Patients who took Merck & Co.‘s experimental anti-flushing drug in combination with extended-release niacin experienced significantly less facial flushing discomfort than those taking the niacin alone, according to a study released on Wednesday.

Merck’s drug, MK-0524, is designed to limit the flushing side effect associated with niacin, which has been shown to raise levels of HDL, or “good” cholesterol.

MK-0524 was able to reduce flushing without lessening the beneficial effects of the niacin on cholesterol, according to researchers who presented the data at a medical meeting in Chicago.

Flushing, a reddening of the skin accompanied by warming or burning on the face and neck, is a common niacin-induced side effect that often leads patients to discontinue the therapy.

“It has been frustrating because its use has been limited by flushing,” said Christie Ballantyne, professor of medicine at Baylor College of Medicine and a co-author of the study.

“This is very encouraging,” Ballantyne told Reuters in a telephone interview. He said MK-0524 could help harness the beneficial effects of niacin by making it easier to use for patients and doctors.

Merck hopes to combine MK-0524 with its own extended-release niacin as a stand-alone treatment and later combine the two with Zocor, the company’s cholesterol-lowering statin drug.

The U.S. drugmaker is counting on the new medicines to help restore earnings growth hurt by the withdrawal of its Vioxx arthritis drug and generic competition for some of its other medicines. If approved, the new medicines would compete with Kos Pharmaceuticals Inc.‘s extended-release niacin, sold as Niaspan.

The 412-patient, 8-week mid-stage study showed that compared with patients taking niacin and a placebo, those on the Merck drug plus niacin significantly reduced flushing discomfort.

During the first week of therapy, patients in the niacin group on average experienced 2.3 days of moderate to severe flushing, compared with 0.8 days for the Merck drug plus niacin group and 0.2 days for the placebo group.

“There was a reduction in overall flushing, but in particular a big reduction in terms of severe and extreme flushing” with the Merck drug, Ballantyne said.

By weeks six through eight of the study, the rate of moderate or severe niacin-induced flushing in patients also treated with MK-0524 was similar to placebo, Merck said.

Ballantyne noted that flushing also went down in the niacin-alone group to 1.1 days of moderate to severe flushing, compared with 0.3 and 0.2 days in the other groups.

“Over time, people tend to tolerate niacin better,” Ballantyne said.

The patients on average saw HDL rise by 22.9 percent, while LDL, or “bad” cholesterol, fell by 13.2 percent and triglycerides fell by 26.5 percent. There was no difference in the MRK-0524 plus niacin group and the niacin-alone group.

No serious safety issues arose during the eight-week trial, Ballantyne said. “We have to do much larger studies, but it looked good here,” he added.