disease control rate, and clinical benefit rate per investigator and independent assessment, cancer-specific health-related quality of life (HRQoL), and safety. Exploratory endpoints include but are not limited to expression of TIGIT, CD226, CD155, CD112, and PD-L1, pharmacokinetics, immunogenicity, and generic HRQoL measures. Clinical trial information: NCT04732494.

AdvanTIG-105: Phase 1 dose-escalation study of anti-TIGIT monoclonal antibody ociperlimab (BGB-A1217) in combination with tislelizumab in patients with advanced solid tumors.

2583 Background: Anti-programmed death 1 (PD-1) therapy has improved clinical outcomes for patients (pts) with advanced solid tumors but unmet needs remain. T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT) is a co-inhibitory, immune checkpoint receptor. Ociperlimab (OCI; BGB-A1217) is a novel, humanized, monoclonal antibody that binds to TIGIT with high affinity and specificity. OCI has demonstrated competent binding with C1q and all Fcγ receptors and induces antibody-dependent cellular cytotoxicity. Preclinical studies demonstrated dual targeting with OCI and tislelizumab (TIS), an anti-PD-1 antibody, produces synergistic immune cell activation and enhanced antitumor activity. Methods: AdvanTIG-105 is a phase 1, open label, multicenter, dose-escalation study (NCT04047862) that assessed the safety and preliminary antitumor activity of OCI plus TIS in pts with advanced, metastatic, unresectable solid tumors, for which standard therapy was ineffective or unavailable. Eligible pts had an Eastern Cooperative Oncology Group performance score ≤1 and no prior therapy targeting TIGIT. Pts received OCI intravenously (IV) on Day 1 of Cycle 1 and TIS 200 mg IV on Day 8. Pts were monitored for dose-limiting toxicities (DLTs) until Day 28. If tolerated, OCI and TIS were administered sequentially on Day 29 and every 3 weeks (Q3W) thereafter. Pts received escalating doses of OCI (50-900 mg) plus TIS 200 mg. The study objective was determination of recommended phase 2 dose (RP2D) of OCI plus TIS. Study endpoints included assessment of adverse events (AEs), pharmacokinetics and antitumor activity. Data cut-off was October 12 2020. Results: 24 pts with various advanced solid tumors received OCI plus TIS. At baseline, pts had undergone a median of 2 prior treatment regimens; 9/24 (37.5%) pts had received prior immunotherapy. Median follow-up time was 17 weeks. No DLTs were observed. 20 pts had ≥1 treatment emergent AE (TEAE) and most TEAEs were grade ≤2; fatigue (6 pts) and diarrhea (4 pts) were most commonly reported. No pts had grade ≥4 TEAEs or TEAEs leading to death. There were 2 grade 3 immune related AEs (colitis and low cortisol). One pt on OCI 450 mg achieved partial response and 9 pts had stable disease. The longest duration of stable disease was 36 weeks (1 pt on OCI 150 mg). After administration, serum concentration of OCI decreased in a biphasic manner. Exposure to OCI increased proportionally with dose, and TIGIT receptor occupancy was sustained at ≥50 mg doses. Conclusions: OCI in combination with TIS was well tolerated across all doses in pts with advanced solid tumors. The RP2D was OCI 900 mg plus TIS 200 mg Q3W. Clinical trial information: NCT04047862.

AdvanTIG-302: Anti-TIGIT monoclonal antibody (mAb) ociperlimab (OCI) plus tislelizumab (TIS) versus pembrolizumab (PEM) in programmed death ligand-1 (PD-L1) selected, previously untreated, locally advanced, unresectable or metastatic non-small cell lung cancer (NSCLC).

