Multiomic evaluation of TEV-56278, a PD-1-targeted attenuated IL-2 molecule, in a human ex vivo tumor model and association with immune activation with enhanced effector CD8 T cell selectivity.

Abstract

e14506 Background: Interleukin-2 (IL-2) is critical for cancer immunity, but its therapeutic use is limited by systemic toxicity and a narrow therapeutic window. To address this, we developed TEV-56278, an antibody-cytokine fusion protein currently under investigation in a Ph1 dose escalation clinical study. TEV-56278 is designed to deliver an attenuated form of IL-2 (AttIL2) to PD-1-expressing T cells. Unlike similar compounds, TEV-56278 binds to a distinct epitope of PD-1, allowing for combined use with PD-1 blocking antibodies. In mice models, it induced elevation of T cell percentages within tumors and mediated tumor regression without systemic toxicity. To characterize TEV-56278’s mechanism of action and identify potential response/resistance signatures in human samples, we conducted a multiomic analysis on patient-derived tumor fragments (PDTF). Methods: PDTF from 15 renal cell carcinoma patients were treated ex vivo with TEV-56278 [100 µg/ml], aldesleukin [100 ng/ml, as positive control], or a control PD-1 non-targeted-AttIL-2 [100 µg/ml]. Baseline and treated PDTFs were dissociated and sorted for live immune cells and single-cell multiomic profiling was performed. The multiomic dataset includes measurements of cell abundance, cell type-specific RNA and protein expression and clonality of T cell subsets. Cytokine production was measured by multiplex ELISA. All measurements were input into Immunai’s ImmunoDynamics Engine, a proprietary machine learning framework to determine the mechanism of action of TEV-56278. Results: TEV-56278 induces pSTAT5 in PDTF model, supporting highly localized activity of AttIL-2 moiety. TEV-56278 selectively triggers IL-2 signaling in PD1 high T cells and promotes reinvigoration of exhausted CD8+ T cells. In contrast, aldesleukin induces broader transcriptional changes in both PD1 low and PD1 high cell types. TEV-56278 elicits varying degrees of immune activation and a secreted profile associated with immune cell infiltration and PD-1 responsiveness (e.g. CXCL10, CCL20, IL12 p40). The features associated with stronger response are being evaluated to inform indication and patient selection on future trials. Conclusions: We performed in-depth characterization of TEV-56278 in a human tumor ex vivo system that incorporates features of the tumor microenvironment and models the dynamic response of TEV-56278. This study confirms that TEV-56278 targets IL-2 activity to PD-1 expressing T cells within the tumor microenvironment and induces strong immune response, thereby promoting anti-tumor activity. Understanding the mechanisms that drive variable responses in PDTF may improve precision immuno-oncology efforts and help optimize our clinical development strategy.