United States Drug Patent 6,596,750: Scope, Claims, Expiration, and Patent Landscape for Deferasirox

U.S. Patent No. 6,596,750 covers methods of treating metal overload, particularly iron overload, with substituted 1,2,4-triazole iron chelators. Its most commercially important compound is deferasirox, the active ingredient in Exjade and Jadenu. The patent issued July 22, 2003, and its U.S. term expired in December 2020, subject to any applicable patent-term adjustment or pediatric exclusivity period. It is no longer an enforceable barrier to U.S. generic or follow-on deferasirox products.

The patent’s claim architecture is broad at the genus level but narrows through multiple dependent claims to specific compounds, including deferasirox and a large group of related triazole derivatives. The claims cover therapeutic use, not the active compound as such, a finished dosage form, a manufacturing process, or a particular pharmaceutical composition.

What does U.S. Patent 6,596,750 cover?

The patent covers methods of treating diseases associated with excess metal, with an emphasis on iron overload, by administering substituted 1,2,4-triazole compounds or their pharmaceutically acceptable salts.

The commercial core is the compound:

4-[3,5-bis(2-hydroxyphenyl)-1,2,4-triazol-1-yl]benzoic acid

This compound is commonly known as deferasirox. The patent claims deferasirox expressly in claims 13 and 17 and includes it within broader compound lists in claims 6, 12, and 18.

The claimed pharmacological concept is iron chelation. The compounds contain two ortho-hydroxyphenyl groups attached to a 1,2,4-triazole ring. Those hydroxyl groups provide the principal metal-binding functionality. Substitution at the triazole nitrogen and on the phenyl rings modifies pharmacokinetic, physicochemical, and formulation properties.

What is the patent’s claim category?

U.S. Patent 6,596,750 is principally a use patent. Its claims require:

A subject, human or animal.
A disease caused by or associated with excess metal.
Administration of a therapeutically effective amount.
A compound within the claimed formula or listed species.
In several claims, iron as the relevant metal.

The patent does not claim:

Deferasirox as an unrestricted chemical composition.
A tablet, granule, suspension, or other dosage form as such.
A specific dose or dosing schedule.
A manufacturing process for deferasirox.
A particular pharmaceutical excipient system.
A diagnostic method for identifying iron overload.
A treatment limited to transfusional iron overload, thalassemia, sickle-cell disease, or myelodysplastic syndromes.

That distinction matters. A product containing deferasirox could implicate this patent during its enforceable term through the method of treatment, even if the product formulation itself was protected by a separate patent.

What compounds are covered by the claims?

The claims cover a large Markush genus built around substituted 1,2,4-triazoles bearing hydroxy-substituted aromatic rings.

Formula I and formula II claim structure

Claims 1 and 3 are the principal genus claims. They define:

R1 and R5 as substituents on the hydroxyphenyl rings.
R2 and R4 as hydrogen, acyl groups, aroyl groups, or protecting groups.
R3 as a substituent attached to the triazole nitrogen.
R6 and R7 as substituents on an amide or amino-containing side chain.

Permitted substituents include:

Hydrogen
Halogen
Lower alkyl
Halo-lower alkyl
Lower alkoxy
Halo-lower alkoxy
Carboxyl
Carbamoyl
Alkyl-substituted carbamoyl
Nitrile
Hydroxyalkyl
Aryl and arylalkyl groups
Heteroaryl and heteroaralkyl groups
Aminoalkyl and substituted aminoalkyl groups
Azaalicyclic rings

The claims therefore extend beyond deferasirox to numerous analogues with altered ring substitution, nitrogen substituents, amide side chains, aminoalkyl groups, heteroaryl groups, and carboxylic acid substituents.

Expressly listed compounds

Claim 6 lists specific compounds, including:

Amide derivatives containing morpholine or methylpiperazine.
Hydroxyethyl, dihydroxypropyl, methoxyethyl, and morpholinoethyl acetamides.
Dimethylacetamide and bis(2-hydroxyethyl)acetamide derivatives.
Pyridylmethyl and substituted benzyl triazoles.
4-substituted benzoic acid derivatives.
Chloro- and fluoro-substituted analogues.

Claim 18 contains an even broader species list, including:

N-substituted triazoles.
Alkyl and haloalkyl triazoles.
Aryl and benzyl triazoles.
Pyridylmethyl derivatives.
Benzoic acid and benzoate derivatives.
Acetamide derivatives.
Aminoalkyl amides.
Morpholine and piperazine derivatives.

The express species claims strengthen coverage against arguments that the genus is insufficiently supported or that a particular commercial compound falls outside the disclosure.

Which claims specifically cover deferasirox?

