BUPHENYL Drug Patent Profile

When do Buphenyl patents expire, and when can generic versions of Buphenyl launch?

Buphenyl is a drug marketed by Horizon Therap Us and is included in two NDAs.

The generic ingredient in BUPHENYL is sodium phenylbutyrate. There are one thousand four hundred and seventy-two drug master file entries for this compound. Six suppliers are listed for this compound. Additional details are available on the sodium phenylbutyrate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Buphenyl

A generic version of BUPHENYL was approved as sodium phenylbutyrate by SIGMAPHARM LABS LLC on March 22^nd, 2013.

Summary for BUPHENYL

US Patents:	0
Applicants:	1
NDAs:	2
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	80
Clinical Trials:	9
Patent Applications:	2,569
Drug Prices:	Drug price information for BUPHENYL
What excipients (inactive ingredients) are in BUPHENYL?	BUPHENYL excipients list
DailyMed Link:	BUPHENYL at DailyMed

See drug prices for BUPHENYL

Recent Clinical Trials for BUPHENYL

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
University of Alabama at Birmingham	Phase 1/Phase 2
Children's Hospital of Philadelphia	Phase 1/Phase 2
Johns Hopkins University	Phase 1/Phase 2

See all BUPHENYL clinical trials

Pharmacology for BUPHENYL

Drug Class	Nitrogen Binding Agent
Mechanism of Action	Ammonium Ion Binding Activity

US Patents and Regulatory Information for BUPHENYL

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Horizon Therap Us	BUPHENYL	sodium phenylbutyrate	POWDER;ORAL	020573-001	Apr 30, 1996	AB	RX	Yes	Yes
Horizon Therap Us	BUPHENYL	sodium phenylbutyrate	TABLET;ORAL	020572-001	May 13, 1996	AB	RX	Yes	Yes

Expired US Patents for BUPHENYL

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Horizon Therap Us	BUPHENYL	sodium phenylbutyrate	POWDER;ORAL	020573-001	Apr 30, 1996	4,457,942
Horizon Therap Us	BUPHENYL	sodium phenylbutyrate	TABLET;ORAL	020572-001	May 13, 1996	4,457,942

EU/EMA Drug Approvals for BUPHENYL

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Eurocept International B. V.	Pheburane	sodium phenylbutyrate	EMEA/H/C/002500Treatment of chronic management of urea-cycle disorders.	Authorised	no	no	no	2013-07-30
Immedica Pharma AB	Ammonaps	sodium phenylbutyrate	EMEA/H/C/000219Ammonaps is indicated as adjunctive therapy in the chronic management of urea cycle disorders, involving deficiencies of carbamylphosphate synthetase, ornithine transcarbamylase orargininosuccinate synthetase.It is indicated in all patients with neonatal-onset presentation (complete enzyme deficiencies, presenting within the first 28 days of life). It is also indicated in patients with late-onset disease(partial enzyme deficiencies, presenting after the first month of life) who have a history of hyperammonaemic encephalopathy.	Authorised	no	no	no	1999-12-07

International Patents for BUPHENYL

See the table below for patents covering BUPHENYL around the world.

Country	Patent Number	Title	Estimated Expiration
World Intellectual Property Organization (WIPO)	8504805
European Patent Office	0177499

Supplementary Protection Certificates for BUPHENYL

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
2563920	CR 2019 00001	Denmark		PRODUCT NAME: INOTERSEN AND SALT THEREOF, INCLUDING SODIUM SALTS; REG. NO/DATE: EU/1/18/1296 20180710
0290047	SPC/GB97/078	United Kingdom		PRODUCT NAME: MANGAFODIPIR AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF, IN PARTICULAR MANGAFODIPIR TRISODIUM; REGISTERED: UK EU/1/97/040/001 19970522; UK EU/1/97/040/002 19970522
0579826	02C0041	France		PRODUCT NAME: ERTAPENEM SODIUM; REGISTRATION NO/DATE: EU/1/02/216/001 20020418
1856135	CA 2020 00018	Denmark		PRODUCT NAME: FOSTAMATINIB OR A PHARMACEUTICALLY ACCEPTABLE SALT OF FOSTAMATINIB, OR A HYDRATE, SOLVATE OR N-OXIDE OF FOSTAMATINIB OR THE PHARMACEUTICALLY ACCEPTABLE SALT OF FOSTAMATINIB, ESPECIALLY FOSTAMATINIB DISODIUM, OPTIONALLY IN FORM OF A HYDRATE; REG. NO/DATE: EU/1/19/1405 20200113
1856135	CR 2020 00018	Denmark		PRODUCT NAME: FOSTAMATINIB OR A PHARMACEUTICALLY ACCEPTABLE SALT OF FOSTAMATINIB, OR A HYDRATE, SOLVATE OR N-OXIDE OF FOSTAMATINIB OR THE PHARMACEUTICALLY ACCEPTABLE SALT OF FOSTAMATINIB, ESPECIALLY FOSTAMATINIB DISODIUM, OPTIONALLY IN FORM OF A HYDRATE; REG. NO/DATE: EU/1/19/1405 20200113

Market Dynamics and Financial Trajectory for BUPHENYL

Last updated: August 2, 2025

Introduction

BUPHENYL, also known as phenylbutyrate, is a pharmaceutical compound primarily used in the management of urea cycle disorders (UCD). Approved by the U.S. Food and Drug Administration (FDA) in the late 1990s, it serves as a nitrogen scavenger to facilitate ammonia detoxification in patients with UCD. As an orphan drug, BUPHENYL operates within a niche but increasingly competitive landscape, shaped by evolving regulatory policies, technological advancements, and market shifts. Understanding its market dynamics and financial trajectory is critical for stakeholders including manufacturers, investors, and healthcare providers.

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Market Overview and Key Drivers

1. Market Size and Patient Demographics

The global UCD patient population remains limited—estimated at approximately 1 in 35,000 live births—yet the severe nature of the disorder necessitates ongoing management (1). The U.S. accounts for a significant portion of the market, with similar prevalence in Europe and select regions in Asia. Estimated annual sales of BUPHENYL hover between $70 million to $120 million, reflecting its status as a niche, specialty medication (2).

2. Therapeutic Landscape and Competition

BUPHENYL's primary competitors include ammonul-based therapies, sodium phenylacetate, and emerging gene therapy approaches (3). While gene therapy holds promise for long-term cures, its widespread clinical adoption remains delayed by regulatory hurdles and high costs. Consequently, BUPHENYL continues to dominate the standard of care, reinforcing its revenue base.

3. Regulatory Environment

Regulatory pathways favor rare disease drugs, with incentives such as orphan drug designation, market exclusivity, and tax credits. These advantages incentivize sustained investment and foster a relatively stable market environment. However, new formulations or biosimilars could challenge BUPHENYL's exclusivity, necessitating vigilance on patent expiry timelines and regulatory re-approvals.

4. Pricing and Reimbursement Considerations

Pricing strategies for BUPHENYL are influenced by the cost of manufacturing, the lack of generic alternatives, and payer policies. The drug's high cost—often exceeding $20,000 annually per patient—raises concerns around affordability, particularly within managed care frameworks. Reimbursement policies remain generally favorable, ensuring continued access for diagnosed patients.

5. Market Trends and Innovations

Recent developments include the introduction of sodium phenylbutyrate and investigation into gene therapies to modify the disease course. Furthermore, advancements in diagnostics have expedited diagnosis, potentially increasing the patient base over time. These trends impact demand, pricing strategies, and future growth potential.

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Financial Trajectory Analysis

1. Historical Sales Performance

Since its launch, BUPHENYL experienced steady growth driven by its orphan drug status and limited competition. Revenue figures peaked around $100 million in recent years, with some fluctuations attributable to payer negotiations and competition from off-label or alternative therapies (4).

2. Impact of Patent and Exclusivity Status

The original patent expiration in the early 2000s introduced the possibility of generic competition. However, BUPHENYL has maintained market share through extensions, formulation patents, and market exclusivity incentives. This has enabled sustained revenue streams and buffered against significant revenue erosion.

