Health advisers on Wednesday unanimously recommended use of Merck & Co's cholesterol-lowering drug Vytorin for preventing stroke and other heart problems in patients with chronic kidney disease, but only in those patients not yet on dialysis.

The panel of outside experts convened by the Food and Drug Administration were less convinced about the drug's effectiveness in patients with end-stage renal disease who are already receiving dialysis, voting 6-10 that trial data supported Vytorin use by those patients.

"I've not said that this is a no, I just feel the data are equivocal and do not support approval for that specific use," said Dr. Robert Smith, a professor at Brown University.

The FDA will make the final decision but usually follows the advice of its advisory panels.
Vytorin pairs a new type of cholesterol fighter Zetia, or ezetimibe, with Merck's older statin drug Zocor, or simvastatin.

Vytorin is already approved for lowering cholesterol, but Merck is now hoping to expand its use to prevent heart problems in patients with chronic kidney disease. If approved, this would be the first such treatment.

Chronic kidney disease affects about 14 percent of the U.S. population and puts people at a high risk of developing heart disease and having a stroke or heart attack.

Previous trials of statins have shown little impact on reducing heart risk in patients with kidney disease and many experts have been skeptical about the effectiveness of such therapy.

Early trials of Vytorin raised further skepticism about the medicine as they showed substantially more cancer cases among patients taking the drug than a placebo. However, later research allayed these fears.

The latest Vytorin trial, which followed nearly 9,500 patients for about five years, showed the drug reduced the risk of major vascular problems in patients with advanced chronic kidney disease by 16 percent.

But the trial's results were less pronounced in patients whose kidney problems progressed so much as to require dialysis. Those patients made up about one-third of all trial participants and a portion of the pre-dialysis patients also began receiving dialysis over the course of the trial.

"I feel that there's really insufficient evidence to discriminate between dialysis patients and non-dialysis patients but there's also insufficient evidence to say this drug is beneficial in dialysis patients," said Dr. David Gordon, a panel member from the Division of Cardiovascular Sciences at the National Institutes of Health.

The trial showed that 6.2 percent of patients taking Vytorin went on to require operations to open blocked arteries, compared with 7.8 percent of those taking a dummy pill. The percentage of people having stroke was 3.5 percent compared with 4.6 percent on placebo. A slight decline in risk was also observed with non-fatal heart attacks and cardiac death.

When separated into subgroups, pre-dialysis patients showed a 23 percent risk reduction in major vascular events, while patients on dialysis saw a 6 percent risk reduction.

But because the trial did not specifically study the two subgroups separately, several panel members expressed reluctance at splitting their vote on the drug into two questions and some said they voted "no" to indicate they did not support separating out dialysis patients.

Merck Research Laboratories President Peter Kim welcomed the panel's recommendation and said the company would continue working with the FDA on its review.

Merck's patents on both Vytorin and Zetia expire in 2017. In 2010, Vytorin posted sales of $2 billion and Zetia reaped $2.3 billion.