Hyperion Therapeutics, Inc. announced that its investigational compound glycerol phenylbutyrate (HPN-100) has been granted Fast Track Designation by the US Food and Drug Administration (FDA) as adjunctive therapy for the chronic management of urea cycle disorders. Hyperion recently completed its phase-III trial which was conducted under a Special Protocol Assessment (SPA) agreement with the FDA. The company plans to announce results from that trial later this year.

The FDA Fast Track Development Programme is designed to facilitate the development and expedite the review of new drugs that are intended to treat serious or life-threatening conditions and that demonstrate the potential to address unmet medical needs. Fast Track designation enables Hyperion to communicate frequently with the FDA through meetings and written correspondence. The Company is also eligible to submit its New Drug Application (NDA) on a rolling basis, which allows the FDA to review sections of the document in advance of receiving the complete submission. Fast Track designated drugs typically qualify for priority review.

"We are very pleased to receive this Fast Track designation and acknowledgement by the FDA of the potential importance of glycerol phenylbutyrate for patients with urea cycle disorders,” said Donald J Santel, chief executive officer of Hyperion Therapeutics. “We look forward to continuing to work closely with the FDA as we unblind our phase-III study later this year and prepare our NDA submission."

Glycerol phenylbutyrate holds orphan product designation from the FDA for maintenance treatment of patients with deficiencies in enzymes of the urea cycle. The four-week, multi-center, randomized, double-blind, cross-over, phase-III study, conducted in adults with urea cycle disorders, was designed to evaluate the non-inferiority of glycerol phenylbutyrate to Buphenyl (sodium phenylbutyrate).

Glycerol phenylbutyrate, an investigational product, is a pre-pro-drug of phenylacetic acid, the active moiety of Buphenyl.

Hyperion Therapeutics is a privately held specialty therapeutics company focused on the development of therapies that address critical unmet needs in the areas of gastroenterology and hepatology.