STING agonist D61 is a compound that activates the stimulator of interferon genes (STING), leading to the induction of IFN3-inducible secreted alkaline phosphatase (SEAP) and IFN-β-inducible reporter genes in cellular assays, with half-maximal effective concentrations (EC50s) of 52.9 and 116 nM, respectively. At concentrations of 4, 6, and 8 µM, D61 enhances the production of IFN-β and chemokine (C-X-C motif) ligand 10 (CXCL10) mRNA, as well as the phosphorylation of TANK-binding kinase 1 (TBK1), IRF3, and STING in THP-1 monocytes. Additionally, when administered at a dose of 0.25 mg/kg every other day, D61 effectively reduces tumor volume in a CT26 murine colon cancer model without impacting the body weight of the subjects.