Horizon Pharma plc Announces the U.S. Patent and Trademark Office Issuance of an Additional Notice of Allowance With Claims Covering RAVICTI(R) (glycerol phenylbutyrate) Oral Liquid

DUBLIN, IRELAND--(Marketwired - Mar 16, 2016) - Horizon Pharma plc (NASDAQ: HZNP), a biopharmaceutical company focused on improving patients' lives by identifying, developing, acquiring and commercializing differentiated and accessible medicines that address unmet medical needs, today announced that it has received a Notice of Allowance from the United States Patent and Trademark Office for U.S. patent application number 14/958,259, entitled "Methods of Therapeutic Monitoring of Nitrogen Scavenging Drugs" that covers Horizon's U.S. approved medicine RAVICTI® (glycerol phenylbutyrate) Oral Liquid.

This Notice of Allowance concludes the substantive examination of the patent application and will result in the issuance of a U.S. patent after administrative processes are completed. The U.S. patent scheduled to issue from this application will expire in 2030. After issuance, Horizon plans to list the U.S. patent in the FDA's Approved Drug Products with Therapeutic Equivalence Evaluations, or Orange Book.

About RAVICTI®
RAVICTI is indicated for use as a nitrogen-binding agent for chronic management of adult and pediatric patients ≥2 years of age with urea cycle disorders (UCDs) who 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 and protein-free calorie supplements). RAVICTI is indicated for use in all 28 Member States of the European Union and 3 Member States of the European Economic Area as a nitrogen-binding agent for chronic management of adult and pediatric patients two months of age and older with UCDs who cannot be managed by dietary protein restriction and/or amino acid supplementation alone.

Important Safety Information

LIMITATIONS OF USE:

• RAVICTI is not indicated for the treatment of acute hyperammonemia in patients with UCDs because more rapidly acting interventions are essential to reduce plasma ammonia levels
• The safety and efficacy of RAVICTI for the treatment of N-acetylglutamate synthase (NAGS) deficiency has not been established
• The use of RAVICTI in patients < 2 months of age is contraindicated

CONTRAINDICATIONS: