Sodium phenylbutyrate - Generic Drug Details

What are the generic drug sources for sodium phenylbutyrate and what is the scope of freedom to operate?

Sodium phenylbutyrate is the generic ingredient in five branded drugs marketed by Acer, Medunik, Horizon Therap Us, Ph Health, Sigmapharm Labs Llc, Alvogen, Glenmark Pharms Ltd, and Amylyx, and is included in ten NDAs. There are eight patents protecting this compound. Additional information is available in the individual branded drug profile pages.

Sodium phenylbutyrate has thirty-one patent family members in twenty-two countries.

There are four drug master file entries for sodium phenylbutyrate. Six suppliers are listed for this compound.

Summary for sodium phenylbutyrate

International Patents:	31
US Patents:	8
Tradenames:	5
Applicants:	8
NDAs:	10
Drug Master File Entries:	4
Finished Product Suppliers / Packagers:	6
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	43
Patent Applications:	4,115
What excipients (inactive ingredients) are in sodium phenylbutyrate?	sodium phenylbutyrate excipients list
DailyMed Link:	sodium phenylbutyrate at DailyMed

Recent Clinical Trials for sodium phenylbutyrate

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

Sponsor	Phase
University of Pennsylvania	EARLY_PHASE1
National Heart, Lung, and Blood Institute (NHLBI)	EARLY_PHASE1
Jerry Vockley, MD, PhD	PHASE1

See all sodium phenylbutyrate clinical trials

Pharmacology for sodium phenylbutyrate

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

Anatomical Therapeutic Chemical (ATC) Classes for sodium phenylbutyrate

A16AX	Various alimentary tract and metabolism products
A16A	OTHER ALIMENTARY TRACT AND METABOLISM PRODUCTS
A16	OTHER ALIMENTARY TRACT AND METABOLISM PRODUCTS
A	Alimentary tract and metabolism

US Patents and Regulatory Information for sodium phenylbutyrate

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Acer	OLPRUVA	sodium phenylbutyrate	FOR SUSPENSION;ORAL	214860-001	Dec 22, 2022		RX	Yes	No	11,433,041		Y
Medunik	PHEBURANE	sodium phenylbutyrate	PELLETS;ORAL	216513-001	Jun 17, 2022		RX	Yes	Yes
Amylyx	RELYVRIO	sodium phenylbutyrate; taurursodiol	FOR SUSPENSION;ORAL	216660-001	Sep 29, 2022		DISCN	Yes	No	11,071,742		Y
Acer	OLPRUVA	sodium phenylbutyrate	FOR SUSPENSION;ORAL	214860-007	Oct 10, 2025		RX	Yes	No	11,154,521		Y
Alvogen	SODIUM PHENYLBUTYRATE	sodium phenylbutyrate	TABLET;ORAL	090910-001	Nov 18, 2011		DISCN	No	No
Acer	OLPRUVA	sodium phenylbutyrate	FOR SUSPENSION;ORAL	214860-002	Dec 22, 2022		RX	Yes	No	11,433,041		Y
Horizon Therap Us	BUPHENYL	sodium phenylbutyrate	TABLET;ORAL	020572-001	May 13, 1996	AB	RX	Yes	Yes

Expired US Patents for sodium phenylbutyrate

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 sodium phenylbutyrate

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 sodium phenylbutyrate

Country	Patent Number	Title	Estimated Expiration
Cyprus	1125450
South Korea	102690703
Singapore	11201807979S
Mexico	2022003969
Mexico	2018011229
Brazil	112018068665
Mexico	391305

Supplementary Protection Certificates for sodium phenylbutyrate

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
1666481	17C1031	France		PRODUCT NAME: TOFACITINIB,EVENTUELLEMENT SOUS LA FORME D'UN SEL PHARMACEUTIQUEMENT ACCEPTABLE,DONT LE CITRATE DE SODIUM; REGISTRATION NO/DATE: EU/1/17/1178 20170324
0788511	SPC/GB08/036	United Kingdom		PRODUCT NAME: MICAFUNGIN AND PHARMACEUTICALLY ACCEPTABLE SALTS THEREOF IN PARTICULAR MICAFUNGIN SODIUM; REGISTERED: UK EU/1/08/448/001 20080425; UK EU/1/08/448/002 20080425

