KORSUVA Drug Patent Profile

When do Korsuva patents expire, and what generic alternatives are available?

Korsuva is a drug marketed by Vifor Intl and is included in one NDA. There are twelve patents protecting this drug and one Paragraph IV challenge.

The generic ingredient in KORSUVA is difelikefalin acetate. There is one drug master file entry for this compound. One supplier is listed for this compound. Additional details are available on the difelikefalin acetate profile page.

DrugPatentWatch^® Generic Entry Outlook for Korsuva

Korsuva was eligible for patent challenges on August 23, 2025.

There have been five 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.

Indicators of Generic Entry

Summary for KORSUVA

US Patents:	12
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	21
Drug Prices:	Drug price information for KORSUVA
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for KORSUVA
What excipients (inactive ingredients) are in KORSUVA?	KORSUVA excipients list
DailyMed Link:	KORSUVA at DailyMed

See drug prices for KORSUVA

Pharmacology for KORSUVA

Drug Class	Kappa Opioid Receptor Agonist
Mechanism of Action	Opioid kappa Receptor Agonists

Paragraph IV (Patent) Challenges for KORSUVA

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
KORSUVA	Intravenous Solution	difelikefalin acetate	0.065 mg/1.3 mL	214916	5	2025-08-25

US Patents and Regulatory Information for KORSUVA

KORSUVA is protected by twelve US patents and one FDA Regulatory Exclusivity.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes			Y	Y
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes			Y	Y
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes
Vifor Intl	KORSUVA	difelikefalin acetate	SOLUTION;INTRAVENOUS	214916-001	Aug 23, 2021		RX	Yes	Yes				Y

International Patents for KORSUVA

When does loss-of-exclusivity occur for KORSUVA?

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

Australia

Brazil

Canada

China

Cyprus

Denmark

European Patent Office

Finland

France

Hong Kong

Hungary

Israel

Japan

Lithuania

Luxembourg

Malaysia

Mexico

Netherlands

New Zealand

Poland

Portugal

Russian Federation

Slovenia

South Africa

South Korea

Spain

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 KORSUVA around the world.

Country	Patent Number	Title	Estimated Expiration
Australia	2007317817
Australia	2007319831
Brazil	PI0718651
Canada	2667155
Canada	2667460
Canada	2898514
China	101535336

Supplementary Protection Certificates for KORSUVA

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
2064228	301199	Netherlands		DETAILS ASSIGNMENT: CHANGE OF OWNER(S), ASSIGNMENT
2064228	CA 2022 00045	Denmark		PRODUCT NAME: DIFELIKEFALIN IN ALL FORMS COVERED BY THE BASIC PATENT; REG. NO/DATE: EU/1/22/1643 20220427
2064228	PA2022522	Lithuania		PRODUCT NAME: DIFELIKEFALINAS, BET KOKIA FORMA, KURIAI TAIKOMA PAGRINDINIO PATENTO APSAUGA ; REGISTRATION NO/DATE: EU/1/22/1643 20220425
2064228	LUC00282	Luxembourg		PRODUCT NAME: DIFELIKEFALIN IN ALL FORMS COVERED BY THE BASIC PATENT; AUTHORISATION NUMBER AND DATE: EU/1/22/1643 20220427
2064228	2022C/546	Belgium		DETAILS ASSIGNMENT: CHANGE OF OWNER(S), ASSIGNMENT
2064228	C20220035 00379	Estonia		PRODUCT NAME: DIFELIKEFALIIN;REG NO/DATE: EU/1/22/1643 27.04.2022
2064228	122022000071	Germany		PRODUCT NAME: DIFELIKEFALIN IN ALLEN DURCH DAS GRUNDPATENT GESCHUETZTEN FORMEN; AUTHORISATION NO/DATE: EU/1/22/1643 20220425

KORSUVA Market Dynamics and Financial Trajectory

Last updated: August 24, 2026

KORSUVA, or difelikefalin injection, has secured a differentiated regulatory position as the first FDA-approved treatment for moderate-to-severe pruritus associated with chronic kidney disease in adults receiving hemodialysis. Commercial performance has remained below the initial opportunity implied by that label. U.S. uptake has been gradual, dialysis-center adoption has constrained demand, and Cara Therapeutics has reduced investment after discontinuing oral difelikefalin development. The product remains commercially viable, but its trajectory depends on execution in dialysis centers, payer coverage, and the ability to expand use outside the original hemodialysis segment.

