GlaxoSmithKline is developing GSK-356278 as a selective, brain-penetrant phosphodiesterase 4 (PDE4) inhibitor that demonstrates anxiolytic and cognition-enhancing effects. Small molecule phosphodiesterase (PDE) 4 inhibitors have long been known to show therapeutic benefit in various preclinical models of psychiatric and neurologic diseases because of their ability to elevate cAMP in various cell types of the central nervous system. The drug was studied for the treatment of Huntington's disease, depressive and anxiety disorders. GSK-356278 has completed phase I clinical trials for evaluation of the safety, tolerability, and pharmacokinetics in male volunteers with the therapeutic dose for future clinical development.