UPDATE 1-Teva copy of Lovenox may be close; Momenta falls

* Bernstein sees 2nd Lovenox generic in U.S. before end 2010

* Launch of Teva product would lead to quicker price erosion

* Novartis and Momenta launched 1st generic last month

* Momenta shares fall 11 percent

(Updates with latest Momenta shares, Teva executive quote)

LONDON, Aug 5 (Reuters) - A second generic version of Sanofi-Aventis's SASY.PA blood-clot drug Lovenox is likely to reach the U.S. market this year, intensifying competition and pushing down prices, a leading analyst said on Thursday.

Tim Anderson of Sanford Bernstein said he had information that a second generic, from Teva Pharmaceutical Industries TEVA.TA, was "zeroing in on FDA approval, and that this is likely to be on the market in the coming months and before year end".

The U.S. Food and Drug Administration (FDA) approved the first generic copy of Lovenox from Novartis NOVN.VX and Momenta Pharmaceuticals MNTA.O last month, dealing a blow to prospects for Sanofi's second-biggest drug, which had worldwide sales of $4 billion last year.

“The importance of this to Sanofi-Aventis is that it means quicker pricing erosion, assuming Teva’s product indeed gets approved,” Anderson said.

“Our understanding is that Sanofi has been cutting the effective price of its branded Lovenox to maintain share with purchasers, but a new, second generic entrant could frustrate these efforts.”

A second entrant would also be bad news for Novartis’s generics unit Sandoz and its smaller partner Momenta. Shares in Momenta, for which generic Lovenox is a key product, fell 11 percent in morning dealings on Nasdaq.

Teva President and CEO Shlomo Yanai said last week, after presenting second-quarter results, that he had good reason to believe his company was close to getting approval for its generic version of Lovenox.

The company’s chief R&D officer, Benzion Weiner, also told Israel’s Calcalist financial newspaper this week: “We are waiting to receive the approval soon and the chances of receiving it is high.”

A Teva spokeswoman declined any further comment on timing.

Mounting generic competition to Lovenox and other blockbusters has driven Sanofi to seek acquisitions as part of a strategy to diversify its business and buy in new products.

Sanofi has proposed buying Genzyme GENZ.O for $18.4 billion, and the two sides are discussing the offer, although Genzyme is holding out for more, according to sources familiar with the situation. The companies have not commented.

The complexity of manufacturing Lovenox, known generically as enoxaparin, had raised doubts about when a generic version might be approved. But generic manufacturers have made better progress in copying the medicine than some analysts had expected.

Anderson said it appeared that other applicants, such as Hospira HSP.N and Amphastar, were further behind.

Lovenox is used to help prevent deep-vein thrombosis, a condition in which blood clots form in veins deep in the body, especially in the lower leg or thigh. (Reporting by Ben Hirschler and Steven Scheer in Jerusalem; Editing by Will Waterman) ($1=.7620 Euro)