HETRAZAN Drug Patent Profile

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

Hetrazan is a drug marketed by Lederle and is included in one NDA.

The generic ingredient in HETRAZAN is diethylcarbamazine citrate. There is one drug master file entry for this compound. Additional details are available on the diethylcarbamazine citrate profile page.

Summary for HETRAZAN

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	87
Clinical Trials:	1
Patent Applications:	714
DailyMed Link:	HETRAZAN at DailyMed

Recent Clinical Trials for HETRAZAN

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

Sponsor	Phase
Case Western Reserve University	Phase 3
Washington University School of Medicine	Phase 3
Regional Hospital of Agboville, Southern Cote d'Ivoire	Phase 3

See all HETRAZAN clinical trials

US Patents and Regulatory Information for HETRAZAN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Lederle	HETRAZAN	diethylcarbamazine citrate	TABLET;ORAL	006459-001	Approved Prior to Jan 1, 1982		DISCN	No	No

# HETRAZAN Market Dynamics, Financial Trajectory, Patent Status, and Generic Competition

Last updated: August 10, 2026

HETRAZAN is the former U.S. brand for diethylcarbamazine citrate, an oral antiparasitic used primarily against lymphatic filariasis, tropical pulmonary eosinophilia, and certain tissue nematode infections. Its commercial trajectory is defined by product maturity, low pricing, limited branded distribution, and public-health procurement rather than conventional specialty-pharmaceutical growth.

No reliable public source reports standalone HETRAZAN revenue. Pfizer does not separately disclose sales for the product, and current U.S. demand is largely institutional or public-health driven. The active ingredient remains clinically relevant, but the HETRAZAN brand has limited commercial importance in the United States compared with generic diethylcarbamazine and donated or government-procured alternatives.

What is HETRAZAN and who manufactures it?

HETRAZAN is a branded formulation of diethylcarbamazine citrate, commonly abbreviated DEC. The drug is an orally administered antifilarial agent. Historical U.S. labeling identified HETRAZAN tablets in 50 mg and 100 mg strengths and indicated use for infections caused by Wuchereria bancrofti, Brugia malayi, and Brugia timori, as well as tropical pulmonary eosinophilia and loiasis in appropriate settings.[1]

Product attribute	HETRAZAN profile
Active ingredient	Diethylcarbamazine citrate
Therapeutic class	Antifilarial antiparasitic
Primary indications	Lymphatic filariasis, tropical pulmonary eosinophilia, selected tissue nematode infections
Dosage form	Oral tablets
Historical strengths	50 mg and 100 mg
U.S. brand owner or marketer	Historically associated with Pfizer and its predecessor commercial operations
Current market model	Generic, institutional, public-health and special-access supply
Biologic status	Not applicable
Patent dependence	No meaningful current composition-of-matter exclusivity identified
U.S. commercial position	Limited and not comparable with a protected branded prescription product

HETRAZAN is not a biologic and does not generate biosimilar exposure. Competition comes from generic DEC suppliers, imported products, public-health procurement channels and alternative antifilarial regimens.

When did HETRAZAN lose exclusivity?

HETRAZAN’s core pharmaceutical exclusivity expired many years ago. Diethylcarbamazine is an old small-molecule drug, and the underlying active ingredient was developed decades before the current patent system became relevant to its commercial life.

The commercial consequences are substantial:

• No current composition-of-matter patent is expected to block generic diethylcarbamazine.
• Any historical U.S. patents would have expired long before the present market period.
• Formulation, tablet-strength and manufacturing patents do not appear to create a material barrier to generic supply.
• Regulatory exclusivity is not a current source of protection for the product.
• The main barriers are procurement qualification, supply continuity, manufacturing economics and regulatory access.

The FDA Orange Book is the principal source for approved drug patents and exclusivity listings in the United States. HETRAZAN does not represent a current patent-protected reference product with a commercially meaningful Orange Book exclusivity position.[2]

What is the FDA and Orange Book status of HETRAZAN?

HETRAZAN has historical FDA approval and labeling as an oral diethylcarbamazine citrate product. Its present commercial availability is more restricted than the historical approval record suggests.

The key regulatory distinction is between:

1. Historical approval of a branded product.
2. Current commercial marketing by the original brand sponsor.
3. Availability of generic or special-access DEC.
4. Procurement for national lymphatic-filariasis programs.

The FDA has identified diethylcarbamazine citrate as a drug with limited U.S. commercial availability. The Centers for Disease Control and Prevention has described mechanisms for obtaining DEC when it is not commercially available through ordinary pharmacy channels.[3]

The practical U.S. status is therefore:

Regulatory issue	Assessment
Historical FDA approval	Yes
Current branded market presence	Limited
Current Orange Book patent value	Minimal or none
Prescription availability	Dependent on supplier and access pathway
Generic competition	Possible and commercially more relevant than brand competition
Paragraph IV exposure	Low strategic relevance because the product is old and largely off-patent
REMS	No major product-specific REMS structure is central to market access
Biosimilar pathway	Not applicable

How large is the HETRAZAN market?

The global market for HETRAZAN as a brand is small. The market for diethylcarbamazine as a public-health medicine is larger but difficult to quantify because much of the volume is purchased through ministries of health, international organizations and special procurement programs.

Demand is concentrated in countries affected by lymphatic filariasis and related parasitic diseases. The World Health Organization has treated DEC as one component of mass drug administration strategies, but its use depends on local disease epidemiology. DEC is generally avoided in areas where onchocerciasis or certain Loa loa infections create a risk of severe adverse reactions.[4]

Market demand has four principal sources:

• National lymphatic-filariasis elimination programs.
• Government hospital and infectious-disease procurement.
• Specialist treatment of individual patients.
• Travel medicine, tropical medicine and special-access channels.

The commercial market is therefore episodic. Volume can rise when a country launches or expands mass drug administration, then decline sharply after treatment targets are met or procurement shifts to another regimen.

What drives HETRAZAN revenue and volume?

HETRAZAN’s financial trajectory is driven by public-health purchasing rather than prescription growth.

Public-health elimination programs

The largest potential demand pool is lymphatic-filariasis control. The WHO recommends annual mass drug administration using combinations that can include albendazole, ivermectin, diethylcarbamazine or other agents depending on local risk.[4]

DEC is especially relevant in settings without onchocerciasis transmission. In those markets, it can be included in triple-drug therapy with ivermectin and albendazole. This creates procurement opportunities but does not create durable brand pricing power.

Disease geography

The relevant geography includes parts of South and Southeast Asia, the Pacific, Africa, the Caribbean and other tropical regions. Country-level demand depends on:

• Endemic population size.
• National elimination strategy.
• Onchocerciasis and Loa loa risk.
• Government budget cycles.
• Availability of donated ivermectin and albendazole.
• Local generic manufacturing capacity.

Product scarcity

Scarcity can support temporary pricing increases, but it does not necessarily increase long-term brand value. When a product is old and off-patent, supply interruptions tend to attract generic, imported or government-sourced alternatives rather than restore the original brand’s market position.

Clinical substitution

DEC competes with ivermectin, albendazole and other antiparasitic medicines. The products are not fully interchangeable in every indication, but national programs select combinations based on safety, disease prevalence, supply and cost.

What is the financial trajectory for HETRAZAN?