What is KORSUVA and which patients does it treat?

KORSUVA is an injectable formulation of difelikefalin, a selective peripheral kappa-opioid receptor agonist. The FDA approved it in August 2021 for moderate-to-severe pruritus associated with chronic kidney disease in adults undergoing hemodialysis. The drug is administered intravenously at the end of each hemodialysis session, three times per week in most patients. [1]

The commercial product is marketed in the United States as KORSUVA. In Europe and certain other territories, difelikefalin injection is marketed as Kapruvia. CSL Vifor holds commercialization rights in markets outside the United States under its collaboration with Cara Therapeutics. [2]

Attribute	KORSUVA
Active ingredient	Difelikefalin
Dosage form	Intravenous injection
FDA indication	CKD-associated pruritus in adults receiving hemodialysis
FDA approval	August 2021
Primary channel	Dialysis centers and nephrology providers
U.S. commercialization	Cara Therapeutics
Ex-U.S. commercialization	CSL Vifor
Administration	At the end of hemodialysis sessions
Direct FDA-approved competitor	None with the same indication and mechanism

KORSUVA’s clinical differentiation comes from its peripheral restriction. Unlike centrally acting opioids, difelikefalin was designed to limit central nervous system exposure, an important consideration in patients with renal impairment and high polypharmacy burdens. The product competes in practice with off-label gabapentin, pregabalin, antihistamines, topical agents and intensified dialysis management.

How large is the KORSUVA addressable market?

The immediate U.S. market is concentrated among adults receiving maintenance hemodialysis, a population of approximately 450,000 to 500,000 patients. Published studies have estimated that clinically significant pruritus affects a substantial share of this population, although prevalence varies by definition and study design. [3]

The commercial market is smaller than the epidemiological market because:

• not every patient reports pruritus to a provider;
• many patients receive inexpensive off-label treatments;
• nephrologists may manage symptoms without adding a new administered drug;
• dialysis-center protocols can delay formulary adoption;
• treatment persistence varies with symptom severity and perceived benefit.

KORSUVA has a structurally attractive administration model because dialysis-center staff can administer the drug during a scheduled treatment. That model also creates a commercial bottleneck. The product must be incorporated into center protocols, billing workflows, inventory systems and nephrologist prescribing habits.

What drives KORSUVA demand?

The principal demand drivers are:

1. Recognition of CKD-associated pruritus as a treatable condition.
2. Dialysis-center formulary and protocol adoption.
3. Reimbursement economics for dialysis providers.
4. Patient-reported symptom improvement.
5. Failure or intolerance of gabapentin and other off-label therapies.
6. Support from nephrology education and care-management programs.

The principal constraints are low diagnostic intensity, budget sensitivity at dialysis providers, provider inertia and competition from low-cost generic therapies.

What were KORSUVA sales and Cara Therapeutics’ financial results?

KORSUVA generated commercial revenue for Cara Therapeutics beginning after the 2021 U.S. launch. The product’s revenue ramp was positive but modest relative to the size of the dialysis population and the company’s development spending.

Cara reported total revenue of approximately $31 million in 2022 and approximately $36 million in 2023, with KORSUVA product sales and related collaboration revenue representing the main commercial sources. [4] Revenue growth reflected broader dialysis-center adoption, but the company continued to report substantial operating losses.

Period	Cara revenue profile	Financial interpretation
2021	Initial launch period	Limited commercial contribution
2022	Approximately $31 million total revenue	Early dialysis-center adoption
2023	Approximately $36 million total revenue	Growth continued, but below scale needed for profitability
2024	Strategic cost reductions and lower development spending	Company prioritized liquidity and commercial discipline

Reported revenue figures include product-related revenue and may not equal gross KORSUVA sales. Contractual arrangements, gross-to-net deductions, collaboration revenue and accounting treatment affect comparisons between periods.

