Abstract 6663: Immunostimulatory gene therapy targeting CD40/4-1BB in combination with chemotherapy induces an inflammatory gene profile in tumors from patients with advanced disease

Abstract In the LOKON002 phase I/II clinical trial (NCT03225989), therapy with LOAd703 (delolimogene mupadenorepvec) is investigated in combination with gemcitabine-based chemotherapy in patients with advanced cancer. LOAd703 is an immunostimulatory gene therapy utilizing an oncolytic adenovirus that is engineered to express two transgenes (trimerized membrane-bound CD40L (TMZ-CD40L) and 4-1BBL), which are key players in the induction of an anti-tumor immune response. Herein, we present the preliminary immunological evaluation of the first 27 patients enrolled in the trial. The primary tumor was pancreatic cancer (n=16), colorectal cancer (n=5), ovarian cancer (n=3) or biliary cancer (n=3). Patients received a maximum of eight intratumoral LOAd703 treatments, given biweekly, and chemotherapy was administered at the same time according to standard protocol. Matched tumor biopsies from the injected tumor lesion were taken at baseline and after six LOAd703 treatments, and analyzed for gene expression with nCounter® PanCancer Immune Profiling Panel from NanoString (n=12; 7 patients analyzed so far). Blood samples were collected for isolation of serum samples and peripheral blood mononuclear cells, and these were analyzed with multiplex assays (Meso Scale Diagnostics) (n=15) and flow cytometry (n=27), respectively. Preliminary results indicate that after treatment, most tumors displayed a strong inflammatory profile with an upregulation of gene profiles, which have been shown to predict responses to immune checkpoint inhibitor therapy (T cell inflamed profile (Ayers et al.) & T effector and IFNγ associated profile (Fehrenbacher et al.)). We also noted an upregulation of genes connected to dendritic cell activation and antigen presentation (MHC class I and II, CD80, CD86, TAP1/2), as well as adenoviral-response genes. Moreover, we observed systemic treatment effects after three LOAd703 treatments, as shown by an increase in serum levels of pro-inflammatory cytokines and chemokines (IFNγ, IL-15, CXCL10, CCL2, IL-8, IL-6), as well as an increased percentage of CD8+ effector memory T cells (CD45RA-CCR7-) and PD-1+ CD8+ T cells in the blood. The fractions of natural killer (NK) cells (CD14-CD3-CD56+CD16+) and M2-like macrophages (CD11b+CD163+) were reduced in the blood at that time point. In conclusion, LOAd703 therapy in combination with chemotherapy generated an inflamed tumor microenvironment in tumors that are normally seen as immunologically “cold”. Hence, LOAd703 may be able to prime tumors for immune checkpoint inhibitors or other immunotherapies, such as adoptive T or NK cell transfer. Citation Format: Jessica Wenthe, Emma Eriksson, Sedigheh Naseri, Linda Sandin, Amanda Hahn, Sandra Irenaeus, Anders Sundin, Justyna Leja-Jarblad, Gustav Ullenhag, Tanja Lövgren, Angelica Loskog. Immunostimulatory gene therapy targeting CD40/4-1BB in combination with chemotherapy induces an inflammatory gene profile in tumors from patients with advanced disease [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 6663.