But consider the source

Icos became the latest target of retail pandemonium when investors traded 23 million shares of the stock on Friday on the basis of a BusinessWeek article discussing the company's erectile dysfunction therapy - IC351 phosphodiesterase type 5 inhibitor. Pfizer's Viagra also is an oral phosphodiesterase type 5 inhibitor.

ICOS traded as high as $24.50 intraday on Friday, before closing at $21.062, up $4.812 on the day. ICOS, which was up 23 percent on the week, averaged 200,400 shares a day in the first quarter. "We traded three times as much as Microsoft today," said ICOS spokesperson Lacy Fitzpatrick, who characterized the buying as largely retail. The ICOS compound is in overseas Phase II trials...