Hyperion HPN-100 phase III pivotal study for urea cycle disorders meets primary endpoint

Hyperion Therapeutics, Inc. today announced that the Company's phase III pivotal study of glycerol phenylbutyrate (HPN-100), an investigational drug for the treatment of urea cycle disorders (UCDs), met its primary endpoint. The non-inferiority study, conducted under a Special Protocol Assessment (SPA) granted by the U.S. Food and Drug Administration (FDA) in June 2009, evaluated the ammonia control of glycerol phenylbutyrate as compared to sodium phenylbutyrate (BUPHENYL^®).

“These findings are an important step in evaluating glycerol phenylbutyrate as a potential treatment option for patients with UCDs”

UCD patients lack enzymes or transporters necessary for the conversion of ammonia to urea and experience heightened levels of ammonia in the bloodstream. Left untreated, UCDs can result in brain damage, coma, and/or death.

"These findings are an important step in evaluating glycerol phenylbutyrate as a potential treatment option for patients with UCDs," said Brendan Lee, M.D., Ph.D., Howard Hughes Medical Institute Investigator and Professor Department of Molecular and Human Genetics, Baylor College of Medicine, who served as principal investigator.

"We appreciate the support we have received from the UCD community throughout our development program. This is an important milestone in our development of a therapy for patients with UCDs," said Donald J. Santel, Chief Executive Officer, Hyperion Therapeutics.