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Hyperion Therapeutics' Glycerol Phenylbutyrate Meets Primary Endpoint in Phase II Study in Episodic Hepatic Encephalopathy

- Company to Request End of Phase II Meeting -

SOUTH SAN FRANCISCO, Calif.--(BUSINESS WIRE)--Jun 6, 2012 - Hyperion Therapeutics, Inc. has announced that its phase II study of glycerol phenylbutyrate, an investigational drug for the treatment of episodic hepatic encephalopathy (HE), met its primary endpoint: the proportion of patients experiencing at least one HE event was significantly lower on glycerol phenylbutyrate versus placebo (21.1% vs. 36.4%; p = 0.0214). The rate of adverse events was similar for glycerol phenylbutyrate versus placebo. The company is planning to request an end of phase II meeting with the US Food and Drug Administration to review the data and plans for phase III.

“I am very encouraged by these results and the potential for glycerol phenylbutyrate to address unmet needs in patients with episodic HE. The data suggest that further exploration of the possible benefits of this agent in patients is warranted,” said Don Rockey, MD, Professor of Medicine and Chief of the Division of Digestive and Liver Diseases at the University of Texas Southwestern Medical Center, who served as a principal investigator.

About the Study

This part B study was a multi-center, randomized, double-blind trial of glycerol phenylbutyrate vs. placebo in 178 patients with episodic HE recruited from 28 sites in the United States, 9 sites in Russia and 7 sites in Ukraine. In order to be included in this 4 month study, patients were required to have had at least two documented HE events in the six months prior to enrollment. Enrolled patients continued to receive their standard of care therapy, including lactulose and/or rifaximin, and were permitted to remain on study after their first HE event. The primary endpoint was predefined as the proportion of patients that experienced at least one HE event while on the study. Hyperion Therapeutics is continuing to analyze the study data. The results have been submitted for consideration for presentation at The Liver Meeting® of the American Association for the Study of Liver Diseases.

About 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 million patients in the US with cirrhosis, of whom approximately 140,000 have overt HE.

About Glycerol Phenylbutyrate

Glycerol phenylbutyrate, an investigational drug, is a pre-pro-drug of phenylacetic acid, the active moiety of BUPHENYL®, the only branded therapy currently FDA-approved as adjunctive therapy for the chronic management of patients with the most prevalent urea cycle disorders. Glycerol phenylbutyrate holds orphan product designations in the US and Europe for the maintenance treatment of patients with urea cycle disorders and in the US for the intermittent or chronic treatment of patients with cirrhosis and any grade of hepatic encephalopathy.

About Hyperion Therapeutics

Hyperion Therapeutics is a biopharmaceutical company focused on the development and commercialization of novel therapeutics to treat disorders in the areas of orphan diseases and hepatology. Hyperion is developing glycerol phenylbutyrate for two orphan indications: urea cycle disorders (brand name, Ravicti™) and hepatic encephalopathy.

BUPHENYL® is a registered trademark of Ucyclyd Pharma, Inc.


Contact: Makovsky + Company
Kristie Kuhl, 212-508-9642



Posted: June 2012