Alexion Thumped After Drug Failure

Alexion Pharmaceuticals (ALXN Quote) shares were taking a pounding after the company's heart drug failed to meet the main target of a study in which it was aiming to prevent heart attacks in a moderate- to high-risk group of patients.

Lately, the shares were plunging $8.19, or 27.7%, to $21.37. Volume was extremely heavy, with 20 times more shares trading than the daily average for the last three months. By midsession, more than 10 million shares had changed hands, compared with about 458,000 on a normal day.

The trial of Alexion's pexelizumab was designed to determine whether the drug could reduce the rate of heart attacks and death 30 days after coronary artery bypass surgery, with or without another valve surgery, compared with a placebo. The drug did reduce both outcomes, but fell short of the threshold for statistical significance. ...