Abstract 3132: A novel dual drug antibody-drug conjugate targeting hTrop2 has synergetic anti-tumor activity in solid tumor models

Abstract Antibody-drug conjugates (ADCs) are emerging therapeutic agents for targeted cancer treatment with remarkable clinical success. However, tumor heterogeneity and microenvironment complexity are still the major factors contributing to drug resistance, recurrence, and metastasis, which cannot be resolved with a mono therapy strategy. We’ve developed a novel dual drug ADC (BiADC), BR113, by conjugating an anti-hTrop2 antibody with a drug linker of a Topoisomerase I inhibitor payload, and another drug linker of an immune stimulator. Our studies show that the homogeneous ADC containing two distinct payloads is a new promising drug class, with two different anti-tumor MOAs, synergistic antigen-specific cell killing potency, desirable pharmacokinetic profiles, and minimal toxicity at therapeutic doses. In the cancer cells and human PBMC co-culture assay, BR113 exerts significantly more potent killing on cancer cells than two individual single-drug ADCs and the combination of two single-drug ADCs, which suggested a synergy on anti-tumor effects of this dual-drug ADC. In the xenograft mouse model studies, BR113 exhibits greater treatment effect and survival benefit than the combo of two single-drug ADCs at various doses. This robust superior anti-tumor activity is further confirmed in a hTrop2-MC38 syngeneic model with a prolonged anti-tumor protection against the tumor re-challenge. Finally, the novel BiADC, BR113, is well tolerated in hTop2 humanized mice after repeated administration. Our findings highlight the therapeutic potential of the BiADC format for treating refractory advanced solid tumors. The outstanding anti-tumor activity across various CDX tumor models and its favorable safety profile in mice support further evaluation of the innovative BiADC, BR113. Citation Format: Jie Zhu, Xiaobei Zhao, Eileen Li, Hong Xu, Lei Nie, Gang Chen, Haibing Wang. A novel dual drug antibody-drug conjugate targeting hTrop2 has synergetic anti-tumor activity in solid tumor models 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 3132.