No public standalone revenue series is available for HETRAZAN. Pfizer’s financial reporting aggregates products into broader business segments and does not identify HETRAZAN revenue as a material reporting line.[5]

The most defensible financial trajectory is:

Period	Financial position
Historical branded period	Established prescription product with conventional commercial distribution
Post-exclusivity period	Declining brand economics as generic and institutional procurement expanded
Public-health procurement period	Irregular volume, price-sensitive tenders and low brand differentiation
Current period	Limited standalone brand value; value resides primarily in active-ingredient supply and regulatory access
Forward outlook	Stable niche demand with low growth and periodic procurement-driven spikes

Revenue is likely constrained by five factors:

1. The drug is off-patent.
2. Treatment courses are inexpensive relative to modern branded therapies.
3. Demand is concentrated in low- and middle-income markets.
4. Procurement is price-sensitive.
5. International health programs may obtain medicines through donations or tender-based purchasing.

The product can still have strategic value for a supplier that controls a reliable API source, qualified manufacturing site or government procurement relationship. That value is operational rather than patent-based.

What generic entry risks exist for HETRAZAN?

Generic entry risk is high in principle and moderate in commercial impact. The product’s age means that legal barriers are weak. The limiting factor is whether a supplier can earn an adequate return from a small, irregular market.

Generic competition can enter through:

• Approved oral tablet products.
• Imported finished-dose products.
• Compounded or special-access supply where legally permitted.
• Government procurement contracts.
• Regional manufacturers serving endemic countries.

The economics are different from a typical blockbuster generic launch. A generic company may face low development costs but also low annual revenue, limited pharmacy demand and uncertain tender timing. Multiple suppliers can remain viable only when public-health procurement expands or when supply shortages create temporary pricing opportunities.

Are there Paragraph IV challenges against HETRAZAN?

Paragraph IV litigation is not a material current issue for HETRAZAN.

A Paragraph IV certification challenges an Orange Book-listed patent for an approved reference drug. Because HETRAZAN is an old, largely off-patent product with no evident current patent barrier of commercial significance, a new Paragraph IV campaign would have limited economic rationale.

The more relevant generic-entry questions are:

• Whether an applicant can obtain approval for the relevant strength and indication.
• Whether the product can meet quality and stability requirements.
• Whether a supplier can access public-health tenders.
• Whether the product is legally importable in each target market.
• Whether procurement agencies recognize the supplier.

What formulation patents protect HETRAZAN?

No commercially significant active formulation patent is apparent for the historical HETRAZAN tablet presentation.

The product’s formulation is relatively simple compared with extended-release, injectable, liposomal or device-enabled medicines. The main technical requirements are standard tablet manufacturing controls, including:

• API identity and assay.
• Citrate salt control.
• Dissolution and stability.
• Content uniformity.
• Tablet hardness and friability.
• Packaging suitable for tropical climates.

These requirements can create quality and manufacturing barriers, but they do not provide durable exclusivity. A supplier with validated production and regulatory documentation may have an execution advantage without holding enforceable formulation rights.

What patent litigation and settlement agreements affect HETRAZAN?

No material current U.S. patent litigation or branded-generic settlement agreement is associated with HETRAZAN in the public commercial record.

The absence of litigation is consistent with the product’s market profile. Patent disputes generally require enough future revenue to justify litigation expense. HETRAZAN’s limited brand sales, old active ingredient and public-health procurement model reduce that incentive.

Potential disputes are more likely to involve:

• Supply contracts.
• Product quality.
• Regulatory approval.
• Government tenders.
• Trademark or parallel-import issues.
• API specifications and manufacturing documentation.

How does HETRAZAN compare with ivermectin and albendazole?

HETRAZAN is commercially weaker than ivermectin and albendazole because its use is more geographically constrained and its brand infrastructure is less important.

Factor	HETRAZAN	Ivermectin	Albendazole
Primary public-health role	Lymphatic filariasis in selected settings	Onchocerciasis and lymphatic filariasis	Soil-transmitted helminths and lymphatic filariasis combinations
Patent position	Long expired	Core patents expired; major public-health use	Core patents expired
Brand strength	Low	Historically stronger	Historically stronger
Donor involvement	More limited	Major donation programs	Major donation programs
Commercial pricing power	Low	Low in mass programs, higher in some private markets	Low in mass programs
Disease geography	Restricted by safety and endemicity	Broad but constrained by Loa loa risk	Broad
Biosimilar risk	None	None	None

Ivermectin and albendazole benefit from larger global procurement ecosystems and more prominent donor programs. DEC remains important where it is clinically appropriate, but its market is narrower.

