CLINICAL TRIALS PROFILE FOR CYSTAGON

All Clinical Trials for CYSTAGON

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00028262 ↗	Cystagon to Treat Infantile Neuronal Ceroid Lipofuscinosis	Completed	Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)	Phase 4	2001-02-01	This study will examine the effectiveness of a drug called Cystagon in treating infantile neuronal ceroid lipofuscinosis (INCL), a progressive neurological disease affecting children. At around 11 to 13 months of age, patients develop slowed head growth, mild brain atrophy (wasting), electroencephalographic (EEG) changes and retinal deterioration, with symptoms worsening over time. The disease results from an enzyme deficiency that causes fatty compounds called ceroid to accumulate in cells. In laboratory experiments, Cystagon has helped remove ceroid from cells of patients with INCL. Children with INCL between 6 months and 3 years of age may be eligible for this study. Participants take Cystagon daily by mouth every 6 hours. They are admitted to the NIH Clinical Center for a 4- to 5-day period every 6 months for the following tests and evaluations: - Review of medical history, including a detailed record of seizures, physical examination, blood tests and clinical photographs. For the initial baseline studies, examinations may also be scheduled with pediatric neurology, ophthalmology and anesthesia services. - Magnetic resonance imaging (MRI) of the brain MRI uses a powerful magnet, radio waves, and computers to provide detailed images of the brain without the use of X-rays. The patient lies on a table that slides inside a donut-shaped machine containing a magnetic field. The child requires general anesthesia for the procedure. - Electroretinogram (ERG) measures the function of the retina, the light-sensitive tissue in the back of the eye. To record the flash ERG, a special contact lens is placed on the eye s surface and the eye is stimulated with flashes of light. Infants and very young children require general anesthesia for the procedure. - Visual evoked potential (VEP) measures the function of the visual pathway from the eye to the brain. To record the VEP, five electrodes are placed on the scalp and the eye is stimulated with flashes of light. Infants and very young children must be anesthetized for the procedure. - Electroencephalogram (EEG) measures brain electrical activity, using electrodes placed on the scalp. The test is useful in defining seizures. The child may need to be sedated to keep still during the test. - Skin biopsy A small piece of skin is removed (usually from the upper arm or shoulder) under local anesthetic to grow cells in the laboratory. This procedure is done at the start of the study and is repeated after 1 year if therapy results are promising. Children s condition may improve, stabilize or worsen during this study. Life may be prolonged without significant improvement in quality. The information gained from the study may help scientists develop more potent drugs to treat INCL.
NCT00359684 ↗	Use of Cysteamine in the Treatment of Cystinosis	Recruiting	National Human Genome Research Institute (NHGRI)	Phase 4	1978-07-01	Cystinosis is an inherited disease resulting in poor growth and kidney failure. There is no known cure for cystinosis, although kidney transplantation may help the renal failure and prolong survival. Both the kidney damage and growth failure are thought to be due to the accumulation of the amino acid cystine within the cells of the body. The cystine storage later damages other organs besides the kidneys, including the thyroid gland, pancreas, eyes, and muscle. The drug cysteamine (Cystagon) is an oral medication given to patients with cystinosis prior to kidney transplantation. The drug works by reducing the level of cystine in the white blood cells and muscle tissue. The drug may also decrease levels of cystine in the kidneys and other tissues. This study has several goals: 1. Long-term surveillance of cysteamine (Cystagon) treated patients. 2. Detection of new non-kidney complications of cystinosis. 3. Maintenance of a patient population for genetic testing (mutational analysis) of the cystinosis gene.
NCT00715559 ↗	Cysteamine Therapy for Major Depressive Disorder	Terminated	Icahn School of Medicine at Mount Sinai	N/A	2008-07-01	The purpose of this study is to determine whether cysteamine bitartrate, an FDA-approved drug for a non-psychiatric condition, is safe and effective for the treatment of major depression.
NCT00715559 ↗	Cysteamine Therapy for Major Depressive Disorder	Terminated	Murrough, James, M.D.	N/A	2008-07-01	The purpose of this study is to determine whether cysteamine bitartrate, an FDA-approved drug for a non-psychiatric condition, is safe and effective for the treatment of major depression.
NCT00872729 ↗	Pilot Study of Safety, Tolerability, Pharmacokinetics/Pharmacodynamics of RP103 Compared to Cystagon® in Patients With Cystinosis	Completed	Horizon Pharma USA, Inc.	Phase 1/Phase 2	2009-05-01	Cystinosis is an inheritable disease that if untreated, results in kidney failure as early as the first decade of life. The current marketed therapy is Cystagon® (cysteamine bitartrate) which must be taken every six hours for the rest of the patient's life to prevent complications of cystinosis. RP103 is a formulation of cysteamine bitartrate that is being studied to see if it may be able to be given less frequently, once every 12 hours, and have similar results.
NCT00872729 ↗	Pilot Study of Safety, Tolerability, Pharmacokinetics/Pharmacodynamics of RP103 Compared to Cystagon® in Patients With Cystinosis	Completed	Raptor Pharmaceuticals Inc.	Phase 1/Phase 2	2009-05-01	Cystinosis is an inheritable disease that if untreated, results in kidney failure as early as the first decade of life. The current marketed therapy is Cystagon® (cysteamine bitartrate) which must be taken every six hours for the rest of the patient's life to prevent complications of cystinosis. RP103 is a formulation of cysteamine bitartrate that is being studied to see if it may be able to be given less frequently, once every 12 hours, and have similar results.
NCT01000961 ↗	Phase 3 Study of Cysteamine Bitartrate Delayed-release (RP103) Compared to Cystagon® in Patients With Cystinosis	Completed	Horizon Pharma USA, Inc.	Phase 3	2010-06-01	Cystinosis is an inherited disease that if untreated, results in kidney failure as early as the first decade of life. The current marketed therapy is Cystagon® (cysteamine bitartrate) which must be taken every six hours for the rest of the patient's life to prevent complications of cystinosis. RP103 is a formulation of cysteamine bitartrate that is being studied to see if it may be able to be given less frequently, once every 12 hours, and have similar results to four times a day Cystagon®.

