T cell immunoglobulin and ITIM domain (TIGIT) is an immune checkpoint inhibitor expressed mainly on NK and T cell populations. Antagonist a-TIGIT mAbs in combination with a-PD(L)-1 demonstrated clinical proof of concept in 1L NSCLC.1 2 Belrestotug (previously known as EOS-448 or GSK4428859A) is an antagonistic anti-TIGIT human immunoglobulin G1 (hIgG1) antibody, designed to prevent ligand binding and to engage Fc gamma receptors (FcγR), resulting in a multifaceted mode of action: (i) activate effector T cells and NK cells (ii) modulate antigen-presenting cells, and (iii) deplete suppressive regulatory T cells (Tregs) as well as terminally exhausted CD8 T cells that express the highest levels of TIGIT.3–5 In a first-in-human trial, belrestotug demonstrated a good tolerability profile with early signs of efficacy6 and we reported for the first time intratumoral TIGIT target engagement in the patient tumors.5 Belrestotug is currently being tested in combination with anti-PD1 in solid tumors.
Results
Pharmacodynamic assessment made by flow cytometry in the blood of patients treated with belrestotug in monotherapy and in combination with anti-PD1 (pembrolizumab or dostarlimab) showed (i) increased proportion of proliferating memory CD8+ T and NK cells during the first treatment cycle, (ii) sustained depletion of immunosuppressive Tregs, and (iii) decreased proportion of TIGIT high CD8+ T cells. We demonstrated the terminally exhausted phenotype of the TIGIT high CD8+ T cells targeted by belrestotug by isolating peripheral blood mononuclear cells (PBMCs) from treatment naïve cancer patients. Tregs in the tumor microenvironment (TME) hinder effective tumor immune response and are mainly localized in the stromal area. Stromal Tregs co-expressing several immune checkpoint inhibitors, including TIGIT, have a high immunosuppressive profile and its density is associated with poor clinical outcome.7 We investigated the functional effect of belrestotug combined with anti-PD1 on the TME using a multiplex immunofluorescence (mIF) panel. We observed a decrease of immunosuppressive TIGIT+ Tregs and PD1+ Tregs in the stroma, as well as a spatial reorganization.
Conclusions
Overall, our data suggests a mechanism whereby belrestotug in combination with anti-PD1 induces a more immunocompetent TME driven by immunosuppressive Treg depletion. These data support the clinical development of the doublet therapy to enhance an anti-tumor immune response.
References
Cho BC, et al. Abstract #LBA2 ESMO-IO; 2021 Jonhson ARC-7 ASCO Dec 2022 Yu X, et al, Nature, 2008 Preillon J, et al. Mol Cancer Ther, 2021. Cuende, et al. AACR 2022 Van den Mooter TF, et al. Abstract #CT118 AACR; 2021 Devi-Marulkar, et al, comms Bio, 2022
Abstract Background This study evaluated the safety and efficacy of salvage endoscopic submucosal dissection (ESD) for Barrett’s neoplasia recurrence after radiofrequency ablation (RFA). Methods Data from patients at 16 centers were collected for a multicenter retrospective study. Patients who underwent at least one RFA treatment for Barrett’s esophagus and thereafter underwent further esophageal ESD for neoplasia recurrence were included. Results Data from 56 patients who underwent salvage ESD between April 2014 and November 2022 were collected. Immediate complications included one muscular tear (1.8%) treated with stent (Agree classification: grade IIIa). Two transmural perforations (3.6%; treated with clips) and five muscular tears (8.9%; two treated with clips) had no clinical impact and were not considered as adverse events. Seven patients (12.5%) developed strictures (grade IIIa), which were treated with balloon dilation. Histological analysis showed 36 adenocarcinoma, 17 high grade dysplasia, and 3 low grade dysplasia. En bloc and R0 resection rates were 89.3% and 66.1%, respectively. Resections were curative in 33 patients (58.9%), and noncurative in 22 patients (39.3%), including 11 “local risk” (19.6%) and 11 “high risk” (19.6%) resections. At the end of follow-up with a median time of 14 (0–75) months after salvage ESD, and with further endoscopic treatment if necessary (RFA, argon plasma coagulation, endoscopic mucosal resection, ESD), neoplasia remission ratio was 37/53 (69.8%) and the median remission time was 13 (1–75) months. Conclusion In expert hands, salvage ESD was a safe and effective treatment for recurrence of Barrett’s neoplasia after RFA treatment.
