Adoptive T cell therapy with T cells expressing affinity-enhanced TCRs has shown promising results in phase 1/2 clinical trials for solid and hematological tumors. However, depth and durability of responses to adoptive T cell therapy can suffer from an inhibitory tumor microenvironment. A common immune-suppressive agent is TGF-β, which is secreted by tumor cells and cells recruited to the tumor. We investigated whether human T cells could be engineered to be resistant to inhibition by TGF-β. Truncating the intracellular signaling domain from TGF-β receptor (TGFβR) II produces a dominant-negative receptor (dnTGFβRII) that dimerizes with endogenous TGFβRI to form a receptor that can bind TGF-β but cannot signal. We previously generated specific peptide enhanced affinity receptor TCRs recognizing the HLA-A*02–restricted peptides New York esophageal squamous cell carcinoma 1 (NY-ESO-1)157–165/l-Ag family member-1A (TCR: GSK3377794, formerly NY-ESO-1c259) and melanoma Ag gene A10254–262 (TCR: ADP-A2M10, formerly melanoma Ag gene A10c796). In this article, we show that exogenous TGF-β inhibited in vitro proliferation and effector functions of human T cells expressing these first-generation high-affinity TCRs, whereas inhibition was reduced or abolished in the case of second-generation TCRs coexpressed with dnTGFβRII (e.g., GSK3845097). TGF-β isoforms and a panel of TGF-β–associated genes are overexpressed in a range of cancer indications in which NY-ESO-1 is commonly expressed, particularly in synovial sarcoma. As an example, immunohistochemistry/RNAscope identified TGF-β–positive cells close to T cells in tumor nests and stroma, which had low frequencies of cells expressing IFN-γ in a non–small cell lung cancer setting. Coexpression of dnTGFβRII may therefore improve the efficacy of TCR-transduced T cells.

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Chimeric Antigen Receptor (CAR)-redirected T cells show great efficacy in the patient-specific therapy of hematologic malignancies. Here, we demonstrate that a DARPin with specificity for CD4 specifically redirects and triggers the activation of CAR engineered T cells resulting in the depletion of CD4+ target cells aiming for elimination of the human immunodeficiency virus (HIV) reservoir.

BackgroundNY-ESO-1–specific T cells (letetresgene autoleucel [lete-cel] GSK3377794) are autologous CD4+ and CD8+ T cells transduced to express a high-affinity T-cell receptor (TCR) capable of recognizing NY-ESO-1 and LAGE-1a antigens in complex with human leukocyte antigen (HLA)-A*02. NY-ESO-1 (CTAG1B) and LAGE-1a (CTAG2) are tumor-associated antigens (TAA) that share the SLLMWITQC peptide bound to human leukocyte antigen HLA-A*02 and are expressed in various cancers. Emerging evidence suggests that TCR-engineered T cells targeting NY-ESO-1 hold promise for patients with solid tumors.1 Approximately 75% of synovial sarcomas can over-express NY-ESO-1 vs 12% of NSCLC,2 however, NSCLC expression of NY-ESO-1/LAGE1-a may have therapeutic potential.3 A separate study using engineered T cells targeting NY-ESO-1 has shown a partial response in a patient with advanced lung adenocarcinoma.4 Decitabine (DAC) is a hypomethylating agent and potent inducer of TAA, including NY-ESO-1.5 We have reported in vitro use of DAC to selectively modulate TAA expression in TAA low-expressing tumor cell lines in order to enhance lete-cel therapy.3 The aim of this study was to assess enhancement of combination therapy with lete-cel and DAC in an in vivo NSCLC model.MethodsNOD scid gamma (NSG) mice were injected subcutaneously with the human NSCLC tumor cell line NCI-H1703. Upon engraftment, tumor-bearing mice were treated with a 5-day course of DAC or vehicle control followed by 2 days of rest. Lete-cel was infused on Day 8. RNA was isolated from tumor formalin-fixed paraffin-embedded blocks, and levels of NY-ESO-1 and LAGE-1a transcript were measured by RT-qPCR. Expression pattern of the NY-ESO-1 protein was assessed via immunohistochemistry. Efficacy was defined by changes in tumor volume and systemic IFN-γ secretion.ResultsConsistent with our previous in vitro studies, DAC treatment in vivo resulted in induction of NY-ESO-1 and LAGE-1a in NSCLC tumors. Lete-cel in combination with DAC significantly enhanced antitumor efficacy in vivo compared with lete-cel alone. This was associated with increased interferon-γ secretion. Mice that received DAC treatment only did not show statistically significant tumor reduction compared with untreated mice.Ethics ApprovalAll animal studies were ethically reviewed and carried out in accordance with Animals (Scientific Procedures) Act 1986 and the GSK Policy on the Care, Welfare and Treatment of Animals. Human biological samples were sourced ethically and their research use was in accord with the terms of the informed consents under an Institutional Review Board/Ethics Committee approved protocol.ConclusionsGSK is currently enrolling a Phase Ib/IIa, multi-arm, open-label pilot study (NCT03709706) of lete-cel as a monotherapy or in combination with pembrolizumab in HLA-A*02–positive patients with NSCLC whose tumors express NY-ESO-1/LAGE-1a. This work may support rationale for the use of DAC in combination with lete-cel to improve adoptive T-cell therapy by increasing levels of target antigens and antitumor effect in NSCLC.AcknowledgementsFunding: GSKReferencesD’Angelo SP, Melchiori L, Merchant MS, et al. Cancer Discov 2018;8:944–957.Kerkar SP, Wang Z-F, Lasota J, et al. J Immunother 2016;39:181–187.Eleftheriadou I, Brett S, Domogala A, et al. Ann Oncol 2019:30(Suppl 5):v475–v532.Xia Y, Tian X, Wang J, et al. Oncol Lett 2018;16:6998–7007.Schrump DS, Fischette MR, Nguyen DM, et al. Clin Cancer Res 2006;12:5777–5785.