TAK-063 is a highly potent, selective, and orally active phosphodiesterase 10A (PDE10A) inhibitor with IC50 of 0.30 nM; >15000-fold selectivity over other PDEs. TAK-063 is currently being evaluated in clinical trials for the treatment of schizophrenia. Phosphodiesterase 10A (PDE10A) is a cAMP/cGMP phosphodiesterase highly expressed in medium spiny neurons (MSNs) in the striatum. TAK-063 represents a promising drug for the treatment of schizophrenia with potential for superior safety and tolerability profiles.