Abstract 3128: HRA00184-C004, preclinical characterization of a novel tissue factor-targeted antibody-drug conjugate

Abstract The physiological function of tissue factor (TF) is to initiate coagulation cascade by forming complex with plasma Factor VII after vascular injury. For Tisotumab vedotin (Tivdak), a TF targeting antibody-drug conjugate (ADC) approved for the treatment of cervical cancer, bleeding events were prespecified as adverse effects (AEs) of interest, besides ocular toxicity and peripheral neuropathy (known MMAE payload related AE). In order to mitigate the bleeding risk, a next generation of TF-targeting ADC is developed by Hengrui Pharmaceuticals. HRA00184-C004 is a novel ADC comprising a differentiated TF-targeted antibody (HRP07132) conjugated to a proprietary topoisomerase I inhibitor (Dxh, an exatecan derivative) via a protease-cleavable linker. In contrast to most TF-targeting antibodies, the naked HRP07132 does not interfere the interaction between TF and Factor VII or Factor X, has no impact on coagulation function in prothrombin time and thrombin generation assay, therefore reduced bleeding incidence is expected for HRA00184-C004. Meanwhile, HRA00184-C004 exhibited not only potent growth inhibition against multiple TF-expressing cancer cell lines but also bystander-killing effect in vitro. HRA00184-C004 also displayed robust and sustained anti-tumor activities in the PDAC HPAFII (TF high), TNBC MDA-MB-231 (TF moderate) and NSCLC H358 (TF low) TF-expressing xenograft models. Furthermore, in cynomolgus monkey, HRA00184-C004 is well-tolerated over a 6-week period with 12 mg/kg dosing every 3 weeks with acceptable PK profile. Notably, neither coagulation disorder nor skin rash was observed, which are superior to the historical NHP data reported by Tivdak. In conclusion, with the encouraging efficacy in preclinical study and promising safety profiles in NHPs, HRA00184-C004 has demonstrated the best-in-class potential and is scheduled to advance into clinical development. Citation Format: Hanxiao Ying, Lingfeng You, Ning He, Shaoyu Xu, Pu Pu, Sophie Lin, Jun Feng, Zhe Zhang, Xin Ye, Min Hu, Feng He. HRA00184-C004, preclinical characterization of a novel tissue factor-targeted antibody-drug conjugate 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 (6Suppl): Abstract nr 3128.