FDA Approves Ravicti (glycerol phenylbutyrate)for the Chronic Management of Some Urea Cycle Disorders
Ravicti is marketed by Hyperion Therapeutics, based in South San Francisco, Calif.
February 1, 2013 — The U.S. Food and Drug Administration today approved Ravicti (glycerol phenylbutyrate) for the chronic management of some urea cycle disorders (UCDs) in patients ages 2 years and older.
UCDs are genetic disorders that involve deficiencies of specific enzymes involved in the urea cycle, a series of biochemical steps normally required to remove ammonia from the blood. When protein is absorbed and broken down by the body, it produces nitrogen as a waste product. 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, a liquid taken three times a day with meals, helps dispose of ammonia in the body. It is intended for patients whose UCD cannot be managed by a protein-restricted diet or amino acid supplements alone. Ravicti must be used with a protein-restricted diet and, in some cases, dietary supplements.
“Ravicti provides another treatment for chronic management of urea cycle disorders, a group of life-threatening conditions,” said Donna Griebel, M.D., director of the Division of Gastrointestinal and Inborn Errors Products in the FDA’s Center for Drug Evaluation and Research. “The approval of this new therapeutic option demonstrates FDA’s commitment to providing treatments for patients suffering from rare diseases.”
Ravicti was reviewed under the agency’s fast track program, designed to facilitate the development and expedite the review of drugs to treat serious diseases, fill unmet medical needs, and get important new drugs to patients earlier. Ravicti also was granted orphan product designation because it is intended to treat a rare disease.
Glycerol phenylbutyrate (HPN-100) is a pro-drug of phenylbutryrate and a pre-pro-drug of phenylacetic acid (PAA), the active moiety of Buphenyl, the only therapy currently FDA-approved as adjunctive therapy for the chronic management of patients with the most prevalent urea cycle disorders — carbamylphosphate synthetase, ornithine transcarbamylase, and argininosuccinic acid synthetase. HPN-100, which is dosed orally in liquid form, provides an alternative pathway to the urea cycle for the disposal of waste nitrogen through the renal excretion of phenylacetylglutamine, which is formed from PAA and glutamine.