ETHIONAMIDE - Generic Drug Details

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

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

Summary for ETHIONAMIDE

US Patents:	0
Tradenames:	1
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	115
Clinical Trials:	7
What excipients (inactive ingredients) are in ETHIONAMIDE?	ETHIONAMIDE excipients list
DailyMed Link:	ETHIONAMIDE at DailyMed

Recent Clinical Trials for ETHIONAMIDE

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

Sponsor	Phase
BioVersys AG	PHASE2
TASK Applied Science	PHASE2
Innovative Medicines Initiative	PHASE2

See all ETHIONAMIDE clinical trials

Medical Subject Heading (MeSH) Categories for ETHIONAMIDE

Antitubercular Agents

Fatty Acid Synthesis Inhibitors

Anatomical Therapeutic Chemical (ATC) Classes for ETHIONAMIDE

J04AD	Thiocarbamide derivatives
J04A	DRUGS FOR TREATMENT OF TUBERCULOSIS
J04	ANTIMYCOBACTERIALS
J	Antiinfectives for systemic use

US Patents and Regulatory Information for ETHIONAMIDE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Wyeth Pharms	TRECATOR	ethionamide	TABLET;ORAL	013026-002	Approved Prior to Jan 1, 1982		DISCN	Yes	No

Ethionamide Market Dynamics and Financial Trajectory

Last updated: September 8, 2026

Ethionamide is an off-patent, low-revenue tuberculosis drug whose commercial outlook is determined by public procurement rather than branded pharmaceutical demand. Its use is declining as multidrug-resistant tuberculosis treatment shifts toward shorter regimens containing bedaquiline, pretomanid, linezolid, delamanid, and clofazimine. Ethionamide remains relevant where resistance patterns, supply constraints, or treatment guidelines require an alternative companion drug, but its pricing power and patent protection are minimal.

What is the current market position of ethionamide?

Ethionamide is a synthetic thioamide antituberculosis agent used with other medicines to treat tuberculosis, including drug-resistant disease. It is generally supplied as 250 mg tablets. The drug has historically been marketed under the Trecator or Trecator-SC brand and is also available from generic manufacturers and public-sector suppliers.

The commercial market has four defining characteristics:

Market factor	Ethionamide position
Product maturity	Originator-era product; generic and off-patent
Main use	Second-line and salvage tuberculosis treatment
Primary buyers	National tuberculosis programs, international procurement agencies, hospitals
Pricing power	Low
Patent barrier	No meaningful current composition-of-matter barrier
Demand trend	Declining in preferred MDR-TB regimens
Revenue visibility	Low; sales are fragmented and generally not disclosed

Ethionamide is not a high-value branded medicine. Its sales are tied to the number of patients requiring resistant-TB treatment and to national treatment protocols. The product does not have a large private-pay market because tuberculosis treatment is usually financed or managed through government programs, donor organizations, hospitals, and public procurement channels.

How large is the ethionamide market?

No reliable public source reports global ethionamide sales as a standalone market category. Manufacturers generally report tuberculosis portfolios in aggregate, while procurement databases often show transaction prices and volumes rather than total market revenue.

A defensible market assessment must therefore use epidemiology and procurement structure rather than a conventional branded-drug revenue model. WHO estimated that approximately 10.6 million people developed tuberculosis globally in 2022, including about 410,000 cases of multidrug-resistant or rifampicin-resistant tuberculosis. Treatment coverage for drug-resistant TB remained incomplete, limiting the addressable population for any second-line medicine.[1]

Ethionamide captures only a fraction of that potential population because:

1. It is not used in standard drug-susceptible tuberculosis treatment.
2. Many MDR-TB regimens now avoid it because of gastrointestinal toxicity, hypothyroidism, and poor tolerability.
3. WHO-preferred regimens prioritize newer or better-tolerated agents.
4. Local resistance testing and formulary decisions determine whether ethionamide is selected.
5. Public tenders favor low-cost suppliers and often substitute among technically equivalent products.

