SAR studies toward discovery of emvododstat (PTC299), a potent dihydroorotate dehydrogenase (DHODH) inhibitor

Dihydroorotate dehydrogenase (DHODH) is the enzyme that catalyzes a rate-determining step during the de novo synthesis of uridine, an important source of cellular pyrimidine nucleotides. Ability to modulate the activity of this enzyme may be used to control diseases associated with rapid, out-of-control cell growth in oncology, immunology, and virology. Emvododstat (PTC299) is a tetrahydro-β-carboline DHODH inhibitor discovered through the GEMS technology (Gene Expression Modulation by Small-Molecules). Described in this paper is the lead optimization campaign that culminated in the discovery of this highly potent DHODH inhibitor.