An investigational drug that combines niacin extended-release (ER) and laropiprant, a prostaglandin D2 receptor antagonist, reduces the flushing that often leads to niacin ER discontinuation while preserving the agent's beneficial effects on lipids, according to lead author Darbie Maccubbin, PhD, Merck Research Laboratories, Rahway, New Jersey, et al. The results of this research were presented at the European Society of Cardiology Congress 2007 in Vienna, Austria, September 1 to 5, 2007. The drug is pending FDA approval.
Although the combination of laropiprant and niacin appears to be promising, the safety of blocking a prostaglandin is unknown, according to Steven E. Nissen, MD, chairman of cardiovascular medicine, Cleveland Clinic, Ohio, who was not involved in the study.
The 24-week, double-blind trial involved 1,613 patients with primary hypercholesterolemia or mixed dyslipidemia. Approximately 65% of all patients were taking a statin at baseline. The patients were randomized to treatment with niacin ER/laropiprant 1 g (n=800), niacin ER 1 g (n=543), or placebo (n=270). After 4 weeks of treatment, the doses of the study agents were doubled and patients were treated for an additional 20 weeks.
The use of niacin ER/laropiprant and niacin ER alone demonstrated similar effects on lipid levels. Niacin ER/laropiprant was associated with an 18.9% reduction (P<.001) in mean LDL cholesterol levels, an 18.8% (P<.001) increase in mean high-density lipoprotein (HDL) cholesterol levels, and a 21.7% decrease in median triglyceride levels compared with placebo.
The effect of niacin ER/laropiprant on lipid levels was similar when the combination was administered alone or when it was added to ongoing statin therapy.
The incidence of flushing was reduced among patients receiving niacin ER/laropiprant compared with those receiving niacin alone. During the first week of treatment, 69% of patients receiving combination therapy reported no flushing to mild flushing symptoms versus 44% of patients who received niacin ER monotherapy.
During Weeks 2 through 24, the number of days per week with at least moderate flushing was significantly lower (P<.001) in patients receiving niacin ER/laropiprant compared with those receiving niacin ER alone.