Horizon Therapeutics

Horizon Therapeutics works on 5 rare diseases tracked on Trial Friend, including CDKL5 Deficiency Disorder, Chronic Granulomatous Disease, Myasthenia Gravis and 2 more, with 1 recruiting clinical trial and 7 FDA-approved rare disease drugs.

Horizon Therapeutics, acquired by Amgen in 2023 for $27.8 billion, develops medicines for rare autoimmune and severe inflammatory diseases. Key products include Tepezza (teprotumumab) for thyroid eye disease, Krystexxa (pegloticase) for chronic refractory gout, and Ravicti (glycerol phenylbutyrate) for urea cycle disorders. The company also markets Uplizna (inebilizumab) for neuromyelitis optica spectrum disorder.

Type
Rare Disease Specialist
Parent
Amgen
Headquarters
Dublin, Ireland
Founded
2008
1
Active Rare Disease Trials
7
Approved Rare Disease Drugs
5
Rare Diseases in Portfolio
18
Years Active

Focus areas at Horizon Therapeutics

As a rare disease specialist, Horizon Therapeutics has active clinical trial programs and drug development efforts across 5 rare diseases, including CDKL5 Deficiency Disorder, Chronic Granulomatous Disease, Myasthenia Gravis, Neuromyelitis Optica, Urea Cycle Disorders. These programs may span orphan drug designation, novel therapeutic mechanisms, and precision medicine approaches targeting the underlying causes of each disease.

The clinical trials section below shows all active and recruiting studies sponsored by Horizon Therapeutics, sourced live from ClinicalTrials.gov. Each trial includes its current recruitment status, study phase (Phase 1 through Phase 4), conditions under investigation, and the number of active trial sites. The FDA-approved drugs section lists treatments that have received U.S. Food and Drug Administration approval, with brand names, generic names, approval dates, and matched rare disease indications from the openFDA database.

Horizon Therapeutics is headquartered in Dublin, Ireland, founded in 2008, a subsidiary of Amgen. The company dedicates its research and development resources exclusively to rare and orphan diseases, working to bring innovative treatments to patients with conditions that have historically had limited or no treatment options.

Horizon Therapeutics Drug Pipeline

Horizon Therapeutics has 1 active clinical trial across 1 development stage, with 1 currently recruiting participants. Clinical trials advance through phases: Phase 1 tests safety in a small group, Phase 2 evaluates effectiveness and side effects, Phase 3 confirms benefit in a larger population, and Phase 4 monitors long-term safety after FDA approval.

Note: This pipeline includes all of Horizon Therapeutics's active interventional trials, not only those targeting rare diseases. We show the full pipeline because a company's broader research activity, therapeutic expertise, and development infrastructure directly shape its ability to advance rare disease programs. A strong overall pipeline often signals deeper clinical operations, faster enrollment capabilities, and greater commitment to bringing new treatments to patients.

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1
Early Phase / Phase 11 trial
STXBP1 Encephalopathy With Epilepsy, SLC6A1 Neurodevelopmental Disorder+1 more
Recruiting

Horizon Therapeutics Clinical Trials (1)

Active and recruiting clinical trials sponsored by Horizon Therapeutics, sourced live from ClinicalTrials.gov. Each trial card shows the study phase, current recruitment status, conditions under investigation, study locations, eligibility criteria, and a direct link to the full ClinicalTrials.gov record. You can also download a one-page PDF summary to share with your doctor.

Note: Recruitment statuses on ClinicalTrials.gov may not immediately reflect recent FDA decisions, sponsor announcements, or enrollment changes. Always confirm a trial's current status directly with the study coordinator.

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ACTIVE NOT RECRUITINGEARLY_PHASE1No updates in a whileNCT04937062

Phenylbutyrate for Monogenetic Developmental and Epileptic Encephalopathy

Intervention: Glycerol Phenylbutyrate 1100 MG/ML [Ravicti]

STXBP1 Encephalopathy With Epilepsy, SLC6A1 Neurodevelopmental DisorderDevelopmental and Epileptic Encephalopathy

This study is to evaluate the use of glycerol phenylbutyrate for monogenetic developmental epileptic encephalopathies (DEEs). DEEs are characterized by epilepsy and developmental delay in early life. Two examples of DEEs are STXBP1 and SLC6A1, though there are dozens of others. STXBP1 Encephalopathy is a severe disease that can cause seizures and developmental delays in infants and children. SLC6A1 neurodevelopmental disorder is characterized by developmental delay and often epilepsy. Both STXBP1 encephalopathy and SLC6A1 neurodevelopmental disorder cause symptoms because there are not enough working proteins made by these genes. It is possible that a medication called phenylbutyrate may help the the remaining proteins work better for STXBP1, SLC6A1, and/or other similar DEEs caused by single genes (i.e. "monogenetic"). This study is to test if glycerol phenylbutyrate is safe and well tolerated in children with monogenetic DEE.

Ages 0 Months - 17 Years2 locations
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Horizon Therapeutics FDA-Approved Drugs (7)

Medications developed or marketed by Horizon Therapeutics that have received U.S. Food and Drug Administration approval. Drug data is sourced from the openFDA database and includes brand names, generic names, approval dates, and matched rare disease indications. Where a drug treats a condition covered by Trial Friend, the disease name links directly to that disease page.

Drug NameBrand NameRare DiseasesApproval Date
INTERFERON GAMMA-1B
Interferon gamma [EPC]
ACTIMMUNE
subcutaneous
Feb 25, 1999
SODIUM PHENYLBUTYRATEBUPHENYL
oral
May 13, 1996
PEGLOTICASE
Uric Acid-specific Enzyme [EPC]
Krystexxa
intravenous
—Sep 14, 2010
CYSTEAMINE BITARTRATEPROCYSBI
oral
—Feb 14, 2020
GLYCEROL PHENYLBUTYRATERavicti
oral
Feb 1, 2013

Horizon Therapeutics Trial Locations

Horizon Therapeutics clinical trials are running at 2 sites in 1 country. Click any country to drill down by state, city, and individual research facility. Proximity to a trial site is one of the most important factors in deciding whether to participate.

United States
2▼

Rare Disease Focus Areas (5)

Diseases targeted by Horizon Therapeutics's clinical trial and drug development programs

CDKL5 Deficiency DisorderNeurological & Neuromuscular

CDKL5 deficiency disorder is a severe genetic condition that causes early-onset seizures, usually beginning within the first few months of life, along with significant developmental delays and movemen...

Prevalence: Approximately 1 in 40,000 to 60,000 live births
Chronic Granulomatous DiseaseBlood & Immune

Chronic granulomatous disease is a rare inherited immunodeficiency affecting the ability of neutrophils to produce reactive oxygen species. Recurrent severe infections and granulomas characterize the ...

Prevalence: 1 in 250,000 people; X-linked form (most common) and autosomal recessive variants
Myasthenia GravisNeurological & Neuromuscular

Myasthenia gravis is a chronic autoimmune neuromuscular disorder causing muscle weakness and rapid fatigue. Antibodies attack acetylcholine receptors at the neuromuscular junction, preventing proper m...

Prevalence: 1 in 5,000 people
Neuromyelitis OpticaAutoimmune & Inflammatory

Neuromyelitis Optica (NMO) is a rare inflammatory autoimmune disorder of the central nervous system characterized by recurrent attacks of optic neuritis (vision loss) and acute myelitis (spinal cord i...

Prevalence: Approximately 0.3 to 1 per 100,000 people; higher prevalence in non-white populations including African, Asian, and Hispanic populations
Urea Cycle DisordersMetabolic & Lysosomal

Urea Cycle Disorders (UCDs) are a group of genetic conditions affecting the enzymes that convert toxic ammonia to urea for excretion. Deficiency of any of the eight enzymes in the urea cycle leads to ...

Prevalence: Approximately 1 per 30,000 live births worldwide; Ornithine Transcarbamylase (OTC) deficiency is most common form

Patient Resources

Organizations and resources related to Horizon Therapeutics's rare disease focus areas

Frequently Asked Questions About Horizon Therapeutics

Common questions about Horizon Therapeutics's rare disease programs, clinical trials, and treatments.