<p>Apremilast is a novel, orally available small molecule inhibitor of type-4 cyclic nucleotide phosphodiesterase (PDE-4). PDE-4 is a cyclic adenosine monophosphate (cAMP)-specific phosphodiesterase that is predominantly located in inflammatory cells. By inhibiting PDE-4, apremilast increases intracellular levels of cAMP and thereby inhibits the production of multiple proinflammatory mediators including PDE-4, TNF-alpha, interleukin-2 (IL-2), interferon-gamma, leukotrienes, and nitric oxide synthase. By targeting a central component of the inflammatory signaling cascade rather than a single inflammatory marker, PDE-4 inhibition may restore the homeostatic balance between pro- and anti-inflammatory signalling.</p>