CAMBRIDGE, Mass. (AP) -- Momenta Pharmaceuticals Inc. said Monday that its partner Sandoz's launch of a generic version of the blood thinner Lovenox will trigger royalty payments when Sandoz starts selling the drug during the fourth quarter.Sandoz, a unit of Novartis AG, will pay Momenta royalties of 10 to 12 percent on sales through June 30, 2012. If Momenta's profits on those sales reach $99.1 million and no other generic versions of the drug have reached the market, Momenta will share 45 percent of profits with Sandoz.Every fiscal year, Sandoz will pay royalties of 10 to 12 percent to Momenta until Momenta's annual profit reaches $135 million, and if there are no competing generics on the market, Momenta will get a 45 percent share of the profits. If other generics go on sale, Momenta will continue to get royalties of 10 to 12 percent.The branded version of Lovenox is marketed by French drugmaker Sanofi. The drug's chemical name is enoxaparin. Generic versions are already on sale in some markets.Lovenox is used to prevent dangerous blood clots, including clots in the veins of the thigh or leg, or in patients who are having a heart attack or chest pain. The original version was approved in 1993.Shares of Momenta rose 62 cents, or 4.7 percent, to $13.96 in Monday trading. The stock slid 96 cents, or 6.9 percent, to $13 aftermarket.