Biogen is a risky $90 billion buyout target

Robert Cyran
A Biogen Idec lab technician
Suzanne Kreiter | The Boston Globe | Getty Images

The $75 billion Biogen may be vulnerable to a takeover. But the biotech giant makes a risky target at a likely value approaching $90 billion. Closing the gap between the Alzheimer's drug optimism built into Biogen's valuation and an acceptable price for a buyer may prove a challenge too far.

George Scangos, the company's chief executive, is to step down, which leaves it at a turning point. And potential acquirers Allergan and Merck have sniffed around, according to the Wall Street Journal on Tuesday. Biogen's treatments for multiple sclerosis are a cash cow, providing most of the $11.5 billion in total revenue expected this year. Big pharmaceutical firms are always on the prowl for approved drugs, and it's rare to find such a concentrated collection.