LEUSTATIN Drug Patent Profile

« Back to Dashboard

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

Leustatin is a drug marketed by Janssen Pharms and is included in one NDA.

The generic ingredient in LEUSTATIN is cladribine. There is one drug master file entry for this compound. Seven suppliers are listed for this compound. Additional details are available on the cladribine profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Leustatin

A generic version of LEUSTATIN was approved as cladribine by HIKMA on February 28^th, 2000.

Summary for LEUSTATIN

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	82
Clinical Trials:	30
DailyMed Link:	LEUSTATIN at DailyMed

Recent Clinical Trials for LEUSTATIN

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

Sponsor	Phase
Gerhard C Hildebrandt	Phase 1
Astellas Pharma Inc	Phase 1
AbbVie	Phase 1

See all LEUSTATIN clinical trials

US Patents and Regulatory Information for LEUSTATIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Janssen Pharms	LEUSTATIN	cladribine	INJECTABLE;INJECTION	020229-001	Feb 26, 1993		DISCN	Yes	No

EU/EMA Drug Approvals for LEUSTATIN

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Merck Europe B.V.	Mavenclad	cladribine	EMEA/H/C/004230Treatment of adult patients with highly active relapsing multiple sclerosis (MS) as defined by clinical or imaging features.	Authorised	no	no	no	2017-08-22
Lipomed GmbH	Litak	cladribine	EMEA/H/C/000504Litak is indicated for the treatment of hairy-cell leukaemia.	Authorised	no	no	no	2004-04-14

Leustatin Market Dynamics, Patent Expiration, FDA Status, and Financial Trajectory

Last updated: November 1, 2026

Leustatin is the U.S. brand name for cladribine injection, a purine nucleoside analog approved for hairy cell leukemia. Its commercial profile is mature and niche: FDA marketing exclusivity and practical patent protection expired long ago, generic cladribine has reduced brand leverage, and the product is no longer a separately reported revenue driver for its former commercial owner. Market value remains tied to the small hairy-cell-leukemia population, treatment durability, hospital procurement, and generic supply continuity.

What is Leustatin and what is it used for?

Leustatin contains cladribine, also known as 2-chlorodeoxyadenosine or 2-CdA. The FDA approved cladribine injection in 1993 for hairy cell leukemia, a rare B-cell malignancy characterized by abnormal lymphocytes in the blood and bone marrow (FDA, 1993).

The labeled regimen is typically a seven-day continuous intravenous infusion at 0.09 mg/kg/day. Treatment is administered in an oncology or hospital setting because cladribine causes prolonged lymphocyte suppression and can produce serious infectious complications.

Attribute	Leustatin
Active ingredient	Cladribine
Dosage form	Intravenous injection
Original U.S. indication	Hairy cell leukemia
FDA approval	1993
Original developer/commercial channel	Ortho Biotech/Janssen-related commercial operations
Therapeutic class	Purine nucleoside analog
Primary competitors	Pentostatin, interferon alfa, rituximab-based regimens
Current commercial stage	Mature, low-volume oncology product
FDA regulatory category	Small-molecule drug, not a biologic
Biosimilar exposure	None

Cladribine is highly active against hairy cell leukemia because the malignant cells accumulate the active phosphorylated metabolite. The drug can produce durable remissions after a single treatment course, limiting repeat-treatment frequency and reducing recurring unit demand.

What is the FDA status of Leustatin?

Leustatin was approved through a standard new drug application rather than a biologics license application. The relevant FDA regulatory history is associated with NDA 020232, according to historical FDA labeling and product records.

FDA approval for the original hairy-cell-leukemia indication dates to the early 1990s. The product’s regulatory exclusivity period has expired. Orphan-drug exclusivity, where applicable, lasts seven years in the United States and does not provide continuing protection decades after launch.

The current commercial status is different from the product’s historical approval status. A drug can remain FDA-approved while the original brand is discontinued, commercially unavailable, or replaced by generic versions. Leustatin has this mature-product profile.

What is the Orange Book status of Leustatin?

The Orange Book is the relevant FDA source for approved drug applications, therapeutic-equivalence information, and listed patents. Leustatin’s commercially important patent and exclusivity periods are historical rather than current.

No active Leustatin patent estate is known to create a meaningful barrier to generic cladribine injection. The product is not comparable to a recently launched specialty drug with several active formulation, method-of-use, and manufacturing patents.

The practical regulatory position is:

Regulatory issue	Leustatin assessment
New chemical entity exclusivity	Expired
Orphan-drug exclusivity	Expired
Current brand exclusivity	None of commercial significance
Orange Book patent protection	No material active estate identified
Generic availability	Generic cladribine injection has reduced brand protection
Reference-product risk	Low for the historical brand; higher for generic supply continuity

When did Leustatin lose exclusivity?

Leustatin lost meaningful U.S. exclusivity no later than the early 2000s. The product was approved in 1993, so any seven-year orphan-drug period would have ended around 2000. Any applicable five-year new-chemical-entity period would also have ended earlier.

Patent terms could have extended beyond regulatory exclusivity, depending on the specific patent family and patent-term adjustments. Those terms are no longer commercially relevant for a 1993 small-molecule approval. The product’s market economics are therefore driven by generic competition, procurement, and clinical preference rather than patent enforcement.

Are there active formulation patents for Leustatin?

No active formulation patent is known to provide a commercially meaningful barrier around the original cladribine injection product. The product is a conventional injectable formulation rather than a complex delivery system, long-acting depot, liposomal product, or device combination.

Potential manufacturing know-how can still matter. Injectable oncology products require validated sterile manufacturing, control of impurities, container-closure testing, stability data, and regulatory compliance. Those requirements create operational barriers but do not recreate brand exclusivity.

Are there Paragraph IV challenges to Leustatin?

Paragraph IV litigation is not a significant current market issue for Leustatin. The relevant patent estate is old, and generic entry has already occurred or been commercially established. Publicly material ongoing Paragraph IV litigation involving the historical Leustatin brand is not a principal driver of the market.

The more important risks are commercial:

1. A generic manufacturer may exit the market.
2. Hospital buyers may face temporary allocation or back-order conditions.
3. A limited supplier base may increase price volatility.
4. Manufacturers may prioritize higher-volume injectable products over cladribine.

For a mature sterile injectable, supply disruption can matter more than patent litigation. A short list of approved suppliers can give remaining manufacturers negotiating power even after exclusivity ends.

How large is the Leustatin market?

The addressable market is limited by the rarity of hairy cell leukemia. The disease represents a small fraction of adult leukemias, and the total treated population is far below that of common hematologic malignancies such as diffuse large B-cell lymphoma or multiple myeloma.

Several factors constrain annual unit demand:

• Hairy cell leukemia is rare.
• Many patients achieve durable remission after one course.
• Retreatment intervals can be long.
• Alternative regimens, including rituximab-based therapy, compete in selected settings.
• Hospital use is concentrated in specialist oncology centers.
• The product is administered intravenously rather than dispensed through a broad retail channel.

The market is therefore a low-volume specialty oncology segment. Volume is more likely to track diagnosis rates, relapse treatment, clinical guidelines, and supplier availability than broad oncology spending.

How does Leustatin compare with Mavenclad?

Mavenclad is an oral cladribine product marketed by Merck KGaA for relapsing forms of multiple sclerosis. It is chemically related to Leustatin but is a different product, dosage form, FDA application, commercial strategy, and therapeutic market.

Factor	Leustatin	Mavenclad
Active ingredient	Cladribine	Cladribine
Form	Intravenous injection	Oral tablets
Main indication	Hairy cell leukemia	Multiple sclerosis
Commercial market	Rare oncology	Specialty neurology
Brand strategy	Mature and generic-exposed	Branded, indication-specific
Patent value	Historical and limited	Potentially more relevant to oral formulation and use
Revenue model	Low-volume hospital oncology	Higher-value specialty pharmacy

The products should not be combined in revenue estimates. Mavenclad’s sales do not represent Leustatin revenue, and Mavenclad patent activity does not automatically protect the intravenous oncology formulation.

What is the financial trajectory for Leustatin?

Leustatin does not have a transparent standalone financial trajectory in public company reporting. Former commercial owners generally reported it within broader oncology, pharmaceutical, or specialty-product portfolios rather than as a separate revenue line.

The financial trajectory can be characterized in four phases:

Launch and adoption

After its 1993 approval, cladribine injection gained adoption because hairy cell leukemia is highly responsive to purine analog therapy. The product benefited from specialist use and the absence of many similarly effective alternatives.

Mature branded sales

During the branded period, demand was stable but inherently limited by disease prevalence and durable response. The product was unlikely to become a large oncology revenue contributor because its indication was narrow.

Generic erosion

Generic entry removed the principal source of brand pricing power. In a small market, even a modest number of generic suppliers can materially reduce branded volume and average selling price.

Mature generic market

The current value pool is likely concentrated among generic suppliers and distributors. The former brand has limited ability to defend price, expand market share, or create new demand without a new indication or reformulation.

No reliable public data support a standalone current Leustatin revenue figure. Any estimate presented as a precise annual sales number would risk confusing Leustatin with total cladribine sales, Mavenclad revenue, or broader oncology portfolio revenue.

Which companies compete with Leustatin?

Competition exists at both the product and treatment-regimen levels.

Direct product competition

Generic cladribine injection is the main direct substitute. The relevant companies can change over time as FDA approvals, supply agreements, and commercial discontinuations change. Generic competition is typically based on therapeutic equivalence, hospital contracting, supply reliability, and price.

Clinical alternatives

Pentostatin has historically been the closest pharmacologic alternative for hairy cell leukemia. Rituximab, either alone or in combination with other therapies, is also used in selected patients. Interferon alfa has a more limited role than in earlier treatment eras.

