Abstract 4509: Discovery of potent and highly efficacious STAT3 PROTAC degraders capable of achieving long-lasting tumor regression

Abstract STAT3 (signal transducer and activator of transcription 3) is a transcription factor and a promising therapeutic targets for cancer and other human diseases. We have previously reported the discovery of SD-36 and SD-91 as potent, selective and highly efficacious STAT3 degraders. In the present study, we report the discovery of highly potent, selective and efficacious new STAT3 degraders. These STAT3 degraders were designed using our high-affinity STAT3 ligands and high-affinity VHL-1 ligands, with UM-STAT3-3100 being the best. In direct comparison, UM-STAT3-3100 is 10-times more potent than SD-36 and SD-91 in inducing STAT3 degradation in cells and are highly selective over other STAT members in vitro and in vivo. A single intravenous administration of UM-STAT3-3100 resulted in complete and long-lasting depletion of STAT3 protein for 48 hrs in tumor and native tissues. Weekly administration of UM-STAT3-3100 at 10 mg/kg achieved complete and long-lasting tumor regression in animal models of human cancer without any signs of toxicity. UM-STAT3-3100 is a promising compound for extensive evaluation for the treatment of human cancers and other human diseases in which STAT3 plays a key role. Citation Format: Ranjan K. Acharyya, Longchuan Bai, Haibin Zhao, Dimin Wu, Metwally Hoda, McEachern Donna, Wen Bo, Duxin Sun, Shaomeng Wang. Discovery of potent and highly efficacious STAT3 PROTAC degraders capable of achieving long-lasting tumor regression 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 4509.