Cara’s financial trajectory was shaped by a mismatch between commercial scale and fixed costs. The company funded:

• U.S. sales and medical-affairs infrastructure;
• manufacturing and supply activities;
• post-approval regulatory obligations;
• late-stage oral difelikefalin trials;
• corporate overhead and public-company costs.

In 2023, the failure of the oral difelikefalin program materially changed the investment case. Cara discontinued the oral program after topline results from the KALM-1 and KALM-2 studies did not support the planned development path. [5] The company then reduced its workforce and narrowed its strategic focus.

Why has KORSUVA adoption been slower than expected?

KORSUVA entered a market with a clear unmet need but a difficult commercialization structure. The product is not dispensed through a conventional retail pharmacy in most cases. It is administered in dialysis facilities, where prescribing authority, purchasing responsibility and reimbursement incentives can be distributed across different stakeholders.

Dialysis-center economics

Large dialysis organizations can influence adoption across hundreds of facilities, but they often require evidence that a new product improves care without creating operational or financial friction. KORSUVA must compete with:

• generic gabapentin;
• pregabalin;
• topical therapies;
• antihistamines;
• informal symptom management;
• no pharmacologic treatment.

A dialysis center may also require a protocol change before regular use. That process can be slower than a traditional specialty-pharmacy launch.

Patient identification

Pruritus is underreported. Patients may not identify itching as a distinct medical condition, and nephrologists may focus visits on anemia, mineral-bone disease, fluid management and dialysis adequacy. Commercial growth therefore depends on screening and documentation, not simply on product availability.

Reimbursement and purchasing

KORSUVA’s economic value depends on how dialysis providers are reimbursed and whether use generates adequate margin after acquisition and administration costs. The product’s administered setting can simplify adherence but makes reimbursement negotiations more important than in a retail prescription market.

What is the competitive landscape for KORSUVA?

KORSUVA has no direct FDA-approved branded competitor for the same U.S. indication. Its practical competition is broad and largely generic.

Competitor category	Examples	Competitive effect
Gabapentinoids	Gabapentin, pregabalin	Low-cost, established off-label alternatives
Antihistamines	Hydroxyzine and others	Often used despite limited disease-specific evidence
Topical products	Emollients, corticosteroids, counterirritants	Useful for localized or mild symptoms
Dialysis management	Adequacy optimization, phosphate control	Addresses contributing factors rather than directly treating itch
Opioid-pathway agents	Naltrexone and other off-label agents	Variable use and evidence
Emerging oral difelikefalin	Development discontinued by Cara	Removed a potential expansion route

KORSUVA’s main commercial argument is not simply efficacy. It is the combination of disease-specific approval, peripheral kappa-opioid activity, dialysis-session administration and a safety profile designed for patients with advanced kidney disease.

What happened to oral difelikefalin?

Cara developed oral difelikefalin to address patients with CKD-associated pruritus who were not receiving hemodialysis, including patients with earlier-stage CKD and potentially peritoneal dialysis patients. That strategy would have expanded the addressable market substantially beyond the injectable product.

The oral program encountered a major setback when phase 3 studies failed to provide the required efficacy outcome. Cara discontinued development in 2023. [5] This decision removed the most important near-term growth option for the difelikefalin franchise.

The consequence is strategic:

• KORSUVA remains concentrated in the hemodialysis population.
• The company lost a pathway to a broader nephrology market.
• Development spending declined, but so did the potential long-term revenue ceiling.
• Commercial success now depends primarily on deeper penetration of existing dialysis centers.

What is the FDA regulatory status of KORSUVA?

KORSUVA is FDA-approved and commercially available in the United States. Its approved indication is limited to adults with moderate-to-severe CKD-associated pruritus who are receiving hemodialysis. [1]

The FDA approval was based on the KALM-1 and KALM-2 development program, which evaluated reductions in itch severity using patient-reported outcomes. The label does not cover patients with non-dialysis CKD or all forms of chronic pruritus.

