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Nov. 16 (Bloomberg) -- A finding that Merck & Co.’s cholesterol pills Vytorin and Zetia didn’t reopen clogged arteries as well as Abbott Laboratories’ Niaspan has set off a medical debate on heart treatment strategies.

In a clinical trial reported yesterday, researchers found a decrease in the thickness of artery walls in patients given Niaspan, while those on Zetia had no change. Artery thickness is believed to be a predictor of risk in heart attack and stroke because it restricts blood flow, the researchers said.

The results released at the annual American Heart Association meeting in Orlando, Florida, may raise doctor awareness of the role of good cholesterol, or HDL, in heart health. It could also pump up sales for Abbott’s drug, a form of niacin, or Vitamin B, that increases HDL, and mean less revenue for Merck’s Zetia and Vytorin, which combines Zetia with the statin simvastatin to lower bad cholesterol, or LDL.

“There will be an up-tick in the use of niacin because of this,” said Steven Nissen, chief of cardiology at the Cleveland Clinic in Ohio, in an interview yesterday. “It was quite a compelling result. Yes, it is a small study; yes, it isn’t a substitute for a large definitive outcomes trial. But I do think it will get attention, and I do think it will inform us about the choices we have about what therapies we should administer.”

Revenue Drop

Revenue for Zetia and Vytorin could fall 20 percent, or $800 million, with a negative finding, said Seamus Fernandez, a Leerink Swann & Co. analyst in a note to investors last week. Sales for the two drugs have dropped 14 percent this year to about $3 billion.

Merck, located in Whitehouse Station, New Jersey, rose 71 cents, or 2.2 percent, to $33.81 in New York Stock Exchange composite trading at 4:15 p.m., and has gained 11 percent this year. Abbott, of Abbott Park, Illinois, increased 68 cents, or 1.3 percent, to $53.63.

Roger Blumenthal, a professor of cardiology at Johns Hopkins University in Baltimore, said the study shouldn’t be used by doctors to decide treatment.

In an editorial released by the New England Journal of Medicine, Blumenthal described artery thickness as a secondary measurement for heart risks that may not give the same result as a study gauging the total number of heart attacks and strokes from use of the drugs. Further, the benefits of Niaspan may also be exaggerated because the study was ended early, he said.

The study wasn’t “large or long enough to draw broad conclusions’,’ said Ken Frazier, Merck’s president of global human health, in an interview yesterday “If people stop lowering LDL there are going to be deaths, that is a fact.”

Four Months Sooner

Allen Taylor, the study author and a cardiologist at Washington Hospital Center in the District of Columbia, said he ended the trial about four months sooner than expected when it became clear that Niaspan had significantly outperformed Zetia.

It wouldn’t have been in the patients’ best interest to keep the trial going, Taylor said in a telephone interview. The study was able to reach a conclusion with fewer patients and over a shorter time period than first thought because the technology being used was more precise than expected, he said.

The negative result is the third in two years for Zetia and Vytorin.

The first trial, dubbed Enhance, found Vytorin didn’t help artery health more than Merck’s Zocor, sold generically as simvastatin for 77 percent less. Data presented in July 2008, in a trial called SEAS, found more patients taking Vytorin developed cancer than those on a placebo, a finding later contradicted in another study.

Merck Study

There are no studies that have shown that Zetia reduces the risk of heart attacks and stroke. Merck is currently working on one such study involving 18,000 patients. The results won’t be available until 2012, a decade after the drug came on the market.

In the Abbott-funded study reported yesterday, called Arbiter-6 Halts, researchers measured the thickness of the neck artery leading to the brain in 208 patients, using an ultra- sound. They were given simvastatin along with either Niaspan, a modified form of vitamin B also known as niacin, or Zetia over 14 months.

The study only looked at patients who had already lowered their LDL cholesterol to the recommended level of 100 milligrams per deciliter of blood or less using a statin.

“We’re answering a simple question that clinicians need to know the answer to in order to take better care of their patients,” said Taylor, the study author. “The trial results are ultra-clear, Niaspan worked better than Zetia and, through that hopefully, patients are going to benefit.”

Heart Attacks, Strokes

Even with statins, which recorded $34 billion in worldwide sales last year, patients are having heart attacks and strokes, so doctors continue to seek additional treatments, said Richard Karas, a professor of medicine at Tufts University medical school in Boston, in a telephone interview.

Previous studies suggest that HDL-raising drugs could double the benefit of lowering bad cholesterol, he said.

Heart disease, the build up of fatty plaque in the arteries, killed 445,687 people in 2005 and is the leading cause of death in the U.S., according to the American Heart Association.

With the introduction of statins and procedures to reopen arteries, the death rate from heart disease declined 34.3 percent between 2005 and 1995 in the U.S., though 1.26 million Americans will have a heart attack this year, according to the heart association.

Digestive Track

One approach to cutting the number of heart attacks has been trying to lower the LDL as much as possible by increasing the dosage of a statin, or using Zetia, which is designed to work in the digestive tract by stopping the absorption of cholesterol from food.

Niaspan, by contrast, works by raising levels of high- density lipoprotein, or HDL cholesterol, believed to protect against heart attacks by collecting excess artery-clogging LDL cholesterol in the blood and taking it to the liver where it can be disposed.

HDL may also provide a protective benefit to the heart and blood vessels through its antioxidants, anti-inflammatory and anti-clotting effects, according to the Mayo Clinic.

Using Niaspan, with $786 million in sales last year, to raise HDL has been limited because the drug can cause facial flushing. Merck is testing a form of niacin in combination with an experimental drug laropiprant and will seek U.S. regulatory approval for the medicine as early as 2010.

“If Niaspan is superior to Zetia in the study, we expect the data to provide the Niaspan franchise with a shot in the arm especially if there are significantly fewer events in the Niaspan group,” said Larry Biegelsen, an analyst with Wells Fargo Advisors LLC in New York, in a note to investors on Oct. 26, before the study’s finding were reported.

Safety Differences

The Arbiter study released today wasn’t large or long enough to detect a significant difference in the rates of heart attacks and strokes, said Taylor, the study author.

Though the research found that 5 percent of patients taking Zetia had a heart attack or stroke compared with 1 percent on Niaspan, that finding is not definitive because of the limited size of the study, Taylor said.

Patients taking Niaspan were more likely to drop out of the study because of side effects, the study showed. About a third of Niaspan patients said they experienced facial flushing.

Zetia and Vytorin have been shown to lower levels of LDL cholesterol better than statins alone and doctors should focus on getting their patients’ LDL cholesterol to the levels recommended by the American Heart Association, said Merck’s head of research Peter Kim said in an interview.

“Lowering LDL is an extremely well validated step toward improving cardiovascular health,” Kim said. “Numerous studies have shown, if you lower LDL you decrease cardiovascular risk and save lives.”

To contact the reporter responsible for this story: Shannon Pettypiece at spettypiece@bloomberg.net.

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