Pfizer, the world's largest drugmaker, will today end one of its most topsy-turvy years in recent memory, with its report of last year's fourth-quarter earnings.

In many ways, it will close the door on a year that Pfizer would like to forget. Numerous challenges took their toll on the company's sales, profits and shareholder morale. Even harder has been persuading Wall Street that robust profit growth is soon on its way.