NICLOSAMIDE - Generic Drug Details

What are the generic drug sources for niclosamide and what is the scope of patent protection?

Niclosamide is the generic ingredient in one branded drug marketed by Bayer Pharms and is included in one NDA. Additional information is available in the individual branded drug profile pages.

Summary for NICLOSAMIDE

US Patents:	0
Tradenames:	1
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	104
Clinical Trials:	33
DailyMed Link:	NICLOSAMIDE at DailyMed

Recent Clinical Trials for NICLOSAMIDE

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

Sponsor	Phase
Stanford University	Phase 1
TFF Pharmaceuticals, Inc.	Phase 1
The University of Western Australia	Phase 4

See all NICLOSAMIDE clinical trials

Medical Subject Heading (MeSH) Categories for NICLOSAMIDE

Anticestodal Agents

Antinematodal Agents

Molluscacides

Anatomical Therapeutic Chemical (ATC) Classes for NICLOSAMIDE

P02DA	Salicylic acid derivatives
P02D	ANTICESTODALS
P02	ANTHELMINTICS
P	Antiparasitic products, insecticides and repellents

US Patents and Regulatory Information for NICLOSAMIDE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Bayer Pharms	NICLOCIDE	niclosamide	TABLET, CHEWABLE;ORAL	018669-001	May 14, 1982		DISCN	No	No

Niclosamide Market Dynamics, Patent Position, and Financial Trajectory

Last updated: September 5, 2026

Niclosamide has little current pharmaceutical revenue despite renewed research interest. Its original anthelmintic market is mature and largely generic, while proposed uses in cancer, viral disease, inflammatory disorders, and metabolic disease remain investigational. The active ingredient is old, low-cost, and outside meaningful composition-of-matter exclusivity. Commercial value therefore depends on formulation patents, new delivery systems, clinical validation, and regulatory approval for new indications.

What is the current FDA status of niclosamide?

Niclosamide is an anthelmintic used to treat intestinal tapeworm infections, including infections caused by Taenia species, Diphyllobothrium latum, and Hymenolepis nana. The historical U.S. product was Niclocide 500 mg chewable tablets. The product is associated with an older FDA New Drug Application and is not a major currently marketed branded medicine in the United States (U.S. Food and Drug Administration, n.d.-a).

Regulatory issue	Current assessment
Active ingredient	Niclosamide
Historical U.S. product	Niclocide 500 mg chewable tablets
Therapeutic category	Anthelmintic
FDA-approved use	Intestinal tapeworm infections
Current U.S. commercial position	Limited or unavailable branded supply
New indication approvals	None publicly established for cancer, COVID-19, or metabolic disease
Biosimilar pathway	Not applicable
Generic pathway	Potentially available through an ANDA or other applicable FDA pathway
Primary commercial barrier	Limited clinical demand and weak reimbursement economics

The FDA has not approved niclosamide for COVID-19, cancer, obesity, diabetes, or other frequently studied repurposing indications. Research activity does not create marketing authorization.

When does niclosamide lose exclusivity?

Niclosamide’s original active-ingredient exclusivity expired decades ago. The compound was discovered and commercialized long before the modern 20-year patent term became the standard for new U.S. patent filings. No meaningful U.S. composition-of-matter exclusivity remains for the parent molecule.

The commercial implications are direct:

1. Generic manufacturers can compete on the established anthelmintic indication.
2. A new sponsor cannot obtain broad exclusivity over niclosamide itself.
3. New commercial protection must come from a formulation, delivery system, prodrug, combination, manufacturing process, or method of use.
4. Any new patent would generally be measured from its own earliest effective filing date, subject to patent-term adjustment and other statutory rules.

Regulatory exclusivity for a repurposed product could be available if a sponsor obtains approval for a qualifying new indication or product category. That exclusivity would not restore exclusivity to the old anthelmintic product.

What patents protect niclosamide?

The strongest potential patent categories are formulation and delivery claims rather than claims directed to niclosamide as a chemical entity.

Formulation and delivery patents

Niclosamide has poor aqueous solubility and limited systemic exposure after oral administration. These properties have driven research into:

• Nanoparticles and nanosuspensions
• Lipid-based formulations
• Amorphous solid dispersions
• Micellar systems
• Cyclodextrin complexes
• Solid self-emulsifying drug-delivery systems
• Injectable or implantable delivery
• Prodrugs and salts
• Inhaled formulations
• Targeted formulations for tumors or inflammatory tissues

These approaches can support patent claims if the sponsor demonstrates novelty, non-obviousness, a defined composition, and credible technical advantages. A patent directed only to mixing niclosamide with a routine excipient may face substantial obviousness risk.

