UPDATE 1-Sanofi to fight on after generic Lovenox setback

* To continue suit on FDA approval of generic clot preventer

* Says injunction refusal did not comment on merit of suit

* Momenta shares up 3.7 pct; Sanofi, Novartis little changed

(Adds shares, analyst comment)

LONDON, Aug 26 (Reuters) - French drugmaker Sanofi-Aventis (SASY.PA) will continue a legal battle in the United States against a generic version of its blood clot preventer Lovenox, despite a court rebuff, it said on Thursday.

Sanofi had asked a federal judge to bar the sale of a generic copy of Lovenox, its second biggest-selling product, pending a final verdict in a case over whether it should have been approved by U.S. regulators.

U.S. District Judge Emmet Sullivan on Wednesday refused to issue a preliminary injunction that would have forced the Food and Drug Administration (FDA) to suspend approval of a generic version of Lovenox that is already being sold by Novartis's (NOVN.VX) Sandoz unit and Momenta (MNTA.O). [ID:nN25165555]

"The company's case against the FDA will continue to move forward, even without preliminary injunctive relief," Sanofi said in a statement.

Momenta said it was pleased by the court decision and continued to believe the FDA had acted correctly.

Shares in the U.S. biotech company -- whose fortunes are closely linked to generic Lovenox -- rose 3.7 percent to $16.26 in early trade on Nasdaq on Thursday.

"The Sanofi suit was always a bit of a moon shot, but the speedy ruling by Judge Sullivan removes an overhang on Momenta shares," said Monness Crespi Hardt analyst Avik Roy.

Shares in Sanofi and Novartis were little changed.

The FDA approved the generic blood thinner in July despite concerns by Sanofi that the agency failed to follow its procedures or ensure the generic drug had the same active ingredient as Lovenox -- a complex injectable drug that Sanofi argues is hard to replicate accurately.

Judge Sullivan said in his decision that an injunction would serve the public interest only if Sanofi was likely to succeed in proving the FDA had exceeded its authority in granting Sandoz approval to sell the generic drug.

But Sanofi noted that the court had not ruled on the merits its suit against the FDA and case would continue.

Lovenox was Sanofi's second-biggest drug worldwide last year with sales of some $4 billion, 60 percent of which was in the United States.

It is one of a number of key drugs facing generic competition -- one factor behind the drive by Sanofi Chief Executive Chris Viehbacher to find new sources of growth via acquisitions, including a potential deal for Genzyme GENZ.O.

Viehbacher sent a takeover proposal valuing Genzyme at about $18.4 billion to Genzyme on Aug. 3 but the two sides are still far apart on price, according to sources familiar with the situation. (Reporting by Ben Hirschler; Editing by Karen Foster and Mark Potter)