Abstract 4506: Discovery of potent, highly selective and orally efficacious SMARCA2 degraders

Abstract In human non-small cell lung cancer, melanoma and other types of human cancers, the mammalian SWItch/Sucrose Non-Fermentable (SWI/SNF) helicase SMARCA4 is frequently mutated, which leads to inactivation of its functions. SMARCA2, a close homologous protein of SMARCA4, is an attractive synthetic lethality target for human cancers with SMARCA4 deficiency. Herein, we report the discovery and biological evaluation of potent, highly selective, orally efficacious SMARCA2 PROTAC degraders exemplified by UM-SMD-8801. UM-SMD-8801 has DC50 <10 nM and Dmax >90% against SMARCA2 and >1,000-fold degradation selectivity over SMARCA4. Consistently, UM-SMD-8801 potently inhibits cell growth in SMARCA4 mutated cancer cell lines with low nanomolar IC50 values and shows >100-fold weaker activity in SMARCA4 wild-type cancer cell lines. UM-SMD-8801 has a good overall pharmacokinetic profile and an excellent oral bioavailability in mice. Oral administration of UM-SMD-8801 is highly effective in reducing SMARCA2 protein by >90% in tumor tissues in mice, while having minimal effect on SMARCA4 protein. UM-SMD-8801 represents a very promising SMARCA2 degrader for extensive evaluation as a potential new therapy for the treatment of SMARCA4-deficient human cancers. Citation Format: Lingying Leng, Lin Yang, Wenbin Tu, Rohan Rej, Srinivasa Rao Allu, Liyue Huang, Wei Jiang, Yu Wang, Jeanne Stuckey, Farzad R Sarkari, Meilin Wang, Lu Wang, Bo Wen, Duxin Sun, Shaomeng Wang. Discovery of potent, highly selective and orally efficacious SMARCA2 degraders [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(6_Suppl):Abstract nr 4506.