Treatment selection depends on remission status, infection risk, cytopenias, comorbidities, prior therapy, and local oncology practice. These alternatives limit the ability of any single cladribine product to expand beyond the narrow disease population.

What patent litigation and settlement agreements affect Leustatin?

No major current patent litigation or settlement agreement is a central commercial issue for Leustatin. The product’s principal patent risk has already passed through expiration and generic entry.

The absence of active litigation does not mean the product has no legal exposure. Generic manufacturers remain subject to product liability claims, manufacturing compliance requirements, labeling obligations, and supply-contract disputes. Those issues are distinct from Orange Book patent litigation.

There is also no biosimilar pathway for Leustatin. Cladribine is a chemically synthesized small molecule, so competitors use abbreviated new drug application pathways rather than biosimilar applications.

How strong is the Leustatin patent estate?

The current patent estate is weak from a commercial-defense perspective.

Patent-estate factor	Assessment
Core compound protection	Expired
Original product protection	Expired
Orphan exclusivity	Expired
Injectable formulation protection	No material current barrier identified
Method-of-use protection	Historical and limited
Manufacturing patents	Possible process know-how, but not a broad market barrier
Generic substitution risk	High
Patent litigation leverage	Low

Leustatin’s remaining defensibility is operational rather than legal. Sterile injectable manufacturing, regulatory maintenance, pharmacovigilance, and reliable supply can support a business, but these advantages do not prevent an approved competitor from entering.

What generic launch scenarios exist for Leustatin?

The most likely market scenarios are:

Scenario	Market effect
Multiple generic suppliers	Lower prices, higher substitution, limited brand relevance
One or two active suppliers	Greater shortage risk and potential price volatility
Brand withdrawal with generic continuity	Minimal clinical disruption if supply remains stable
Generic shortage	Temporary pricing power for remaining suppliers
New formulation or indication	Potential market expansion, but no established current pathway
Increased rituximab use	Reduced cladribine demand in selected treatment settings

The base case is a stable but small generic market. A sudden increase in demand is unlikely without a change in diagnosis rates, treatment standards, or the use of cladribine in an expanded indication.

What are the key commercial risks and opportunities?

The main commercial risks are low patient volume, durable responses that reduce repeat treatment, generic price competition, and sterile injectable supply constraints. Brand relaunch economics would be difficult unless the product acquired a differentiated indication, delivery system, or supply advantage.

Opportunities are limited but identifiable. A supplier with reliable U.S. sterile manufacturing could benefit from shortages or competitor withdrawal. A new formulation could reduce administration burden, but development would require clinical, regulatory, and reimbursement support. Expansion into other hematologic indications would face competition from newer targeted therapies and established antibody regimens.

Key Takeaways

• Leustatin is cladribine injection for hairy cell leukemia.
• FDA approval dates to 1993, and regulatory exclusivity has expired.
• The product has no material current patent barrier identified.
• Generic cladribine, not the historical brand, drives current market competition.
• Leustatin revenue is not separately disclosed in a reliable public reporting stream.
• The market is small because hairy cell leukemia is rare and treatment responses are durable.
• Sterile manufacturing and supply reliability are more important than patent litigation.
• Mavenclad revenue and patents should not be attributed to Leustatin.
• Biosimilar competition is irrelevant because cladribine is a small molecule.
• The most plausible outlook is a stable, low-volume generic market with episodic supply risk.

FAQs About Leustatin Market and Patent Protection

Is Leustatin still commercially available in the United States?

The historical brand has limited commercial significance, while generic cladribine injection is the relevant source of supply. FDA approval status and commercial availability are separate issues.

Does Leustatin have orphan-drug exclusivity today?

No. Any orphan-drug exclusivity associated with the original 1993 approval expired years ago.

Is cladribine injection the same product as Mavenclad?

No. Both contain cladribine, but they are different dosage forms with different indications, FDA applications, dosing regimens, and commercial markets.

Can a generic manufacturer launch cladribine without a Paragraph IV dispute?

Yes. Once relevant patents and exclusivities have expired or are absent, a generic manufacturer can rely on an abbreviated new drug application without facing a current patent barrier of commercial significance.

What is the biggest investment risk in the Leustatin market?

The largest risk is market scale. The treated population is small, repeat use is limited by durable remissions, and generic pricing restricts revenue growth. Supply interruptions may affect short-term pricing but do not create durable market expansion.

References

1. U.S. Food and Drug Administration. (1993). Leustatin (cladribine) injection prescribing information. FDA.

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

3. National Cancer Institute. (n.d.). Hairy cell leukemia treatment. National Institutes of Health.

4. National Cancer Institute. (n.d.). Surveillance, epidemiology, and end results program: Leukemia incidence and survival data. National Institutes of Health.

5. U.S. Food and Drug Administration. (2023). Drugs@FDA: FDA-approved drugs database. FDA.

6. Merck KGaA. (2024). Annual report 2023. Darmstadt, Germany: Merck KGaA.