Horizon Pharma Receives FDA Fast Track Designation For ACTIMMUNE In The Treatment Of Friedreich's Ataxia

DUBLIN, IRELAND--(Marketwired - April 10, 2015) - Horizon Pharma plc (NASDAQ: HZNP), a specialty biopharmaceutical company focused on improving patients' lives by identifying, developing, acquiring and commercializing differentiated products that address unmet medical needs, today announced the U.S. Food and Drug Administration (FDA) granted Fast Track designation for ACTIMMUNE® (interferon gamma-1b) in the treatment of Friedreich's ataxia (FA), a degenerative neuro-muscular disorder.

"We commend the FDA for granting Fast Track designation for ACTIMMUNE in Friedreich's ataxia to potentially help treat patients suffering from this debilitating disorder, for which there are no FDA approved treatments available," said Timothy P. Walbert, chairman, president and chief executive officer, Horizon Pharma plc. "We look forward to continuing our ongoing clinical development program as we evaluate ACTIMMUNE in this patient population."

Medicines may qualify for Fast Track designation if they are intended to treat a serious or life-threatening disease or condition and demonstrate the potential to address unmet medical needs. Fast Track designation provides greater access to and more frequent communication with the FDA throughout the entire drug development and review process, with the goal of possibly expediting approval. In addition, Fast Track Designation also provides the opportunity to submit sections of the registration dossier for the target indication on a rolling basis and to be considered for priority review at the time of submission based on forthcoming clinical data.

The Company submitted the Investigational New Drug (IND) application for ACTIMMUNE in the treatment of FA in February 2015 and announced plans to begin a Phase 3 study in the second quarter in collaboration with the Friedreich's Ataxia Research Alliance (FARA) and a sub-set of FARA's Collaborative Clinical Research Network (CCRN) study centers in FA.

About Friedreich's ataxia (FA)
FA is a debilitating, life-shortening and degenerative neuro-muscular disorder that affects about one in 50,000 people in the United States. Onset of symptoms can vary from five years old to adulthood, with the childhood onset tending to be associated with a more rapid progression. A progressive loss of coordination and muscle strength leads to motor incapacitation and often the full-time use of a wheelchair. Most young people diagnosed with FA require mobility aids such as a cane, walker or wheelchair by their teens or early 20's. There are currently no approved treatments for FA. For more information about FA, visit the Friedreich's Ataxia Research Alliance (FARA) website at www.curefa.org.

About ACTIMMUNE®
ACTIMMUNE (interferon gamma-1b) is a biologically manufactured protein similar to one the body makes naturally to help prevent infection. ACTIMMUNE is currently approved by the U.S. Food and Drug Administration (FDA) for use in two rare diseases. It is indicated to reduce the frequency and severity of serious infections associated with Chronic Granulomatous Disease (CGD), a genetic disorder that affects the functioning of some cells of the immune system. In addition, ACTIMMUNE is indicated to slow the worsening of severe, malignant osteopetrosis (SMO), a genetic disorder that affects normal bone formation. For more information, please see www.ACTIMMUNE.com.

IMPORTANT SAFETY INFORMATION

APPROVED USES FOR ACTIMMUNE (interferon gamma 1-b)

Chronic Granulomatous Disease (CGD)
ACTIMMUNE is indicated to reduce the frequency and severity of serious infections associated with Chronic Granulomatous Disease. CGD is a genetic disorder that affects the functioning of some cells of the immune system.

Severe, Malignant Osteopetrosis (SMO)
ACTIMMUNE is indicated to slow the worsening of severe, malignant osteopetrosis. SMO is a genetic disorder that affects normal bone formation.

IMPORTANT SAFETY INFORMATION (ISI)

The most common side effects with ACTIMMUNE are "flu-like" symptoms such as fever, headache, chills, myalgia (muscle pain) or fatigue, which may decrease in severity as treatment continues. Bedtime administration of ACTIMMUNE may minimize some of these symptoms. Acetaminophen may be helpful in preventing fever and headache.

