Cholesteryl ester transfer protein inhibitor torcetrapib and off-target toxicity: A pooled analysis of the rating atherosclerotic disease change by imaging with a new CETP inhibitor (RADIANCE) trials

Background - Torcetrapib, an inhibitor of cholesteryl ester transfer protein, has been shown to increase the cardiovascular event rate despite conferring a significant high-density lipoprotein cholesterol increase. Using data from the Rating Atherosclerotic Disease Change by Imaging with a New CETP Inhibitor (RADIANCE) trials, which assessed the impact of torcetrapib on carotid intima-media thickness (cIMT), we sought to explore potential mechanisms underlying this adverse outcome. Methods and Results - Data from the RADIANCE 1 and 2 studies, which examined cIMT in 904 subjects with familial hypercholesterolemia and in 752 subjects with mixed dyslipidemia, were pooled. Subjects were randomized to either atorvastatin or torcetrapib combined with atorvastatin. Mean common cIMT progression was increased in subjects receiving torcetrapib plus atorvastatin compared with subjects receiving atorvastatin alone (0.0076±0.0011 versus 0.0025±0.0011 mm/y; P=0.0014). Subjects treated with torcetrapib plus atorvastatin displayed higher postrandomization systolic blood pressure and plasma sodium and bicarbonate levels in conjunction with lower potassium levels. The decrease in potassium levels was associated with the blood pressure increase. Markedly, the use of renin-angiotensin-aldosterone system inhibitors tended to aggravate the blood pressure increase. Subjects receiving torcetrapib plus atorvastatin with the strongest low-density lipoprotein cholesterol reduction showed the smallest cIMT progression, whereas subjects with the highest systolic blood pressure increase showed the largest cIMT progression. High-density lipoprotein cholesterol increase was not associated with cIMT change. Conclusions - These analyses support mineralocorticoid-mediated off-target toxicity in patients receiving torcetrapib as a contributing factor to an adverse outcome. The absence of an inverse relationship between high-density lipoprotein cholesterol change and cIMT progression suggests that torcetrapib-induced high-density lipoprotein cholesterol increase does not mediate atheroprotection. Future studies with cholesteryl ester transfer protein inhibitors without off-target toxicity are needed to settle this issue

Efficacy and Safety of Alirocumab 150 mg Every 4 Weeks in Patients With Hypercholesterolemia Not on Statin Therapy: The ODYSSEY CHOICE II Study

Background: The PCSK9 antibody alirocumab (75 mg every 2 weeks; Q2W) as monotherapy reduced low-density lipoprotein-cholesterol (LDL-C) levels by 47%. Because the option of a monthly dosing regimen is convenient, ODYSSEY CHOICE II evaluated alirocumab 150 mg Q4W in patients with inadequately controlled hypercholesterolemia and not on statin (majority with statin-associated muscle symptoms), receiving treatment with fenofibrate, ezetimibe, or diet alone. Methods and Results: Patients were randomly assigned to placebo, alirocumab 150 mg Q4W or 75 mg Q2W (calibrator arm), with dose adjustment to 150 mg Q2W at week (W) 12 if W8 predefined LDL-C target levels were not met. The primary efficacy endpoint was LDL-C percentage change from baseline to W24. Mean baseline LDL-C levels were 163.9 mg/dL (alirocumab 150 mg Q4W, n=59), 154.5 mg/dL (alirocumab 75 mg Q2W, n=116), and 158.5 mg/dL (placebo, n=58). In the alirocumab 150 mg Q4W and 75 mg Q2W groups (49.1% and 36.0% of patients received dose adjustment, respectively), least-squares mean LDL-C changes from baseline to W24 were -51.7% and -53.5%, respectively (placebo [+4.7%]; both groups P<0.0001 versus placebo). In total, 63.9% and 70.3% of alirocumab-treated patients achieved their LDL-C targets at W24. Treatment-emergent adverse events occurred in 77.6% (alirocumab 150 mg Q4W), 73.0% (alirocumab 75 mg Q2W), and 63.8% (placebo) of patients, with injection-site reactions among the most common treatment-emergent adverse events. Conclusions: Alirocumab 150 mg Q4W can be considered in patients not on statin with inadequately controlled hypercholesterolemia as a convenient option for lowering LDL-C. Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02023879