Acute coronary syndrome (ACS) survivors have heightened risk for subsequent cardiovascular events. All baseline characteristics collected in both the Dal-Outcomes and Dal-GenE trials were considered a Show more
Acute coronary syndrome (ACS) survivors have heightened risk for subsequent cardiovascular events. All baseline characteristics collected in both the Dal-Outcomes and Dal-GenE trials were considered as potential risk markers. A prediction index for subsequent fatal and non-fatal myocardial infarction (MI) following ACS was developed using Cox proportional hazards modeling on data from Dal-Outcomes placebo patients (n=7086). This prediction index was then applied in all Dal-GenE participants (n=5989) to determine whether the reduction in MI observed with dalcetrapib (versus placebo) in patients with the AA genotype at rs1967309 in the ADCY9 gene remained significant, independent of the other markers integrated into the prediction index. Of the 36 baseline variables considered as potential risk markers, 18 contributed to the prediction index with a Harrell's C-index of 0.72 (95% CI, 0.69-0.75) in Dal-Outcomes placebo patients. Prior history of coronary events, LDL-C, blood pressure, A1c, hs-CRP, smoking and age were contributors. The prediction index was strongly predictive when applied to the 5989 AA genotype patients from Dal-GenE, with a HR for MI of 1.92 (95%CI: 1.78-2.08) for each SD increase in score. When adjusting for the prediction index, the HR for dalcetrapib versus placebo was 0.77 (95% CI, 0.63-0.94) in Dal-GenE. Despite guideline directed therapy following ACS, history of prior coronary events and on-treatment LDL-C, A1c, hs-CRP and blood pressure remain determinants of future MI. In the Dal-GenE AA genotype patients, dalcetrapib reduced the rate of MI, independently of those variables. The Dal-GenE 2 trial is designed to confirm this pharmacogenetic hypothesis. Show less
The large HDL particles generated by administration of cholesteryl ester transfer protein inhibitors (CETPi) remain poorly characterized, despite their potential importance in the routing of cholester Show more
The large HDL particles generated by administration of cholesteryl ester transfer protein inhibitors (CETPi) remain poorly characterized, despite their potential importance in the routing of cholesterol to the liver for excretion, which is the last step of the reverse cholesterol transport. Thus, the effects of the CETPi dalcetrapib and anacetrapib on HDL particle composition were studied in rabbits and humans. The association of rabbit HDL to the LDL receptor (LDLr) in vitro was also evaluated. New Zealand White rabbits receiving atorvastatin were treated with dalcetrapib or anacetrapib. A subset of patients from the dal-PLAQUE-2 study treated with dalcetrapib or placebo were also studied. In rabbits, dalcetrapib and anacetrapib increased HDL-C by more than 58% (P < 0.01) and in turn raised large apo E-containing HDL by 66% (P < 0.001) and 59% (P < 0.01), respectively. Additionally, HDL from CETPi-treated rabbits competed with human LDL for binding to the LDLr on HepG2 cells more than control HDL (P < 0.01). In humans, dalcetrapib increased concentrations of large HDL particles (+69%, P < 0.001) and apo B-depleted plasma apo E (+24%, P < 0.001), leading to the formation of apo E-containing HDL (+47%, P < 0.001) devoid of apo A-I. Overall, in rabbits and humans, CETPi increased large apo E-containing HDL particle concentration, which can interact with hepatic LDLr. The catabolism of these particles may depend on an adequate level of LDLr to contribute to reverse cholesterol transport. Show less