WASHINGTON (AP) -- Drugmaker AstraZeneca said Friday the Food and Drug Administration rejected a request that would have delayed the launch of generic versions of the company's blockbuster psychiatric drug Seroquel.
The London-based drugmaker filed a petition with the FDA in September requesting the agency withhold approval of any generic versions of Seroquel, known chemically as quetiapine, that do not include certain safety warnings about elevated blood sugar. The pill is approved to treat schizophrenia, bipolar disorder and severe depression.
The company said in a statement the FDA denied its request Wednesday, and it "is evaluating the FDA's decision and reasoning."
AstraZeneca's patent exclusivity on Seroquel expires March 26, opening the door to low-cost generic competition. Generic drugs can cost anywhere from 30 to 80 percent less than the original version.
Branded drugmakers routinely file petitions with the FDA as a business tactic to slow their generic competitors.
Seroquel was the fifth best-selling drug in the world in 2010 with sales of $6.8 billion, according to data tracker IMS Health. Only AstraZeneca's heartburn medication Nexium racked up higher sales for the company, with$8.4 billion.
Shares of AstraZeneca, which has its U.S. headquarters in Wilmington, Del., rose 18 cents to $45.01 in trading Friday.