The addressable market is therefore a residual segment within MDR-TB treatment, not the full global tuberculosis market.

When does ethionamide lose exclusivity?

Ethionamide lost meaningful market exclusivity decades ago. The active ingredient was developed and commercialized long before modern patent terms became commercially relevant to current pharmaceutical portfolios. Any original composition-of-matter patent protection has expired.

Exclusivity category	Status
Original active-ingredient patent	Expired
Original branded-product exclusivity	Expired
Pediatric exclusivity	None identified as commercially relevant
Orphan exclusivity	None identified
Current composition-of-matter protection	None identified
Current formulation exclusivity	No material barrier identified
Generic substitution	Broadly available

The U.S. Food and Drug Administration lists ethionamide tablets through legacy product and label records, but the product does not have the commercial profile of a protected modern branded medicine.[2] The current market is based on abbreviated applications, generic manufacturing, institutional procurement, and country-specific registration.

What patents protect ethionamide products?

No commercially meaningful live patent estate has been identified for ethionamide as an active pharmaceutical ingredient. The principal intellectual-property position is therefore weak.

Composition patents

The original ethionamide molecule is old, and any historic composition patent would be expired. Generic manufacturers can produce the active ingredient without paying royalties to an originator patent holder.

Formulation patents

Ethionamide tablets are conventional oral solid dosage forms. The product does not depend on a complex delivery system, long-acting injection, liposomal formulation, or device. No widely recognized active formulation patent portfolio materially restricts generic tablet manufacture.

Manufacturers may hold process know-how involving crystallization, impurity control, tablet compression, coating, or stability. Those capabilities can affect regulatory approval and manufacturing quality, but they are not equivalent to broad market exclusivity.

Method-of-use patents

No commercially significant current method-of-use patent position has been identified for the established use of ethionamide in tuberculosis treatment. Treatment protocols are controlled primarily by clinical guidelines, national registrations, and resistance patterns.

What is the FDA regulatory status of ethionamide?

Ethionamide is an FDA-recognized antituberculosis medicine used in combination therapy. The U.S. label describes its use for active tuberculosis in patients who cannot tolerate or respond to other drugs, and it emphasizes administration with other antituberculosis agents because monotherapy creates a high risk of resistance.[2]

The product is associated with several clinically important risks:

• Gastrointestinal intolerance, including nausea and vomiting
• Hepatotoxicity
• Hypothyroidism, particularly when used with other agents
• Neurologic and psychiatric adverse effects
• Poor adherence caused by tolerability problems

These safety issues reduce its attractiveness compared with newer agents and create additional monitoring requirements for tuberculosis programs.

FDA regulatory status does not create commercial exclusivity for a generic product. A manufacturer must still demonstrate pharmaceutical quality, bioequivalence where applicable, and compliance with current manufacturing requirements.

What is the Orange Book status of ethionamide?

Ethionamide has no meaningful Orange Book patent position comparable to newer small-molecule products. Any listed patents associated with historic branded products are either expired or no longer capable of supporting a commercially material period of deferred generic entry.

For competitive analysis, the important conclusion is that an applicant is unlikely to face a strategic patent barrier based on the active ingredient, ordinary tablet formulation, or established tuberculosis indication. The main U.S. barriers are regulatory execution, market size, supply economics, and procurement access.

How is ethionamide demand changing in MDR-TB treatment?

Demand is structurally declining because treatment guidelines increasingly favor all-oral regimens built around more effective or better-tolerated drugs.

