Identification and Optimization of 3-Pyrimidin-4-yl-oxazolidin-2-ones as Allosteric and Mutant Specific Inhibitors of IDH1

High throughput screening and subsequent hit validation identified 4-isopropyl-3-(2-((1-phenylethyl)amino)pyrimidin-4-yl)oxazolidin-2-one as a potent inhibitor of IDH1R132H. Synthesis of the 4 diastereomers identified the (S,S)-diastereomer (IDH125) as the most potent isomer, with reasonable cellular activity and excellent selectivity vs IDH1wt. Initial SAR exploration identified the key tolerances and potential for optimization. X-ray crystallography of IDH125 in the homodimer of IDH1R132H identified the allosteric binding site and aided the rationalization for excellent mutant selective inhibition, as well as the lack of activity vs mutant IDH2. Potency improvement and modulation of the in-vitro ADME profile identified (S)-3-(2-(((S)-1-(5-(4-fluoro-3-methylphenyl)pyrimidin-2-yl)ethyl)amino)pyrimidin-4-yl)-4-isopropyloxazolidin-2-one (IDH889) with good in-vivo exposure and in-vivo activity in a mutant IDH1 mouse xenograft model

Discovery and Evaluation of Clinical Candidate IDH305, a Brain Penetrant Mutant IDH1 Inhibitor

Inhibition of mutant IDH1 is being evaluated clinically as a promising treatment option for various cancers with hotspot mutation at Arg¹³². Having identified an allosteric, induced pocket of IDH1^R132H, we have explored 3-pyrimidin-4-yl-oxazolidin-2-ones as mutant IDH1 inhibitors for <i>in vivo</i> modulation of 2-HG production and potential brain penetration. We report here optimization efforts toward the identification of clinical candidate <b>IDH305</b> (<b>13</b>), a potent and selective mutant IDH1 inhibitor that has demonstrated brain exposure in rodents. Preclinical characterization of this compound exhibited <i>in vivo</i> correlation of 2-HG reduction and efficacy in a patient-derived IDH1 mutant xenograft tumor model. <b>IDH305</b> (<b>13</b>) has progressed into human clinical trials for the treatment of cancers with IDH1 mutation

Optimization of 3‑Pyrimidin-4-yl-oxazolidin-2-ones as Allosteric and Mutant Specific Inhibitors of IDH1

High throughput screening and subsequent hit validation identified 4-isopropyl-3-(2-((1-phenylethyl)­amino)­pyrimidin-4-yl)­oxazolidin-2-one as a potent inhibitor of IDH1^R132H. Synthesis of the four separate stereoisomers identified the (<i>S</i>,<i>S</i>)-diastereomer (<b>IDH125</b>, <b>1f</b>) as the most potent isomer. This also showed reasonable cellular activity and excellent selectivity vs IDH1^wt. Initial structure–activity relationship exploration identified the key tolerances and potential for optimization. X-ray crystallography identified a functionally relevant allosteric binding site amenable to inhibitors, which can penetrate the blood–brain barrier, and aided rational optimization. Potency improvement and modulation of the physicochemical properties identified (<i>S</i>,<i>S</i>)-oxazolidinone <b>IDH889</b> (<b>5x</b>) with good exposure and 2-HG inhibitory activity in a mutant IDH1 xenograft mouse model