UPDATE 1-FDA says Dendreon's drug application is complete

* Dendreon says FDA has accepted Provenge application

* Says will respond to the application by May 1, 2010

BOSTON, Nov 20 (Reuters) - Dendreon Corp (DNDN.O) said on Friday that the U.S. Food and Drug Administration has accepted its application to market its experimental prostate cancer vaccine and will rule on whether to approve it by May 1, 2010.

The drug, Provenge, is designed to treat men with advanced prostate cancer. If approved, it would be the first in a new class of treatment which use live human cells to activate a patient's own immune system.

The company has said it would be able to make enough Provenge to generate potential sales of $60 million to $125 million in the second half of next year. It expects to ramp up production to full capacity by late 2011 at plants in New Jersey, Atlanta and Los Angeles -- enough to support potential annual sales of $1.2 billion to $2.5 billion.

(Reporting by Toni Clarke, editing by Dave Zimmerman)