Hyperion Therapeutics announced that the first patient has been enrolled in its phase-II clinical trial of investigational compound HPN-100 (glycerol phenylbutyrate). The multi-centre study consists of an open label safety component followed by a randomized, double-blind, placebo-controlled study that will enrol approximately 140 patients with episodic hepatic encephalopathy in the US and Eastern Europe. The primary efficacy measure will be the proportion of patients who exhibit a hepatic encephalopathy episode during the four-month treatment period.

HPN-100 (glycerol phenyl butyrateeeeeeeeee), an investigational product, is a pre-pro-drug of phenylacetic acid, the active moiety of Buphenyl (sodium phenylbutyrate) Tablets and Powder, 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.

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).

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.