WHO has moved MDR-TB treatment toward shorter, more standardized regimens that use bedaquiline, pretomanid, linezolid, moxifloxacin, clofazimine, and delamanid where clinically appropriate. Ethionamide and prothionamide are generally lower-priority options and may be used when preferred drugs cannot be used because of resistance, toxicity, contraindications, or availability.[3]

Competitive substitution

Drug or class	Effect on ethionamide
Bedaquiline	Replaces older injectable and companion-drug strategies in many MDR-TB regimens
Pretomanid	Supports shorter BPaL or related regimens for selected resistant-TB patients
Linezolid	Provides a key component of newer resistant-TB regimens, despite toxicity monitoring
Clofazimine	Used in many longer all-oral regimens
Delamanid	Alternative newer agent for selected patients
Injectable aminoglycosides	Reduced use because of toxicity and regimen changes
Ethionamide	Retained mainly as an alternative or salvage component

This substitution pattern limits volume growth even if global MDR-TB diagnosis and treatment expand.

What are the main financial drivers for ethionamide?

Ethionamide’s financial trajectory is governed by volume erosion and price compression rather than innovation-led growth.

Revenue drivers

Demand can increase temporarily when:

• MDR-TB detection expands;
• national programs replenish stock;
• suppliers face shortages of preferred medicines;
• resistance patterns reduce the available use of newer agents;
• countries introduce or expand decentralized drug-resistant TB treatment.

Revenue constraints

Revenue is constrained by:

• Generic competition;
• Public tender price reductions;
• Small order sizes in high-income markets;
• Declining use in WHO-preferred regimens;
• Low patient willingness to tolerate the medicine;
• Limited private-sector prescribing;
• Long procurement cycles;
• Donor and government budget pressure.

A reasonable financial classification is mature-to-declining, low-margin, and procurement-dependent. Ethionamide can provide stable niche revenue to an efficient generic manufacturer, but it is unlikely to generate material growth without a supply disruption or a change in treatment guidelines.

Which companies are challenging or supplying ethionamide?

The competitive field consists mainly of generic manufacturers, regional pharmaceutical companies, and suppliers to public tuberculosis programs. The market has historically included branded legacy suppliers and multiple generic producers across Asia and other manufacturing regions.

The most relevant competitive advantages are:

1. Registration in major procurement countries.
2. WHO prequalification or acceptance under applicable quality-assurance programs.
3. Reliable active-ingredient sourcing.
4. Low-cost tablet production.
5. Ability to meet tender volume and delivery requirements.
6. Stability data suitable for hot and humid markets.
7. Established relationships with national TB programs and procurement agencies.

There is no significant patent litigation landscape comparable to markets for oncology, autoimmune, or specialty medicines. Commercial disputes are more likely to involve tender awards, product quality, supply failures, or regulatory status than patent infringement.

What manufacturing and intellectual-property barriers exist?

The intellectual-property barrier is low, but manufacturing and regulatory barriers remain relevant.

Ethionamide manufacturers must control:

• Active-ingredient purity and impurity profile;
• Batch-to-batch assay consistency;
• Tablet dissolution;
• Stability under elevated temperature and humidity;
• Packaging integrity;
• Bioequivalence or comparative quality requirements;
• Pharmacovigilance and adverse-event reporting.

The active ingredient is chemically established, and the dosage form is relatively simple. Manufacturing therefore does not require the specialized biologics, sterile fill-finish, high-containment oncology facilities, or complex drug-device systems that can protect margins in other pharmaceutical categories.

What generic launch risks exist?

A new generic entrant faces limited patent risk but meaningful commercial risk.

Launch risk	Business impact
Low market volume	Difficult to recover registration and validation costs
Tender concentration	A single lost procurement contract can eliminate expected sales
Price competition	Limits gross margin
Guideline substitution	Reduces future demand
Product discontinuation by competitors	Can create short-term opportunity but not durable growth
Regulatory delays	May exceed the value of the target market
Supply-chain disruption	Can cause missed tenders and loss of institutional trust

A generic launch is most defensible when the company already has a tuberculosis portfolio, existing public-sector registrations, or a manufacturing platform that can add ethionamide at low incremental cost.

How does ethionamide compare with newer MDR-TB drugs?

