Hyperion Makes RAVICTI(TM) Available for Shipment to UCD Patients

Hyperion Makes RAVICTI(TM) Available for Shipment to UCD Patients

SOUTH SAN FRANCISCO, Calif., Feb. 28, 2013 (GLOBE NEWSWIRE) -- Hyperion
Therapeutics, Inc. (Nasdaq:HPTX) today announced that RAVICTI™ (glycerol
phenylbutyrate) Liquid is now available for shipment to patients. RAVICTI was
approved by the U.S. Food and Drug Administration (FDA) on February 1, 2013,
for use as a nitrogen-binding agent for the chronic management of adult and
pediatric patients two years of age or older with urea cycle disorders (UCD),
who cannot be managed by dietary protein restriction and/or amino acid
supplementation alone. The new drug is being distributed exclusively via
select specialty pharmacies. To prescribe RAVICTI or for more information
regarding the medication, reimbursement, and other patient support services,
individuals may call 1-855-UCD-SUPT (1-855-823-7878) or visit www.ravicti.com.

RAVICTI Indications, Usage and Safety Information

RAVICTI is indicated for use as a nitrogen-binding agent for chronic
management of adult and pediatric patients ≥ two years of age with UCD that
cannot be managed by dietary protein restriction and/or amino acid
supplementation alone. RAVICTI must be used with dietary protein restriction
and in some cases, dietary supplements (e.g. essential amino acids, arginine,
citrulline, protein-free calorie supplements).

Limitations of Use:

  oRAVICTI is not indicated for the treatment of acute hyperammonemia (HA) in
    patients with UCD because more rapidly acting interventions are essential
    to reduce plasma ammonia levels.
  oThe safety and efficacy of RAVICTI for the treatment of N-acetylglutamate
    synthase (NAGS) deficiency has not been established.

RAVICTI is Contraindicated in Patients:

  oLess than two months of age. Children less than two months of age may have
    immature pancreatic exocrine function which could impair hydrolysis of
    RAVICTI, leading to impaired absorption of phenylbutyrate and HA.
  oWith known hypersensitivity to phenylbutyrate. Signs of hypersensitivity
    include wheezing, shortness of breath, coughing, low blood pressure,
    flushing, nausea and rash.

The major metabolite of RAVICTI, PAA, is associated with neurotoxicity at
levels ≥ 500 μg/mL. If symptoms of vomiting, nausea, headache, drowsiness, or
confusion are present in the absence of high ammonia or other intercurrent
illnesses, reduce the RAVICTI dosage.

Pancreatic insufficiency or intestinal malabsorption may result in reduced or
absent digestion of RAVICTI and/or absorption of phenylbutyrate and reduced
control of plasma ammonia. Monitor ammonia levels closely in these patients.

Most common adverse reactions in 10% or more of patients are: diarrhea,
flatulence, headache, nausea, vomiting, fatigue, decreased appetite, HA,
dizziness, headache, upper abdominal (stomach) pain and rash.

Corticosteroids, valproic acid, or haloperidol may increase plasma ammonia
levels; monitor ammonia levels closely when used concomitantly with RAVICTI.
Probenecid may affect renal excretion of metabolites of RAVICTI including PAGN
and PAA.

The use of RAVICTI in pregnant women may cause fetal harm. Breastfeeding is
not recommended during RAVICTI treatment.

Please see full Prescribing Information for RAVICTI at www.hyperiontx.com.

About Hyperion Therapeutics

Hyperion Therapeutics, Inc. is a commercial stage biopharmaceutical company
committed to developing and delivering life-changing treatments for orphan
diseases and hepatology. For more information, please visit www.hyperiontx.com

Forward-Looking Statements

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. Examples of forward-looking
statements contained in this press release include, among others, statements
regarding our expectations regarding the timing of to establishing
comprehensive payor coverage. Forward-looking statements in this release
involve substantial risks and uncertainties that could cause future results,
performance or achievements to differ significantly from those expressed or
implied by the forward-looking statements. Such risks and uncertainties
include, among others, risks related to: the ability to comply with
requirements established by the FDA, including post-marketing requirements and
label restrictions; the success and timing of commercialization efforts of
Ravicti; the uncertain clinical development process; the satisfaction of the
FDA with preclinical data, including carcinogenicity data; the fact that the
patient population suffering from UCD is small and has not been established
with precision; the ability to obtain adequate clinical supplies of Ravicti;
and the ability to raise sufficient capital to complete the development of and
commercialize Ravicti in UCD. Hyperion undertakes no obligation to update or
revise any forward-looking statements. For a further description of the risks
and uncertainties that could cause actual results to differ from those
expressed in these forward-looking statements, as well as risks relating to
the business of the company in general, see the section entitled "Risk
Factors" in Hyperion's Annual Report on Form 10-K/A for the year ended
December 31, 2012, and in subsequent filings with the Securities and Exchange

CONTACT: Shari Annes, Investor Relations
         (650) 888-0902
         Kristie Kuhl, Media Relations
         (203) 556-7417
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