If you are pregnant or plan to become pregnant or plan to nurse you should consult your physician.

ACTIMMUNE can cause severe allergic reactions and/or rash. Do not use ACTIMMUNE if you are allergic to interferon-gamma, E. coli-derived products or any component of the product (See Full Prescribing Information for a list of components). If you develop a serious reaction to ACTIMMUNE, discontinue it immediately and contact your doctor or seek medical help.

At high doses, ACTIMMUNE can cause (flu-like) symptoms, which may worsen some pre-existing heart conditions. Tell your doctor if you have a cardiac condition, such as irregular heartbeat, heart failure or decreased blood flow to your heart.

ACTIMMUNE may cause reversible changes to your nervous system, including decreased mental status, walking disturbances and dizziness. Tell your doctor if you have a history of seizures or other neurologic disorders.

Bone marrow function may be suppressed with ACTIMMUNE and decreased production of cells important to the body may occur. This effect, which can be severe, is usually reversible when the drug is discontinued or the dose is reduced. Tell your doctor if you have, or have had, reduced bone marrow function. Your doctor will monitor these cells with blood tests at the beginning of therapy and at 3 month intervals thereafter.

Taking ACTIMMUNE may cause reversible changes to your liver function, particularly in patients less than one year old. Your doctor will monitor your liver function with blood tests at the beginning of therapy and at 3 month intervals. If the patient is 1 year or less, monitoring will be done on a monthly basis.

If you are receiving ACTIMMUNE at home, your doctor will provide to you or your caregiver appropriate instructions on the administration of the drug and disposal of the container, needles and syringes.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.

This information is not intended to replace discussions with your doctor. For additional information about ACTIMMUNE, please consult the Full Prescribing Information and the Information for the Patient/Caregiver and talk to your doctor. ACTIMMUNE is available by prescription only.

Visit www.ACTIMMUNE.com to download a copy of the ACTIMMUNE Full Prescribing Information.

About Horizon Pharma plc
Horizon Pharma plc is a specialty biopharmaceutical company focused on improving patients' lives by identifying, developing, acquiring and commercializing differentiated products that address unmet medical needs. The company markets a portfolio of products in arthritis, inflammation and orphan diseases. The company's U.S. marketed products are ACTIMMUNE® (interferon gamma-1b), DUEXIS® (ibuprofen/famotidine), PENNSAID® (diclofenac sodium topical solution) 2% w/w, RAYOS® (prednisone) delayed-release tablets and VIMOVO® (naproxen/esomeprazole magnesium). Horizon's global headquarters are in Dublin, Ireland. For more information, please visit www.horizonpharma.com.

Forward-Looking Statements
This press release contains forward-looking statements, including statements regarding potential clinical trials evaluating ACTIMMUNE in Friedreich's ataxia patients, the potential benefits of Fast Track designation, and Horizon's plans to conduct clinical development of ACTIMMUNE in Friedreich's ataxia. Forward-looking statements speak only as of the date of this press release and Horizon does not undertake any obligation to update or revise these statements, except as may be required by law. These forward-looking statements are based on management's expectations and assumptions as of the date of this press release and actual results may differ materially from those in these forward-looking statements as a result of various factors. These factors include, but are not limited to, risks regarding whether results of subsequent studies will be consistent with results of prior studies, whether Horizon will conduct further studies of ACTIMMUNE or have the financial resources to do so, whether Horizon realizes any of the potential benefits of Fast Track designation, and the risks associated with pre-clinical and clinical development of drug candidates. For a further description of these and other risks facing Horizon, please see the risk factors described in Horizon's filings with the United States Securities and Exchange Commission, including those factors discussed under the caption "Risk Factors" in those filings. Forward-looking statements speak only as of the date of this press release and Horizon undertakes no obligation to update or revise these statements, except as may be required by law.