Returning to the theme of winners and losers in 2004, these companies stood out for their performance, both positive and negative. Biogen Idec, at Tuesday's close of $67.86, was up almost 84% in 2004, largely on the back of its recently approved multiple sclerosis drug Tysabri. Shares of Biogen Idec first soared in February when the company surprised almost everyone by announcing that it would seek earlier-than-expected FDA approval for Tysabri. The drug, a blockbuster in the making with potential sales well in excess of $1 billion, was approved in late November. Amgen, the biotech sector's largest company, was a laggard for most of the year, stung by investor concerns over changes to Medicare drug reimbursement rules and slowing sales growth. But negative returns in 2004 were erased by a late fall rally. At Tuesday's close of $64.60, the stock is up 3.6% for the year. Gilead Sciences ( GILD), buoyed by strong sales growth in its core AIDS/HIV drug franchise and the approval of a new combination HIV medicine Truvada, is up 21% for the year. ImClone Systems ( IMCL) started the year strong with the approval of its colon cancer drug Erbitux, but the stock swooned midyear and is now up just 14.5%. OSI Pharmaceuticals had a seesaw year, with shares shooting up, down and then up again on the prospects for its lung cancer drug Tarceva.