Merck & Co and Schering-Plough’s Vytorin appears to be better at lowering low-density lipoprotein, or “bad" cholesterol, than Pfizer’s current market-leader Lipitor, according to a new analysis of a previously-reported study, presented at the American College of Cardiology's 55th Annual Scientific Session.

The groups said yesterday that results of the Vytorin Versus Atorvastatin (Vyva) trial revealed that significantly more patients taking Vytorin showed lower levels of bad cholesterol, widely regarded as a major risk factor for cardiovascular disease, than those using Pfizer’s Lipitor (atorvastatin).

32.5% of the Vytorin group (n=891) achieved levels of LDL cholesterol of less than 70 mg/dL as well as Apo B levels of less than 90 mg/dL, versus 16% of patients taking Lipitor (n=899) across the dosing range. And the new analysis also indicates that Vytorin beat Lipitor in cutting down levels of C-Reactive Protein (CRP), an emerging risk marker for cardiovascular disease.

Commenting on the findings, lead study investigator, Christie Ballantyne, said: “This post hoc analysis showed that Vytorin was not only significantly better than Lipitor in helping patients achieve an LDL cholesterol of less than 70 mg/dL but significantly more of the patients taking Vytorin also achieved lower levels of Apo B or CRP than those taking Lipitor.” But she went on to say that, although the analysis is interesting, “the clinical significance of these comparisons has not been established and additional studies will be needed to confirm these findings.”

Vytorin, a combination of Merck's Zocor (simvastatin) and Zetia (ezetimibe), first hit the US market in 2004 and made sales of $355 million in the fourth quarter of 2005. The agent has the dual effect of inhibiting the absorption of cholesterol from the intestine and its production by the liver, giving it a considerable advantage over simple statins, such as Pfizer’s Lipitor. But, for now, Lipitor remains not only the market leader but also the world’s number one prescription drug, having pulled in sales of $12 billion last year.