Glycerol phenylbutyrate or HPN-100 from Hyperion Therapeutics has been granted orphan product designation from the US Food and Drug Administration to treat hepatic encephalopathy.
Glycerol phenylbutyrate (HPN-100), which will go for phase-II clinical programme later this year is indicated for intermittent or chronic treatment of patients with cirrhosis and any grade of hepatic encephalopathy.
Glycerol phenylbutyrate HPN-100 is a pre-pro-drug of phenylacetic acid, 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 such as carbamylphosphate synthetase, ornithine transcarbamylase, and argininosuccinic acid synthetase deficiencies.
Buphenyl is indicated as adjunctive therapy in the chronic management of patients with urea cycle disorders involving deficiencies of carbamylphosphate synthetase, ornithine transcarbamylase, or argininosuccinic acid synthetase.Buphenyl is a registered trademark of Ucyclyd Pharma, Inc.
Hyperion and Ucyclyd Pharma, Inc., a subsidiary of Medicis Pharmaceutical Corporation, entered into a collaboration agreement for HPN-100 in August 2007. Under the terms of the agreement, Hyperion is conducting ongoing research and development of HPN-100 for urea cycle disorders, hepatic encephalopathy, and other forms of hyperammonemia.
Glycerol phenylbutyrate is administered orally in liquid form. 17.4 ml of glycerol phenylbutyrate (~ 3.5 teaspoons) delivers the same amount of active ingredient as the maximum daily dose of Buphenyl (forty tablets or 6.67 teaspoons of powder mixed with food or dissolved in liquid).
Hepatic encephalopathy (HE) is a serious but potentially reversible neurological disorder that can occur in patients with cirrhosis of any etiology or acute liver failure. Hepatic encephalopathy has range of neurological signs and symptoms from mild (e.g. minimal disorientation) to severe (e.g. coma, death) and is believed to occur when the brain is exposed to gut-derived toxins such as ammonia that are normally removed from the blood by a healthy liver.
There are approximately one million patients in the US with cirrhosis, of whom approximately 140,000 have overt hepatic encephalopathy, according to estimates presented in the Hyperion release.
There are no therapies currently FDA-approved for the treatment of hepatic encephalopathy.
What is an orphan drug ?
Orphan drug designation is granted by US FDA to novel drugs that treat a rare disease or condition affecting fewer than 200,000 patients in the U.S.
Orphan drug designation provides the drug developer with tax credits for clinical research costs, the ability to apply for annual grant funding, clinical research trial design assistance, waiver of Prescription Drug User Fee Act (PDUFA) filing fees, and a seven-year period of U.S. marketing exclusivity if the drug is the first of its type approved for the specified indication or if it demonstrates superior safety, efficacy, or a major contribution to patient care versus another drug of its type previously granted the designation for the same indication.
Hyperion Therapeutics is a privately held specialty therapeutics company focused on the development of therapies in the areas of gastroenterology and hepatology. Hyperion is headquartered in South San Francisco, CA.
Hyperion Therapeutics is a privately held specialty therapeutics company focused on the development of therapies that address critical unmet needs and underserved patient populations in the areas of gastroenterology and hepatology.