Shares of partners Momenta Pharmaceuticals and Novartis AG moved notably lower early Tuesday, the day after rival Sanofi-Aventis filed a federal lawsuit to prevent the companies from launching a generic version of Sanofi's blockbuster drug Lovenox.

The U.S. Food and Drug Administration, which was also named in the suit, approved a generic version of the blood-thinner last Friday. Sanofi's suit is seeking to have the approval rescinded.

In a statement, Momenta said that the court will hold a hearing on Aug. 17 to consider a temporary injunction against the generic product. The company added that the court has not placed any sales restrictions on the product in the meantime.