Market Dynamics and Financial Trajectory for Sodium Phenylbutyrate

Last updated: July 27, 2025

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Introduction

Sodium phenylbutyrate (SPB) is a nitrogen-scavenging agent primarily used in the treatment of urea cycle disorders (UCD). As an ammonia detoxifier, SPB has gained regulatory approval and clinical acceptance, positioning itself within the niche but critical domain of rare disease therapeutics. This article explores the evolving market landscape and financial trajectory of sodium phenylbutyrate, considering key drivers, market challenges, competitive dynamics, and future growth prospects.

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Market Landscape and Key Drivers

Unmet Medical Need and Rare Disease Treatment

Urea cycle disorders are life-threatening inborn errors of metabolism characterized by defective ammonia detoxification, leading to hyperammonemia. SPB’s role as an ammonia scavenger makes it indispensable for managing acute and chronic cases. The rarity of UCD patients ensures a niche but stable demand, although challenges in diagnosis and treatment awareness can influence market penetration levels.

Regulatory Framework and Approvals

SPB, under various brand names such as Ravicti (more recently replaced by glycerol phenylbutyrate), holds FDA approval for managing certain UCDs (notably, cyclic forms). Regulatory agencies’ firm stance on orphan drug designation fosters investment incentives, including market exclusivity, which bolsters financial prospects for developers and manufacturers.

Advancements in Alternative Therapies

Newer formulations, such as glycerol phenylbutyrate, are gradually supplanting sodium phenylbutyrate, offering improved pharmacokinetics and patient compliance. Nonetheless, cost considerations and existing infrastructure mean SPB retains a position as an affordable option, especially in developing markets.

Market Globalization and Access

Emerging markets, particularly in Asia and Latin America, exhibit expanding access to orphan drugs, driven by improved healthcare infrastructure and policy reforms. These dynamics may moderate the global growth potential of SPB, while also presenting opportunities for generic manufacturers.

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Market Challenges and Constraints

Pricing and Reimbursement

SPB’s high cost relative to traditional therapies, along with limited reimbursement in certain regions, constrains market expansion. Healthcare systems aiming to optimize treatment costs may favor alternative or newer therapies with superior efficacy profiles, impacting SPB sales.

Generic Competition

As patents lapse, generic manufacturers enter the market, exerting downward pressure on prices. The availability of cost-effective alternatives can erode the revenue streams of branded SPB formulations, especially in regions with stringent price controls.

Market Awareness and Diagnostic Challenges

Delayed diagnosis of UCD hampers timely intervention with SPB. Improved awareness and newborn screening programs are imperative; however, disparities exist between high-income and emerging economies, affecting the uniformity of market growth.

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Financial Trajectory Analysis

Revenue Patterns and Market Valuation

The global SPB market remains modest, primarily driven by UCD prevalence estimates (~1 in 35,000 live births in the US). Historical revenues for SPB products such as Ravicti and branded versions of sodium phenylbutyrate have shown steady but moderate growth, reflecting the niche status of UCD treatment.

Impact of the Glycerol Phenylbutyrate Transition

The FDA’s approval and subsequent uptake of glycerol phenylbutyrate, endorsed for its enhanced patient compliance, have introduced a competitive tension. Existing SPB formulations face potential revenue decline as healthcare providers switch to newer formulations, which are often reimbursed at higher price points.

Market Expansion Prospects

Emerging markets offer incremental growth opportunities, driven by increasing awareness, improved healthcare access, and governmental longitudinal support for orphan diseases. Moreover, pipeline developments exploring SPB analogs or combination therapies could stimulate future revenues.

Investment and R&D Outlook

Pharmaceutical companies continue to invest in the development of long-acting and more tolerable ammonia scavengers, possibly relegating SPB to a market segment focused on cost-sensitive regions. Mergers and acquisitions, especially among generic players, could influence the financial landscape by consolidating market share and influencing pricing strategies.