TPS9128 Background: Monotherapy with programmed death 1 (PD-1)/PD-L1 antibodies has improved clinical outcomes for patients (pts) with non-oncogenic driven NSCLC but clinical responses are limited by primary and secondary resistance, and improvements in durability of response are required. T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain (TIGIT) is a co-inhibitory, immune checkpoint receptor upregulated on T-cells and natural killer cells in multiple solid tumors, which can inhibit anticancer immune responses. OCI (BGB-A1217) is a novel, humanized mAb that binds to TIGIT with high affinity and specificity, which has demonstrated competent binding with C1q and all Fcγ receptors while inducing antibody-dependent cellular cytotoxicity. Preclinical and clinical studies suggest that dual targeting with anti-TIGIT and anti-PD-1 antibodies produces synergistic immune cell activation and enhanced antitumor activity. Methods: AdvanTIG-302 is a Phase 3, multicenter, international, randomized, double-blind study (NCT04746924) investigating OCI in combination with TIS compared with PEM in adult pts (≥ 18 years of age) with PD-L1 selected, previously untreated, locally advanced, unresectable or metastatic NSCLC without oncogenic EGFR or ALK mutation. Approximately 605 pts will be randomized 5:5:1 to receive: OCI 900 mg intravenously (IV) plus TIS 200 mg IV every three weeks (Q3W; Arm A), PEM 200 mg IV plus placebo IV Q3W (Arm B) or TIS 200 mg IV plus placebo IV Q3W (Arm C). Pts will be treated until disease progression, loss of clinical benefit, intolerable toxicity or withdrawal of consent. Stratification factors include histology (squamous vs non-squamous) and region (Asian vs non-Asian). Cross-over is not permitted. Key eligibility criteria include histologically confirmed disease, PD-L1 expression ≥ 50%, no known EGFR or ALK mutations and no prior checkpoint inhibitor therapy. Dual primary endpoints are investigator-assessed progression-free survival (PFS; RECIST v1.1) and overall survival (Arms A and B) in the Intention-to-Treat population. Secondary endpoints include PFS (assessed by Blinded Independent Review Committee), investigator-assessed overall response rate and duration of response, safety and tolerability, and patient-reported health-related quality of life (EORTC-QLQ-C30, QLQ-LC13 and EQ-5D-5L; Arms A and B). Exploratory endpoints include disease control rate, clinical benefit rate and time to response. This study will also evaluate the association between biomarkers and response or resistance. Study enrollment has begun and recruitment is ongoing. Clinical trial information: NCT04746924.

Characterization of an Expanded IL-10-Producing-Suppressive T Cell Population Associated with Immune Tolerance.

An increase in the number of glucocorticoid-induced tumor necrosis factor receptor-family related gene/protein (GITR)+CD25- (or fork-head box protein 3: Foxp3-) CD4+ T cells, after treating a mouse model of arthritis with fingolimod (FTY720), and a pathogenic antigen may play a key role in the establishment of immune tolerance. In this study, we characterized a specific expanded T cell subset in this population. Mice with glucose-6-phosphate isomerase peptide (GPI325-339)-induced arthritis were treated with FTY720 (1 mg/kg, per os) and GPI325-339 (10 µg/mouse, intravenously) for five days, starting from the onset of symptoms. The expanded GITR+CD25- (or Foxp3-) CD4+ T cell population and its cytokine production were examined using flow cytometry. Furthermore, time-dependent changes in T-bet and/or early growth response gene 2 (Egr-2) expression in this T cell subset were examined. The density of T cell immunoreceptors with immunoglobulin (Ig) and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)+CD39+ cell subset in the GITR+Foxp3-CD4+ T cell population was significantly increased only in the combined treatment group, compared to that in the untreated and single-treatment groups. In the TIGIT+CD39+GITR+Foxp3-CD4+ T cell population, T-bet+Egr-2+/T-bet+Egr-2- cell ratio increased in the latter stage of the treatment. Furthermore, this T cell subset, which corresponded to a T helper 1 (Th1) response, produced high levels of both interleukin (IL)-10 and interferon (IFN)-γ. In conclusion, expanded TIGIT+CD39+GITR+Foxp3-CD4+ T cells shifted from an effector Th1 to IL-10-producing-suppressor T cell phenotype, which may promote an immune-tolerant state.