Claim	Deferasirox relevance	Scope
Claim 1	Potentially covers	Broad formula I method claim
Claim 2	Potentially covers	Claim 1 limited to iron
Claim 3	Potentially covers	Broad formula II method claim
Claim 4	Potentially covers	Narrower formula II substituent set
Claim 5	Potentially covers	Further narrowed formula II
Claim 6	Yes, by express listing	Specific compound group including deferasirox
Claim 7	Yes, if used for iron	Claim 6 limited to iron
Claim 8	Yes, if used for iron overload	Claim 3 compound used to treat iron overload
Claim 9	Potentially covers	Alternative formula II genus
Claim 10	Potentially covers	Narrower claim 9 genus
Claim 11	Potentially covers	Further narrowed claim 9 genus
Claim 12	Yes, by express listing	Specific compound group including deferasirox
Claim 13	Yes	Deferasirox specifically
Claim 14	No, or not the same compound	2-substituted benzoic acid isomer
Claim 15	Yes, if used for iron	Claim 9 compound used for iron excess
Claim 16	Yes	Formula II compound for iron overload
Claim 17	Yes	Deferasirox specifically for iron overload
Claim 18	Yes, by express listing	Specific group including deferasirox

Claims 13 and 17 are the clearest deferasirox claims. Claim 13 covers treatment of metal-excess diseases with deferasirox or a pharmaceutically acceptable salt. Claim 17 narrows the indication to iron overload.

What is the legal scope of claims 13 and 17?

Claim 13 requires treatment of a disease that causes or results from excess metal using:

4-[3,5-bis(2-hydroxyphenyl)-[1,2,4]triazol-1-yl]benzoic acid

or a pharmaceutically acceptable salt.

Claim 17 imposes the same compound limitation but narrows the disease to iron overload.

The principal infringement theory would have been induced or contributory infringement associated with an approved product labeled for treating iron overload. A generic applicant whose labeling expressly instructed treatment of iron overload could face a method-of-use assertion during the patent term.

The claims do not require proof that all administered drug chelates iron in vivo. They require administration of the claimed compound for the claimed therapeutic purpose. Claim construction would focus on:

Whether the accused compound is deferasirox or falls within the relevant Markush group.
Whether the label or use is directed to a qualifying metal-overload disease.
Whether the amount administered is therapeutically effective.
Whether the relevant conduct occurred before expiration.
Whether the accused party induced physicians or patients to perform the claimed method.

When did U.S. Patent 6,596,750 expire?

The patent issued July 22, 2003. Public regulatory and patent records associated the patent with an expiration date in December 2020. FDA Orange Book records for deferasirox historically listed U.S. Patent 6,596,750 in connection with Exjade [1][2].

Exclusivity timeline

Event	Date or period
Earliest priority and patent-family activity	Late 1990s
U.S. patent grant	July 22, 2003
FDA approval of Exjade	2005
U.S. patent term expiration	December 2020
Pediatric exclusivity, where applicable	Potentially extended regulatory protection into 2021
FDA approval of Jadenu	2015
Post-expiration generic competition	Began after patent and regulatory barriers ended

Patent expiration and FDA regulatory exclusivity are separate. A patent can expire while pediatric exclusivity, orphan-drug exclusivity, or another regulatory period remains in force. For deferasirox, the commercial significance of U.S. Patent 6,596,750 ended after December 2020, while other patents and product-specific regulatory protections had to be assessed separately.

What was the Orange Book status of U.S. Patent 6,596,750?

The patent was listed in FDA’s Orange Book for deferasirox products, including Exjade-related approvals. Its listing connected the approved drug to patent protection for the claimed therapeutic use.

An Orange Book listing did not establish that every claim was valid or enforceable. It did create the regulatory framework for an ANDA applicant to submit:

Paragraph I certification, if no relevant patent was listed.
Paragraph II certification, if the patent had expired.
Paragraph III certification, accepting delayed approval until expiration.
Paragraph IV certification, asserting that the patent was invalid, unenforceable, or not infringed.

After the patent expired, a Paragraph II certification became the relevant pathway for that expired patent. A later applicant could still face other listed patents covering formulations, salts, polymorphs, dosage forms, or additional uses.

Were there Paragraph IV challenges involving deferasirox?

Deferasirox was subject to generic-development activity and patent-certification risk during the life of the listed patents. The principal legal exposure involved ANDA applicants seeking approval for tablets, dispersible tablets, oral suspensions, or other deferasirox products.

A Paragraph IV challenge to U.S. Patent 6,596,750 would have focused on:

Anticipation or obviousness of the claimed triazole chelators.
Written-description and enablement support for the broad Markush claims.
Whether an ANDA product’s proposed labeling induced the claimed treatment method.
Whether the patent claims covered the specific deferasirox salt or dosage form.
Whether the asserted claims were enforceable after any terminal disclaimer, prosecution-history limitation, or regulatory exclusivity period.

