Cilomilast-d9 is a deuterium-labeled compound that is an inhibitor of phosphodiesterase enzymes, particularly LPDE4 and HPDE4, with IC50 = 100 nM and 120 nM, respectively. These phosphodiesterases are responsible for the hydrolysis of cAMP, a secondary messenger molecule with a variety of roles. Prolonging the lifetime of cAMP has a potentiating effect on signal transduction.
