Pfizer's LDL cholesterol-lowering atorvastatin (Lipitor) defines what it means to be a blockbuster drug. Patented in 1997, it has raked in around US$130 billion for Pfizer during its 14 years on the market, making it the world's bestselling drug of all time. Indeed, Pfizer's business model has relied on the huge profits from Lipitor and a few other blockbuster drugs. But things are set to change. The patent for Lipitor expired on Nov 30.