Abstract A009: AFNT-111: A novel TCR-engineered T cell therapy targeting the oncogenic driver KRAS G12V

Abstract

Abstract Mutations in the RAS family are highly prevalent in human cancers, including up to 35% of non-small cell lung, 45% of colorectal, and 95% of pancreatic cancers. Kirsten rat sarcoma viral oncogene homologue (KRAS) is the most frequently mutated RAS oncogene and patients with KRAS mutations have poor responses to standard treatment regimens. Therefore, successful KRAS-targeted therapies represent a high unmet need. The AFNT-111 cellular therapy consists of autologous CD8+ and CD4+ T cells expressing a high affinity TCR specific for the prevalent KRASG12V mutation presented by HLA-A*11:01, one of the most common HLA alleles worldwide. AFNT-111 is engineered to express the CD8α/β coreceptor, enabling a coordinated CD4+/CD8+ tumor response to induce robust T cell activity and persistence while minimizing T cell exhaustion. Lentiviral vector was used to transduce primary healthy human CD4+ and CD8+ T cells with the KRASG12V-specific human TCR and CD8α/β coreceptor. Engineered T cells were assessed against exogenous KRASG12V peptide as well as a panel of tumor cell lines endogenously expressing KRASG12V and probed for in vitro activation, proliferation, cytotoxicity and cytokine secretion. In parallel, in vitro safety studies were performed to evaluate autoantigen cross-reactivity and alloreactivity. In vivo efficacy studies were conducted using established human KRASG12V xenografts in NSG mice. AFNT-111 demonstrated potent functional avidity towards the KRASG12V peptide with no reactivity against KRASWT. Several naturally expressing KRASG12V human tumor cell lines led to significant AFNT-111 T cell activation and proliferation, as well as potent cytotoxicity. The addition of the CD8α/β coreceptor revealed a coordinated and synergistic cytotoxic CD4+ and CD8+ T cell response, enhancing activation of the AFNT-111 cell product. Robust cytotoxicity was associated with increased T cell secretion of IFNγ and TNFα. Durable in vivo anti-tumor efficacy was observed in three established mouse xenograft tumor models. XScan studies using amino acid substitutions of the index KRASG12V peptide revealed a restrictive TCR recognition motif. Further, potentially cross-reactive human self-peptides matching this motif were tested and no significant cross-reactivities were identified. To test alloreactivity, a large lymphoblastoid cell line library was assessed with no alloreactive responses detected. A streamlined manufacturing process has also been developed in which CD4+/CD8+ T cell ratios are controlled, with the final AFNT-111 product retaining a high degree of stem-like properties. AFNT-111 preclinical data demonstrate a highly potent and specific TCR-engineered T cell product that is cytotoxic to KRASG12V-expressing tumor cells both in vitro and in vivo. Cross-reactivity and alloreactivity assessments establish a potentially favorable safety profile of AFNT-111, supporting clinical translation. First-in-human clinical studies will focus on advanced or metastatic pancreatic, colorectal, and lung cancer indications. Citation Format: Michele Hoffmann, Xingyue He, Cheryl Black, Joshua Francis, James Parsons, Christian Roy, Jinsheng Liang, Hongjing Qu, Martin Campbell, Tomasz Sewastianik, Jessica Webb, Aude Chapuis, Thomas Schmitt, Philip Greenberg, Damien Hallet, Markus Vallaster, Piotr Pierog, Gary Shapiro, Hubert Lam, Loic Vincent. AFNT-111: A novel TCR-engineered T cell therapy targeting the oncogenic driver KRAS G12V [abstract]. In: Proceedings of the AACR Special Conference: Targeting RAS; 2023 Mar 5-8; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Res 2023;21(5_Suppl):Abstract nr A009.