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Competitive and Regulatory Outlook

The competitive environment centers around branded formulations (e.g., Ravicti) versus generics, with regulatory agencies strongly shaping market access. The expiration of existing patents and regulatory approvals for alternative formulations will potentially accelerate generic entry, impacting pricing and margins.

Meanwhile, regulatory agencies' emphasis on pediatric and orphan drug designation sustains the incentive landscape for continued innovation. Any shifts favoring gene therapies or enzyme replacement strategies could redefine the market trajectory for SPB.

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Future Market Trends and Opportunities

1. Market Penetration in Emerging Economies: As healthcare infrastructure improves, demand for affordable ammonia scavengers remains high, sustaining SPB’s relevance.
2. Development of Novel Derivatives: Investment in next-generation phenylbutyrate analogs or combination treatments could augment or replace existing formulations.
3. Gene Therapy Integration: Advances in genetic correction therapies for UCD may diminish reliance on small-molecule scavengers, influencing long-term sales.
4. Pricing Strategies: Manufacturers may adopt tiered pricing models to penetrate low-income markets while maximizing margins in high-income regions.
5. Regulatory Incentives: Orphan drug exclusivities and fast-track approvals will continue to influence the financial outcome of research and product launches.

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Key Takeaways

• Niche but Critical Market: Sodium phenylbutyrate sustains demand primarily in rare urea cycle disorders, benefiting from orphan drug policies.
• Competitive Dynamics: The advent of glycerol phenylbutyrate and generic entrants pose challenges; market share is shifting accordingly.
• Pricing Pressure: High-cost formulations face reimbursement and cost-containment pressures, especially amid increasing generic penetration.
• Growth Potential in Emerging Markets: Expanding healthcare infrastructure in developing regions offers incremental revenue opportunities.
• Future Outlook: Innovation in gene therapies and improved formulations may redefine SPB's role, with current revenues likely plateauing or declining in mature markets.

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FAQs

1. What factors are influencing the decline or growth of sodium phenylbutyrate sales?
Sales are impacted by the introduction of newer formulations (e.g., glycerol phenylbutyrate), patent expirations leading to generics, pricing pressures, and increased awareness and diagnosis of Urea Cycle Disorders, especially in emerging markets.

2. How does regulatory approval affect the financial outlook for sodium phenylbutyrate?
Regulatory approvals, especially orphan drug designations, can extend market exclusivity and provide reinforcement against generics, sustaining revenues. Conversely, approvals for superior formulations may shift market preference away from traditional SPB.

3. Is sodium phenylbutyrate a sustainable long-term investment?
While it remains essential for certain patient populations, the long-term outlook is challenged by reformulations, pipeline therapies, and gene treatments. Its sustainability hinges on niche market maintenance and expanding access in cost-sensitive regions.

4. What are the key market segments where sodium phenylbutyrate is expected to grow?
Emerging markets with limited access to newer therapies, global neonatal screening programs, and areas with constrained healthcare budgets are primary segments where SPB may see continued demand.

5. How do pipeline developments impact the future of sodium phenylbutyrate?
Innovations like gene therapy for UCD may threaten the market share of small-molecule therapies. However, until such therapies are widely accessible, SPB remains a vital treatment, and pipeline developments may serve as secondary options or complementary therapies.

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References

[1] FDA. (2022). Orphan designation and approval details for phenylbutyrate formulations.
[2] Pharmacovigilance data for Ravicti and generic sodium phenylbutyrate products.
[3] Market analysis reports on rare disease therapeutics and urea cycle disorder management.
[4] Recent publications on advancements in gene therapy for Urea Cycle Disorders.
[5] Healthcare policies influencing orphan drug pricing and reimbursement in emerging markets.

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This comprehensive review offers vital insights for pharmaceutical strategists, investors, and healthcare policy makers seeking to understand the intricate market forces shaping sodium phenylbutyrate’s financial journey.