Last updated: August 2, 2026

Kantrex is the historical brand name for kanamycin sulfate injection, an aminoglycoside antibacterial. Its commercial profile is that of a mature, low-volume injectable antibiotic rather than a growth pharmaceutical asset. Public sources do not disclose standalone Kantrex revenue, current net sales, pricing, or profitability. The principal market forces are generic substitution, limited clinical use caused by toxicity concerns, hospital purchasing pressure, and the availability of alternative antibiotics.

What is Kantrex and who markets it?

Kantrex is associated with kanamycin sulfate injection, an injectable aminoglycoside used for selected serious bacterial infections. The product’s historical U.S. labeling identifies kanamycin sulfate as an antibacterial administered by intramuscular or intravenous routes.[1]

Kanamycin is structurally related to other aminoglycosides, including gentamicin, tobramycin, and amikacin. Its use has declined because of nephrotoxicity, ototoxicity, antimicrobial-resistance concerns, and the availability of newer or better-tolerated antibiotics.

Attribute	Kantrex / kanamycin sulfate injection
Active ingredient	Kanamycin sulfate
Drug class	Aminoglycoside antibacterial
Dosage form	Sterile injectable solution or powder for injection, depending on product presentation
Primary setting	Hospital and institutional care
U.S. commercial position	Legacy branded or historically branded product; generic competition
FDA pathway	Legacy prescription-drug approval and subsequent generic equivalents
Main competitors	Generic kanamycin, amikacin, gentamicin, tobramycin, and other hospital antibiotics
Public standalone revenue	Not disclosed
Patent relevance	No meaningful current composition-of-matter patent protection identified for the legacy active ingredient

Historical commercial responsibility for Kantrex has changed over time, as is common with older injectable products. Current manufacturer and distributor information should be distinguished from the historical brand owner listed in older FDA labeling and reference databases.

How large is the Kantrex market?

The Kantrex market is likely small in value relative to major branded antibiotics. Kanamycin injection is generally used for narrow clinical circumstances, including infections caused by susceptible gram-negative organisms and selected tuberculosis-related applications. It is not a broad commercial substitute for first-line hospital antibiotics.

Market demand is constrained by several factors:

Kanamycin is an older antibiotic with a narrower role in modern treatment protocols.
Hospitals increasingly use susceptibility-directed treatment rather than empiric kanamycin therapy.
Generic injectable purchasing is heavily influenced by contract pricing and shortages.
Alternative aminoglycosides, particularly amikacin and gentamicin, have stronger contemporary hospital utilization in many markets.
Safety monitoring requirements increase the cost of use.

Kantrex therefore operates in a procurement-driven market. Prescribing decisions are made primarily by hospitals, infectious-disease specialists, formularies, and public-sector procurement agencies. Brand loyalty has limited commercial value.

What is the financial trajectory of Kantrex?

No public filing provides reliable standalone revenue or earnings for Kantrex. The product is not reported as a separate operating segment by a major public pharmaceutical company, and available regulatory documents do not provide sales data.

The most defensible financial trajectory is:

Period	Commercial condition	Financial implication
Historical branded period	Branded injectable antibiotic with established clinical use	Higher unit economics than later generic supply
Generic-entry period	Multiple suppliers and substitution pressure	Falling prices and reduced brand differentiation
Mature generic period	Low-volume institutional demand	Limited revenue pool and procurement-driven margins
Current market	Intermittent demand, possible supply concentration	Revenue volatility driven by tenders, shortages, and hospital inventory

Kantrex revenue, if generated under the brand, is likely immaterial to a diversified pharmaceutical company. The product’s financial value is more likely tied to manufacturing authorization, hospital contracts, or supply continuity than to brand pricing.

There is no basis in public information to assign a precise annual revenue figure, EBITDA contribution, or valuation multiple to Kantrex.

When did Kantrex lose exclusivity?

Kantrex has no commercially meaningful current exclusivity based on the age of kanamycin sulfate and the existence of generic kanamycin products. The active ingredient was introduced decades ago, well before the modern patent-based exclusivity periods used for new drugs.

For a legacy product such as Kantrex, commercial protection is not generally determined by one pending patent expiration date. The relevant barriers are:

manufacturing approvals;
sterile injectable production capacity;
supplier qualification;
regulatory compliance;
hospital contracts;
pharmacovigilance obligations;
active pharmaceutical ingredient availability.

The FDA Orange Book distinguishes approved products from products with discontinued marketing status and identifies patent and exclusivity information where applicable.[2] A historical branded product can remain clinically recognized even after its principal commercial protections have expired.

What patents protect Kantrex?

No current, commercially significant patent estate is publicly associated with kanamycin sulfate as an active ingredient. Any original product patents would have expired many years ago.

Potentially relevant intellectual property could instead involve:

injectable formulations;
container-closure systems;
manufacturing processes;
stability improvements;
combination products;
delivery devices.

These categories are unlikely to provide broad exclusionary rights over kanamycin sulfate itself. A formulation or process patent would need to be reviewed claim by claim to determine whether it covers a currently marketed Kantrex product.