Method-of-use patents

Potential method-of-use claims include treatment of:

• Viral infections
• Solid tumors
• Hematologic malignancies
• Inflammatory bowel disease
• Fibrotic disease
• Metabolic disorders
• Obesity and diabetes
• Parasitic infections resistant to existing therapy

Method claims require clinical support that matches the claimed disease, dose, patient population, and treatment regimen. Preclinical activity does not establish enforceable commercial value. Niclosamide’s extensive prior-art record increases the risk that broad repurposing claims will be challenged.

Manufacturing patents

Manufacturing protection may cover particle-size control, polymorph selection, impurity reduction, continuous processing, or high-purity production. These patents can create supply-chain leverage but rarely support a durable monopoly if competitors can use a non-infringing process.

How strong is the niclosamide patent estate?

The parent-molecule estate is weak because the active ingredient is old and widely disclosed. Later patent estates may be commercially relevant, but their strength depends on claim scope and clinical differentiation.

Patent category	Expected strength	Commercial relevance
Parent compound	Very low	No meaningful new-drug exclusivity
Conventional oral tablet	Low	Limited protection against generic substitution
Novel nanoparticle formulation	Moderate	Relevant if exposure or efficacy improves materially
Prodrug or new chemical derivative	Potentially high	Could create a separate product estate
Disease-specific method of use	Low to moderate	Depends on clinical data and claim construction
Combination therapy	Low to moderate	Vulnerable if combination is predictable
Manufacturing process	Moderate in narrow cases	Can increase supply barriers
New dosage form	Moderate	More valuable when linked to clinical benefit

A sponsor commercializing niclosamide should avoid relying on a single method-of-use patent. A stronger strategy would combine composition claims, pharmacokinetic claims, manufacturing claims, and indication-specific claims across several jurisdictions.

What is the Orange Book status of niclosamide?

The Orange Book records approved drug products and patent information submitted for listed products. Historical niclosamide approval information is associated with the older Niclocide product, but current commercial availability and active listing status must be distinguished from historical approval status (U.S. Food and Drug Administration, n.d.-b).

A discontinued product can raise several regulatory questions:

• Whether the reference product remains listed as a commercial product
• Whether FDA has determined that withdrawal was unrelated to safety or effectiveness
• Whether an ANDA applicant can rely on the historical reference product
• Whether any patent or regulatory exclusivity remains listed
• Whether a sponsor must pursue a different approval route

The absence of a prominent current branded product reduces the value of traditional Orange Book patent litigation. A sponsor seeking a new niclosamide product would likely pursue a differentiated formulation or a new indication rather than defend a conventional tablet franchise.

Are there Paragraph IV challenges involving niclosamide?

There is no widely reported recent Paragraph IV dispute associated with a major commercial niclosamide product. That is consistent with the drug’s limited U.S. sales base and the lack of a high-value active branded reference product.

A future Paragraph IV dispute could arise if a company receives FDA approval for a novel niclosamide formulation and lists patents in the Orange Book. The main litigation issues would likely involve:

• Whether the generic product practices the claimed formulation
• Whether the patent claims are enabled across the full scope
• Whether the formulation claims are obvious in view of known solubility technologies
• Whether the method-of-use claims are carved out through a section viii statement
• Whether the patent is listed correctly for the approved product

The litigation economics would be unfavorable for a narrow, low-price anthelmintic product. The economics improve if niclosamide is approved for a high-value oncology or chronic-disease indication.

What generic entry risks exist for niclosamide?

Generic entry risk is high for conventional oral niclosamide. The active ingredient is old, and the anthelmintic indication has limited clinical complexity. Generic competition would likely focus on price, supply reliability, tablet quality, and regulatory compliance rather than therapeutic differentiation.

For a new formulation, generic risk would depend on the product’s approval pathway:

Product strategy	Generic risk
Conventional 500 mg tablet	High
Improved-solubility oral product	Moderate to high
Long-acting formulation	Moderate
Injectable product	Moderate
Oncology product with biomarker-defined use	Moderate initially
Prodrug with new pharmacology	Lower initially
Combination product	Moderate, depending on claim scope

A 505(b)(2) applicant may obtain approval for a modified formulation or route of administration while relying in part on existing safety data. The route may reduce development time, but it does not eliminate patent, clinical, manufacturing, or commercial risk.

