Darapladib (SB-480848) is a reversible lipoprotein-associated phospholipase A2 (Lp-PLA2) inhibitor with IC50 of 0.25 nM. Phase 3.
During the copper catalysed oxidation of human LDL, Darapladib prevents the production of lyso-PtdCho with IC50 of 4 nM and subsequent monocyte chemotaxis with IC50 of 4 nM.
In the WHHL rabbits, Darapladib (30 mg/kg p.o.) exhibits excellent inhibition of Lp-PLA2 within the atherosclerotic plaque by 95%. Darapladib, as an inhibitor of Lp-PLA2, reduces development of advanced coronary atherosclerosis in diabetic and hypercholesterolemic (DMHC) pigs. In DMHC pigs, darapladib reduces the amount of IgG-immunopositive material that leaked into the brain and also the density of Aβ42-containing neurons.
Treatment of atherosclerosis.
Darapladib (SB-480848) is a reversible lipoprotein-associated phospholipase A2 (Lp-PLA2) inhibitor.
plaque rupture is responsible for the clinical events of ischemic death, myocardial infarction, acute coronary syndromes and ischemic strokes. lipoprotein-associated phospholipase a2 (lp-pla2) seems to play a major role in the development of such high-risk lesions, in both the coronary and carotid arteries. darapladib is a selective inhibitor of lp-pla2.
darapladib potently inhibited lp-pla2 with an ic50 of 270 pm. a lack of selectivity against other secretory pla2s postulated to play a role in atherogenesis had been demonstrated. the percentage inhibition achieved when 1 μm darapladib was evaluated against human secretory pla2s iia, v and x, was 0, 0 and 8.7%, respectively [1].
inhibition of lp-pla2 by darapladib led to attenuation of inflammation in vivo and decreased plaque formation in apoe-deficient mice, suggesting an anti-atherogenic role during the progression of atherosclerosis [2].
[1] bui qt, wilensky rl. darapladib. expert opin investig drugs. 2010;19(1):161-8.
[2] wang wy, zhang j, wu wy, li j, ma yl, chen wh, yan h, wang k, xu ww, shen jh, wang yp. inhibition of lipoprotein-associated phospholipase a2 ameliorates inflammation and decreases atherosclerotic plaque formation in apoe-deficient mice. plos one. 2011;6(8):e23425.
[3] mohler er 3rd, ballantyne cm, davidson mh, hanefeld m, ruilope lm, johnson jl, zalewski a; darapladib investigators. the effect of darapladib on plasma lipoprotein-associated phospholipase a2 activity and cardiovascular biomarkers in patients with stable coronary heart disease or coronary heart disease risk equivalent: the results of a multicenter, randomized, double-blind, placebo-controlled study. j am coll cardiol. 2008;51(17):1632-41.
