welireg Drug Patent Profile

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

Welireg is a drug marketed by Merck Sharp Dohme and is included in one NDA. There are three patents protecting this drug and one Paragraph IV challenge.

This drug has sixty-two patent family members in twenty-eight countries.

The generic ingredient in WELIREG is belzutifan. One supplier is listed for this compound. Additional details are available on the belzutifan profile page.

DrugPatentWatch^® Generic Entry Outlook for Welireg

Welireg was eligible for patent challenges on August 13, 2025.

By analyzing the patents and regulatory protections it appears that the earliest date for generic entry will be September 5, 2034. This may change due to patent challenges or generic licensing.

There is one Paragraph IV patent challenge for this drug. This may lead to patent invalidation or a license for generic production.

Indicators of Generic Entry

Summary for welireg

International Patents:	62
US Patents:	3
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	29
Clinical Trials:	4
Drug Prices:	Drug price information for welireg
What excipients (inactive ingredients) are in welireg?	welireg excipients list
DailyMed Link:	welireg at DailyMed

See drug prices for welireg

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

Constraining patent/regulatory exclusivity:

9,908,845

NDA:

215383

Dosage:

TABLET;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.

Recent Clinical Trials for welireg

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

Sponsor	Phase
Merck Sharp & Dohme LLC	PHASE1
HiberCell, Inc.	PHASE1
Merck Sharp & Dohme Corp.	Phase 1

See all welireg clinical trials

Pharmacology for welireg

Drug Class	Hypoxia-inducible Factor Inhibitor
Mechanism of Action	Cytochrome P450 3A4 Inducers Hypoxia-inducible Factor 2 alpha Inhibitors

Paragraph IV (Patent) Challenges for WELIREG

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
WELIREG	Tablets	belzutifan	40 mg	215383	3	2025-08-13

US Patents and Regulatory Information for welireg

welireg is protected by seven US patents and four FDA Regulatory Exclusivities.

This potential generic entry date is based on patent 9,908,845.

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

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Merck Sharp Dohme	WELIREG	belzutifan	TABLET;ORAL	215383-001	Aug 13, 2021		RX	Yes	Yes	RE49948		Y	Y
Merck Sharp Dohme	WELIREG	belzutifan	TABLET;ORAL	215383-001	Aug 13, 2021		RX	Yes	Yes	12,358,870		Y
Merck Sharp Dohme	WELIREG	belzutifan	TABLET;ORAL	215383-001	Aug 13, 2021		RX	Yes	Yes
Merck Sharp Dohme	WELIREG	belzutifan	TABLET;ORAL	215383-001	Aug 13, 2021		RX	Yes	Yes	9,908,845		Y	Y

International Patents for welireg

When does loss-of-exclusivity occur for welireg?

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

Argentina

Australia

Canada

China

Croatia

Cuba

Cyprus

Denmark

Eurasian Patent Organization

European Patent Office

Hong Kong

Hungary

Israel

Japan

Lithuania

Mexico

New Zealand

Peru

Poland

Portugal

Serbia

Singapore

Slovenia

South Korea

Spain

Taiwan

Uruguay

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 welireg around the world.

Country	Patent Number	Title	Estimated Expiration
Japan	7425794
European Patent Office	3586835	ÉTHERS D'ARYLE ET LEURS UTILISATIONS (ARYL ETHERS AND USES THEREOF)
Lithuania	3417851
Hungary	E045462

Market Dynamics and Financial Trajectory for Welireg (Belzutifan): An In-Depth Analysis

Last updated: July 27, 2025

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Introduction

Welireg (belzutifan), developed by Merck & Co., is an innovative pharmaceutical agent targeting hypoxia-inducible factor 2-alpha (HIF-2α). Approved by the U.S. Food and Drug Administration (FDA) in August 2021 for the treatment of adult patients with von Hippel-Lindau (VHL) disease associated renal cell carcinoma (RCC), Welireg exemplifies a growing class of targeted therapies designed to address specific genetic mutations. Its emergence signals significant shifts in the oncology treatment landscape, influencing market dynamics and financial trajectories intra- and post-launch.

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Market Landscape and Competitive Environment

1. The Therapeutic Niche:
Welireg addresses VHL-associated RCC—a rare, hereditary form of kidney cancer characterized by unpredictable tumor development. The rarity of VHL disease limits the patient pool, but the drug's approval extends to a broader indication: treatment of adult patients with previously treated pancreatic neuroendocrine tumors (pNET) and hemangioblastomas linked to VHL [1].

2. Competitive Positioning:
Prior to Welireg, treatment options for VHL-related tumors were primarily surgical or observational, with no targeted systemic therapies approved specifically for these indications. The first-in-class status of Welireg grants Merck a competitive advantage. However, as of 2023, emerging therapies like MLN0128 (an mTOR inhibitor) and emerging immunotherapies could pose future competition, albeit not directly targeting the same genetic pathway.