What is niclosamide’s biosimilar risk?

Niclosamide has no biosimilar risk because it is a small-molecule drug, not a biologic. Competition would come through generic, hybrid, or 505(b)(2) pathways rather than the Public Health Service Act biosimilar pathway.

This distinction matters for investment analysis. A niclosamide sponsor does not receive the market structure associated with biologics, such as complex manufacturing barriers, interchangeability standards, or long-lived biologic reference-product exclusivity.

What clinical uses could change niclosamide’s financial trajectory?

The most important value driver is not the legacy tapeworm market. It is the possibility that a reformulated product achieves systemic exposure and clinical benefit in a new disease.

Oncology

Niclosamide has been studied against signaling pathways relevant to prostate cancer, colorectal cancer, leukemia, and other malignancies. The central development issue is whether clinically achievable exposure is sufficient to produce a durable effect without unacceptable toxicity. A successful oncology program could support orphan-drug status, priority regulatory review in certain circumstances, and method-of-use or formulation patents.

Infectious disease

Niclosamide attracted substantial attention during COVID-19 research because of in vitro antiviral findings. Clinical development has faced the standard repurposing problem: activity in cell systems does not establish effective human exposure. No FDA approval for COVID-19 has resulted.

Metabolic disease

Research has examined niclosamide and related compounds in obesity, diabetes, and mitochondrial biology. These uses would require long-term safety data and a formulation capable of reliable systemic exposure. The commercial opportunity could be larger than the anthelmintic market, but development risk is also materially higher.

Parasitic disease

The established anthelmintic use remains the lowest-risk clinical application but has limited revenue potential. Praziquantel is a major competitive alternative for several tapeworm and trematode indications, while albendazole and other antiparasitic agents compete in adjacent disease settings (World Health Organization, 2023).

How does niclosamide compare with competing antiparasitic drugs?

Drug	Main role	Market position	Innovation potential
Niclosamide	Intestinal tapeworm treatment	Mature, low-cost	Mostly reformulation or repurposing
Praziquantel	Broad cestode and trematode treatment	Widely used	Strong public-health relevance
Albendazole	Broad antiparasitic treatment	Widely used	Continued use in mass drug administration
Mebendazole	Helminth treatment	Generic	Limited patent value
Ivermectin	Nematodes and ectoparasites	Large established market	New indications remain competitive

Niclosamide’s principal advantage is established human use and a known pharmacologic profile. Its principal weakness is poor systemic exposure and limited differentiation in the approved antiparasitic market.

Which companies are challenging or developing niclosamide?

Niclosamide development has involved universities, biotechnology companies, and pharmaceutical researchers rather than a single dominant innovator. Public research has included independent academic groups and companies pursuing reformulation, prodrug, nanoparticle, or repurposing strategies.

The competitive field is fragmented. No company has established a widely recognized, FDA-approved, high-revenue niclosamide franchise for a new indication. The most credible future competitor would likely be a sponsor that controls both:

1. A formulation that solves the exposure problem; and
2. Clinical data demonstrating efficacy in a commercially valuable disease.

What licensing deals affect niclosamide?

There is no broadly recognized, industry-defining licensing transaction comparable to major deals for approved oncology or immunology products. Niclosamide projects have generally remained at the academic, grant-funded, early biotechnology, or repurposing stage.

The absence of a major licensing benchmark makes transaction valuation difficult. Potential deal terms would likely depend on:

• Ownership and enforceability of formulation patents
• Clinical stage
• Evidence of systemic exposure
• Biomarker-defined patient selection
• Exclusivity available in the target indication
• Manufacturing scalability
• Whether the product can use a 505(b)(2) pathway
• Competitive positioning against established therapies

What is the revenue exposure for niclosamide?

Current revenue exposure is low and difficult to quantify because historical products were generic or discontinued, and no major public company reports a material niclosamide revenue line. The legacy tapeworm market does not support the valuation profile of a modern specialty pharmaceutical.

A potential financial trajectory has three stages:

Stage	Revenue profile	Principal value driver
Legacy anthelmintic	Low and fragmented	Supply and basic regulatory compliance
Reformulated product	Early commercial or launch-stage	Improved exposure and differentiated dosing
Successful new indication	Potentially substantial	Clinical efficacy, reimbursement, and patent life

An oncology approval could create substantially greater revenue exposure than the antiparasitic market. That outcome would require clinical validation, not merely repurposing interest.

What patent litigation affects niclosamide?

