Financing to fund specialty pharmaceutical company's Phase III clinical program for urea cycle disorders and Phase II study in low grade hepatic encephalopathy.

South San Francisco, CA -- June 30/PRNewswire/ -- Hyperion Therapeutics, a privately held specialty pharmaceutical company focused on the development of therapies that address critical unmet needs in the areas of gastroenterology and hepatology, today announced it has closed a$60 millionSeries C financing. New investors Bay City Capital and Panorama Capital co-led the financing. Series A and B investors Highland Capital Partners, NEA, and Sofinnova Ventures also participated.

The Series C financing follows the Company's recent announcement of Phase II results and orphan drug designation for HPN-100 in its lead indication, the chronic treatment of patients with urea cycle disorders (UCD). The capital will fund the Phase III clinical program for UCD as well as a Phase II study in low grade hepatic encephalopathy.

Concurrent with the Series C financing,H. Daniel Perez, M.D. of Bay City Capital, andGaurav Aggarwal, M.D. of Panorama Capital have joined the Hyperion Therapeutics Board of Directors.

"Considerable unmet needs remain in the treatment of both urea cycle disorders and hepatic encephalopathy," saidDaniel Perezof Bay City Capital. "We believe the Hyperion management team, with their extensive drug development and regulatory expertise, is well positioned to lead a clinical development program focused on potential treatment options for these patients."

About HPN-100

HPN-100 is an investigational product that is a pre-pro-drug of phenylacetic acid, the active moiety of BUPHENYL(R), 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. HPN-100, which is dosed orally in liquid form, is under clinical investigation as providing a potential alternative pathway to the urea cycle for the disposal of ammonia through the renal excretion of phenylacetylglutamine, which is formed from phenylacetic acid and glutamine.

About Urea Cycle Disorders

Urea cycle disorders are inherited, inborn errors of metabolism present in an estimated 1 in 10,000 births inthe United States. Patients with urea cycle disorders are deficient in one of the key enzymes that comprise the urea cycle, the body's primary vehicle for removing ammonia, a potent neurotoxin, from the bloodstream. Onset may occur at any age depending on the severity of the disorder. Left untreated, urea cycle disorders can cause dangerously heightened levels of ammonia in the bloodstream (hyperammonemia) resulting in brain damage, coma, and/or death.

About Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a serious but potentially reversible neurological disorder that can occur in patients with acute liver failure and, most commonly, in patients with cirrhosis of any etiology. It 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. There are no therapies currently FDA-approved for the treatment of HE.

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.