A substantially optically-pure (S)-trans-{4-[({2-[({1-[3,5-bis(trifluoromethyl) phenyl] ethyl}{5-[2-(methylsulfonyl) ethoxy] pyrimidine-2-yl} amino) methyl]-4-(trifluoromethyl) phenyl} (ethyl) amino) methyl] cyclohexyl} aceitic acid having the effect of reducing the amount of PCSK9 proteins and increasing the amount of LDL receptors, or a salt thereof, or a solvate thereof.本發明係關於降低PCSK9蛋白質量,具有增加LDL受體量作用之實質上為純粹光學性(S)-trans-{4-[({2-[({1-[3,5-雙(三氟甲基)苯基]乙基}{5-[2-(甲基磺醯基)乙氧基]嘧啶-2-基}胺基)甲基]-4-(三氟甲基)苯基}(乙基)胺基)甲基]環己基}乙酸或其鹽,或彼等的溶劑合物。