Expression of NrasQ61R and MYC transgene in germinal center B cells induces a highly malignant multiple myeloma in mice

AbstractNRAS Q61 mutations are prevalent in advanced/relapsed multiple myeloma (MM) and correlate with poor patient outcomes. Thus, we generated a novel MM model by conditionally activating expression of endogenous NrasQ61R and an MYC transgene in germinal center (GC) B cells (VQ mice). VQ mice developed a highly malignant MM characterized by a high proliferation index, hyperactivation of extracellular signal-regulated kinase and AKT signaling, impaired hematopoiesis, widespread extramedullary disease, bone lesions, kidney abnormalities, preserved programmed cell death protein 1 and T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domain immune-checkpoint pathways, and expression of human high-risk MM gene signatures. VQ MM mice recapitulate most of the biological and clinical features of human advanced/high-risk MM. These MM phenotypes are serially transplantable in syngeneic recipients. Two MM cell lines were also derived to facilitate future genetic manipulations. Combination therapies based on MEK inhibition significantly prolonged the survival of VQ mice with advanced-stage MM. Our study provides a strong rationale to develop MEK inhibition–based therapies for treating advanced/relapsed MM.

Discovery of a novel anti PD-L1 X TIGIT bispecific antibody for the treatment of solid tumors.

The emergence of immune checkpoint inhibitors (ICIs), mainly based on PD-1/PD-L1 blockade has revolutionized the therapeutic landscape of cancer. Despite the huge clinical success ICIs have achieved, about 70% of patients still showed de novo and adaptive resistance. Exploring novel and complementary immune checkpoint molecules in addition to PD-1/PD-L1 is in great urgency. T cell immunoglobulin and ITIM domain (TIGIT) is a co-inhibitory molecule containing an immunoreceptor tyrosine-based inhibition motif (ITIM) within its cytoplasmic tail, and is highly expressed on regulatory T cells and activated CD4+ T, CD8+ T, and NK cells. We generated a novel single chain Fab heterodimeric bispecific IgG antibody format targeting PD-L1 and TIGIT with one binding site for each target antigen. The bispecifc antibody BiAb-1 is based on “knob-into-hole” technology for heavy chain heterodimerization with a glycine serine linker connecting the 3′ end of Cκand the 5′ end of VH to prevent wrong pairing of light chains. BiAb-1 was produced with high expression yields and show simultaneous binding to PD-L1 and TIGIT with high affinity. Importantly, cytokine production was enhanced by BiAb-1 from staphylococcal enterotoxin B (SEB) stimulated PBMCs. BiAb-1 also demonstrated potent anti-tumor efficacy in multiple tumor models and superior activity to PD-1/PD-L1 blockade molecules. In conclusion, we have applied rational antibody engineering technology to develop a monovalent heterodimeric bispecifc antibody, which combines the blockade of both PD-1/PD-L1 and TIGIT/CD155 pathways simultaneously and results in superior anti-tumor efficacy in multiple tumor models over existing anti PD-1/PD-L1 molecules.

Research progress in immune checkpoint inhibitors for lung cancer in China

Immune checkpoint inhibitors (ICIs) have come to play an increasingly prominent role in the treatment of lung cancer, and some are recommended as a first-line treatment for late-stage non-small-cell lung cancer, either as a monotherapy or in combination with chemotherapy. Accordingly, the indications of Food and Drug Administration-approved ICIs have increased. In this background, China has implemented various policies to encourage and accelerate the marketing of domestic and imported innovative antitumor drugs. Eight ICIs have been approved in China. Among these, four imported programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitors have received approval for six indications, and one domestic PD-1 inhibitor has received approval for one indication for lung cancer in 2018. Numerous clinical trials of ICIs for lung cancer are underway in China. This review aims to summarize the recent advances and future directions of ICIs, including PD-1 inhibitors, PD-L1 inhibitors, cytotoxic T lymphocyte-associated antigen-4 inhibitors, bi-specific antibodies, and a novel inhibitor of T-cell immune-receptor with Ig and immunoreceptor tyrosine-based inhibitory motif domains in immunotherapies for lung cancer in China.

Modelling of Immune Checkpoint Network Explains Synergistic Effects of Combined Immune Checkpoint Inhibitor Therapy and the Impact of Cytokines in Patient Response.