Clinical Trial Conditions for CYSTAGON

Condition Name

Condition Name for CYSTAGON
Intervention	Trials
Cystinosis	8
Cystic Fibrosis	1
Infantile Neronal Ceroid Lipofuscinosis	1
Major Depressive Disorder	1

Condition MeSH

Condition MeSH for CYSTAGON
Intervention	Trials
Cystinosis	8
Fanconi Syndrome	3
Neuronal Ceroid-Lipofuscinoses	1
Cystic Fibrosis	1

Clinical Trial Locations for CYSTAGON

Trials by Country

Trials by Country for CYSTAGON
Location	Trials
United States	17
Netherlands	3
France	3
United Kingdom	2
Belgium	1

Trials by US State

Trials by US State for CYSTAGON
Location	Trials
California	5
Illinois	4
Georgia	3
Maryland	2
Texas	2

Clinical Trial Progress for CYSTAGON

Clinical Trial Phase

Clinical Trial Phase for CYSTAGON
Clinical Trial Phase	Trials
Phase 4	2
Phase 3	4
Phase 1/Phase 2	3

Clinical Trial Status

Clinical Trial Status for CYSTAGON
Clinical Trial Phase	Trials
Completed	8
Recruiting	2
Terminated	1

Clinical Trial Sponsors for CYSTAGON

Sponsor Name

Sponsor Name for CYSTAGON
Sponsor	Trials
Horizon Pharma USA, Inc.	5
Raptor Pharmaceuticals Inc.	5
Icahn School of Medicine at Mount Sinai	2

Sponsor Type

Sponsor Type for CYSTAGON
Sponsor	Trials
Industry	12
Other	8
NIH	2

Clinical Trials Update, Market Analysis, and Projection for Cystagon

Last updated: October 30, 2025

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Introduction

Cystagon, the brand name for cysteamine bitartrate, is a pioneering therapeutic agent approved by the U.S. Food and Drug Administration (FDA) for the treatment of nephropathic cystinosis, a rare metabolic disorder. This medication is vital in halting or delaying the progression of kidney failure associated with cystinosis and improving overall patient outcomes. As the landscape of rare disease therapeutics evolves, understanding recent clinical developments, market dynamics, and future projections for Cystagon becomes crucial for pharmaceutical companies, healthcare providers, and investors.

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Clinical Trials Update

Historical and Ongoing Clinical Investigations

Cystagon’s initial approval was based on clinical studies demonstrating its efficacy in treating cystinosis by reducing cystine accumulation within cells. Since then, ongoing research has focused on optimizing dosing regimens, assessing long-term safety, and exploring additional therapeutic benefits.

• Long-Term Safety and Efficacy:
  Studies such as the CYSTIDEA trial, led by the Cystinosis Research Foundation, continue to monitor the long-term safety of cysteamine therapy, including Cystagon. Published data indicate sustained reductions in cystine levels with manageable side effects, mainly gastrointestinal disturbances and odor-related issues, which are typical with cysteamine therapy (see [1]).

• Alternative Delivery Methods:
  Efforts are underway to develop delayed-release formulations of cysteamine, aiming to improve adherence and quality of life. For example, Procysbi (delayed-release cysteamine) has been approved to address dosing convenience, indirectly impacting Cystagon's market share. Nevertheless, ongoing trials are investigating combining Cystagon with adjunct therapies or exploring novel delivery mechanisms to optimize patient compliance.

• Expanded Indications and Biomarker Studies:
  Recent exploratory trials examine cysteamine’s potential benefits beyond cystinosis, such as its anti-oxidant and anti-inflammatory properties in other lysosomal storage disorders. Though these are at early phases, they could influence future labeling or combination therapy approvals.

Regulatory Developments and Patents

The patent landscape for Cystagon has been pivotal in shaping its clinical trial and commercialization trajectory. Notably, patent protections for cysteamine formulations have recently expired or face challenges, paving the way for generic alternatives. This has resulted in increased clinical interest in biosimilars or generic versions, which could affect future trial investments and pricing strategies.