3. Market Size and Patient Population:
VHL disease affects approximately 1 in 36,000 live births, translating into an estimated 2,500 to 3,000 diagnosed patients in the U.S. [2]. While small, the orphan drug designation offers incentives such as market exclusivity and premium pricing. Additionally, the drug's efficacy data suggests potential expansion into broader RCC indications, broadening the market size significantly.

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Market Dynamics Factors

1. Regulatory Environment:
The FDA’s breakthrough designation and subsequent approval underpin market confidence. Nonetheless, approval in other jurisdictions like the EU or Japan remains pending, impacting global revenue prospects. Regulatory clarity and expedited review processes can accelerate market penetration.

2. Pricing and Reimbursement Strategies:
Given the orphan status and no direct comparables, Merck set a substantial price point—estimated at $17,950 per month in the U.S. [3]. Payer acceptance hinges on demonstrating clinical value over the standard of care and managing high-cost reimbursement negotiations. Contractual agreements and patient assistance programs will influence uptake.

3. Clinical Efficacy and Safety Profile:
Clinical trial data from the phase II LITESPARK-001 study demonstrated meaningful tumor responses and manageable safety profile—key drivers for physician adoption. Long-term data remains pending, with potential impacts on market expansion depending on durability of response and adverse event profile.

4. Market Penetration Strategies:
Merck’s focus on targeted marketing towards oncologists and genetic specialists, combined with KOL advocacy and patient advocacy coalition support, are central to accelerating sales. Clinical guides and real-world evidence are expected to bolster prescriber confidence.

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Financial Trajectory

1. Revenue Projections (2023–2030):
Initial sales post-approval are expected to grow modestly, with projections ranging between $200 million and $400 million annually within the first three years. As awareness and indications expand, revenues could approach $1 billion by 2030, contingent upon regulatory approvals and broader adoption.

2. Elephants in the Room – Cost Considerations:
Development costs are minimized due to previous oncology platform investments by Merck; however, commercialization, patient monitoring, and reimbursement costs are substantial. Investment in healthcare infrastructure and digital engagement will influence profit margins.

3. Growth Drivers:

• Indication Expansion: Approval for additional tumors related to VHL and other renal cancers.
• Global Expansion: Entering EU, Japan, and emerging markets after regulatory clearance.
• Combination Therapies: Potential synergistic partnerships for combination with existing oncolytics or immunotherapies could enhance efficacy, broadening the market.

4. Risks and Challenges:

• Limited Patient Pool: Constrains revenue potential unless indications expand.
• Pricing Pushback: Payers may challenge high pricing, particularly in cost-sensitive markets.
• Competition and Biosimilars: While current exclusivity is substantial, future biosimilar entrants and generics remain a risk.

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Strategic Outlook and Recommendations

Investors and Stakeholders should monitor clinical trial developments, regulatory milestones, and market entry strategies closely. Merck's emphasis on additional indications, global commercialization efforts, and real-world evidence provision will determine Welireg’s financial trajectory. Cost-management strategies—especially around reimbursement and patient access—are critical for rapid revenue growth.

Stakeholders should also consider the competitive landscape evolution, especially with new treatments emerging for RCC and other VHL-related tumors, which could pressure market share or lead to inroads into broader oncology segments.

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Key Takeaways

• Welireg’s niche focus in VHL-associated tumors offers a valuable but small market, with significant upside if indications expand.
• Pricing remains premium, supported by orphan drug status and targeted efficacy, influencing initial revenue streams.
• Regulatory momentum and global expansion will be decisive in shaping Welireg’s revenues, with European and Asian markets presenting significant growth opportunities.
• Long-term financial performance hinges on clinical data stability, indication expansion, and managing payer negotiations effectively.
• Competitive threats are limited currently but will intensify as more therapies and biosimilars enter the space.

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FAQs

1. What is Welireg, and what does it treat?
Welireg (belzutifan) is a HIF-2α inhibitor approved primarily for treating adult VHL disease-associated RCC, pNET, and hemangioblastomas.

2. What is the market potential for Welireg in the next decade?
Initially modest due to its orphan indication, the global market could exceed $1 billion annually by 2030 if approvals expand and indications broaden, driven by strong clinical data and strategic commercial efforts.

3. How does Welireg compare to existing RCC therapies?
Unlike traditional VEGF inhibitors and immunotherapies for sporadic RCC, Welireg targets a specific genetic mutation linked to VHL disease, offering personalized treatment for a niche population.

4. What are the primary risks facing Welireg’s financial success?
Limited patient pool, high drug costs, payor resistance, and competitive development of new therapies pose significant risks.

5. Are there ongoing clinical trials for Welireg?
Yes, multiple trials are evaluating its efficacy in broader RCC populations and combination therapies, which could influence future indications and revenues.

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References

[1] Food and Drug Administration. FDA approves Welireg for von Hippel-Lindau disease-associated tumors. August 2021.
[2] National Organization for Rare Disorders. VHL Disease Overview. 2022.
[3] Merck Press Release. Welireg pricing and reimbursement details. August 2021.