GenVec

Ticker: GNVC

Friday's close: $1.28

Week's change: -52%

The Gaithersburg biotech firm's stock plummeted after the Food and Drug Administration halted clinical trials of TNFerade, a drug GenVec was developing to treat rectal, pancreatic and esophageal cancer. The FDA plans to review data that suggest a potential increase in blood clots among some esophageal cancer patients who received the drug.

Opnet Technologies

Ticker: OPNT

Friday's close: $7.50

Week's change: -27%

The Bethesda software-solutions firm cut its revenue forecast for the second quarter of its fiscal year, which ended Sept. 30, in part because of declines in licensing and international sales.

WebMethods

Ticker: WEBM

Friday's close: $6.27

Week's change: +14%

Shares of the Fairfax software products and services company jumped after it announced the appointment of a new chief executive, David L. Mitchell. He replaces Phillip Merrick, who resigned for health reasons, the company said.

XM Satellite Radio

Ticker: XMSR

Friday's close: $28.17

Week's change: -8.7%

The District company's stock fell on news that its rival, New York-based Sirius Satellite Radio Inc., had signed syndicated radio show host Howard Stern to a five-year, $500 million contract. Stern is to join Sirius on Jan. 1, 2006.