FILE PHOTO: A building belonging to Teva Pharmaceutical Industries, the world's biggest generic drugmaker and Israel's largest company, is seen in Jerusalem February 8, 2017. REUTERS/Ronen Zvulun/File Photo

(Reuters) - Israel-based Teva Pharmaceutical Industries Ltd said the U.S. Food and Drug Administration had approved its drug to treat chorea stemming from Huntington’s disease, a fatal degenerative disorder.

Chorea is an abnormal, involuntary writhing movements disorder that occur in 90 percent of Huntington’s disease patients at some point in the course of their illness.

The company said on Monday that the FDA approval was based on results from a late-stage study of the drug, Austedo, in reducing chorea in patients with Huntington’s disease.

Huntington’s disease is an inherited condition that causes the progressive breakdown of nerve cells in the brain, resulting in a gradual decline in motor control, cognition and mental stability.

Analysts forecast annual sales reaching $850 million by 2023 for Teva’s Austedo, according to Thomson Reuters data.

Teva, the world’s largest generic drugmaker, said on May 31 that approval for the drug had been held up by U.S. regulators seeking further blood study.

The company’s stock was up 1.2 percent at $32.59 in U.S. extended trading on Monday.