Hyperion Therapeutics Receives Orphan Drug Designation For HPN-100 For The Treatment Of Hepatic Encephalopathy

Main Category: Neurology / Neuroscience
Article Date: 20 Sep 2009 - 0:00 PDT

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Hyperion Therapeutics, Inc. announced that its investigational product HPN-100 (glycerol phenylbutyrate) has received orphan product designation from the U.S. Food and Drug Administration for intermittent or chronic treatment of patients with cirrhosis and any grade of hepatic encephalopathy. The Company is planning to initiate a phase II clinical program in this indication later this year.

About Orphan Drug Designation

Orphan drug designation is granted by the FDA Office of Orphan Drug Products to novel drugs or biologics that treat a rare disease or condition affecting fewer than 200,000 patients in the U.S. The 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.

About Hepatic Encephalopathy

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. HE comprises a spectrum of neurological signs and symptoms ranging 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. Based on the current epidemiological literature, Hyperion estimates that there are approximately one million1 patients in the US with cirrhosis, of whom approximately 140,000 have overt HE. There are no therapies currently FDA-approved for the treatment of HE.

About HPN-100 (glycerol phenylbutyrate)

HPN-100 (glycerol phenylbutyrate), an investigational product, 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: carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), and argininosuccinic acid synthetase (AS) deficiencies. 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). Glycerol phenylbutyrate holds orphan product designation from the FDA for maintenance treatment of patients with enzymes of the urea cycle.

About BUPHENYL

BUPHENYL is indicated as adjunctive therapy in the chronic management of patients with urea cycle disorders involving deficiencies of carbamylphosphate synthetase (CPS), ornithine transcarbamylase (OTC), or argininosuccinic acid synthetase (AS). BUPHENYL should not be administered to patients with known hypersensitivity to sodium phenylbutyrate or any component of this preparation. The most common adverse reactions associated with BUPHENYL were amenorrhea dysfunction, decreased appetite, body odor (probably caused by its metabolite phenylacetate) and bad taste or taste aversion. Patients with urea cycle disorders should not take valproic acid, haloperidol, or steroids as these drugs have been reported to increase blood ammonia levels, and probenecid may affect the kidneys' excretion. Use with great care, if at all, in patients with congestive heart failure or severe renal insufficiency, and in clinical states where there is sodium retention with edema. Use caution when administering to patients with hepatic or renal insufficiency or inborn errors of beta oxidation. The safety or efficacy of doses in excess of 20 grams (40 tablets) per day has not been established.

References

1 Bell BP, Manos MM, Zaman A, et al. The epidemiology of newly diagnosed chronic liver disease in gastroenterology practices in the United States: results from population-based surveillance. Am J Gastroenterol 2008; 103:2727-2735.

1 Dufour MC. Chronic liver disease and cirrhosis. In digestive diseases in the United States: epidemiology and impact. JE Everhart, Editor, 1994; NIH publication No. 94-1447:615-646.

Source
Hyperion Therapeutics

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