Discovery of SMD-3236: A Potent, Highly Selective and Efficacious SMARCA2 Degrader for the Treatment of SMARC4-Deficient Human Cancers

SMARCA2 is an attractive synthetic lethal target in human cancers with mutated, inactivated SMARCA4. We report herein the discovery of highly potent and selective SMARCA2 PROTAC degraders, as exemplified by SMD-3236, which was designed using a new, high-affinity SMARCA ligand and a potent VHL-1 ligand. SMD-3236 achieves DC₅₀ < 1 nM and D_max > 95% against SMARCA2 and >2000-fold degradation selectivity over SMARCA4. SMD-3236 potently inhibits cell growth in a panel of SMARCA4-deficient cell lines and displays minimal activity in SMARCA4 wild-type cell lines. SMD-3236 induces profound and persistent SMARCA2 depletion in tumor tissues for 1 week with a single administration, while sparing SMARCA4 protein. SMD-3236 effectively inhibits tumor growth with weekly administration in the H838 SMARCA4-deficient human cancer xenograft model at well-tolerated dose schedules. SMD-3236 represents a promising SMARCA2 degrader for extensive evaluation as a new therapy for the treatment of SMARCA4-deficient human cancers.