April 3 (Bloomberg) -- Apotex Inc., a Canadian maker of generic drugs, won U.S. clearance to sell copies of AstraZeneca Plc’s asthma drug Pulmicort.

The Food and Drug Administration approved Apotex’s product this week, according to information posted on the agency’s Web site. Elie Betito, director of public and government affairs for Toronto-based Apotex, couldn’t be reached immediately to comment on whether the closely held company has started selling the drug.

The approval surprised investors who thought the threat to Pulmicort had ended after AstraZeneca’s November settlement with Teva Pharmaceutical Industries Ltd. The drug had $982 million in U.S. sales last year. London-based AstraZeneca, looking to curb competition, filed a patent-infringement lawsuit against Apotex in New Jersey on March 31.

“With Apotex now gaining a surprise full approval, if the company decides to launch soon our current AstraZeneca revenue/earnings per share estimates could be too high,” said Timothy Anderson, an analyst at Sanford Bernstein in New York, in a note to clients today. “The maximal impact to AstraZeneca’s earnings per share in 2009 would be on the order of 4 percent.”

AstraZeneca fell 76 pence, or 3.1 percent, to 2,383 pence today in London trading. The shares also were hurt by an FDA staff report suggesting the schizophrenia drug Seroquel XR may pose risks with long-term use.

Apotex may be liable for damages if the company sells copies and is later found to infringe AstraZeneca’s patents. AstraZeneca doesn’t think the copies have been introduced and hasn’t yet filed a preliminary injunction or temporary restraining order to halt sales, according to Blair Hains, a spokesman.

“I’m not going to rule anything in or out as potential actions,” Hains said today in a telephone interview. “It wouldn’t be unusual in these types of cases to consider all types of action, including talking to Apotex.”

To contact the reporter on this story: Catherine Larkin in Washington at clarkin4@bloomberg.net.

Last Updated: April 3, 2009 14:36 EDT