Green Mountain slips, Anthera sinks after hours

LOS ANGELES (MarketWatch) � Shares of Anthera Pharmaceuticals Inc. plunged Friday evening after the company said it has halted a late-stage clinical study of a coronary-disease treatment, while shares of Green Mountain Coffee Roasters Inc. slightly extended day-session losses spurred by competition concerns among investors.

Anthera shares ANTH �came off a trading halt during the evening session and dropped $3.92, or 61%, to $2.50. The company said has closed enrollment in the Phase 3 clinical study of VISTA-16, aimed for the treatment of Acute Coronary Syndrome, and told investigators to remove patients from therapy immediately.

The moves came after the study�s data-safety monitoring board recommended the study be stopped because of a lack of efficacy �that could not be reasonably overcome in the remainder of the trial,� said Anthera in a statement.

Anthera was �surprised by the recommendation� from the monitoring board, said Dr. Stephen Nicholls, chairman of the executive committee overseeing the VISTA-16 trial, in a statement. �We believed that the study was coming along as expected, and this new information was totally unexpected and disappointing given the potential benefits of this drug.�

Late-traded Green Mountain Coffee shares GMCR reversed course to trade lower by 9 cents, or 0.2%, at $52.50.

Green Mountain Coffee shares began to sell off Thursday evening when Starbucks Corp. SBUX �said it will begin selling a single-cup coffee brewing machine later this year. Green Mountain Coffee makes the market-leading Keurig line of single-cup brewers.

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U.S. job creation remains solid in February and was stronger in previous months than initially thought, marking one of the economy's best stretches of the nearly three-year-old recovery.

Both Green Mountain Coffee and Starbucks highlighted differences between the machines, noting the Keurig uses low pressure to brew non-espresso coffee and tea while Starbucks�s Verismo is for espresso-based beverages and brewed coffee using a high-pressure system.

Starbucks Chief Executive Howard Schultz said the company will continue its relationship with Green Mountain Coffee. Read First Take column about Starbucks's Verismo.

But investors during the day pushed shares of Green Mountain Coffee down 15.7% to $52.59 in heavy volume, the worst performer on the Nasdaq-100 index.

Late-traded shares of Starbucks turned up 0.2% to $51.99. They finished the regular session up 2.9% at $51.84.

U.S. stocks closed the regular session modestly higher, aided by a U.S. government report that nonfarm payrolls rose by 227,000 in February, exceeding expectations. Read about U.S. stocks in Market Snapshot.

The Dow Jones Industrial Average DJIA �gained 14 points, or 0.1%, at 12,922.02. The S&P 500 Index SPX �rose 0.4% to 1,370.87 and the Nasdaq Composite Index COMP �advanced 0.6% to 2,988.34.