Ever since American Cyanamid Co. became the majority owner of Immunex Corp. in 1993, it's been widely assumed that the biotech company eventually would be fully acquired. But the passage of time, and one blockbuster success, have changed the calculus, and IMNX is looking to a renewed independence with a fat wallet, an appetite for partnerships and a tripling or quadrupling of its clinical programs.

Last week current owner American Home Products Corp. announced it would reduce its majority stake in IMNX, which it inherited in its 1994 takeover of American Cyanamid Co. and has since appreciated in value by some 4,900 percent.