The combined application of linear amplification-mediated PCR (LAM-PCR) protocols with next-generation sequencing (NGS) has had a large impact on our understanding of retroviral pathogenesis. Previously, considerable effort has been expended to optimize NGS methods to explore the genome-wide distribution of proviral integration sites and the clonal architecture of clinically important retroviruses like human T-cell leukemia virus type-1 (HTLV-1). Once sequencing data are generated, the application of rigorous bioinformatics analysis is central to the biological interpretation of the data. To better exploit the potential information available through these methods, we developed an optimized bioinformatics pipeline to analyze NGS clonality datasets. We found that short-read aligners, specifically designed to manage NGS datasets, provide increased speed, significantly reducing processing time and decreasing the computational burden. This is achieved while also accounting for sequencing base quality. We demonstrate the utility of an additional trimming step in the workflow, which adjusts for the number of reads supporting each insertion site. In addition, we developed a recall procedure to reduce bias associated with proviral integration within low complexity regions of the genome, providing a more accurate estimation of clone abundance. Finally, we recommend the application of a "clean-and-recover" step to clonality datasets generated from large cohorts and longitudinal studies. In summary, we report an optimized bioinformatics workflow for NGS clonality analysis and describe a new set of steps to guide the computational process. We demonstrate that the application of this protocol to the analysis of HTLV-1 and bovine leukemia virus (BLV) clonality datasets improves the quality of data processing and provides a more accurate definition of the clonal landscape in infected individuals. The optimized workflow and analysis recommendations can be implemented in the majority of bioinformatics pipelines developed to analyze LAM-PCR-based NGS clonality datasets.
Bovine Leukemia Virus (BLV) and its close relative Human T-cell leukemia virus-1 (HTLV-1) display similar patterns of pathogenesis and genome organisation. The natural host of BLV is cattle, however it is possible to experimentally infect sheep with the virus. Infected sheep develop tumors following a significantly reduced latency period compared to cattle (20 months on average), making for an attractive cancer model. Like HTLV-1, BLV mRNAs/proteins transcribed from the 5’ LTR are silenced in tumors. However, our group and others have recently reported the presence of five highly expressed micro-RNAs transcribed from the BLV genome via a noncanonical RNA polymerase III pathway in BLV induced tumors. It has been noted that one of these micro-RNAs (BLV-miR-B4-3p) shares a seed sequence with miR-29, a regulator of the tumor suppressor HBP1. This observation points to one potential role for a single micro-RNA, however the role of the remaining micro-RNAs remains to be uncovered. In order to further explore potential targets of the BLV micro-RNAs we have carried out high throughput RNA sequencing of a number of experientially induced ovine and natural bovine BLV tumors, in addition to ovine derived BLV tumor cell lines. As a result we have identified a target of the viral-microRNAs and have begun exploring its role in the life cycle of the virus and its potential contribution to tumorigenesis. Data describing the results obtained to date will be discussed.
Abstract Background and aims Inflammatory bowel disease (IBD) is associated with a higher risk of developing colorectal cancer, according to the inflammation-dysplasia-cancer (IDC) sequence from inflammation to colitis-associated colorectal cancer (CAC). The objective of this study was to identify and generate a transcriptomic signature and score, related to the IDC sequence, that could ultimately classify dysplasia and cancer in IBD. Methods Demographics, clinical parameters, histological characteristics and RNA-sequencing data were evaluated on 134 formalin-fixed paraffin-embedded lesions from 2 independent cohorts of IBD patients with low- or high-grade dysplasia (LGD, HGD) and/or CAC. An ordinal logistic regression screened for significant IDC sequence-associated genes that were computed in a transcriptomic signature score. Results Principal component analysis and unsupervised clustering on 1% of the most variable genes showed a good clustering between the 4 lesion groups (Normal Mucosa, Inflamed Mucosa, LGD/HGD, and CAC). A gene signature was identified on 27 genes that correlated with the lesion groups in the exploratory cohort. The most weighted gene in this transcriptomic signature was the long non-coding regulatory RNA KCNQ1OT1, a gate keeper against genomic instability and transposon activation. Based on these 27- genes expression, we built and validated a transcriptomic signature score to classify dysplasia and CAC. The overall accuracy of the transcriptomic signature score was 85.71% in the exploratory cohort and 90.91% in the validation cohort. Conclusion We identified a tissue-based transcriptomic score to classify IDC lesions in IBD patients and uncovered some of the pivotal genes in the carcinogenesis related to inflammation in IBD.
