UPDATE 1-AstraZeneca asks for U.S. approval of Brilinta

* Drug seen as multibillion-dollar a year seller

* Submitted in Europe in October

* To compete with Plavix, one of world's most used medicines (Adds details)

LONDON, Nov 19 (Reuters) - Britain's AstraZeneca (AZN.L) came a step closer to getting one of its top new drug hopes onto the market after it submitted a request to U.S. regulators to have its Brilinta blood clot preventer approved for sale.

The drugmaker said on Thursday that it had submitted a New Drug Application for Brilinta, also known as ticagrelor, to the U.S. Food and Drug Administration.

The drug, which analysts see as a potential multibillion-dollar a year seller for AstraZeneca, has already been submitted for approval in Europe.

It will compete with Plavix, one of the world's most widely used medicines, sold by Bristol-Myers Squibb (BMY.N) and Sanofi-Aventis (SASY.PA) with annual sales of some $9 billion.

AstraZeneca said in May that Brilinta had proved superior to Plavix in a head-to-head Phase III trial. [ID:nLB630992]

(Reporting by Ben Deighton)