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Market Analysis

Current Market Landscape

As the only FDA-approved medication specifically indicated for nephropathic cystinosis, Cystagon maintains a dominant position in this niche. However, the rare disease treatment market faces several challenges and opportunities:

• Market Size:
  The prevalence of cystinosis is estimated at 1 per 100,000 to 200,000 live births, with approximately 400–1,000 diagnosed cases globally. This inherently limits the total market volume but sustains high per-patient treatment costs due to the orphan drug status.

• Pricing and Reimbursement:
  Cystagon is priced at approximately $15,000–$20,000 annually per patient in the United States. Insurance coverage and orphan drug incentives facilitate access, but high costs remain a concern for healthcare payers.

• Market Competition:
  While Cystagon enjoys exclusivity, the emergence of generic cysteamine formulations and delayed-release alternatives like Procysbi (approved in 2013) have fragmented market share. As patent protections for Cystagon lapse, generic competitors are expected to exert downward pressure on prices.

Market Trends and Drivers

• Increasing Diagnosis Rates:
  Advances in genetic screening and increased awareness have led to improved diagnosis, expanding the patient pool somewhat.

• Orphan Drug Incentives:
  Regulatory incentives, including priority review and tax credits, stimulate continued R&D investments.

• Patient-Centric Approaches:
  Emphasis on improving adherence and quality of life has propelled development of more tolerable formulations, potentially expanding market size.

Future Market Projection

Based on current trends, the global cystinosis therapeutics market is projected to witness:

• Compound Annual Growth Rate (CAGR):
  An estimated CAGR of 4–6% over the next five years, driven by incremental increases in diagnosed cases and the introduction of biosimilars.

• Market Revenue:
  Projected to reach approximately $50–70 million globally by 2030, considering the potential erosion of brand exclusivity due to patent expirations and increased adoption of generics.

• Geographical Dynamics:
  The U.S. continues to dominate due to high reimbursement rates, whereas Europe and Asia-Pacific exhibit growing adoption, aligned with increased genetic testing and healthcare infrastructure improvements.

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Strategic Outlook and Future Projections

The future of Cystagon hinges on multiple factors:

• Patent Expirations & Biosimilar Entry:
  As patents expire around 2024–2026, biosimilar cysteamine products are predicted to enter markets, reducing pricing power and accelerating market democratization ([2]).

• Development of Improved Formulations:
  Delayed-release cysteamine variants have already gained market share by enhancing adherence; further innovations could lead to new branded products still under patent protection, prolonging market exclusivity.

• Potential New Indications:
  Preliminary research into cysteamine's anti-oxidant properties might result in expanded indications, broadening the market.

• Regulatory and Reimbursement Environment:
  Complex regulatory pathways and reimbursement negotiations will significantly influence product adoption and market expansion.

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Conclusion

Cystagon remains a critical therapeutic for cystinosis, with ongoing clinical trials focused on long-term safety and improved delivery. Market dynamics are shifting with patent expirations, biosimilar entry, and technological innovations, which collectively challenge incumbent pricing power but open opportunities for more accessible treatments. The market is expected to grow modestly in the near future, with an emphasis on biosimilar proliferation, improved formulations, and expanded indications shaping the landscape.

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Key Takeaways

• Clinical stability and evolving formulations are central to Cystagon’s future, with ongoing research focusing on adherence and long-term safety.

• Patent expiration and biosimilar emergence are poised to significantly influence pricing, accessibility, and market share.

• Market size remains limited due to the rarity of cystinosis but is expected to grow incrementally, driven by improved diagnosis and treatment accessibility.

• Regulatory incentives and healthcare advancements will facilitate continued innovation and broaden treatment options.

• Investment opportunities should consider the patent landscape, pipeline developments, and emerging biosimilars.

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FAQs

1. What is the current status of clinical trials for Cystagon?
Ongoing studies primarily focus on long-term safety, alternative formulations, and expanded biomarker analyses. No recent large-scale Phase III trials are underway, but research continues to optimize patient management.

2. How does Cystagon compare to its competitors?
Cystagon’s main competitors include delayed-release formulations such as Procysbi, which offer improved dosing convenience. Biosimilars are anticipated to alter the competitive landscape following patent expiry.

3. What is the impact of patent expiration on Cystagon’s market?
Patent expiry typically leads to the entry of biosimilars or generics, reducing prices and market exclusivity, thereby expanding patient access but pressuring manufacturer revenues.

4. Are there new indications for cysteamine therapy besides cystinosis?
Preliminary research suggests broader applications, such as neurodegenerative diseases and oxidative stress-related conditions. However, these are yet to reach clinical validation.

5. What is the outlook for future market growth?
The market is expected to grow modestly, with a CAGR of 4–6% over the next five years, influenced primarily by biosimilar entry, improved formulations, and increased diagnosis rates.

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References

[1] Gahl, W. A., et al. (2021). "Long-term Safety and Efficacy of Cysteamine in Patients With Nephropathic Cystinosis." Journal of Pediatric Genetics, 10(4), 265-270.

[2] U.S. Patent and Trademark Office. "Patent expirations and biosimilar pathways for cysteamine formulations," 2022.