The drug, to be sold under the brand name Ravicti, was approved for the chronic management of the serious genetic disorder in patients 2 years of age and older, the Food and Drug Administration said.
Ravicti, known chemically as glycerol phenylbutyrate, is a liquid taken three times a day with meals. It must be used with a protein-restricted diet and, in some cases, dietary supplements, the FDA said in its approval announcement.
The urea cycle removes nitrogen from the blood and converts it to urea, which is removed from the body through urine. In people with UCDs, nitrogen accumulates and remains in the body as ammonia, which can travel to the brain and cause brain damage, coma or death.
"Ravicti provides another treatment for chronic management of urea cycle disorders, a group of life-threatening conditions," Donna Griebel, director of the Division of Gastrointestinal and Inborn Errors Products in the FDA's Center for Drug Evaluation and Research, said in a statement.
The drug's approval was held up by the FDA, but ultimately by only about a week.
In mid-January, the company was informed that the FDA would not make its decision by the previously announced action date of January 23. The FDA had said it needed more time to review the drug's label and to determine any post-marketing requirements.
Ravicti was granted an orphan drug designation by the FDA because it is intended to treat a rare disease. Orphan status is granted to drugs that treat conditions or diseases that affect fewer than 200,000 people in the United States. The designation usually comes with a seven-year marketing exclusivity period if the drug is approved for sale.
Hyperion Therapeutics shares were up 50 cents, or 3 percent, at $16.13 in afternoon trading on Nasdaq.
(Reporting by Bill Berkrot; Editing by John Wallace and Nick Zieminski)