Teva won a tentative approval yesterday for a generic version of Merck & Co’s blockbuster cholesterol-lowering drug, Zocor (simvastatin), one of the big patent expiries due in 2006.

The Israeli generics company said the US Food and Drug Administration (FDA) cleared 5mg, 10mg, 20mg, 40mg and 80mg tablet formulations of simvastatin. Merck’s Zocor franchise has annual sales of around $4.4 billion, and the US drugmaker has said that the onset of generic competition for this drug, due mid-year, will cut 2006 profits by 4.4%.

Other blockbuster products due to lose US patent protection this year include Pfizer’s antidepressant Zoloft (sertraline), Bristol-Myers Squibb’s cholesterol-lowerer Pravachol (pravastatin), and Sanofi-Aventis’ sleep drug Ambien (zolpidem).

Teva is in the latter stages of a merger with US firm Ivax which will make it the biggest generics company in the world, ahead of Novartis’ subsidiary Sandoz.