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Publication Abstract from PubMed

Indoleamine 2,3-dioxygenase 1 (IDO1), a heme-containing enzyme that mediates the rate-limiting step in the metabolism of l-tryptophan to kynurenine, has been widely explored as a potential immunotherapeutic target in oncology. We developed a class of inhibitors with a conformationally constrained bicyclo[3.1.0]hexane core. These potently inhibited IDO1 in a cellular context by binding to the apoenzyme, as elucidated by biochemical characterization and X-ray crystallography. A SKOV3 tumor model was instrumental in differentiating compounds, leading to the identification of IACS-9779 (62) and IACS-70465 (71). IACS-70465 has excellent cellular potency, a robust pharmacodynamic response, and in a human whole blood assay was more potent than linrodostat (BMS-986205). IACS-9779 with a predicted human efficacious once daily dose below 1 mg/kg to sustain >90% inhibition of IDO1 displayed an acceptable safety margin in rodent toxicology and dog cardiovascular studies to support advancement into preclinical safety evaluation for human development.

Discovery of IACS-9779 and IACS-70465 as Potent Inhibitors Targeting Indoleamine 2,3-Dioxygenase 1 (IDO1) Apoenzyme.,Hamilton MM, Mseeh F, McAfoos TJ, Leonard PG, Reyna NJ, Harris AL, Xu A, Han M, Soth MJ, Czako B, Theroff JP, Mandal PK, Burke JP, Virgin-Downey B, Petrocchi A, Pfaffinger D, Rogers NE, Parker CA, Yu SS, Jiang Y, Krapp S, Lammens A, Trevitt G, Tremblay MR, Mikule K, Wilcoxen K, Cross JB, Jones P, Marszalek JR, Lewis RT J Med Chem. 2021 Aug 12;64(15):11302-11329. doi: 10.1021/acs.jmedchem.1c00679., Epub 2021 Jul 22. PMID:34292726^[2]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.