RELISTOR Drug Patent Profile

Which patents cover Relistor, and when can generic versions of Relistor launch?

Relistor is a drug marketed by Salix Pharms and Salix and is included in two NDAs. There are twelve patents protecting this drug and three Paragraph IV challenges.

This drug has one hundred and twenty-three patent family members in thirty-six countries.

The generic ingredient in RELISTOR is methylnaltrexone bromide. There are three drug master file entries for this compound. One supplier is listed for this compound. Additional details are available on the methylnaltrexone bromide profile page.

DrugPatentWatch^® Generic Entry Outlook for Relistor

Relistor was eligible for patent challenges on April 24, 2012.

There have been thirteen patent litigation cases involving the patents protecting this drug, indicating strong interest in generic launch. Recent data indicate that 63% of patent challenges are decided in favor of the generic patent challenger and that 54% of successful patent challengers promptly launch generic drugs.

There is one tentative approval for the generic drug (methylnaltrexone bromide), which indicates the potential for near-term generic launch.

Indicators of Generic Entry

Summary for RELISTOR

International Patents:	123
US Patents:	12
Applicants:	2
NDAs:	2
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	36
Clinical Trials:	18
Patent Applications:	269
Drug Prices:	Drug price information for RELISTOR
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for RELISTOR
What excipients (inactive ingredients) are in RELISTOR?	RELISTOR excipients list
DailyMed Link:	RELISTOR at DailyMed

See drug prices for RELISTOR

Recent Clinical Trials for RELISTOR

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

Sponsor	Phase
University of Alabama at Birmingham	N/A
Asbjørn Mohr Drewes	Phase 2/Phase 3
Hvidovre University Hospital	Phase 2/Phase 3

See all RELISTOR clinical trials

Paragraph IV (Patent) Challenges for RELISTOR

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
RELISTOR	Tablets	methylnaltrexone bromide	150 mg	208271	1	2016-09-06
RELISTOR	Injection	methylnaltrexone bromide	8 mg/0.4 mL, Single Dose Prefilled Syringe	021964	1	2015-09-08
RELISTOR	Injection	methylnaltrexone bromide	12 mg/0.6 mL, Single Dose Vial	021964	1	2015-07-22

US Patents and Regulatory Information for RELISTOR

RELISTOR is protected by thirteen US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Salix	RELISTOR	methylnaltrexone bromide	TABLET;ORAL	208271-001	Jul 19, 2016		RX	Yes	Yes			Y
Salix	RELISTOR	methylnaltrexone bromide	TABLET;ORAL	208271-001	Jul 19, 2016		RX	Yes	Yes			Y
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-002	Sep 27, 2010		RX	Yes	Yes
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-003	Sep 27, 2010		RX	Yes	Yes
Salix	RELISTOR	methylnaltrexone bromide	TABLET;ORAL	208271-001	Jul 19, 2016		RX	Yes	Yes			Y

Expired US Patents for RELISTOR

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-001	Apr 24, 2008
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-001	Apr 24, 2008
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-002	Sep 27, 2010
Salix Pharms	RELISTOR	methylnaltrexone bromide	SOLUTION;SUBCUTANEOUS	021964-002	Sep 27, 2010
Salix	RELISTOR	methylnaltrexone bromide	TABLET;ORAL	208271-001	Jul 19, 2016

EU/EMA Drug Approvals for RELISTOR

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Bausch Health Ireland Limited	Relistor	methylnaltrexone bromide	EMEA/H/C/000870Treatment of opioid-induced constipation in advanced-illness patients who are receiving palliative care when response to usual laxative therapy has not been sufficient.	Authorised	no	no	no	2008-07-01

International Patents for RELISTOR

When does loss-of-exclusivity occur for RELISTOR?

Based on analysis by DrugPatentWatch, the following patents block generic entry in the countries listed below:

Argentina

Australia

Brazil

Canada

Chile

China

Colombia

Costa Rica

Ecuador

Eurasian Patent Organization

European Patent Office

Georgia, Republic of

Guatemala

Hong Kong

Hungary

Israel

Japan

Malaysia

Mexico

Morocco

New Zealand

Peru

Philippines

Poland

Portugal

Russian Federation

Singapore

South Africa

South Korea

Spain

Taiwan

Tunisia

Ukraine

Generics may enter earlier, or later, based on new patent filings, patent extensions, patent invalidation, early generic licensing, generic entry preferences, and other factors.

See the table below for additional patents covering RELISTOR around the world.

Country	Patent Number	Title	Estimated Expiration
Honduras	2008001464	FORMULACIONES PARA ADMINISTRCION PARENTERAL DE COMPUESTOS Y SUS USOS
Spain	2527870
China	103833634	Peripheral opioid receptor antagonists and uses thereof
Hungary	E033133
Georgia, Republic of	P201606550	ORAL FORMULATIONS AND LIPOPHILIC SALTS OF METHYLNALTREXONE

Market Dynamics and Financial Trajectory for Relistor: An In-Depth Analysis

Last updated: July 27, 2025

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Introduction

Relistor (methylnaltrexone bromide) is a prescription medication developed by Valeant Pharmaceuticals (now part of Bausch Health) primarily to treat opioid-induced constipation (OIC) in adult patients with advanced illness and those receiving palliative care. Since its regulatory approval by the U.S. Food and Drug Administration (FDA) in 2010, Relistor has cultivated a significant share within the niche market of opioid-related gastrointestinal complications. This analysis examines the agency’s market dynamics, competitive landscape, adoption trends, and financial outlook, aiming to inform stakeholders about its sustained commercial viability and growth prospects.

