US Patent 7,067,551: Claim Scope, LAQ824 Protection, Expiration and HDAC-Inhibitor Patent Landscape

US Patent 7,067,551 covers methods of treating proliferative disorders and regulating the p21 promoter with broad classes of substituted cinnamoyl hydroxamic acids. Its most commercially relevant claims narrow to LAQ824, also known as N-hydroxy-3-[4-[[(2-hydroxyethyl)[2-(1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide, a hydroxamic-acid histone deacetylase inhibitor developed in the Novartis pipeline. The patent does not claim LAQ824 as a composition of matter in the claims supplied. It claims methods using the compound or its pharmaceutically acceptable salts.

The patent is not associated with an FDA-approved product, has no known Orange Book-listed drug, and does not create a current FDA exclusivity barrier. Its principal value is historical and freedom-to-operate related: it identifies a broad chemical and therapeutic field around LAQ824 and related HDAC inhibitors, but its enforceability depends on the patent’s expiration, prosecution history, maintenance status, claim construction, and any later continuation or divisional patents.

What does US Patent 7,067,551 cover?

US 7,067,551 covers two distinct categories of method claims:

Methods of treating proliferative disorders in mammals.
Methods of regulating the p21 promoter by introducing a claimed compound into the environment of a mammalian cell.

The patent’s central chemical class is represented by formula (I), a heavily substituted cinnamamide or cinnamoyl hydroxamic-acid framework. The claims permit extensive variation at the side chains, ring substituents, amino substituents, heterocycles and terminal functional groups.

What is the independent therapeutic claim?

Claim 1 requires:

A method for treating a proliferative disorder.
Administration to a mammal.
A compound within formula (I), or a pharmaceutically acceptable salt.

The claim does not require a particular dose, route, schedule, tumor biomarker, combination therapy, or treatment line. It is therefore broad as a method claim, subject to the chemical limitations embedded in formula (I).

Claim 5 supplies a long list of covered disorders, including:

Breast, lung, colon, gastrointestinal, ovarian, pancreatic, prostate, bladder, renal, brain and gastric cancers.
Small-cell and non-small-cell lung cancer.
Hormone-refractory prostate cancer.
Chemotherapy-refractory and multidrug-resistant tumors.
Leukemia and other hyperproliferative disorders.
Fibrosis, pulmonary fibrosis and renal fibrosis.
Angiogenesis, psoriasis and atherosclerosis.
Smooth-muscle proliferation, stenosis and restenosis after angioplasty.

Claims 7 through 9 narrow the field to lung cancer, non-small-cell lung cancer, colon cancer and fibroblasts, while specifying the LAQ824-type compound.

What is the p21 promoter claim?

Claim 3 covers regulating the p21 promoter by introducing a formula (I) compound into the environment of a mammalian cell. Claim 4 narrows that claim to three named indole-containing compounds, including LAQ824.

This claim is materially different from claim 1. It is directed to a cellular or biological-use method rather than administration to a mammal. Potentially relevant activities could include laboratory research, cell-based screening, mechanistic studies or ex vivo testing, depending on how “introducing ... into the environment of a mammalian cell” is construed.

The claim does not expressly require that p21 regulation produce a therapeutic effect. That omission broadens the functional language, but the claim remains exposed to validity issues involving written description, enablement, anticipation and obviousness across the very large formula (I) genus.

Which compounds are specifically protected by the patent?

Claims 2 and 4 identify three specific compounds:

Compound	Technical description	Relevance
LAQ824	N-hydroxy-3-[4-[[(2-hydroxyethyl)[2-(1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide	Principal named compound
Desmethyl analog	N-hydroxy-3-[4-[[[2-(1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide	Secondary specific embodiment
2-Methyl-indole analog	N-hydroxy-3-[4-[[[2-(2-methyl-1H-indol-3-yl)ethyl]amino]methyl]phenyl]-2E-2-propenamide	Secondary specific embodiment

Claims 6, 8 and 9 focus on the hydroxyethyl-substituted compound corresponding to LAQ824.

The claims supplied contain drafting and transcription defects, including inconsistent brackets, a missing dash in “C4 C9,” and differences between “n” and “n1.” Those defects should be evaluated against the issued patent PDF and prosecution record. Claim interpretation normally gives priority to the issued claim text, specification, drawings and prosecution history, not an unverified transcription.

How broad is formula (I) in US Patent 7,067,551?

Formula (I) covers a large Markush genus. The breadth comes from the cumulative alternatives for R1 through R17, the ring systems, heteroatoms, alkyl and aryl groups, and optional substituents.

