CHDI-390576, a potent, cell permeable and CNS penetrant class IIa histone deacetylase (HDAC) inhibitor with IC50s of 54 nM, 60 nM, 31 nM, 50 nM for class IIa HDAC4, HDAC5, HDAC7, HDAC9, respectively, shows >500-fold selectivity over class I HDACs (1, 2, 3) and ~150-fold selectivity over HDAC8 and the class IIb HDAC6 isoform.