Attribute	Ethionamide	Bedaquiline	Pretomanid
Product age	Legacy medicine	Modern targeted agent	Modern targeted agent
Patent position	Expired	Historically protected, with jurisdiction-specific expiry considerations	Patent-protected in relevant periods and markets
Primary role	Alternative or salvage component	Core MDR-TB medicine	Selected shorter MDR-TB regimens
Tolerability	Generally poor	Requires cardiac monitoring	Used in combination with other agents
Commercial model	Generic public procurement	Branded and generic transition	Branded or licensed supply, depending on market
Growth outlook	Declining	Higher strategic importance	Regimen-dependent growth
Pricing power	Low	Higher than ethionamide	Higher than ethionamide

Ethionamide is commercially disadvantaged because its clinical role is shrinking while its product economics remain commodity-like.

What is the likely financial trajectory for ethionamide?

The base case is gradual revenue decline, interrupted by country-specific procurement cycles and occasional supply shortages. Unit prices are likely to remain low or fall as additional generic suppliers compete. Any increase in the number of MDR-TB patients treated will not necessarily translate into higher ethionamide sales because newer regimens are capturing treatment share.

Base-case outlook

• Volume: declining over the medium term
• Price: flat to declining
• Gross margin: low
• Patent risk: minimal
• Regulatory risk: moderate
• Supply disruption opportunity: possible but temporary
• Long-term investment case: weak as a standalone product
• Portfolio value: reasonable as part of a broader TB or essential-medicines portfolio

The principal upside case is a temporary shortage of bedaquiline, pretomanid, delamanid, or other preferred agents. The downside case is accelerated guideline removal, improved access to newer medicines, or further deterioration in public procurement prices.

Key Takeaways

• Ethionamide is an old, off-patent tuberculosis medicine with no material current patent moat.
• Its market is concentrated in public and donor-funded MDR-TB procurement.
• Demand is declining as treatment guidelines favor shorter, all-oral regimens using newer agents.
• No reliable public source discloses standalone global ethionamide revenue.
• The product has low pricing power and limited private-sector demand.
• Regulatory and manufacturing execution matter more than intellectual property.
• The strongest commercial rationale is portfolio inclusion, not standalone investment.
• Generic entry is technically feasible but can be economically unattractive because of low volume and tender pricing.
• Temporary supply shortages may create sales spikes, but they are unlikely to change the long-term trajectory.

FAQs About Ethionamide Market and Exclusivity

Is ethionamide still used for tuberculosis?

Yes. It remains available for selected drug-resistant tuberculosis cases, particularly when preferred medicines cannot be used because of resistance, toxicity, contraindications, or supply limitations.

Does ethionamide have an active composition-of-matter patent?

No commercially meaningful active composition-of-matter patent protection has been identified. The drug is an established generic active ingredient.

Is ethionamide included in preferred MDR-TB regimens?

It is generally not a preferred first-choice component when newer, better-tolerated medicines are available. Its use is more common as an alternative or salvage option.

Can a generic company profit from launching ethionamide?

A company can earn revenue if it has low-cost manufacturing and access to government tenders. Standalone profitability is less attractive because of limited demand, price competition, and declining clinical use.

What is the main substitute for ethionamide?

There is no single universal substitute. Depending on resistance and patient factors, programs may use bedaquiline, pretomanid, linezolid, clofazimine, delamanid, or other regimen components selected under current tuberculosis guidelines.

References

1. World Health Organization. (2023). Global tuberculosis report 2023. Geneva, Switzerland: World Health Organization.

2. U.S. Food and Drug Administration. (n.d.). Ethionamide tablets prescribing information and Drugs@FDA records. Silver Spring, MD: U.S. Department of Health and Human Services.

3. World Health Organization. (2022). WHO consolidated guidelines on tuberculosis: Module 4: Treatment - drug-resistant tuberculosis treatment. Geneva, Switzerland: World Health Organization.