Simple SummaryThe future of cancer immunotherapy relies on a combination of individually targeted therapies. However, a lot of experiments are needed to define the most effective combinations of drugs. A computational and modelling approach could help reduce the number of experiments and suggest optimal treatments to test. This article presents a logical model of T cell activation influenced by immune checkpoints, and explores the effect of these checkpoints, suggests mechanisms that would explain why some treatments might be better suited than others. The model includes not only programmed cell death protein 1 (PD1) and cytotoxic T-lymphocyte-associated protein 4 (CTL4) downstream pathways but also those of other immune checkpoints such as T cell immunoglobulin and ITIM (immunoreceptor tyrosine-based inhibition motif) domain (TIGIT), lymphocyte activation gene 3 (LAG3), T cell immunoglobulin and mucin domain-containing protein 3 (TIM3), cluster of differentiation 226 (CD226), inducible T-cell costimulator (ICOS), and tumour necrosis factor receptors (TNFRs).After the success of the new generation of immune therapies, immune checkpoint receptors have become one important center of attention of molecular oncologists. The initial success and hopes of anti-programmed cell death protein 1 (anti-PD1) and anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) therapies have shown some limitations since a majority of patients have continued to show resistance. Other immune checkpoints have raised some interest and are under investigation, such as T cell immunoglobulin and ITIM (immunoreceptor tyrosine-based inhibition motif) domain (TIGIT), inducible T-cell costimulator (ICOS), and T cell immunoglobulin and mucin domain-containing protein 3 (TIM3), which appear as promising targets for immunotherapy. To explore their role and study possible synergetic effects of these different checkpoints, we have built a model of T cell receptor (TCR) regulation including not only PD1 and CTLA4, but also other well studied checkpoints (TIGIT, TIM3, lymphocyte activation gene 3 (LAG3), cluster of differentiation 226 (CD226), ICOS, and tumour necrosis factor receptors (TNFRs)) and simulated different aspects of T cell biology. Our model shows good correspondence with observations from available experimental studies of anti-PD1 and anti-CTLA4 therapies and suggest efficient combinations of immune checkpoint inhibitors (ICI). Among the possible candidates, TIGIT appears to be the most promising drug target in our model. The model predicts that signal transducer and activator of transcription 1 (STAT1)/STAT4-dependent pathways, activated by cytokines such as interleukin 12 (IL12) and interferon gamma (IFNG), could improve the effect of ICI therapy via upregulation of Tbet, suggesting that the effect of the cytokines related to STAT3/STAT1 activity is dependent on the balance between STAT1 and STAT3 downstream signalling.

Recombinant oncolytic adenovirus expressing a soluble PVR elicits long-term antitumor immune surveillance

Oncolytic virotherapy (OVT) has been suggested to be effective. However, the suppressive effects of checkpoints and insufficient costimulatory signals limit OVT-induced antitumor immune responses. In this study, we constructed a replicative adenovirus, Ad5sPVR, that expresses the soluble extracellular domain of poliovirus receptor (sPVR). We showed that sPVR can bind to both T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) and CD226, and the binding affinity of sPVR to TIGIT is stronger than that of PVR to CD226. In the H22 hepatocellular carcinoma (HCC) ascites model, Ad5sPVR treatment increased the infiltration of CD8+ T cells and the release of interferon (IFN)-γ, exhibiting an antitumor effect with long-term tumor-specific immune surveillance. In line with this, Ad5sPVR also effectively improved antitumor outcomes in solid tumors. In conclusion, while Ad5sPVR plays a role in oncolysis and transforms cold tumors into hot tumors, sPVR expressed by Ad5sPVR can block the PVR/TIGIT checkpoint and activate CD226, thereby greatly improving the efficacy of OVT. This study provides a new way to develop potential oncolytic viral drugs.

