MK-015(Compound 37) is an inhibitor of CD38. MK-0159 inhibits human, mouse, and rat CD38 (cell-free assays) with IC50 values of 22, 3, and 70 nM, respectively. MK-0159 increases NAD+ (nicotinamide adenine dinucleotide) and reduces ADPR (adenosine diphosphate ribose) in whole blood and heart.