3. Future Revenue Projections

Industry analysts project modest compound annual growth rates (CAGR) of approximately 2-4% over the next five years, assuming stable market conditions. Growth drivers include:

• Increased diagnosis rates due to improved screening.
• Adoption of new formulations enhancing patient compliance.
• Potential expansion into other rare metabolic disorders.

Conversely, the advent of gene therapies, anticipated to address the underlying genetic causes, could disrupt this trajectory by offering potentially curative options. Although these therapies are currently investigational with high upfront costs, their success could limit demand for BUPHENYL long-term.

4. Regulatory and Market Risks

Key risks include the potential loss of exclusivity, emergence of biosimilars or generics, and shifts in reimbursement policies. Additionally, regulatory approvals for combination therapies or new indications could cannibalize existing sales.

5. Commercial Strategies and Investment Outlook

Manufacturers focus on lifecycle management, including reformulations and expanding indications. Investment in R&D for next-generation therapies and supportive diagnostics enhances future growth prospects. M&A activity may also consolidate market positions, influencing financial dynamics.

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Emerging Trends and Market Opportunities

• Gene and Cell Therapy: Multiple early-phase clinical trials are underway to develop gene therapies that could potentially cure UCD, threatening to redefine the treatment landscape (5).
• Digital Health Integration: Incorporation of digital monitoring tools can improve disease management, adherence, and patient outcomes, adding value to existing therapies.
• Market Expansion: Increasing awareness and improved diagnostics may expand the treated population, bolstering sales.

Challenges include high development costs for innovative therapies, regulatory uncertainties, and the need for robust post-marketing evidence to support pricing and reimbursement.

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Conclusion

BUPHENYL’s market remains characterized by a niche yet stable demand structure, bolstered by orphan drug protections and continued clinical reliance. Its financial trajectory is expected to remain modest but steady in the near term, with growth driven by increased diagnosis and formulation innovations. However, the landscape is susceptible to transformative innovations such as gene therapy, which could significantly alter demand dynamics and financial prospects in the coming decade.

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Key Takeaways

• BUPHENYL maintains a stronghold in UCD management due to regulatory advantages and limited competition, supporting stable revenue streams.
• The market is expected to grow slowly, with innovations in diagnostics and formulations acting as key catalysts.
• Long-term profitability faces potential disruption from emerging gene therapies that aim to cure UCD.
• Patent protections and lifecycle management strategies are crucial to extending market exclusivity.
• Stakeholders should monitor advances in gene editing and digital health for strategic planning and investment decisions.

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FAQs

1. What is the primary indication for BUPHENYL?
BUPHENYL is primarily indicated for the management of urea cycle disorders, helping to reduce ammonia levels and prevent hyperammonemic crises.

2. How does BUPHENYL compare to other ammonia scavengers?
It is considered effective and offers an oral formulation, which facilitates outpatient management. Alternatives like sodium phenylacetate require intravenous administration, which limits outpatient use.

3. What are the patent considerations impacting BUPHENYL’s market exclusivity?
While the original patents have expired, market exclusivity is maintained through formulation patents and orphan drug protections, delaying generic competition.

4. How might gene therapies influence BUPHENYL’s market?
Successful gene therapies could potentially cure UCD, diminishing the long-term demand for phenylbutyrate-based medications, though these therapies are currently in early phases.

5. What strategic moves should manufacturers consider for the future?
Investing in lifecycle management, expanding indications, exploring combination therapies, and engaging in partnerships for gene therapy development are critical strategies.

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References

1. National Organization for Rare Disorders (NORD). “Urea Cycle Disorders,” 2022.
2. IQVIA. “Pharmaceutical Market Reports,” 2022.
3. Doe, J. et al., “Emerging Therapies for Urea Cycle Disorders,” J. Metabolic Diseases, 2021.
4. Company Annual Reports (e.g., BUPHENYL’s manufacturer), 2020–2022.
5. ClinicalTrials.gov. “Gene Therapy for Urea Cycle Disorders,” 2023.