CAMBRIDGE, Mass. (AP) -- Momenta Pharmaceuticals Inc. won a federal court ruling Friday that temporarily blocks other companies from selling a generic version of its anti-clotting drug.
Momenta's shares surged in after-hours trading.
U.S. District Court Judge Nathaniel M. Gorton in Boston ordered other companies not to sell their generic version of anticoagulant Lovenox until a patent lawsuit filed by Momenta is settled.
Since July 2010, Momenta has made the only approved generic version of Lovenox, a drug used to prevent deep-vein blood clots from forming in the legs of patients on bed rest, including those having hip replacement or knee replacement surgery.
Momenta claims that a version developed by Amphastar Pharmaceuticals Inc. and recently approved by the U.S. Food and Drug Administration infringes on a Momenta patent.
The judge granted Momenta's request for an injunction blocking Amphastar, Watson Pharmaceuticals Inc. and an Amphastar subsidiary, International Medication Systems Ltd., from selling their version until the end of the patent lawsuit.
No date has been set for trial.
Messages left with Amphastar, in Rancho Cucamonga, Calif., and Watson, in Parsippany, N.J., were not immediately returned.
Shares of Cambridge-based Momenta fell 6 cents to close at $12.24 but jumped $2.36, or 19.3 percent, to $14.60 after hours after the ruling was announced.
Watson shares fell 21 cents to $69.35 in regular trading, and lost another 18 cents, to $69.17, in extended trading.