Higher TIGIT+CD226- γδ T cells in Patients with Acute Myeloid Leukemia

ABSTRACT The diverse structural and functional heterogeneity of γδ T cells is related to their distinct role in cancer immunity. The different phenotypes of γδ T cells in patients with acute myeloid leukemia (AML) is far from clear. In particular, the expression pattern of co-inhibitory and co-stimulatory receptors on γδ T cells remains unknown. In this study, we analyzed the distribution of γδ T cell subsets by expression of the immune checkpoint co-inhibitor TIGIT (T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain) and its competing co-stimulatory receptor CD226 in AML patients of different clinical statuses (including de novo AML, AML in non-remission (NR), and AML in complete remission (CR)). Our data demonstrated an imbalanced distribution of TIGIT and CD226 on γδ T cells with a decrease in CD226+ γδ T cells and an increase in TIGIT+ γδ T cells in de novo AML patients, while TIGIT−CD226+ γδ T cells were restored in AML patients who achieved CR after chemotherapy. Moreover, the patients who had higher TIGIT+CD226− γδ T cells showed lower overall survival rate for non-M3 AML, which may be considered a novel prognostic immune biomarker. In conclusion, our study reveals for the first time that imbalance in the TIGIT/CD226 axis might be related to different clinical outcomes for AML patients. Abbreviations: AML: acute myeloid leukemia; CR: complete remission; ICs: immune checkpoints; PD-1: programmed death-1; γδ T cells: gamma delta T cells; TCR: T cell receptor; MHC: major histocompatibility complex; TIGIT: T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain; NK: natural killer; PB: Peripheral blood; NR: non-remission; FAB: French-American-British; WHO: World Health Organization; HIs: healthy individuals; OS: overall survival

TIGIT Can Exert Immunosuppressive Effects on CD8+ T Cells by the CD155/TIGIT Signaling Pathway for Hepatocellular Carcinoma In Vitro.

The efficacy of adoptive cellular immunotherapy against cancer cells is limited due to the presence of immunosuppressive cells within the solid tumor microenvironment. The upregulation of certain coinhibitory receptors may lead to exhaustion of the immune effector cells. T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an immune inhibitory receptor expressed by regulatory T cells and activated T cells and natural killer cells. The aim of this study was to determine the immunosuppressive effects of CD155/TIGIT signaling on CD8 T cells of adoptive cellular immunotherapy in hepatocellular carcinoma (HCC). Our studies found that CD155 was overexpressed in HCC, and CD155 HCC cells upregulated TIGIT on CD8 T cells, which decreased the secretion of interferon-γ, tumor necrosis factor-α, and interleukin-17A and increased that of interleukin-10 from the effector cells. However, TIGIT blockade or CD155-knockdown reversed the inhibitory effect of HCC cells on CD8 T-cell effector function. These results indicate that TIGIT can exert an immunosuppressive effect on CD8 T cells by modulating cytokine production through CD155, and is a promising target to optimize adoptive cellular immunotherapy against HCC.

TIM-3 and TIGIT are possible immune checkpoint targets in patients with bladder cancer.

The resurgence of immunotherapy as an effective anticancer strategy has been coupled with more mature understandings of the underlying immune pathways and the development of novel immune checkpoint targets. The clinical development of antibodies first directed against cytotoxic T-lymphocyte-associated antigen 4, and later against program death 1, achieved durable disease control in a subset of patients across a large number of tumor types. Previous work demonstrates that targeting the programmed death 1 pathway alone does not result in complete restoration of T cell function and in some cancers, targeting this axis does not restore T cell function at all, suggesting a need to identify other molecules and inhibitory pathways that are involved in T cell exhaustion. In a comprehensive immune profiling study of patients with bladder cancer, we demonstrate T-cell immunoglobulin domain and mucin domain-containing molecule and T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain as possible targets as perhaps monotherapy or in combination with other immune checkpoint inhibitors.

Immune Response Dysfunction in Chronic Lymphocytic Leukemia: Dissecting Molecular Mechanisms and Microenvironmental Conditions.