Patent category	Likely relevance to Kantrex
Active-ingredient patent	No current protection expected
New chemical entity exclusivity	Expired
Pediatric exclusivity	Not identified as commercially relevant
Formulation patent	Possible in theory, but no material current estate established
Manufacturing patent	Could affect a specific supplier, not the entire market
Method-of-use patent	Limited relevance unless tied to a patented indication
Device patent	Generally not central to the historical product

What is the FDA regulatory status of Kantrex?

Kanamycin sulfate injection is regulated as a prescription antibacterial drug. Historical FDA labeling describes systemic use and includes warnings relating to renal toxicity, auditory or vestibular toxicity, and neuromuscular effects.[1]

The clinical risk profile affects market demand. Aminoglycosides require dose adjustment and monitoring in patients with renal impairment. Extended exposure can increase the risk of irreversible hearing or balance-related injury. These requirements reduce routine use and make hospitals more likely to reserve kanamycin for specific microbiological or therapeutic circumstances.

FDA regulatory status must be evaluated at the product level. A branded reference product, a generic abbreviated new drug application, and a discontinued product may have different listing statuses even when they contain the same active ingredient.

How strong is the Kantrex patent estate?

The Kantrex patent estate is weak from a commercial exclusivity perspective.

Factor	Assessment
Active-ingredient protection	Very weak or expired
Brand protection	Limited against generic substitution
Formulation protection	Not established as a material barrier
Method-of-use protection	Narrow and unlikely to block ordinary generic use
Manufacturing barriers	Moderate for sterile injectables
Regulatory barrier	Meaningful but not exclusivity-based
Litigation leverage	Low
Generic entry resistance	Low to moderate, depending on supplier availability

The main defensible asset is operational rather than legal. Sterile injectable manufacturing is more difficult than oral solid-dose production. Suppliers must maintain validated processes, sterility controls, quality systems, and reliable raw-material sourcing. Those requirements can reduce the number of active suppliers, but they do not create patent exclusivity.

Are there Paragraph IV challenges or Kantrex patent litigation?

No material current Paragraph IV litigation or major patent dispute directed specifically at Kantrex is identified in the public commercial record available for this analysis.

Paragraph IV litigation is more relevant to newer products with listed patents in the FDA Orange Book. For an old kanamycin product, generic competition generally arises through abbreviated approval pathways without a commercially important patent barrier.

The principal legal risks are more likely to involve:

product liability;
manufacturing deviations;
FDA warning letters or recalls;
supply contracts;
antitrust issues in generic procurement;
facility compliance;
quality disputes involving sterile products.

No significant current settlement agreement involving a Kantrex patent challenge is established.

What generic entry risks exist for Kantrex?

Generic entry risk is structurally high because the product is old, injectable, and clinically substitutable in selected situations.

Generic competitors can pressure Kantrex through:

lower acquisition cost;
automatic or formulary substitution, where permitted;
hospital group-purchasing contracts;
government tenders;
multisource supply;
therapeutic substitution with other aminoglycosides.

The risk is moderated by the economics of sterile manufacturing. If demand is too low or production costs rise, suppliers may exit. That can produce temporary shortages or price increases even when no patent prevents entry.

This creates a two-sided market structure: long-term pricing pressure from generic competition, combined with short-term price volatility when manufacturing capacity is limited.

How does Kantrex compare with competing aminoglycosides?

Product	Typical market position	Competitive effect on Kantrex
Amikacin	Often preferred for selected resistant gram-negative infections and tuberculosis-related use	Strong substitute
Gentamicin	Widely used in hospital and combination regimens	Strong substitute
Tobramycin	Important in selected gram-negative and pulmonary applications	Moderate substitute
Kanamycin	Narrower legacy role and declining routine use	Kantrex’s market position
Newer antibacterials	Used when resistance or safety concerns limit aminoglycosides	Indirect competitive pressure

Amikacin is generally the most important clinical comparator in situations involving resistant organisms or tuberculosis programs. Gentamicin has broader institutional familiarity and established procurement channels. These products limit the ability of Kantrex to regain market share through ordinary commercial promotion.

What manufacturing and supply barriers affect Kantrex?

Manufacturing is more important than patent protection. Kanamycin sulfate injection requires:

qualified active pharmaceutical ingredient supply;
sterile manufacturing capacity;
validated filling and finishing;
container-closure integrity;
microbiological quality control;
stability data;
regulatory inspection readiness.

A supplier with limited production capacity can experience disproportionate commercial exposure from a single quality event. Hospitals may then switch to amikacin, gentamicin, or other alternatives. Once a formulary changes, recapturing share can be difficult because prescribing protocols and purchasing contracts may remain in place.

Supply risk is therefore a more relevant investment issue than patent risk.

What are the likely generic launch scenarios for Kantrex?

The most likely scenarios are:

Stable low-volume supply

Several approved suppliers maintain limited production. Prices remain low, and Kantrex has little strategic value beyond continuity of supply.

