Pfizer's patent on the best-selling cholesterol-lowering drug of all-time, Lipitor, expired on Wednesday, opening the market for generic competitors for America's most popular medication.
Lipitor came on the market in 1997, and has raked in some $100 billion for Pfizer even in a crowded market that includes various other cholesterol-lowering statins, many of which have already gone generic.
In the United States, anti-cholesterol drugs account for 255 million prescriptions a year, and about nine million people are taking Lipitor.
US-based Watson Pharmaceuticals immediately announced its launch of a generic version of Lipitor, atorvastatin calcium, under an exclusive supply and distribution agreement with Pfizer, whereby Pfizer manufactures the drug and Watson sells it, sharing net sales with Pfizer until 2016.
Indian-based Ranbaxy, which was also expected to release its generic in the next six months, still awaits the green light from US authorities due to delays over problems with quality control and some of their Indian factories.
"There should be a price war in that first six months," said Morningstar analyst Damien Conover.
As companies elbow for market share of the cheaper generic version of Lipitor, Pfizer is left hunting for new sources of revenue to replace the cash flow from its longtime star, which made up 15 percent of Pfizer's annual sales.
Pfizer has not released its projected losses due to the patent expiration, but its company forecasts call for sales in 2012 of $63-63.5 billion , versus $67.8 billion in 2010.
Lipitor global sales were over $10 billion last year. Conover estimated a sales figure of $3.8 billion in 2012.