Abstract 7329: Overcoming systemic toxicity of IL-12-based immunotherapy by tumor-targeting and IL-12 attenuation

Abstract With the recent success of immune checkpoint inhibitors, there is a renewed interest in cytokines as promising agents for cancer immunotherapy. Cytokines are well-established immunomodulators, and several inflammatory cytokines, including IL-12, have demonstrated potent anti-tumor activity. However, systemic administration of IL-12 has been associated with severe immune related adverse events, significantly limiting its therapeutic application. To overcome such narrow therapeutic window, we developed KNP-101, a bispecific Fc-fusion protein consisting of anti-FAP and attenuated IL-12. KNP-101 accumulates in the tumor microenvironment via anti-FAP and thus induces IL-12 activity at the tumor site. In addition, additional mutations were introduced into IL-12 to further mitigate systemic toxicity. Although the IL-12 activity was attenuated, KNP-101 mouse surrogate maintained significant anti-tumor potency in various mouse syngeneic models with a single intravenous injection. In combination therapies with anti-PD-L1, KNP-101 mouse surrogate demonstrated a synergistic anti-tumor effect. Analysis of tumor infiltrated lymphocytes via FACS demonstrated that the effects were mediated by immune cell infiltration. In naïve mouse toxicity test, KNP-101 mouse surrogate was tolerable up to 150 ug/head and no survival issue was observed. Similar toxicity studies were performed in tumor-bearing mice and, KNP-101 mouse surrogate showed safe profiles being tolerable up to 500 ug/head with no survival issues. Noticeably, KNP-101 mouse surrogate induced far less IFNg in serum compared to null/IL-12 suggesting that systemic toxicity was greatly reduced. Furthermore, KNP-101 was tolerable at doses up to 2.4 mg/kg in repeat-dose non-GLP studies conducted in cynomolgus monkey. Notably, KNP-101demonstrated that systemic toxicity of IL-12 therapy can be overcome by tumor-targeting and IL-12 attenuation strategies. KNP-101 exhibited a wide therapeutic window, by showing potent anti-tumor activities and significantly improved safety profiles. These attributes position KNP-101 as a promising therapeutic option for patients facing resistance to current cancer therapies. Citation Format: Jihoon Chang, Byoung Chul Lee. Overcoming systemic toxicity of IL-12-based immunotherapy by tumor-targeting and IL-12 attenuation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 7329.