Representing the major cause of morbidity and mortality for chronic lymphocytic leukemia (CLL) patients, immunosuppression is a common feature of the disease. Effectors of the innate and the adaptive immune response show marked dysfunction and skewing towards the generation of a tolerant environment that favors disease expansion. Major deregulations are found in the T lymphocyte compartment, with inhibition of CD8+ cytotoxic and CD4+ activated effector T cells, replaced by exhausted and more tolerogenic subsets. Likewise, differentiation of monocytes towards a suppressive M2-like phenotype is induced at the expense of pro-inflammatory sub-populations. Thanks to their B-regulatory phenotype, leukemic cells play a central role in driving immunosuppression, progressively inhibiting immune responses. A number of signaling cascades triggered by soluble mediators and cell–cell contacts contribute to immunomodulation in CLL, fostered also by local environmental conditions, such as hypoxia and derived metabolic acidosis. Specifically, molecular pathways modulating T-cell activity in CLL, spanning from the best known cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death 1 (PD-1) to the emerging T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)/CD155 axes, are attracting increasing research interest and therapeutic relevance also in the CLL field. On the other hand, in the microenvironment, the B cell receptor (BCR), which is undoubtedly the master regulator of leukemic cell behavior, plays an important role in orchestrating immune responses, as well. Lastly, local conditions of hypoxia, typical of the lymphoid niche, have major effects both on CLL cells and on non-leukemic immune cells, partly mediated through adenosine signaling, for which novel specific inhibitors are currently under development. In summary, this review will provide an overview of the molecular and microenvironmental mechanisms that modify innate and adaptive immune responses of CLL patients, focusing attention on those that may have therapeutic implications.

Immune Exhaustion of T Cells in Alveolar Echinococcosis Patients and Its Reversal by Blocking Checkpoint Receptor TIGIT in a Murine Model.

The cestode Echinococcus multilocularis infection, a serious health problem worldwide, causes alveolar echinococcosis (AE), a tumor-like disease predominantly located in the liver and able to spread to any organs. Until now, there have been few studies that explore how T-cell exhaustion contributes to the parasite's escape from immune attack and how it might be reversed. In this study, we found that liver T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) expression was significantly enhanced and positively correlated with lesion activity in AE patients. High TIGIT expression in both liver-infiltrating and blood T cells was associated with their functional exhaustion, and its ligand CD155 was highly expressed by hepatocytes surrounding the infiltrating lymphocytes. In co-culture experiments using human blood T cells and hepatic cell line HL-7702, CD155 induced functional impairment of TIGIT+ T cells, and in vitro blockade with TIGIT antibody restored the function of AE patients' T cells. Similar TIGIT-related functional exhaustion of hepatic T cells and an abundant CD155 expression on hepatocytes were observed in E. multilocularis-infected mice. Importantly, in vivo blocking TIGIT prevented T-cell exhaustion and inhibited disease progression in E. multilocularis-infected mice. Mechanistically, CD4+ T cells were totally and CD8+ T cells partially required for anti-TIGIT-induced regression of parasite growth in mice. This study demonstrates that E. multilocularis can induce T-cell exhaustion through inhibitory receptor TIGIT, and that blocking this checkpoint may reverse the functional impairment of T cells and represent a possible approach to immunotherapy against AE.

Psoriasiform Dermatitis Related with T-Cell Immunoreceptor with Immunoglobulin and Immunoreceptor Tyrosine-Based Inhibitory Motif Domains Inhibitor in a Patient with Non-Small-Cell Lung Cancer

Psoriasiform Dermatitis Related with T-Cell Immunoreceptor with Immunoglobulin and Immunoreceptor Tyrosine-Based Inhibitory Motif Domains Inhibitor in a Patient with Non-Small-Cell Lung Cancer