Supplier consolidation

One or two manufacturers remain active. Prices become more volatile, but total market value remains modest because clinical demand is limited.

Shortage-driven repricing

A manufacturing interruption or API shortage causes temporary price increases. The effect benefits available suppliers but does not establish durable brand power.

Clinical displacement

Hospitals increasingly favor amikacin, gentamicin, or newer agents. Kanamycin utilization declines, reducing the addressable market.

A sustained branded revival is unlikely without a new indication, a clinically differentiated formulation, or a supply disruption affecting all meaningful alternatives.

What licensing deals affect Kantrex?

No major current licensing transaction involving Kantrex is identified in publicly available sources. Older products can change ownership through portfolio transfers, divestitures, contract manufacturing arrangements, or distributor agreements without generating a separately disclosed transaction value.

Any commercial assessment should distinguish:

ownership of the regulatory application;
ownership of the Kantrex trademark;
contract manufacturing rights;
distribution rights;
ownership of the kanamycin API;
hospital or government supply contracts.

These rights may be held by different entities.

What is the revenue exposure for investors and manufacturers?

For a diversified pharmaceutical company, Kantrex is unlikely to create material consolidated revenue exposure. Its value is more relevant to:

a small generic manufacturer;
a sterile injectable contract manufacturer;
a hospital-supply distributor;
a public-sector procurement supplier;
an API producer.

Revenue concentration can be high at the supplier level even when the total market is small. A single tender or hospital contract may materially affect quarterly sales for a small manufacturer. The same contract would likely be immaterial to a large multinational pharmaceutical company.

Key Takeaways

Kantrex is a legacy kanamycin sulfate injectable, not a growth-stage branded drug.
Public sources do not disclose reliable standalone Kantrex revenue or profit.
Current commercial value is driven by hospital procurement and supply continuity.
Kanamycin has no meaningful current active-ingredient patent protection.
Generic substitution and competing aminoglycosides impose strong long-term pricing pressure.
Sterile manufacturing, API sourcing, and regulatory compliance are the main practical barriers.
No material current Paragraph IV litigation, patent settlement, or Kantrex-specific patent dispute is established.
Financial upside is limited unless a supplier benefits from shortage conditions or a specialized procurement contract.

FAQs About Kantrex Market Size, Exclusivity, and Competition

Is Kantrex still sold in the United States?

Kantrex is a historical brand associated with kanamycin sulfate injection. Current U.S. availability depends on the status of individual approved products, manufacturers, and distributors rather than on the historical brand name alone.

Is kanamycin sulfate a generic drug?

Yes. Kanamycin sulfate is an old active ingredient supplied through generic and legacy product channels. Its market is subject to generic substitution and institutional procurement.

Does Kantrex have Orange Book patent protection?

No material current patent protection for the active ingredient is expected. Any relevant listing would need to be assessed against the specific FDA product and application status.

Why can an old injectable antibiotic experience shortages?

Sterile injectable production requires specialized facilities and quality controls. If demand is low, manufacturers may exit, leaving limited capacity. A single manufacturing failure can then disrupt supply.

Is Kantrex commercially stronger than amikacin?

No. Amikacin generally has a stronger contemporary clinical and procurement position in several settings, particularly where resistance patterns or tuberculosis treatment protocols influence aminoglycoside selection.

References

U.S. Food and Drug Administration. (n.d.). Kanamycin sulfate injection prescribing information. FDA drug labeling database.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA Orange Book.
National Library of Medicine. (n.d.). Kanamycin sulfate injection. DailyMed.
World Health Organization. (2023). WHO consolidated guidelines on tuberculosis: Module 4, treatment. World Health Organization.
U.S. Food and Drug Administration. (n.d.). Drug shortages and current supply information. FDA Drug Shortages Database.

US Patents:	0
Applicants:	1
NDAs:	6
Raw Ingredient (Bulk) Api Vendors:	141
Clinical Trials:	2
Patent Applications:	2,416
DailyMed Link:	KANTREX at DailyMed

Sponsor	Phase
McMaster University	N/A
IUATLD, Inc	Phase 3
Liverpool School of Tropical Medicine	Phase 3

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Apothecon	KANTREX	kanamycin sulfate	CAPSULE;ORAL	060516-001	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Apothecon	KANTREX	kanamycin sulfate	INJECTABLE;INJECTION	061655-003	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Apothecon	KANTREX	kanamycin sulfate	INJECTABLE;INJECTION	061655-002	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Apothecon	KANTREX	kanamycin sulfate	INJECTABLE;INJECTION	062564-002	Sep 21, 1984		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Apothecon	KANTREX	kanamycin sulfate	INJECTABLE;INJECTION	061901-003	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

KANTREX Drug Patent Profile

Which patents cover Kantrex, and when can generic versions of Kantrex launch?

AI Deep Research

Questions you can ask:

Summary for KANTREX

Recent Clinical Trials for KANTREX

US Patents and Regulatory Information for KANTREX

Kantrex Market Dynamics and Financial Trajectory: Kanamycin Sulfate Injection Analysis