* Halts trial due to lack of efficacy
* Shares fall 62 pct aftermarket
March 9 Anthera Pharmaceuticals Inc said it stopped a late-stage trial of its experimental lead drug to treat a heart disease due to lack of efficacy, sending its shares down 62 percent in aftermarket trade.
Anthera, which develops drugs to treat cardiovascular and autoimmune disorders, said it halted enrollment in the clinical trial, known as VISTA-16, following recommendation by the independent Data Safety Monitoring Board (DSMB).
"This is a very severe blow. Theoretically, they can do another Phase 3 program once they see what went wrong in this one. But, whether they'll have this opportunity is unknown," Wedbush Securities analyst Duane Nash told Reuters.
He expects the stock to lose half of its value on Monday.
The Hayward, California-based company was testing its drug, varespladib methyl, in patients suffering from a heart condition known as acute coronary syndrome (ACS), which includes symptoms such as chest pain caused by reduced blood flow to the heart.
"Based on all the evidence we have seen regarding varespladib and secretory phospholipase, and in light of previous study results, we were surprised by the recommendation from the DSMB," the company said in a statement.
The VISTA-16 trial was designed to prove the hypothesis that reduction of inflammation, particularly following an ACS, leads to improved outcomes in patients with cardiovascular disease.
Currently, the best practice to slow coronary artery disease progression and reduce the risk of a subsequent heart attack is directed at the treatment of individual cardiovascular risk factors such as high cholesterol or clotting.
Anthera, which went public in March 2010 , is currently testing two other drugs -- for lupus and acute chest syndrome -- in separate mid-stage trials.
Shares of the company were trading down at $2.68 in extended trade. They closed at $6.42 on Friday on the Nasdaq.