* Study shows blood pressure benefits for naproxcinod

* Shares rise 9.59 percent

(Adds analyst comments, background)

By Matt Gil

PARIS (Reuters) - French biotech firm NicOx (NCOX.PA: Quote, Profile, Research) said its naproxcinod experimental arthritis treatment significantly reduced blood pressure among patients compared to standard treatment naproxen, sending its shares sharply higher.

A pooled study, agreed with the U.S. Food and Drug Administration, collated a 13-week analysis of 2,734 patients from phase 3 studies for the anti-inflammatory treatment and showed a "significant reduction" in blood pressure compared to naproxen, the company said.

The stock was 9.23 percent higher at 9.59 euros by 1004 GMT.

Natixis analysts said that while the results contained "no big surprise... even the most sceptical minds have to recognise this time that the data is solid," given the size of the overall study."

The French firm expects to submit naproxcinod for U.S. marketing approval by mid-2009.