Beyond PD-1: Investigating the Therapeutic Potential of TIGIT Blockade in DLBCL

Background: The PD-1/PD-L1 axis is a dominant cancer immune escape pathway, and PD-1 blockade therapy has greatly benefited patients with select solid tumors and lymphomas. Unfortunately, anti-PD-1 monotherapy has limited efficacy against relapsed/refractory (r/r) diffuse large B cell lymphoma (DLBCL) - a disease where new therapies are needed. Because numerous inhibitory checkpoint receptors have been implicated in driving tumor-specific T cell dysfunction, we hypothesized that combinatorial checkpoint blockade therapy (CBT) would enhance the activity of PD-1-based therapy in r/r DLBCL. T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is a recently identified co-inhibitory receptor expressed on dysfunctional tumor-infiltrating T cells. PD-1 and TIGIT co-blockade therapy has demonstrated impressive activity in pre-clinical solid tumor and myeloma models. However, the degree to which TIGIT is involved in mediating T cell suppression in DLBCL is not fully known. Methods: TIGIT expression on lymphoma-infiltrating T cells (LITs) from 18 fresh lymphoma samples was analyzed by flow cytometry. Multiplex IHC on tissue microarrays (TMAs) was also performed to investigate TIGIT expression in DLBCL samples. The syngeneic murine A20 B cell lymphoma model was employed to study: 1) the kinetics of TIGIT and other co-receptor expression on LITs, 2) the association of TIGIT expression with effector function among LITs, and 3) the effectiveness of anti-TIGIT mono- and combination CBT in mice with established A20 lymphomas. A20 lymphoma tumors were established in groups of Balb/c mice by subcutaneous (SQ) injections of 5 x 106 cells. Expression of TIGIT and other co-receptors in A20 LITs was examined by flow cytometry at various time points. Function of TIGIT+ LITs was assessed by examining cytokine production following ex vivo stimulation with PMA and ionomycin. To test the efficacy of TIGIT blockade, mice received intraperitoneal injections of anti-TIGIT, anti-PD-1, anti-4-1BB, or combinations of these antibodies. Treatments began once tumors reached a diameter of 10 mm and were continued every 3 days for 5 doses. Tumor growth was monitored and compared to that in A20-bearing mice treated with isotype control antibodies. In some experiments, mice that achieved complete tumor rejection following single or dual CBT were re-challenged with A20 cells to investigate immunological memory responses. Results: Across a variety of human lymphomas, flow cytometric analysis revealed that TIGIT was broadly upregulated on LITs, including regulatory T cells and conventional CD4+and CD8+ T cells (Figure A and B). TIGIT expression on LITs in DLBCL was particularly high. Nearly all TIGIT+ LITs were also PD-1+, suggesting that these receptors co-orchestrate a T cell dysfunctional state in the lymphoma environment. Multiplex immunofluorescence staining of DLBCL samples demonstrated that TIGIT was most highly expressed on CD8+ T cells and that TIGIT+ T cells tended to be localized near, and in some cases, surrounding CD20+ lymphoma cells. Consistent with observations in human lymphomas, LITs isolated from murine A20 lymphoma commonly co-expressed TIGIT and PD-1, and the degree of expression correlated directly with tumor volume. This correlation was also present for other co-receptors, including 4-1BB, TIM3, and CTLA-4. Ex vivo restimulation of A20 LITs revealed that TIGIT+ T cells produced lower levels of effector cytokines, such as TNF-α, compared with TIGIT- T cells. In mice with established A20 lymphomas, both TIGIT and PD-1 mono-blockade led to modest delays in tumor outgrowth compared with mice treated with isotype control antibodies. Strikingly, however, combined PD-1 and TIGIT blockade resulted in complete rejection of A20 lymphomas in most mice and led to significantly prolonged survival compared to mice treated with single agent CBT (Figure C). Combination TIGIT and 4-1BB CBT was also remarkably effective in driving rejection of A20 lymphomas, and led to remarkable memory responses. Conclusions: TIGIT promotes immune tolerance in the DLBCL environment. While TIGIT monotherapy has anti-lymphoma activity, combinatorial CBT incorporating anti-TIGIT antibodies drives extremely potent rejection of established lymphomas in mice. These results provide rationale for further study of TIGIT blockade as a therapeutic strategy in r/r lymphomas, including DLBCL. Disclosures Sunseri: iTeos Therapeutics: Research Funding. Wald:iTeos Therapeutics: Employment. Preillon:iTeos Therapeutics: Employment. Smith:Portola Pharmaceuticals: Research Funding. Driessens:iTeos Therapeutics: Employment. Kline:Merck: Honoraria; Merck: Research Funding.

