(Adds study details, background, quotes)
By Ransdell Pierson and Bill Berkrot
NEW YORK, Oct 4 (Reuters) - An experimental Merck & Co. (MRK.N) cholesterol drug from the same class as one that failed for Pfizer Inc (PFE.N) had dramatic results in a small clinical trial without safety problems that doomed the Pfizer medicine.
The new treatments, which block a protein known as CETP, are designed to raise levels of “good” HDL cholesterol and the Merck candidate did so spectacularly, according to data presented on Thursday at the Drugs Affecting Lipid Metabolism meeting in New York.
At the second-highest dose tested in the 8-week trial, the Merck drug MK-859 raised levels of heart-protective HDL by 139 percent and cut levels of “bad” LDL cholesterol by 40 percent.
By contrast, the current best-selling drugs to boost HDL — whose active ingredient is niacin — typically raise good cholesterol by only 20 to 30 percent.
Doctors are increasingly turning to HDL drugs because a high percentage of people who suffer heart attacks have low levels of HDL and relatively normal levels of LDL.
The Merck drug did not cause a rise in blood pressure, a side effect that had dogged Pfizer’s now-abandoned torcetrapib and which many believe caused increased deaths that doomed it.
“As hard as we looked, we couldn’t find any increase in blood pressure,” said Daniel Bloomfield, a senior Merck research official who helped lead the study of MK-859.
“The data really point out you can inhibit CETP with MK-859, and substantially reduce LDL and increase HDL, and importantly not raise blood pressure,” he said.
Four doses of the drug, 10 milligrams, 40 mg, 150 mg and 300 mg, were tested against placebo.
“The data suggest any dose would be safe to go forward with” in any future late-stage trials, Bloomfield said.
The incidence of side effects among patients taking the Merck drug, at whatever dose, was similar to those seen among patients given placebos.
But Bloomfield cautioned that his drug’s true safety would not be known until it goes through much larger studies, which typically take 4 to 7 years and focus on the risk of heart attacks and death.
Despite its impressive effects on LDL and HDL cholesterol, Bloomfield said Merck believes U.S. regulators are unlikely to approve MK-859 until such studies are completed.
Pfizer saw an $800 million late stage development program for torcetrapib go down in flames last December when safety monitors shut it down after finding increased deaths among patients taking the drug in clinical trials.
It had been expected to replace Pfizer’s $13 billion a year Lipitor when the world’s most widely prescribed medicine faces generic competition as soon as 2010.
Torcetrapib’s sensational failure left researchers and investors anxious to find out if its dangers might crop up with other CETP inhibitors in development or if they were specific to the Pfizer drug.
Swiss drugmaker Roche Holding AG ROG.VX and its partner Japan Tobacco (2914.T) said on Tuesday they would decide later this year whether to move their own CETP inhibitor into late stage trials.
Merck’s trial of MK-859 involved 589 patients with high levels of LDL cholesterol and/or low levels of HDL.
HDL levels rose by 44 percent and 86 percent, respectively, among patients taking daily 10 milligram and 40 milligram doses of MK-859, while results seen with the highest 300 mg dose were similar to those of the 150 mg group.
Levels of LDL cholesterol fell 16 percent and 27 percent, respectively, among those receiving the two smallest doses of the drug, and fell 39 percent in the highest-dose group.
HDL levels rose only 4 percent in the placebo group, while LDL levels rose 2 percent.
The Merck drug was also tested at all doses in combination with 20 mg doses of Lipitor. The combination did not have any additional impact on raising HDL. But it magnified the impact on LDL, lowering it as much as 68 percent at the highest dose of MRK-859.