The present invention provides a CETP activity inhibitor comprising as an
active ingredient a compound represented by the formula (I):wherein R represents a
straight chain or branched
alkyl group; a
straight chain or branched alkenyl group; a lower haloalkyl group; a substituted or unsubstituted cycloalkyl group; a substituted or unsubstituted cycloalkenyl group; a substituted or unsubstituted cycloalkylalkyl group; a substituted or unsubstituted
aryl group, or a substituted or unsubstituted heterocyclic group, X1, X2, X3, and X4 may be the same or different and each represents a
hydrogen atom, a
halogen atom, a lower
alkyl group, a lower haloalkyl group; a lower
alkoxy group; a cyano group; a nitro group; an
acyl group; or an
aryl group, Y represents —CO— or —SO2—, and Z represents a
hydrogen atom or a mercapto-
protecting group, or a
prodrug compound, a pharmaceutically acceptable salt, or
hydrate or solvate thereof. The compounds represented by the formula (I) can increase HDL and at the same time decrease LDL through
selective inhibition of CETP activity and, therefore, is expected to be useful as a new type of a preventive or therapeutic agent for atherosclerosis or
hyperlipidemia.