Abstract 6390: N17350 is an emerging therapeutic modality that selectively kills cancer cells and stimulates anti-tumor immunity
Authors: Gujar Ravindra , Cui Chang , Valdovinos Lilibet , Lee Christine , Arjmand Arezoo , Grigaitis Nicole , Khalid Asna , Reardon Catherine A. , Schoenfelt Kelly Q. , Feau Sonia , Twitty Chris , Becker Lev 
Published: April 2023

Abstract
INTRODUCTION: Cancer is a disease driven by variable genetic mutations. Overcoming this variability while sparing normal cells has stymied broad-acting therapy development. Our innate immune system evolved to clear genetically diverse pathogens and limit host toxicity, raising the possibility that it can produce similar effects in cancer. Previous studies showed that neutrophil elastase (ELANE) - a neutrophil-derived serine protease - killed a wide range of cancer cells without harming non-cancer cells by cleaving CD95, the FAS receptor (Cui et al.,Cell, 2021). ELANE attenuated primary tumor growth and produced a CD8+T cell-mediated abscopal effect to attack metastases. Here we leveraged this ELANE-mediated pathway to produce an optimized N17350 biologic and tested its effects on tumor development, both as a monotherapy and in combination with checkpoint inhibitors. Our findings underscore the viability of N17350 as a new therapeutic modality leveraging innate immunity.
METHODS: Anti-cancer effects of N17350 were examined in vitro and in vivo and compared with standard of care (SoC) agents. For in vitro studies, cells were treated with N17350 and viability was quantified by calcein-AM and immunogenic cell death (ICD) markers. Cancer/non-cancer cells included human/murine cell lines and primary cells isolated from healthy donors and ovarian cancer patients. We further tested the ability of cancer cells to develop resistance to N17350 and FAS-L. For in vivo studies, a single dose of N17350 was delivered intratumorally into CT26 (colon) and 4T1 (metastatic breast) tumors. Effects on primary and metastatic tumor growth, immunology, and survival were assessed in comparison to SoC agents (oxaliplatin, cyclophosphamide) or in combination with a checkpoint inhibitor (anti-CTLA4).
RESULTS: N17350 killed and induced ICD markers in all cancer cell types tested without harming non-cancer cells, while SoC agents were similarly toxic to both cell types. Repeatedly killing E0771 cancer cells with N17350 did not produce resistance, which was observed with a FAS-L that targets CD95 via a distinct mechanism. A single intra-tumoral dose of N17350 produced durable effects in the 4T1 and CT26 models (CT26:75%-100% tumor-free). N17350 induced a robust innate/adaptive immune profile, abscopal effect to limit 4T1 lung metastasis, and synergized with anti-CTLA4 in cold (4T1) and hot (CT26) tumors. Finally, N17350 showed markedly improved efficacy over SoC agents in both models.
CONCLUSIONS: Taken together, our data suggest that N17350 selectively kills cancer cells, produces complete responses in a subset of mice, induces favorable innate and adaptive immunology, and combines with checkpoint inhibitors in cold and hot tumors. Its ability to escape resistance, produce abscopal effects, and outperform SoC chemotherapies warrants further studies of this unique therapeutic modality in a clinical setting.
Citation Format: Ravindra Gujar, Chang Cui, Lilibet Valdovinos, Christine Lee, Arezoo Arjmand, Nicole Grigaitis, Asna Khalid, Catherine A. Reardon, Kelly Q. Schoenfelt, Sonia Feau, Chris Twitty, Lev Becker. N17350 is an emerging therapeutic modality that selectively kills cancer cells and stimulates anti-tumor immunity [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 6390.