The FDA has just approved the first generic version of Lovenox, a popular blood thinner. The drug’s entry into the market could mean hundreds of dollars in savings for someone who depends on the drug for stroke/heart disease treatment.

Lovenox is used to treat and prevent deep vein thrombosis, a condition that, if left unchecked, can cause stroke or pulmonary embolism (blood clots in the lung).

Momenta, the company whose technology was used to produce the new generic (M-Enoxaparin), has been awaiting approval for five years. They’ve spent the last half-decade battling Sanofi-Aventis, makers of Lovenox, over the drug’s efficacy.

According to Sanofi-Aventis, the biologically derived drug is complex and difficult to reproduce, and that it could fail with even the slightest error. They argue that the new generic may not be safe for consumers. The U.S. District Court in Washington, D.C. is considering the company’s case, but for now Sandoz/Momenta’s M-Enoxaparin is legal and available for use.

“The approval of M-Enoxaparin marks a key milestone for Momenta, and we are extremely pleased,” said Momenta president and CEO Craig Wheeler in a press release. “This is the first product based on Momenta’s technology platform to be approved, and demonstrates our ability to characterize and develop a complex mixture drug like Lovenox.”

Read the original article in the New York Times, or read Momenta’s press release for more details.