Key structural features

The claim permits variation in:

The alpha and beta substituents of the unsaturated amide.
The amino-linked benzyl or aryl portion.
Indole, heteroaryl, polyheteroaryl and fused-ring systems.
Alkyl, cycloalkyl, heterocycloalkyl, arylalkyl and heteroarylalkyl groups.
Amides, esters, ethers, thioethers, sulfoxides and sulfones.
Primary, secondary and cyclic amines.
Carbonyl, thiocarbonyl and imine functionality.
Pharmaceutically acceptable salts.

The terminal N-hydroxyamide is the feature most closely associated with HDAC inhibition. The claims, however, do not expressly recite “histone deacetylase inhibitor” as a structural limitation. The therapeutic claims instead use the broader functional category of proliferative-disorder treatment.

What does the claim breadth mean for infringement?

A compound can fall within claim 1 only if its full structure maps to the formula (I) limitations. A generic or follow-on compound cannot be assessed by looking solely at its HDAC activity. The relevant analysis requires:

Structural mapping of every substituent.
Determination whether the compound is within the literal Markush alternatives.
Assessment of the claimed therapeutic use.
Analysis of salt, stereochemical and formulation differences.
Review of prosecution-history estoppel and any disclaimer.

Because claims 6, 8 and 9 are directed to LAQ824 in specified disease settings, they are narrower and easier to map structurally than claim 1. They are also more vulnerable to prior-art and obviousness challenges if LAQ824 or closely related compounds were disclosed before the relevant filing date.

What was the technical invention behind the patent?

The patent concerns substituted cinnamides designed to regulate cell proliferation. The named compounds are hydroxamic acids, a class that includes several HDAC inhibitors. HDAC inhibition can increase acetylation of histone and non-histone proteins and can affect transcriptional pathways involving p21, a cyclin-dependent kinase inhibitor.

The p21 claims connect the chemistry to a biological mechanism. That connection is commercially useful for identifying the intended pharmacology, but it does not convert the patent into a general claim to all HDAC inhibition or all p21-modulating compounds. A competing HDAC inhibitor with a different chemical structure would not infringe merely because it increases p21 expression.

When does US Patent 7,067,551 lose exclusivity?

The patent issued on June 27, 2006, as US Patent No. 7,067,551. US patent term is generally 20 years from the earliest effective nonprovisional US filing date, subject to patent-term adjustment, patent-term extension and terminal disclaimers. The issue date does not determine expiration.

The patent’s practical exclusivity period is therefore tied to its underlying US filing and priority chain, not to 2006. A current status review should distinguish:

Patent expiration by ordinary term.
Expiration for failure to pay maintenance fees.
Patent-term adjustment.
Patent-term extension under 35 U.S.C. § 156.
Patent-term adjustment under 35 U.S.C. § 154.
Continuation or divisional patents with later expiration dates.

No FDA-approved LAQ824 product is identified in the Orange Book, and no FDA patent-term extension is associated with LAQ824. As a result, the patent does not provide an active regulatory exclusivity period for a marketed drug. The relevant enforceability question is the patent’s statutory term and any related family members, not FDA exclusivity.

What is the Orange Book status of LAQ824 and US 7,067,551?

LAQ824 has no identified FDA-approved reference-listed drug. It was investigated clinically as an HDAC inhibitor but did not become an approved US medicine.

Consequences include:

No Orange Book-listed LAQ824 product.
No Orange Book patent listing for LAQ824 under an approved NDA.
No 30-month stay based on an LAQ824 Paragraph IV filing.
No FDA small-molecule exclusivity period tied to LAQ824.
No US generic approval pathway directed specifically to LAQ824 under an existing reference product.

A manufacturer developing LAQ824 today would likely need an independent full NDA pathway unless it could rely on an applicable regulatory mechanism that does not depend on an existing reference-listed product.

Were there Paragraph IV challenges or patent litigation?

No publicly reported Paragraph IV litigation or settlement agreement is associated with an approved LAQ824 product because LAQ824 does not have an identified Orange Book reference product.

The absence of Paragraph IV litigation does not establish that all patent risks are absent. Relevant risks could arise from:

A patent-infringement action based on a still-enforceable family member.
A research-use or cell-based-use dispute under the p21 claims.
A later patent covering a salt, polymorph, formulation or manufacturing process.
A continuation patent with claims directed to a specific HDAC inhibitor or therapeutic indication.
A contract or license dispute involving development rights.

The supplied claims themselves do not identify a formulation, dosage regimen, combination, pharmaceutical composition, manufacturing process or specific crystalline form.

What formulation and manufacturing protections exist?

