While Pfizer already makes the world's biggest-selling drug, Lipitor, and also produces the mega drug Viagra, they are hoping to soon add additional drugs to their arsenal that will have sales in excess of $1 billion.

Martin Mackay, president of pharmaceutical research at Pfizer, announced, "We're in the golden age of drug discovery." Pfizer is currently researching new treatment options for pain, inflammation, cancer, and Alzheimer's disease. One new product under development is tasocitinib, a treatment for rheumatoid arthritis.

"Blockbuster" drugs are generally considered those that sell at least $1 billion per year, and Pfizer had 9 drugs that qualified as such last year. However, Lipitor, which currently accounts for more than one-fifth of Pfizer's revenue, faces patent expiration in November 2011.

Mackay says that Pfizer's strategy going forward will be to focus on increasing the variety of products it sells, instead of just replacing one blockbuster drug with another. At the end of 2007, Pfizer had only 8 drugs in phase-three trials; at the end of 2009 they had 26 drugs in phase-three trials. That number does not include the treatments it acquired when Pfizer bought rival drugmaker Wyeth last October.