UPDATE 1-CV Therapeutics, Astellas agent gets FDA approval

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TOKYO, April 11 (Reuters) - Drug makers CV Therapeutics (CVTX.O: Quote, Profile, Research, Stock Buzz) and Astellas Pharma Inc (4503.T: Quote, Profile, Research, Stock Buzz) said on Friday the U.S. Food and Drug Administration (FDA) had approved their heart-imaging agent regadenoson, also called Lexiscan.

Astellas shares were up 4.4 percent at 4,260 yen in early trade in Tokyo.

CV Therapeutics' stock fell last month when the U.S. company said it expected the FDA to respond to its application for the agent a few weeks later, rather the original deadline for a decision of March 14.

The company then said the timeline for a launch by its commercial partner Astellas would not be affected if approval were received within a few weeks.

The two firms aim to sell regadenoson for use as a stress agent during certain cardiovascular tests to gauge whether a patient's heart is getting enough blood to function properly.

CV Therapeutics retains all rights to the product outside of North America while Astellas will market it in the United States. (Reporting by Yuko Inoue; Editing by Hugh Lawson)