An agonist TIGIT mab suppresses regulatory T cell activity via an IL-2-mediated mechanism

Abstract The co-inhibitory receptor TIGIT (T cell immunoreceptor with Ig and ITIM domains) is a 26 kDa immunoglobulin domain-containing transmembrane protein that contains both intracellular ITIM (Immunoreceptor Tyrosine-based Inhibitory Motif) and ITT (Immunoreceptor Tail Tyrosine) like domains and is found on the surface of Natural Killer and T cells. CD155 (or the poliovirus receptor) and CD112 (or Nectin-2) are natural ligands for both TIGIT and the activating receptor CD226 (or DNAM-1). In addition to the complexity of the TIGIT/DNAM-1 interplay, TIGIT has been demonstrated to drive both cell intrinsic and extrinsic functions. TIGIT binding to CD155 on Dendritic cells can drive reduction of pro-inflammatory cytokines while inducing tolerogenic cytokine secretion (Yu, 2009). More recently regulatory T cells have been demonstrated to express high levels of TIGIT and upon ligation have been demonstrated to induce effector molecules like FGL2 and reported to promote suppressive function (Joller, 2014). We’ve identified an agonist anti-TIGIT monoclonal antibody, TGTB227, that inhibits T cell responses in vitro in both cellular reporter assays and primary memory T cell assays. TGTB227 is a human IgG1k mab that reduced the expression of the transcription factor, Foxp3, on Tregs. Moreover, TGTB227, but not the related TGTB277, reduced the functional suppressive ability of both natural and induced Tregs. Finally, these data support a TIGIT driven intrinsic CD25/IL-2-dependent mechanism for the modulation of Treg activity.

Clinical Significance of Serum Galectin-9 and Soluble CD155 Levels in Patients with Systemic Sclerosis.

Signaling through coinhibitory receptors downregulates the immune response to prevent excessive immune activation and maintain optimal immunity and tolerance. The aim of this study was to examine the levels of the soluble forms of coinhibitory receptors and their ligands, namely, galectin-9 (the ligand of T-cell immunoglobulin and mucin domain 3) and CD155 (the ligand of T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain), and their association with clinical features in patients with systemic sclerosis (SSc). The serum levels of galectin-9 and soluble sCD155 were examined by enzyme-linked immunosorbent assays in patients with SSc, and the results were evaluated with respect to clinical features. Patients with SSc exhibited raised serum levels of galectin-9, but not sCD155. Serum galectin-9 levels were raised not only in patients with diffuse cutaneous SSc but also in patients with limited cutaneous SSc. Furthermore, serum galectin-9 levels correlated positively with the erythrocyte sedimentation rate. In addition, increased serum galectin-9 levels tended to be associated with higher mortality and serious organ involvement. These results suggest that galectin-9, but not CD155, may be involved in the pathogenesis of SSc. In addition, the measurement of serum galectin-9 levels could be used to predict serious organ involvement and high mortality in patients with SSc.

Expression of T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain on CD4+ T cells in patients with atopic dermatitis.

The T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is a co-inhibitory receptor mainly expressed on T cells. Although TIGIT plays an important role in various autoimmune diseases, its role in atopic dermatitis (AD) remains unclear. In this study, we examined the expression levels of TIGIT and their association with clinical features in patients with AD. TIGIT expression on CD4+ T cells, central memory T cells, effector memory T cells and regulatory T cells was determined by flow cytometry. CD4+ T cells exhibited enhanced TIGIT expression in patients with AD compared with healthy individuals. In particular, effector memory T cells and regulatory T cells, but not central memory T cells, exhibited higher TIGIT expression in patients with AD than in healthy individuals. The frequency of TIGIT+ cells among CD4+ T cells was significantly increased in patients with mild AD compared with healthy individuals, while decreased in patients with severe AD. Consistently, the frequency of TIGIT+ cells among CD4+ T cells was negatively correlated with both serum thymus and activation-regulated chemokine levels and immunoglobulin E levels in patients with AD. Furthermore, TIGIT expression on CD4+ T cells inhibited cell proliferation in patients with AD. These results suggest that TIGIT expression on CD4+ T cells in patients with AD may be increased to suppress chronic cutaneous inflammation. Moreover, TIGIT expression may be impaired in a subset of patients with AD, leading to a deterioration of skin inflammation. Our study may provide new insight into a TIGIT pathway-based therapeutic approach for AD.