What manufacturing and intellectual-property barriers affect HETRAZAN?

Manufacturing barriers are more relevant than intellectual-property barriers.

A supplier must maintain:

• Reliable diethylcarbamazine citrate API sourcing.
• Compliance with applicable good manufacturing practice standards.
• Validated tablet production.
• Stability data for hot and humid climates.
• Registration in procurement countries.
• Pharmacovigilance and batch-release systems.
• Capacity to support large government orders on short notice.

The largest risk is supply fragility. A small number of qualified suppliers can create procurement bottlenecks, while low routine demand can discourage manufacturers from maintaining excess capacity.

What is the competitive outlook for HETRAZAN?

The outlook is stable but low-growth. HETRAZAN is unlikely to regain a major branded position. Its commercial relevance will remain linked to:

• Lymphatic-filariasis elimination programs.
• Continued use in countries where DEC is clinically appropriate.
• Shortages of alternative antifilarial medicines.
• Government procurement cycles.
• Availability of generic DEC products.

The highest-value commercial position is not ownership of the historical brand. It is control of compliant manufacturing, reliable supply and access to public-health tenders.

Key Takeaways

• HETRAZAN is the historical brand for diethylcarbamazine citrate.
• Its core exclusivity expired decades ago, and no meaningful current patent moat is evident.
• Standalone HETRAZAN revenue is not publicly disclosed.
• Current demand is concentrated in public-health, institutional and special-access channels.
• Generic entry is legally feasible but commercially constrained by small and irregular demand.
• The product has no biosimilar exposure.
• Formulation and manufacturing requirements create execution barriers, not durable patent exclusivity.
• Ivermectin and albendazole have broader public-health procurement ecosystems.
• HETRAZAN’s forward value depends on supply reliability and government procurement rather than brand pricing power.

FAQs About HETRAZAN Market and Financial Performance

Is HETRAZAN still sold in the United States?

HETRAZAN is not widely distributed through ordinary U.S. retail channels. Diethylcarbamazine may be obtained through limited commercial or public-health access mechanisms when clinically indicated.[3]

Does Pfizer still report HETRAZAN sales?

Pfizer does not separately report HETRAZAN revenue in its public financial statements. Any sales are aggregated within broader product or business categories.[5]

Is diethylcarbamazine available as a generic?

Generic or non-branded diethylcarbamazine products may be available in selected countries and through specialized procurement channels. Availability varies by jurisdiction, registration status and supplier.

Can HETRAZAN be used for all filarial infections?

No. DEC is not appropriate for every filarial infection or geographic setting. Safety concerns involving onchocerciasis and Loa loa exposure can affect treatment selection.[4]

Does HETRAZAN have an exclusivity date that would delay generic launch?

No commercially meaningful current exclusivity period is apparent. A generic launch would depend mainly on regulatory approval, manufacturing qualification, market access and procurement economics.

References

1. U.S. Food and Drug Administration. (n.d.). HETRAZAN (diethylcarbamazine citrate) tablets prescribing information. FDA labeling archive.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/

3. Centers for Disease Control and Prevention. (n.d.). Clinical care of lymphatic filariasis. https://www.cdc.gov/filarial-worms/hcp/clinical-care/index.html

4. World Health Organization. (2023). Lymphatic filariasis: Guidelines for stopping mass drug administration and verifying elimination. World Health Organization. https://www.who.int/teams/control-of-neglected-tropical-diseases/lymphatic-filariasis

5. Pfizer Inc. (2024). Annual report 2023. https://www.pfizer.com/investor/financial-reports-annual-reports-functions-reports.cgi