Multiparameter Lead Optimization to Give an Oral Checkpoint Kinase 1 (CHK1) Inhibitor Clinical Candidate: (R)-5-((4-((Morpholin-2-ylmethyl)amino)-5-(trifluoromethyl)pyridin-2-yl)amino)pyrazine-2-carbonitrile (CCT245737).Osborne, J.D., Matthews, T.P., McHardy, T., Proisy, N., Cheung, K.M., Lainchbury, M., Brown, N., Walton, M.I., Eve, P.D., Boxall, K.J., Hayes, A., Henley, A.T., Valenti, M.R., De Haven Brandon, A.K., Box, G., Jamin, Y., Robinson, S.P., Westwood, I.M., van Montfort, R.L., Leonard, P.M., Lamers, M.B., Reader, J.C., Aherne, G.W., Raynaud, F.I., Eccles, S.A., Garrett, M.D., Collins, I.
(2016) J.Med.Chem. 59: 5221-5237
- PubMed: 27167172
- DOI: 10.1021/acs.jmedchem.5b01938
- PubMed Abstract:
Multiparameter optimization of a series of 5-((4-aminopyridin-2-yl)amino)pyrazine-2-carbonitriles resulted in the identification of a potent and selective oral CHK1 preclinical development candidate with in vivo efficacy as a potentiator of deoxyribo ...
Multiparameter optimization of a series of 5-((4-aminopyridin-2-yl)amino)pyrazine-2-carbonitriles resulted in the identification of a potent and selective oral CHK1 preclinical development candidate with in vivo efficacy as a potentiator of deoxyribonucleic acid (DNA) damaging chemotherapy and as a single agent. Cellular mechanism of action assays were used to give an integrated assessment of compound selectivity during optimization resulting in a highly CHK1 selective adenosine triphosphate (ATP) competitive inhibitor. A single substituent vector directed away from the CHK1 kinase active site was unexpectedly found to drive the selective cellular efficacy of the compounds. Both CHK1 potency and off-target human ether-a-go-go-related gene (hERG) ion channel inhibition were dependent on lipophilicity and basicity in this series. Optimization of CHK1 cellular potency and in vivo pharmacokinetic-pharmacodynamic (PK-PD) properties gave a compound with low predicted doses and exposures in humans which mitigated the residual weak in vitro hERG inhibition.
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