Because the patent has expired, a current Paragraph IV challenge to this patent would have limited practical value. Generic applicants now compete primarily through post-expiration approval, manufacturing scale, product quality, supply reliability, and any remaining formulation or process patents.

What related patents formed the deferasirox patent landscape?

The commercial patent estate for deferasirox was broader than U.S. Patent 6,596,750. It included related patents and applications directed to:

The active chemical entity.
Alternative triazole analogues.
Pharmaceutical compositions.
Dispersible tablets and oral formulations.
Salts, crystalline forms, and solid-state properties.
Methods of treating iron overload.
Pediatric dosing or administration.
Formulation improvements associated with Jadenu.

U.S. Patent 7,049,413 is commonly associated with the U.S. deferasirox patent family and commercial protection surrounding the drug. The precise scope and expiration of each related patent must be evaluated claim by claim because a compound-use patent does not necessarily have the same term, listing status, or enforceability as a formulation patent.

Core landscape categories

Patent category	Typical protected subject matter	Relevance after 2020
Compound and use patents	Deferasirox and iron-overload treatment	Generally expired for this patent family
Formulation patents	Tablets, dispersible tablets, granules, suspensions	Could delay or shape specific product launches
Solid-state patents	Crystalline forms, salts, hydrates	Relevant if a generic uses the protected form
Manufacturing patents	Synthetic steps, purification, crystallization	Relevant to process selection and freedom to operate
Method-of-use patents	Specific patient groups or dosing approaches	Relevant only if valid, listed, and still in force
Regulatory exclusivity	Orphan, pediatric, or approval-related periods	Separate from patent expiration

How strong was the patent estate?

Strengths

The patent had several commercially important strengths:

It expressly claimed deferasirox.
It included narrower species claims that reduced dependence on the broadest Markush language.
It covered iron overload, the primary commercial use.
It included pharmaceutically acceptable salts.
It included both broad formula claims and individually named compounds.
It aligned closely with the approved therapeutic use of Exjade.

Claims 13 and 17 were materially stronger from an enforcement perspective than the broad formula claims because the active ingredient and therapeutic indication were identified with precision.

Vulnerabilities

The estate also had conventional risks:

The broad genus claims covered a large number of substituent combinations.
Prior-art triazole chelators and iron-binding compounds could support obviousness attacks.
Method claims depend on proof of the claimed treatment use.
The claims do not independently protect every formulation or manufacturing route.
Deferasirox products could potentially avoid particular formulation claims through alternative excipients, dosage forms, or solid-state forms.
The patent’s remaining commercial value declined sharply as expiration approached and generic applicants developed non-infringing formulations.

The broad claims would likely receive narrower practical treatment than their literal chemical breadth suggests. A court would construe the structural limitations, provisos, substituent definitions, and formula drawings in the specification. The express deferasirox claims would remain the central enforcement provisions.

What generic entry risks existed?

Before expiration, generic entry risk depended on the combination of:

The compound-use claims in U.S. Patent 6,596,750.
Related listed patents.
FDA regulatory exclusivity.
The proposed generic label.
The generic product’s dosage form and formulation.
Any settlement or launch agreement between the patent holder and ANDA applicant.

After expiration, the principal risks shifted from basic compound patent infringement to:

Remaining formulation patents.
Solid-form and salt patents.
Process patents.
Labeling that includes still-protected indications.
Manufacturing quality and supply constraints.
Product-specific FDA requirements.
Commercial switching from Exjade to Jadenu.

A generic could reduce risk by using a different formulation architecture, selecting an unclaimed solid form, relying on a permissible carved-out label where legally available, and avoiding protected manufacturing steps.

How does U.S. Patent 6,596,750 compare with formulation patents?

Issue	U.S. Patent 6,596,750	Formulation patent
Primary subject	Therapeutic use of triazole chelators	Dosage form or composition
Commercial target	Iron overload treatment	Product presentation and delivery
Deferasirox expressly claimed	Yes	May or may not be
Requires therapeutic administration	Yes	Usually no, depending on claim
ANDA litigation focus	Label and induced use	Product composition and manufacturing
Design-around options	Alternative indication or non-covered compound	Alternative excipients, process, form, or dosage form
Expiration impact	Removes method barrier	Separate expiration analysis required

The distinction is central to freedom-to-operate analysis. Expiration of the method patent does not automatically clear every formulation, process, or solid-state patent associated with deferasirox.

What is the competitive landscape for deferasirox?

Deferasirox competes in the iron-chelation market with:

Deferoxamine, an older parenteral iron chelator.
Deferiprone, an oral iron chelator with a different chemical structure.
Generic deferasirox products.
Branded Exjade and Jadenu products.
Potential combination or disease-specific treatment strategies.

