UPDATE 1-Astra, Pozen seek U.S. OK for new painkiller

* Submits application for arthritis drug 'VIMOVO'

* Astra to make $10 mln milestone payment to Pozen

LONDON, June 30 (Reuters) - AstraZeneca (AZN.L) and drug development partner Pozen (POZN.O) are seeking United States approval for new painkiller PN400, which could be used to treat various forms of arthritis.

The new drug, which would be given the trade name VIMOVO, is a combination of Astra drug Nexium and the older generic painkiller narproxin. It is one of a number of new products Astra is hoping to file for regulatory approval this year.

Astra said in a statement that Pozen had submitted a regulatory application to the U.S. Food and Drug Administration (FDA). The firm will pay Pozen a $10 million milestone payment on confirmation that the application has been received.

(Reporting by John Bowker and Ben Hirschler)