Zetia doesn’t even move the needle.

That’s the upshot of a long-delayed report on the results of Merck and Schering-Plough’s Enhance trial. The study, which tracked the buildup of fatty plaques in patients using the firms’ Zetia-plus-Zocor combo, Vytorin, to that in patients using Zocor (simvastatin) alone, suggest that while the combination drug does a better job of lowering LDL, or bad cholesterol, Zetia does nothing to enhance the atherosclerosis-slowing benefits of Zocor, a onetime Merck cash cow that lost patent protection in mid-2006.

In fact, the plaques actually grew faster in patients on the combination drug than they did in patients taking Zocor alone.

Dr. Steven Nissen, of the Cleveland Clinic, called the results “shocking” and said Zetia should be relegated to last-resort status among cholesterol-lowering drugs, to be used only if nothing else gets LDL levels down. Vytorin, he said, “is expensive and it adds no benefits” over simvastatin.  

The two-year trial included about 720 patients with a rare inherited condition that causes extremely high cholesterol – most in the Netherlands. Schering-Plough CEO Fred Hassan sought to pooh-pooh the study earlier this month by saying that the (then yet-to-be-released) results couldn’t be extrapolated to the broader population.

Results of the study, completed in April 2006, were initially to be released by March 2007, but the companies stalled, citing the complexity of the data, and proposed changing the primary endpoint before reversing themselves as the delay began attracting press and congressional attention.

Vytorin has been among the most visible and best-supported prescription drugs in recent years. For the first three quarters of 2005, Merck/Schering-Plough spent $115 million on DTC ads for the drug, according to TNS Media Intelligence figures, and the joint venture spent another $94 million on consumer ads for the same period in 2006.

Consumer advertising for the brand is handled by DDB New York, while professional advertising for both Vytorin and Zetia is handled  by Corbett Accel.