The ARBITER 6-HALTS Trial (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies in Atherosclerosis): final results and the impact of medication adherence, dose, and treatment duration.

OBJECTIVES: This report describes the final results of the ARBITER 6-HALTS (Arterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6-HDL and LDL Treatment Strategies in Atherosclerosis) trial. BACKGROUND: The ARBITER 6-HALTS trial was terminated early on the basis of a pre-specified interim analysis showing superiority of niacin over ezetimibe on change in carotid intima-media thickness (CIMT). After termination, an additional 107 subjects completed a close-out assessment. METHODS: Patients with coronary heart disease (CHD) or CHD equivalent with low-density lipoprotein cholesterol <100 mg/dl and high-density lipoprotein cholesterol <50 mg/dl for men or 55 mg/dl for women while receiving stable statin treatment were randomly assigned to ezetimibe (10 mg/day) or extended-release niacin (target dose, 2,000 mg/day). The primary end point was change in mean CIMT, analyzed according to a last observation carried forward method. The relationships of study medication adherence, dosage, and cumulative exposure (product of adherence, dose, and time) with change in CIMT were explored. RESULTS: Results in 315 patients included 208 with 14-month follow-up and 107 after mean treatment of 7 +/- 3 months. Niacin (n = 154) resulted in significant reduction (regression) in mean CIMT (-0.0102 +/- 0.0026 mm; p < 0.001) and maximal CIMT (-0.0124 +/- 0.0036 mm; p = 0.001), whereas ezetimibe (n = 161) did not reduce mean CIMT (-0.0016 +/- 0.0024 mm; p = 0.88) or maximal CIMT (-0.0005 +/- 0.0029 mm; p = 0.88) compared with baseline. There was a significant difference between ezetimibe and niacin treatment groups on mean changes in CIMT, favoring niacin, for both mean CIMT (p = 0.016) and maximal CIMT (p = 0.01). Increased cumulative drug exposure was related to regression of CIMT with niacin, and progression of CIMT with ezetimibe. CONCLUSIONS: Niacin induces regression of CIMT and is superior to ezetimibe for patients taking statins. (Comparative Study of the Effect of Ezetimibe Versus Extended-Release Niacin on Atherosclerosis; NCT00397657).

Extended-release niacin or ezetimibe and carotid intima-media thickness.

BACKGROUND: Treatment added to statin monotherapy to further modify the lipid profile may include combination therapy to either raise the high-density lipoprotein (HDL) cholesterol level or further lower the low-density lipoprotein (LDL) cholesterol level. METHODS: We enrolled patients who had coronary heart disease or a coronary heart disease risk equivalent, who were receiving long-term statin therapy, and in whom an LDL cholesterol level under 100 mg per deciliter (2.6 mmol per liter) and an HDL cholesterol level under 50 mg per deciliter for men or 55 mg per deciliter for women (1.3 or 1.4 mmol per liter, respectively) had been achieved. The patients were randomly assigned to receive extended-release niacin (target dose, 2000 mg per day) or ezetimibe (10 mg per day). The primary end point was the between-group difference in the change from baseline in the mean common carotid intima-media thickness after 14 months. The trial was terminated early, on the basis of efficacy, according to a prespecified analysis conducted after 208 patients had completed the trial. RESULTS: The mean HDL cholesterol level in the niacin group increased by 18.4% over the 14-month study period, to 50 mg per deciliter (P < 0.001), and the mean LDL cholesterol level in the ezetimibe group decreased by 19.2%, to 66 mg per deciliter (1.7 mmol per liter) (P < 0.001). Niacin therapy significantly reduced LDL cholesterol and triglyceride levels; ezetimibe reduced the HDL cholesterol and triglyceride levels. As compared with ezetimibe, niacin had greater efficacy regarding the change in mean carotid intima-media thickness over 14 months (P = 0.003), leading to significant reduction of both mean (P = 0.001) and maximal carotid intima-media thickness (P < or = 0.001 for all comparisons). Paradoxically, greater reductions in the LDL cholesterol level in association with ezetimibe were significantly associated with an increase in the carotid intima-media thickness (R = -0.31, P < 0.001). The incidence of major cardiovascular events was lower in the niacin group than in the ezetimibe group (1% vs. 5%, P = 0.04 by the chi-square test). CONCLUSIONS: This comparative-effectiveness trial shows that the use of extended-release niacin causes a significant regression of carotid intima-media thickness when combined with a statin and that niacin is superior to ezetimibe. (ClinicalTrials.gov number, NCT00397657.)