Merck & Co and partner Schering-Plough have won a green light for a new application for Zetia, their cholesterol absorption inhibitor.

The US Food and Drug Administration has cleared Zetia (ezetimibe) for use in combination with fenofibrate for the treatment of mixed hyperlipidemia, characterised by elevated levels of LDL or ‘bad’ cholesterol and reduced levels of HDL or ‘good’ cholesterol.

Zetia, sold as Ezetrol in some markets, was first approved in 2002 for combating elevated LDL cholesterol, and along with sister product Vytorin (ezetimibe and simvastatin) represents a major new franchise for Merck and Schering-Plough. The two drugs garnered $793 million in sales in the first quarter of this year, winning 15% of all new prescriptions for cholesterol-lowering drugs during that period, according to IMS figures.

The approval was based on a clinical trial which showed that combination therapy of 10mg ezetimibe plus 160mg fenofibrate reduced LDL cholesterol levels by 20%, significantly better than either treatment used alone.

Meanwhile, results from a new, 1,229-patient clinical trial comparing Vytorin to arch-rival Lipitor (atorvastatin) from Pfizer reveal that Merck and S-P’s drug is more effective in reducing LDL cholesterol in patients with type 2 diabetes. Lipitor is currently the top-selling drug in the world, with sales of over $12 billion in 2005.

The data, presented at the American Diabetes Association annual meeting in Washington DC, found that – at usual recommended starting doses – Vytorin (10mg ezetimibe and 20mg simvastatin) reduced LDL cholesterol by 54% from baseline, while Lipitor cut it by 38% for a 10mg dose and 45% for 20mg. A high-dose comparison of Vytorin 20mg/40mg and Lipitor 40mg revealed reductions of 58% and 51%, respectively.