Deferasirox’s commercial position came from oral administration and once-daily or simplified dosing relative to parenteral deferoxamine. The principal commercial exposure for the originator was the transition from branded Exjade to generic deferasirox after loss of patent and regulatory exclusivity.

Revenue exposure was concentrated in:

Transfusion-dependent thalassemia.
Sickle-cell disease.
Myelodysplastic syndromes.
Other chronic transfusional iron-overload conditions.
Pediatric and adult hematology practices.

The end of U.S. Patent 6,596,750 removed one of the main barriers to competition, but market erosion depended on FDA approvals, payer substitution, product availability, and differences between dispersible and film-coated tablet presentations.

Does the patent create biosimilar risk?

No. Deferasirox is a chemically synthesized small molecule, not a biologic. Biosimilar rules under the Public Health Service Act do not apply.

The relevant competitors are ANDA-based generic drugs under the Federal Food, Drug, and Cosmetic Act. Generic applicants must establish pharmaceutical equivalence and bioequivalence or otherwise satisfy the applicable FDA requirements. The dispute framework is patent certification under the Hatch-Waxman Act, not biosimilar interchangeability.

What manufacturing and geographic barriers remain?

The U.S. patent expired, but manufacturing freedom to operate remains jurisdiction-specific. A company assessing global launch risk must review:

National-phase counterparts.
Patent-term adjustments and supplementary protection certificates.
Local formulation and process patents.
Salt and crystalline-form rights.
Regulatory data exclusivity.
Country-specific use patents.
Manufacturing-site and supplier restrictions.

A U.S. expiration does not establish freedom to operate in Europe, Japan, China, Canada, Australia, or emerging markets. The relevant geographic analysis must separate the active compound, dosage form, manufacturing process, and therapeutic indication in each country.

Key Takeaways

U.S. Patent 6,596,750 is a method-of-treatment patent for substituted 1,2,4-triazole metal chelators.
Its central commercial compound is deferasirox.
Claims 13 and 17 expressly cover deferasirox for metal-overload disease and iron overload, respectively.
The patent also covers broad Markush genera and numerous expressly listed analogues.
The patent claims therapeutic use, not an unrestricted composition, dosage form, or manufacturing process.
Its U.S. term expired in December 2020, eliminating it as a current U.S. patent barrier.
Deferasirox is a small molecule, so generic ANDA competition applies rather than biosimilar competition.
Remaining risks must be assessed separately for formulation, solid-state, manufacturing, labeling, and jurisdiction-specific patents.
The strongest historical claims were the express deferasirox species claims tied to iron-overload treatment.
Current commercial protection depends more on regulatory approval, formulation differentiation, supply, and remaining related patent rights than on U.S. Patent 6,596,750.

FAQs About U.S. Patent 6,596,750 and Deferasirox

Is deferasirox directly named in U.S. Patent 6,596,750?

Yes. Deferasirox is expressly identified in claims 13 and 17 as 4-[3,5-bis(2-hydroxyphenyl)-[1,2,4]triazol-1-yl]benzoic acid.

Did U.S. Patent 6,596,750 cover Exjade tablets?

It covered methods of using the claimed compounds, including deferasirox, to treat metal overload and iron overload. Separate patents were needed to protect particular Exjade formulations, dosage forms, or manufacturing processes.

Can a generic company now market deferasirox in the United States?

The expiration of U.S. Patent 6,596,750 removes that patent as a barrier. A generic applicant must still satisfy FDA approval requirements and avoid any unexpired related patents or regulatory exclusivity.

Was U.S. Patent 6,596,750 a composition-of-matter patent?

No. Its issued claims are method claims. They require administration of specified compounds for treatment of metal overload or iron overload.

Does the patent cover deferiprone or deferoxamine?

No. The claims are directed to substituted 1,2,4-triazole compounds, including deferasirox. Deferiprone and deferoxamine have different chemical structures and are not covered by these claims.

Sources

U.S. Patent and Trademark Office. (2003). U.S. Patent No. 6,596,750, substituted 1,2,4-triazoles and their use as iron chelators.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2005). Exjade (deferasirox) prescribing information and approval history.
U.S. Food and Drug Administration. (2015). Jadenu (deferasirox) prescribing information and approval history.
U.S. Patent and Trademark Office. (n.d.). Patent term adjustment and patent-term information resources.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Switzerland	1593/96	Jun 25, 1996

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0914118	⤷ Start Trial	300248	Netherlands	⤷ Start Trial
European Patent Office	0914118	⤷ Start Trial	PA2007001	Lithuania	⤷ Start Trial
European Patent Office	0914118	⤷ Start Trial	CA 2006 00035	Denmark	⤷ Start Trial
European Patent Office	0914118	⤷ Start Trial	06C0049	France	⤷ Start Trial
European Patent Office	0914118	⤷ Start Trial	SPC 035/2006	Ireland	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,596,750

Summary for Patent: 6,596,750