WELIREG Drug Patent Profile

Which patents cover Welireg, and what generic alternatives are available?

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-four patent family members in twenty-nine 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 June 30, 2042. 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:	64
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:

12,358,870

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 12,358,870.

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
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

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:

Canada

China

European Patent Office

Japan

Malaysia

Mexico

Singapore

South Korea

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
Canada	3117563
China	112955130
European Patent Office	3873443
Japan	2022506062
Japan	7425794
South Korea	20210091191

DrugChatter Q&A for WELIREG

Welireg fda approval history?
Umbria welireg belzutifan?
Is welireg used for vhl disease?
What are the side effects of welireg?