However, Pfizer's 2007 sales have stagnated at $48 billion, representing a 0.1% growth from the previous year.[2] Sales of depression drug Zoloft have declined precipitously after its patent expired in 2005. The patent for Lipitor will expire in 2010, and there are no guarantees that another equally profitable drug will come to maturity before then. The cholesterol drug Torcetrapib was once hailed as Pfizer's next blockbuster drug but failed late stage clinical trials in 2006, severely setting back profit expectations and shaking investor confidence.