Discovery of SD-2301 as a Highly Potent and Selective PROTAC STAT3 Degrader Capable of Achieving Complete Tumor...

STAT3 is a promising therapeutic target for human cancers and other diseases. Herein, we report our development of novel STAT3 proteolysis-targeting chimera degraders using high-affinity STAT3 and Von Hippel-Lindau 1 ligands, which led to the discovery of SD-2301 as a highly potent, selective, and efficacious STAT3 degrader. SD-2301 achieved DC₅₀ = 4 nM and D_max of >95% and is >100 times more potent than SD-36 and SD-91. SD-2301 is highly selective for inducing STAT3 degradation over other Signal Transducer and Activator of Transcription members. SD-2301 inhibited cell growth with IC₅₀ = 5-11 nM in the SU-DHL-1 and SUP-M2 lymphoma cell lines. SD-2301 displayed an excellent pharmacokinetic profile in mice and achieved rapid and persistent depletion of STAT3 protein in native and xenograft tumor tissues in mice. SD-2301 was capable of achieving complete and long-lasting tumor regression in vivo and is a promising STAT3 degrader for the treatment of human cancers and other human diseases.