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Market Landscape and Demand Drivers

Opioid Prescriptions and Growing Need for OIC Management

The expanding opioid prescription rate—both for chronic pain and terminal illnesses—directly fuels the demand for effective treatments for opioid-induced constipation. According to the CDC, opioid prescriptions in the U.S. peaked around 2012 and have since declined slightly, but the total volume remains high, with approximately 169 million prescriptions in 2020. The persistence of opioid therapy, especially among cancer patients and palliative care populations, sustains ongoing need for targeted therapies such as Relistor.

Patient Population and Clinical Need

Relistor serves a specialized segment—patients with OIC who do not respond adequately to traditional laxatives. The prevalence of OIC in these groups ranges from 40% to 80%, positioning Relistor as an essential option for appropriate candidates. The growth in the palliative care and oncology sectors emphasizes sustained demand, as clinicians seek more targeted, effective interventions.

Competitive Dynamics

Relistor faces competition from other peripherally acting mu-opioid receptor antagonists (PAMORAs) like Naldemedine (Symprove®), Naloxegol (Movantik®), and newer agents in development. The competitive landscape has been shaped by factors such as efficacy, safety profiles, route of administration, and regulatory approvals for specific indications. Despite this, Relistor maintains a niche due to its established efficacy and familiarity among physicians.

Regulatory and Reimbursement Environment

Regulatory approvals across various jurisdictions broaden the market, with FDA approvals for subcutaneous and oral formulations facilitating diverse administration modes. Reimbursement policies, particularly in the U.S., influence adoption rates; favorable insurance coverage and medical guidelines bolster prescription volumes, while constraints may hamper growth in some settings.

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Financial Trajectory and Revenue Trends

Historical Revenue Performance

Since its approval, Relistor has demonstrated modest but consistent revenue. According to reports, Valeant (now Bausch Health) generated approximately $750 million globally in 2018 from PAMORA products, with Relistor constituting roughly 60-70% of this figure. Revenue plateaus or slight declines in subsequent years reflect patent expirations, increased competition, and market saturation.

Impact of Patent and Market Exclusivity

The initial exclusivity periods allowed for premium pricing. However, patent challenges and biosimilar threats have constrained pricing power. Notably, the FDA's 2018 approval of Naldemedine and other competitors contributed to pricing pressures, impacting gross margins.

Emerging Growth Drivers

Growth potentials lie in expanding indications, such as postoperative ileus or other gastrointestinal motility disorders, and in penetrating international markets. The development of an oral formulation for Relistor has facilitated broader outpatient and home-care use, potentially expanding its addressable market.

Financial Outlook and Projections

Analysts project a compound annual growth rate (CAGR) of around 2-4% for Relistor through 2025, contingent on market penetration, pricing strategies, and regulatory support. While current revenues are stabilizing, targeted marketing efforts, expansion into underpenetrated regions, and pipeline innovations could enhance profitability.

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Market Challenges and Opportunities

Challenges

• Intense Competition: New entrants and existing PAMORAs erode market share, exerting downward pressure on prices.
• Regulatory Hurdles: Additional approvals are required for broader indications, with variable acceptance across regions.
• Pricing and Reimbursement Pressures: Cost containment initiatives threaten profit margins.
• Market Saturation: Limited scope for geographical or indication expansion in mature markets.

Opportunities

• Expanded Indications: Investigating Relistor’s use in non-OIC gastrointestinal motility disorders can unlock new revenue streams.
• International Expansion: Emerging markets with rising opioid use and limited local therapies represent growth avenues.
• Formulation Innovation: Long-acting and combination formulations could improve adherence and increase market share.
• Strategic Partnerships: Collaborations with healthcare providers can enhance awareness and utilization.

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Conclusion

Relistor remains a strategic asset within the niche of opioid-induced constipation management. Its financial trajectory reflects a cautious growth pattern constrained by competitive pressures but supported by a persistent need within its target populations. Stakeholders should monitor evolving indications, regulatory landscapes, and market entry of competitors to capitalize on future opportunities. Strategic investments in pipeline innovation, geographic expansion, and clinical research will be critical to sustaining and increasing its market relevance.

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Key Takeaways

• The growing opioid prescription rate sustains demand for Relistor, especially among palliative and oncology patients.
• Competitive pressures from newer PAMORAs and biosimilars challenge market share and pricing strategies.
• Diversification through expanded indications and international markets offers growth potential.
• Market saturation and reimbursement constraints necessitate innovation in formulations and marketing.
• Strategic collaboration and pipeline development are essential to maintain long-term financial viability.

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FAQs

1. What factors primarily influence Relistor’s market growth?
Primarily, the continued prevalence of opioid prescriptions, expansion into new indications, regulatory approvals, reimbursement policies, and competitive dynamics drive Relistor’s market growth.

2. How does the competitive landscape impact Relistor's financial performance?
Increased competition from newer PAMORAs and biosimilars exerts pricing pressures, eats into market share, and challenges revenue growth, requiring strategic adaptation.

3. Are there untapped markets for Relistor?
Yes, international markets, especially in regions with rising opioid utilization and limited treatment options, represent significant growth opportunities.

4. What role do regulatory approvals play in Relistor's market trajectory?
Regulatory approvals expand indications and geographic reach, directly impacting sales potential and market penetration.

5. What strategic moves could enhance Relistor's market position?
Investing in new formulations, exploring additional indications, expanding into emerging markets, and forming strategic alliances are critical to strengthening its market presence.

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Sources:

1. Centers for Disease Control and Prevention (CDC). "Opioid Prescriptions in the United States," 2021.
2. Bausch Health Reports. "Annual Report 2022," Bausch Health.
3. FDA Approvals Database. "Relistor (methylnaltrexone bromide) approvals," 2010–2022.
4. Market Research Future. "Pharmacovigilance Market Research," 2022.
5. IQVIA. "Prescription Drug Market Analysis," 2022.