The regulatory position is therefore strong within a narrow population but does not provide a broad dermatology or general-pruritus label.

What patents protect KORSUVA and when could generic entry occur?

KORSUVA is a small-molecule drug, not a biologic. Biosimilar risk is therefore not the relevant challenge. Any future competitor would generally pursue an abbreviated new drug application, or ANDA, and could challenge listed patents through Paragraph IV certification.

The relevant protection can include:

• compound patents covering difelikefalin;
• salt or stereochemical-form patents;
• formulation patents;
• injectable composition patents;
• method-of-use patents covering CKD-associated pruritus;
• manufacturing or purification patents.

The operative generic-entry date depends on the current Orange Book listing, patent-term adjustment, pediatric exclusivity, any applicable regulatory exclusivity and the outcome of patent litigation. FDA’s Orange Book should be used as the controlling source for listed patents and expiration data. [6]

KORSUVA’s commercial exposure is reduced by the limited size of the labeled population, but the product also has fewer obvious lifecycle extensions after the oral program failure. A narrow method-of-use estate could delay an identical labeled generic while leaving room for off-label substitution with existing drugs.

Does KORSUVA have biosimilar risk?

No. Difelikefalin is a chemically synthesized small molecule. The relevant threat is generic substitution, not biosimilar competition. Generic applicants may challenge composition, formulation or method-of-use patents through the ANDA Paragraph IV process.

Which companies are challenging KORSUVA?

No major commercial generic challenger had established a material U.S. market position through the company disclosures and public regulatory information available for the period reviewed. The likely future challengers are generic-drug manufacturers with nephrology or injectable portfolios.

The principal competitive pressure has come from existing therapies rather than a launched generic difelikefalin product. That distinction matters. KORSUVA can lose volume without losing patent protection if providers substitute gabapentin, pregabalin or other low-cost treatments.

What patent litigation and settlement agreements affect KORSUVA?

Publicly disclosed commercial litigation has not been the central driver of KORSUVA’s financial trajectory. The more immediate issues have been adoption, the economics of dialysis-center purchasing and the failure of oral difelikefalin development.

No material public settlement establishing an early generic launch date was identified in the cited company and FDA materials. Any later ANDA litigation or settlement would need to be assessed against the current Orange Book listing and the specific Paragraph IV certifications filed by each applicant.

What licensing deals support KORSUVA?

Cara and Vifor entered a strategic collaboration under which Vifor obtained commercial rights to difelikefalin outside the United States. The agreement included upfront and milestone economics, as well as commercial participation tied to the product’s development and launch. [2]

The arrangement gave Cara access to Vifor’s nephrology commercial infrastructure and dialysis relationships outside the United States. It also reduced the need for Cara to build a global commercial organization. The tradeoff was shared economics and reliance on a partner whose portfolio priorities could change.

CSL’s acquisition of Vifor created a larger commercial owner with an established renal-care franchise. That structure supports international distribution but does not solve the U.S. dialysis-center adoption problem, which remains primarily Cara’s commercial responsibility.

How strong is the KORSUVA patent and commercial estate?

KORSUVA has a differentiated regulatory position, but its overall franchise strength is moderate rather than broad.

Estate component	Assessment
Regulatory differentiation	Strong within hemodialysis-associated pruritus
Clinical differentiation	Meaningful against off-label therapies, but dependent on symptom response
Patient population	Clearly defined but limited
Formulation breadth	Narrow injectable use limits expansion
Lifecycle management	Weakened by discontinuation of oral development
Generic risk	Delayed by valid enforceable patents, but eventual ANDA risk remains
Commercial infrastructure	More established than at launch, but adoption remains uneven
International reach	Supported by CSL Vifor collaboration

The strongest asset is the combination of FDA approval and an administration model aligned with dialysis care. The main weakness is concentration in a single, operationally complex market.

What generic launch scenarios exist for KORSUVA?

Three scenarios are commercially relevant:

Scenario 1: Continued branded growth before generic entry

Cara and its partners increase screening, secure more dialysis-center protocols and expand payer coverage. KORSUVA revenue rises gradually without a major label expansion.

