Merck & Co and Schering-Plough added to the comparative data claiming superiority for their lipid lowering combination product Vytorin over rival brands yesterday, this time placing AstraZeneca’s Crestor in the spotlight.

The two sponsors presented results from a clinical study showing that Vytorin (ezetimibe/simvastatin) provided superior reduction in low-density lipoprotein cholesterol than Crestor across all doses tested.

Vytorin is a critical product for both Merck and S-P, providing the greatest sales potential of any product in either companies near-term portfolio, and has already racked up multibillion dollar sales since being launched in the third quarter of 2004.

Part of that success as come from data showing that the drug is more potent at lowering blood cholesterol than its big-selling rivals. Last month, Merck and S-P presented data showing that Vytorin was superior to Pfizer’s Lipitor (atorvastatin), the number one drug in the world with annual sales of more than $12 billion in 2005, and Merck’s own Zocor (simvastatin) brand, which made $4.4 billion last year but will see sales fall off after it loses patent protection in the USA later this month.

Now, the companies are claiming a better profile than Crestor, a newer, fast-growing product with sales of $1.3 billion last year. Sales of Vytorin and single-agent Zetia (zetimibe) in 2005 totaled $2.4 billion worldwide, twice the level achieved a year earlier.

LDL cholesterol reductions of 52%-61% were seen for Vytorin across the dose range tested (10mg/20mg to 10mg/80mg) compared to reductions of 46%-57% for Crestor 10mg to 40 mg. In addition, both drugs raised the beneficial, high-density lipoprotein cholesterol by 8%. The drugs’ effects on triglycerides, another risk factor for cardiovascular disease, were roughly equivalent.

A subgroup analysis of 715 high-risk patients showed that Vytorin helped significantly more high-risk patients achieve an LDL of less than 70mg/dL compared to Crestor (50% versus 29%), while the proportions of patients reaching a target LDL cholesterol of less than 100mg/dL were 90% and 82%, respectively.

The data were presented at the International Symposium on Atherosclerosis meeting, held in Rome, Italy.

Crestor combination

Meanwhile AstraZeneca fought back at the meeting by presenting data from the EXPLORER study which revealed that a combination regimen of Crestor and Zetia produced a 70% reduction in LDL cholesterol, claimed to be the largest fall ever seen in a clinical trial.

The firm said the results add to clinical data consistently showing that Crestor “is the most effective statin at reducing LDL cholesterol, enabling most patients with high cholesterol to successfully achieve their guideline LDL cholesterol goal.”

Significantly more patients to achieve their US LDL cholsterol target of less than 100 mg/dL on the combination (94%) compared to Crestor monotherapy (79%) after six weeks’ treatment.