Abstract 3281: GEN1042 (DuoBody-CD40x4-1BB)®in combination with PD-1 blockade reverses T-cell exhaustion in vitro

Abstract GEN1042 (DuoBody®-CD40x4-1BB) is an investigational, novel, agonistic, bispecific antibody that combines targeting and conditional activation of CD40 and 4-1BB on immune cells for priming and (re-) activation of tumor-specific immune responses. We previously showed that GEN1042 induces conditional CD40 and 4-1BB agonist activity, leading to dendritic-cell maturation and enhanced T-cell activation and effector functions in vitro. However, dysfunction of exhausted T cells in the solid tumor microenvironment may represent a potential resistance mechanism to checkpoint inhibitors/agonists. Here we utilized a multi-omics approach to evaluate whether GEN1042 could reverse T-cell exhaustion in vitro. Publicly available single cell RNA sequencing datasets were harmonized across multiple solid-tumor indications (including treatment-naïve and anti-PD-1 and/or anti-CTLA-4 pretreated samples) and analyzed for expression of CD40, 4-1BB and PD-1 on various immune-cell subsets based on their transcriptomic signatures to characterize target prevalence. In vitro mixed lymphocyte reaction (MLR) functional assays were performed where unstimulated healthy donor CD3+ T cells or CD3+ T cells exhausted by repeated stimulation with anti-CD3/CD28 beads were co-cultured with allogeneic lipopolysaccharide (LPS)-matured dendritic cells. Cultures were analyzed for cytokine secretion and expression of cell surface proteins. In the unstimulated T cell/mDC MLR assay, concurrent treatment with GEN1042 and PD-1 blockade potentiated IFNγ, TNFα and IL-2 production compared with either compound alone. In the T-cell exhaustion MLR assay, T cells showed increased expression of inhibitory receptors (e.g., TIM-3, LAG-3) and exhibited hyporesponsiveness for both proliferation and cytokine secretion upon restimulation with anti-CD3/CD28 beads. Here, the combined functional effect of GEN1042 plus PD-1 blockade further potentiated IFNγ secretion compared to single agent activity and induced IL-2 at similar levels to that observed for GEN1042 alone. These data suggest that, in addition to enhancing T-cell effector functions during T cell priming, GEN1042 can amplify the magnitude of the immune response in combination with PD-1 blockade by re-establishing the functional activity of dysfunctional T cells. GEN1042 is currently being evaluated in patients with advanced solid tumors in a phase 1/2 clinical trial (NCT04083599). Citation Format: Vanessa M. Spires, Gregg Masters, Christina Yu, Matt Hancock, Monique N. Luijten, Alexander Muik, Kristina Nuermberger, Friederike Gieseke, Tahamtan Ahmadi, Özlem Türeci, Maria Jure-Kunkel, Ugur Sahin, Mark Fereshteh, Homer C. Adams, Jordan M. Blum. GEN1042 (DuoBody-CD40x4-1BB)®in combination with PD-1 blockade reverses T-cell exhaustion in vitro [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3281.