Ready to rumble: Pfizer's generic biotech drug push could pit it against Amgen

For years, Pfizer (PFE) has been trying to prepare for the "patent cliff" it's heading for in 2011. That's when its cholesterol drug Lipitor -- the biggest-selling drug ever with $12 billion in annual sales -- will fall off the rolls of protected drugs. Mindful of that date, the world's No. 1 drugmaker has pursued a variety of different strategies. It restructured with massive layoffs, it completed a megamerger with Wyeth, it made a big push into generics and, more recently, it moved into treating rare diseases.

The latest pursuit? Pfizer is now planning to enter the business of making cheaper copies of pricey, injectable biologic drugs, or biosimilars, Bloomberg reports. With Pfizer reportedly hatching plans to sell the first copies of medicines developed by the world's largest independent biotech Amgen, says Bloomberg, the move is causing concern not just at Amgen, but at other biotechs that fear such competition.