SJN309

SJN309 is a preclinical-stage small molecule immunotherapeutic being developed by Samjin Pharmaceutical for the treatment of solid tumors. It acts as an antagonist of nuclear receptor subfamily 2 group F member 6 (NR2F6), an intracellular immune checkpoint that suppresses T-cell activation within the tumor microenvironment. By inhibiting NR2F6, SJN309 restores T-cell function and enhances anti-tumor immune responses, offering potential efficacy in immunologically inactive 'cold tumors' that do not respond to conventional immune checkpoint inhibitors. The program was selected as a national project by the Korea Drug Development Fund (KDDF) in 2024 to support its global development and IND-enabling studies.