Apremilast-d 3 (CC-10004-d 3 ) is deuterium labeled Apremilast. Apremilast (CC-10004) is an orally available inhibitor of type-4 cyclic nucleotide phosphodiesterase ( PDE-4 ) with an IC 50 of 74 nM. Apremilast inhibits TNF-α release by lipopolysaccharide (LPS) with an IC 50 of 104 nM.