Abstract 4081: rhIL-7-hyFc (efineptakin-alfa, NT-I7) increases tumor-specific CD8+ T cells despite FOLFOX cytotoxicity effect

Abstract

Abstract rhIL-7-hyFc (efineptakin-alfa; NT-I7) is a potent T cell amplifier, comprised of two molecules of interleukin-7 (IL-7) fused to the hybrid Fc domain of IgD/IgG4 immunoglobulin. NT-I7 safely, significantly, and persistently increases the absolute lymphocyte counts (ALC) in humans in a dose-proportional manner. Importantly, this increase is primarily due to an increase in T cells (1). Previous studies have shown that NT-I7 not only significantly increases the number of CD8+ T cells in peripheral blood but also dramatically boosts the presence of tumor-infiltrating CD8+ T cells, including both tumor-specific (p15E+PD-1+) and tumor non-specific (PD-1-) CD8+ T cells in mice (2). FOLFOX is a chemotherapy regimen composed of 5-fluorouracil, leucovorin, and oxaliplatin that inhibits DNA duplication and eradicates rapidly dividing cells (3). Although the mechanism of FOLFOX results in direct tumor killing, it also has the potential to kill newly dividing lymphocytes during NT-I7 treatment (4-6). Therefore, in this study, we aimed to evaluate the feasibility of combining FOLFOX with NT-I7 in a syngeneic MC38 mouse tumor model. Our results show that NT-I7 improves the efficacy of FOLFOX, irrespective of the timing of NT-I7 administration: simultaneous administration or delayed 3 hours, or 2 days after FOLFOX administration. This improvement persists despite a significant decrease in ALC for the first 6 days, which was significantly lower than the ALC observed with FOLFOX alone. FOLFOX decreases the absolute numbers of tumor non-specific CD8+ T cells. However, adding FOLFOX does not affect the NT-I7-driven increase of tumor-specific CD8+ T cells within the tumor. Taken together, our data demonstrate that FOLFOX does not compromise NT-I7’s ability to increase tumor-specific T cells within the tumor and the combination enhances the anti-tumor response irrespective of the timing of NT-I7 administration. Citation Format: Soung-Min Lee, Miyoung Kim, Sara Ferrando-Martínez, Sun-Kyoung Im, Mankyu Ji, Donghoon Choi. rhIL-7-hyFc (efineptakin-alfa, NT-I7) increases tumor-specific CD8+ T cells despite FOLFOX cytotoxicity effect [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4081.