Hyperion Notified That FDA Will Not Meet the PDUFA Action Date for Ravicti(TM)

Hyperion Notified That FDA Will Not Meet the PDUFA Action Date for Ravicti(TM)

SOUTH SAN FRANCISCO, Calif., Jan. 16, 2013 (GLOBE NEWSWIRE) -- Hyperion
Therapeutics, Inc. (Nasdaq:HPTX) said that the U.S. Food and Drug
Administration (FDA) has advised the Company not to expect a final action by
the Prescription Drug User Fee Act (PDUFA) action date of January 23, 2013.
The agency explained it is continuing to work on label and post-marketing
requirements in connection with Hyperion's New Drug Application (NDA) for
Ravicti™ (glycerol phenylbutyrate) for the treatment of Urea Cycle Disorders

About Ravicti™ (glycerol phenylbutyrate)

Ravicti, 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. Ravicti 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 Therapeutics is
developing Ravicti™ (glycerol phenylbutyrate) for two orphan indications: urea
cycle disorders and hepatic encephalopathy.

Forward-Looking Statement

To the extent that statements contained in this press release are not
descriptions of historical facts regarding Hyperion, they are forward-looking
statements reflecting the current beliefs and expectations of management made
pursuant to the safe harbor provisions of the Private Securities Litigation
Reform Act of 1995. Words such as "may," "will," "expect," "anticipate,"
"estimate," "intend," and similar expressions (as well as other words or
expressions referencing future events, conditions or circumstances) are
intended to identify forward-looking statements. Forward-looking statements
contained in this press release include statements regarding expectations
about the timing of any FDA action as well as the content, nature and extent
of any label or post-marketing requirements. Hyperion undertakes no obligation
to update or revise any forward-looking statements. For a further description
of the risks and uncertainties relating to the business of the company in
general, see Hyperion's Quarterly Report on Form 10-Q filed with the
Securities and Exchange Commission on November 7 and any subsequent filings
with the Securities and Exchange Commission.

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

CONTACT: Shari Annes, Investor Relations
         Cell: 650 888 0902
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