Scenario 2: Early Paragraph IV challenge

A generic company challenges Orange Book patents before their nominal expiration. The result could be litigation, a settlement with a delayed entry date or an at-risk launch. The commercial impact would depend on whether the generic product can obtain dialysis-center formulary access.

Scenario 3: Off-label erosion without generic difelikefalin

KORSUVA remains patent-protected, but providers increasingly use generic alternatives. This scenario is plausible because the principal substitutes are already available and inexpensive.

What is the investment outlook for KORSUVA?

KORSUVA is a focused commercial asset with a credible but limited revenue base. Its upside depends more on execution than on new clinical innovation. The discontinued oral program removed a major expansion catalyst and increased the importance of dialysis-center penetration.

The financial trajectory has four defining characteristics:

• revenue growth from a low base;
• persistent operating losses;
• declining research spending after oral-program termination;
• high sensitivity to commercial adoption and liquidity management.

KORSUVA can support a specialized renal franchise if adoption improves, but the product alone has limited capacity to support a large public-company cost structure. The value proposition is stronger for a strategic buyer with an existing dialysis, nephrology or hospital portfolio than for a standalone company carrying substantial development and corporate expenses.

Key Takeaways

• KORSUVA is the first FDA-approved therapy specifically indicated for CKD-associated pruritus in adult hemodialysis patients.
• U.S. commercial uptake has been gradual because dialysis-center adoption and reimbursement are more important than conventional retail prescribing.
• Cara Therapeutics reported approximately $31 million of total revenue in 2022 and approximately $36 million in 2023, while remaining unprofitable.
• The discontinuation of oral difelikefalin eliminated the principal pathway to a broader CKD-pruritus market.
• KORSUVA faces generic, not biosimilar, risk.
• Existing generic therapies are a major source of commercial erosion even before a difelikefalin ANDA reaches the market.
• The asset has strong regulatory differentiation but a narrow patient population and limited lifecycle breadth.
• International commercialization benefits from the CSL Vifor relationship.
• The most likely value-creation path is deeper dialysis-center penetration, lower operating costs and strategic ownership by a renal-focused company.

FAQs About KORSUVA Market Dynamics

Is KORSUVA a blockbuster drug?

No. KORSUVA has generated commercial revenue but has not approached blockbuster scale. Its target population and dialysis-center distribution model constrain peak sales potential.

Is KORSUVA covered by Medicare?

Coverage depends on the applicable Medicare benefit, dialysis-provider reimbursement structure and payer policy. Coverage decisions can differ by facility and jurisdiction.

Can KORSUVA be used in patients who are not on dialysis?

The FDA-approved U.S. indication is limited to adults receiving hemodialysis. Use in non-dialysis CKD would be outside the approved label.

What is the main alternative to KORSUVA?

Gabapentin is one of the most common practical alternatives because it is inexpensive and familiar to nephrologists. Pregabalin, topical agents and antihistamines are also used.

Could a generic KORSUVA launch before all patents expire?

Potentially. An ANDA applicant could file a Paragraph IV certification and challenge listed patents. Commercial entry would then depend on litigation, settlement terms, court decisions and regulatory exclusivity.

References

1. U.S. Food and Drug Administration. (2021). KORSUVA (difelikefalin) injection prescribing information. FDA.

2. Cara Therapeutics, Inc. (2018). Cara Therapeutics and Vifor Pharma enter global collaboration for difelikefalin. Company announcement.

3. Narita, I., Iguchi, S., Omori, K., & Gejyo, F. (2006). Uremic pruritus in chronic hemodialysis patients. Journal of Nephrology, 19(3), 360-367.

4. Cara Therapeutics, Inc. (2024). Annual report on Form 10-K for the fiscal year ended December 31, 2023. U.S. Securities and Exchange Commission.

5. Cara Therapeutics, Inc. (2023). Cara Therapeutics announces topline results from phase 3 KALM-1 and KALM-2 oral difelikefalin studies. Company announcement.

6. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.