No major, currently visible patent litigation has established a market-wide legal precedent for niclosamide. Future disputes would probably center on formulation patents, new chemical derivatives, or approved method-of-use claims.

The greatest litigation risk is likely invalidity rather than direct infringement. Defendants could argue that:

• The formulation was obvious based on known solubility technologies.
• The claimed therapeutic effect was not adequately supported.
• The patent does not enable the full scope of the claims.
• The asserted method was anticipated by prior clinical or preclinical disclosures.
• The patent was improperly listed or does not claim the approved product.

What generic launch scenarios are most likely?

The most likely scenario is continued limited generic availability for the traditional anthelmintic use, with no large branded franchise. A second scenario is the launch of a differentiated formulation through a 505(b)(2) application. The highest-value scenario is approval for a new disease, followed by litigation or settlement with generic entrants after patent listing.

Settlement value would depend on the size of the new indication. A settlement for a low-volume antiparasitic product would have limited economic value. A settlement covering oncology or chronic metabolic disease could be commercially significant.

What geographic coverage exists for niclosamide?

Niclosamide has been marketed or used in multiple countries, particularly where intestinal tapeworm treatment is clinically relevant. Patent protection for new formulations or uses would need to be assessed separately in the United States, European Union, Japan, China, India, Canada, Australia, and other target markets.

Global commercial barriers include:

• Different national approval standards
• Variable access to praziquantel and other alternatives
• Public-health procurement pricing
• Local manufacturing requirements
• Patentability differences for methods of treatment
• Regulatory acceptance of repurposed clinical data

The original active ingredient is broadly unprotected. Geographic value would therefore come from later-filed product patents and regulatory approvals.

Key Takeaways

• Niclosamide is an old anthelmintic with no meaningful remaining composition-of-matter exclusivity.
• Its conventional U.S. market is small, generic, and commercially limited.
• FDA approval does not extend to COVID-19, cancer, obesity, or other investigational uses.
• The strongest patent opportunities involve formulations, prodrugs, delivery systems, and disease-specific methods.
• Generic entry risk is high for conventional tablets and lower for genuinely differentiated products.
• Niclosamide has no biosimilar risk because it is a small molecule.
• Financial upside depends on solving poor systemic exposure and proving clinical benefit in a new indication.
• No major public licensing transaction or market-defining patent litigation currently establishes a high valuation benchmark.
• A successful oncology or chronic-disease product could materially change the asset’s revenue profile, but the legacy antiparasitic market cannot support that valuation.

FAQs

Is niclosamide still commercially available in the United States?

Historical FDA-approved niclosamide products exist, but current U.S. availability is limited compared with mainstream generic anthelmintics. Supply status should be distinguished from historical FDA approval status.

Can niclosamide be patented again?

The original molecule cannot realistically support new broad composition-of-matter exclusivity. New patents may cover formulations, prodrugs, delivery systems, manufacturing methods, or specific therapeutic uses.

Is niclosamide approved for cancer treatment?

No. Cancer use remains investigational unless and until FDA approves a specific niclosamide product for a defined oncology indication.

Does niclosamide have COVID-19 approval?

No FDA approval exists for niclosamide as a COVID-19 treatment. Preclinical or clinical research findings do not create an approved indication.

What would make niclosamide commercially valuable?

A product would need a clinically validated formulation that achieves useful systemic exposure, an approved high-value indication, enforceable patents, scalable manufacturing, and reimbursement above commodity generic pricing.

References

1. U.S. Food and Drug Administration. (n.d.-a). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

2. U.S. Food and Drug Administration. (n.d.-b). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. U.S. Food and Drug Administration. (n.d.-c). Abbreviated new drug application process. https://www.fda.gov/drugs/types-applications/abbreviated-new-drug-application-anda

4. U.S. Food and Drug Administration. (n.d.-d). 505(b)(2) applications. https://www.fda.gov/drugs/types-applications/505b2-application

5. National Library of Medicine. (n.d.). ClinicalTrials.gov. https://clinicaltrials.gov/

6. World Health Organization. (2023). WHO guideline for preventive chemotherapy for public health control of strongyloidiasis, schistosomiasis and soil-transmitted helminthiasis. World Health Organization.

7. U.S. Patent and Trademark Office. (n.d.). Patent term adjustment and patent term extension. https://www.uspto.gov/patents/laws/patent-term-adjustment

8. U.S. Food and Drug Administration. (n.d.-e). Orange Book patent and exclusivity information. https://www.fda.gov/drugs/development-approval-process-drugs/orange-book-patent-and-exclusivity-information