gabapentin enacarbil - Profile

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

Gabapentin enacarbil is the generic ingredient in one branded drug marketed by Azurity and is included in one NDA. There are three patents protecting this compound. Additional information is available in the individual branded drug profile pages.

Gabapentin enacarbil has seventy-three patent family members in twenty-four countries.

Summary for gabapentin enacarbil

International Patents:	73
US Patents:	3
Tradenames:	1
Applicants:	1
NDAs:	1

DrugPatentWatch^® Estimated Loss of Exclusivity (LOE) Date for gabapentin enacarbil

Constraining patent/regulatory exclusivity:

8,795,725

Dosage:

TABLET, EXTENDED RELEASE;ORAL

^*The generic entry opportunity date is the latter of the last compound-claiming patent and the last regulatory exclusivity protection. Many factors can influence early or later generic entry. This date is provided as a rough estimate of generic entry potential and should not be used as an independent source.

Paragraph IV (Patent) Challenges for GABAPENTIN ENACARBIL

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
HORIZANT	Extended-release Tablets	gabapentin enacarbil	300 mg and 600 mg	022399	1	2019-04-29

US Patents and Regulatory Information for gabapentin enacarbil

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011		RX	Yes	No	8,114,909
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011		RX	Yes	No	8,795,725		Y
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011		RX	Yes	No	8,026,279		Y	Y
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-001	Apr 6, 2011		RX	Yes	Yes	8,795,725		Y
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-001	Apr 6, 2011		RX	Yes	Yes	8,114,909

Expired US Patents for gabapentin enacarbil

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011	6,818,787
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-001	Apr 6, 2011	8,686,034
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-001	Apr 6, 2011	8,048,917
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011	8,048,917
Azurity	HORIZANT	gabapentin enacarbil	TABLET, EXTENDED RELEASE;ORAL	022399-002	Dec 13, 2011	8,686,034

International Patents for gabapentin enacarbil

Country	Patent Number	Title	Estimated Expiration
New Zealand	579515	Treating or preventing restless legs syndrome using prodrugs of gaba analogs
Hong Kong	1090850	CRYSTALLINE FORM OF GAMMA-AMINOBUTYRIC ACID ANALOG
Norway	20061655
Japan	4308263
Cyprus	1113583

Investment Scenario and Fundamentals Analysis for Gabapentin Enacarbil

Last updated: February 20, 2026

What is the current market position of gabapentin enacarbil?

Gabapentin enacarbil is an extended-release intellectual property (IP) licensed prodrug of gabapentin. It is marketed as Horizant by XenoPort, approved by the FDA since 2011 for restless legs syndrome (RLS) and postherpetic neuralgia (PHN). The drug targets a niche market, primarily addressing neurological and pain management indications.

Market Size and Growth

• Estimated global RLS market value: $500 million (2022)
• PHN market in the U.S.: approximately $300 million (2022)
• Compound annual growth rate (CAGR): approximately 3-5%, driven by aging populations and increased diagnosis rates

Sales and Revenue

• Horizant sales in 2022: approximately $200 million globally
• U.S. market share: dominant in RLS segment, with limited competition
• Other geographies: minimal commercialization, primarily due to patent protections and regulatory delays

Patent and Regulatory Status

• Patent expiry: expected 2027-2030, depending on jurisdiction
• Patent protection: strong through 2025, with potential for extension via patent litigations and formulation patents
• Regulatory landscape: approval granted by FDA; similar regulatory environment in Europe and Asia pending or under review

What are the key fundamentals for investment?

Clinical Efficacy and Safety Profile

• Demonstrates efficacy in RLS and PHN
• Known adverse effects: dizziness, fatigue, peripheral edema
• Competitive advantage: improved bioavailability over immediate-release gabapentin; less frequent dosing

Manufacturing and Supply Chain

• Manufacturing partnerships with contract manufacturing organizations (CMOs)
• Supply chain risks are moderate; depend on quality controls and regional manufacturing capacities
• Pricing pressure: moderate, due to generic gabapentin availability

Competitive Landscape

• Main competitors: pregabalin (Lyrica), duloxetine, opioids (regulatory constraints)
• Differentiators: targeted indications, once-daily dosing, patent exclusivity
• Patent litigation: ongoing in some jurisdictions, which could impact future exclusivity

What is the outlook for future growth and risks?

Growth Drivers

• Aging populations increase RLS and PHN prevalence
• Expanded indications: potential off-label uses and new formulations
• Strategic partnerships for licensing and market expansion

Risks

• Patent expiration: opens market to generics post-2025
• Regulatory hurdles: delays or rejections in new markets
• Competition: new drugs with better efficacy or safety profile entering the market

R&D Pipeline

• Possible investigation of gabapentin enacarbil for other neuropathic conditions
• Development of biosimilars or combination therapies

Investment Recommendations

• Positioning: Consider as a mid-stage biotech with a stable income base from licensed rights
• Timing: Monitor patent expirations, regulatory approvals, and competition
• Risks: Evaluate patent litigation outcomes and generic entry threats
• Opportunity: Potential upside via expanded indications and market penetration

Key Takeaways

• Gabapentin enacarbil operates with a niche, stable revenue stream, primarily in RLS and PHN markets
• Patent protection sustains exclusivity until approximately 2025-2030
• Competitive threats from generics will emerge post-patent, pressuring margins
• Growth opportunities exist through indication expansion and strategic alliances
• Risks include patent expiry, regulatory delays, and competitive innovations

FAQs

1. When will gabapentin enacarbil face generic competition?
Patent exclusivity is expected to last until 2025-2030, varying by jurisdiction and patent litigation outcomes.

2. Can gabapentin enacarbil be used off-label for other conditions?
Off-label use is possible but not officially approved; clinical trials would be required for new indications.

3. How does gabapentin enacarbil compare to generic gabapentin?
It offers once-daily dosing and improved bioavailability, making it more convenient but at a higher cost.

4. Are there regulatory hurdles for expanding its market?
Yes; approval in new markets depends on local regulatory reviews and compliance.

5. What are main competitive threats?
Generic gabapentin, pregabalin, duloxetine, and emerging therapies that target similar neuropathic conditions.

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References

1. Market data from EvaluatePharma (2022).
2. FDA approval details from the U.S. Food and Drug Administration (2011).
3. Patent and regulatory information from XenoPort filings (2022).