Abstract 5585: ARK102, a novel tri-specific T cell engager targeting TROP2, HER2, and CD3 for treatment of solid tumors

Abstract ARK102 is a novel trispecific T-cell engager in a fragment format lacking an Fc domain, engineered using proprietary platform technology to simultaneously target HER2 and TROP2 while recruiting CD3 T cells for potent redirected cytotoxicity. HER2 and TROP2 are clinically validated tumor-associated antigens that have demonstrated favorable outcomes across multiple therapeutic modalities. However, limited target expression in some tumors can restrict therapeutic efficacy. As HER2 and TROP2 are broadly co-expressed across diverse malignancies, dual targeting of these antigens offers an innovative strategy to enhance tumor binding through increased avidity and to overcome challenges such as tumor heterogeneity, antigen loss, and resistance to existing therapies.Comprehensive in vitro analyses showed that ARK102 effectively binds both target antigens, activates T cells, and mediates T-cell-dependent cytotoxicity in dual and single target-expressing cancer cell lines at sub-nanomolar concentrations. In vivo, ARK102 demonstrated robust, dose-dependent antitumor activity in human PBMC-reconstituted immunodeficient mice bearing HER2- and/or TROP2-expressing tumor xenografts, without dose-limiting toxicity at efficacious doses, and showed antitumor efficacy comparable to or greater than that of benchmark TROP2-ADC and HER2-ADC therapies.Together, these results highlight ARK102 as a potent and selective dual-targeting T-cell engager with the potential to expand treatment options for patients with solid tumors co-expressing HER2 and TROP2. The compelling preclinical efficacy and favorable safety profile strongly support its further clinical evaluation. Citation Format: Kyeongsik Min, Deukjoo Ahn, Sangwoo Park, Jaejin Jeon, Heeyeon Kim, Yongwon Jung, Yong-Boo Kuk, Jeongmin An, Taehwan Jeong, Seungwon Lee. ARK102, a novel tri-specific T cell engager targeting TROP2, HER2, and CD3 for treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5585.