Results tagged “atherosclerosis” from Pathophilia

Niacin, the B vitamin, may only provide protective benefits in a select group of patients with atherosclerotic vascular disease. This conclusion is based on the somewhat conflicting results of 2 studies, both of which were presented at the ongoing Scientific Sessions of the American Heart Association.

In a highly anticipated, Abbott-sponsored phase 4 trial (abbreviated ARBITER 6-HALTS), extended-release niacin (Niaspan) outperformed Merck's ezetimibe (Zetia) in 5 of 7 outcomes, including a composite clinical outcome. But the small study population (N = 208) was a selective one, in which high-risk statin-treated adults had already attained target LDL levels (<100 mg/dL) and had moderately low HDL levels. Niacin therapy in such patients would be expected to elevate HDL, and ezetimibe treatment would be expected to further lower total cholesterol and LDL levels—which is what the investigators found.

Change in Outcome*	Extended-Release Niacin 2000 mg/d (n = 97)	Ezetimibe 10 mg/d (n = 111)	Statistical Significance
Mean CIMT, mm (primary outcome)	–0.0142 ± 0.0041	-0.0007 ± 0.0035	P = .01
Mean CIMT at 8 months, mm	–0.0102 ± 0.0030	+0.0014 ± 0.0020	P = .001
LDL, mg/dL	–10.0 ± 24.5	–17.6 ± 20.1	P = .01
HDL, mg/dL	+7.5 ± 9.2	–2.8 ± 5.7	P < .001
Cholesterol, mg/dL	–6.9	–18.8	P = .025
Triglycerides, mg/dL	–36	–9	P = .018
Major CV events	2/160	9/165	P = .04
Adverse events leading to study withdrawal	17/27	3/9	P = .12
Adherence to study medication, %	88 ± 15	95 ± 8	P = .001

In another small study (Abstract 685), this time of 145 statin-treated elderly patients in the Baltimore area, extended-release niacin (1500 mg/d) significantly lowered LDL and raised HDL at 18 months, when compared with placebo. But declines in carotid-wall plaque (as measured by MRI) were comparable in the 2 treatment groups. The investigators concluded that the addition of niacin to statin therapy did not provide "further benefit," despite the lipid panel changes.

The hurdle with using and maintaining high-dose niacin therapy is tolerability of the drug. In ARBITER 6-HALTS, 36% of niacin-treated patients experienced flushing, and adherence to study medication was significantly lower.

According to the Niaspan package insert, therapy must be initiated at 500 mg and given at bedtime to reduce the incidence and severity of side effects. The dosage should not be increased by more than 500 mg in any 4-week period. (Consequently the dosage used in ARBITER 6-HALTS could be attained in 3 months or more.) The most common side effects with Niaspan treatment are flushing, diarrhea, nausea, vomiting, increased cough, and pruritus. 

ARBITER 6-HALTS = ARterial Biology for the Investigation of the Treatment Effects of Reducing Cholesterol 6 - HDL and LDL Treatment Strategies in Atherosclerosis; HDL = high-density lipoprotein; LDL = low-density lipoprotein.

N.B.--ARBITER 6-HALTS was terminated early, in June, and stock analysts speculated that the findings favored the addition of niacin to statin monotherapy.

* ARBITER 6-HALTS outcomes were assessed at 14 months, unless otherwise indicated.

News source: HealthDay.

Image of niacin structure from Wikipedia.