By Lewis Krauskopf and Bill Berkrot
ORLANDO, Florida (Reuters) - A high-profile U.S. study raising doubts about the heart-protective effects of widely used niacin came under severe criticism on Tuesday at a major medical meeting.
The government-funded study, whose initial results were released in May and presented at the American Heart Association meeting on Tuesday, found that adding Abbott Laboratories Inc's Niaspan, a long-acting version of niacin, to cholesterol-lowering statins did not further prevent heart attacks, strokes and other adverse events.
Niacin raises "good" HDL cholesterol and the findings raised doubts about the benefits of increasing HDL.
But at a press conference at the meeting, Dr. Philip Barter of the Heart Research Institute in Sydney, Australia, said the Aim-High study was not properly designed to test the benefits of niacin.
"This trial disturbs me greatly," said Barter, who was designated by the AHA conference to critique the study. "The design was such that in no way could it test the hypothesis of raising HDL or the benefit of niacin."
Barter said any conclusions on niacin needed to wait for the results of a much larger study involving a Merck & Co drug that includes niacin. That study involves more than 25,000 patients, as opposed to 3,414 in Aim-High, and is expected to be completed next year.
"If that trial doesn't show a positive effect, niacin is finished," Barter said. "We shouldn't draw any conclusions or change practice based on this."
Niacin, also known as Vitamin B3, has long been known to raise HDL and lower triglycerides, another type of blood fat that raises heart risks.
Millions of heart patients take niacin on the assumption that it will reduce heart risks. Heart disease remains the world's leading cause of death.
AN OVERLY AMBITIOUS GOAL?
In the Aim-High study, all participants were given Zocor, also known as simvastatin, while some were given a second cholesterol-lowering drug, Zetia, to make sure their bad LDL cholesterol stayed at very low levels. More than half of the patients had suffered a heart attack prior to the trial.
The National Heart, Lung, and Blood Institute, part of the National Institutes of Health, announced in May it had stopped the Aim-High study early. An independent panel looked at the interim results and concluded niacin offered no benefits beyond statins, even though it significantly increased HDL and cut triglycerides.
In criticizing the study, Barter said researchers were being "incredibly ambitious" in setting a goal of 25 percent reduction in cardiac events including stroke and heart attack.
Given the study's design, Barter said it would have taken 15 to 20 years to draw any such conclusions.
The results also may have been confounded by the fact that patients who were taking Zocor but not niacin saw their good cholesterol rise, limiting the difference with the group taking niacin.
Other cardiologists also took issue with the study.
"I think the study was poorly designed in the first place, and I agree with Dr. Barter that it doesn't answer the question," said Dr. Steven Nissen, chief of cardiology at the Cleveland Clinic.
Asked if patients should stop taking niacin until its benefit can be clearly determined, Dr Stephen Nicholls also of the Cleveland Clinic said, "Don't throw the baby out with the bath water. It has a number of metabolic effects" beyond HDL raising.
Dr. William Boden, who presented the Aim-High results, said he "respectfully" disagreed with Barter and defended the trial.
"The result is not what we expected to find," said Boden, of the University at Buffalo, New York.
Abbott's Niaspan, the market-leading form of prescription niacin, has annual sales of about $1 billion but is expected to lose exclusivity in late 2013. Abbott's shares were up 0.1 percent in morning trading.
(Reporting by Lewis Krauskopf and Bill Berkrot, additional reporting by Ransdell Pierson in New York; editing by Dave Zimmerman and Gunna Dickson)