US 7,067,551 is principally a method patent. The supplied claims do not expressly cover:

Tablets or capsules.
Injectable formulations.
Sustained-release delivery.
Nanoparticle or liposomal delivery.
Specific excipient combinations.
Particle size.
Polymorphs or solvates.
Purity thresholds.
Commercial manufacturing routes.
Intermediates or process conditions.

A company could therefore face little direct exposure under this patent from manufacturing or selling a non-LAQ824 HDAC inhibitor, even if the product has similar pharmacology. Exposure would depend on whether the final compound falls within formula (I) and whether the use satisfies the treatment or cell-regulation limitations.

Separate process and formulation patents would be more significant for commercial launch planning. Such patents must be reviewed across the relevant US, European and Asian family members.

How does this patent compare with competing HDAC-inhibitor patents?

HDAC inhibitor	Representative protection	Commercial status	Relationship to US 7,067,551
Vorinostat	Composition and therapeutic patents, including US 5,369,108	FDA-approved	Different chemical scaffold; generally outside the LAQ824 genus
Romidepsin	Macrocyclic depsipeptide patent families	FDA-approved	Structurally distinct
Belinostat	Hydroxamic-acid patent families, including US 7,982,060	FDA-approved	Different substituted benzene-sulfonamide scaffold
Panobinostat	Hydroxamic-acid and formulation patent families	FDA-approved	Structurally distinct from LAQ824
LAQ824	US 7,067,551 and related family review required	Not FDA-approved	Specific named compound and broad cinnamoyl hydroxamate genus

The principal competitive distinction is between a broad early chemical genus and later product-specific estates. A broad genus patent can cover many research compounds but may have limited remaining commercial value after expiration or after the market moves to structurally unrelated HDAC inhibitors.

How strong is the patent estate for LAQ824?

The patent’s strength is mixed.

Strengths

Claim 1 covers a broad chemical genus.
Claims 6, 8 and 9 identify LAQ824 directly.
The patent links the compounds to cancer and other proliferative disorders.
The p21 promoter claims provide a separate biological-use theory.
The claims cover salts, which reduces the value of a simple salt-selection workaround.

Weaknesses

The patent is a method patent rather than a composition claim in the supplied claims.
Formula (I) contains extensive alternatives, increasing written-description and enablement pressure.
The p21 claims may face questions about claim scope and experimental support.
The named LAQ824 claims are vulnerable if earlier disclosures identify the compound or close analogs.
No approved product creates no Orange Book enforcement framework.
The absence of an approved LAQ824 product limits commercial damages and generic litigation relevance.

For a current launch assessment, the most important question is whether any continuation, divisional, reissue or related foreign-family patent remains enforceable. US 7,067,551 alone is unlikely to create a modern regulatory barrier for an LAQ824 program.

What licensing and development activity involved LAQ824?

LAQ824 was developed as an investigational HDAC inhibitor in the Novartis research and clinical pipeline. Public clinical literature describes LAQ824 as a hydroxamic-acid HDAC inhibitor evaluated in oncology, including hematologic malignancies and solid tumors.

No publicly established commercial license or active co-development arrangement creates a current FDA market barrier for LAQ824. Any diligence should separate:

Patent ownership.
Clinical development rights.
Know-how and manufacturing rights.
Data ownership.
Inactive or terminated licenses.
Rights to related compounds and follow-on patents.

Patent ownership alone does not establish control over clinical data, regulatory submissions or manufacturing know-how.

What generic launch risks exist for LAQ824?

A generic launch analysis has three scenarios:

Scenario 1: Direct LAQ824 development

The developer would face the historical patent family, but no Orange Book-listed reference product is available for an ANDA strategy. The practical route would likely involve a full clinical and regulatory development program.

Scenario 2: Structurally unrelated HDAC inhibitor

A different HDAC inhibitor, such as a benzamide, cyclic peptide or distinct hydroxamate scaffold, would generally avoid literal infringement if its structure is outside formula (I). Similar p21 activity or anticancer activity would not alone establish infringement.

Scenario 3: LAQ824 analog or salt

An analog with substitutions covered by formula (I), or a pharmaceutically acceptable salt of LAQ824, could implicate claims 1, 2 and 6. Claims 8 and 9 add disease-specific limitations and may be narrower. A noninfringing-use theory would require careful separation of label language, induced infringement, clinical-trial activity and actual use.

What is the geographic scope of the patent landscape?

US 7,067,551 has territorial effect only in the United States. Commercial risk requires a family review in at least:

European Patent Office jurisdictions.
United Kingdom.
Canada.
Japan.
China.
South Korea.
Australia.
India.

Foreign family members may have different claim scope, prosecution amendments, expiration dates, oppositions and maintenance status. A US patent expiration does not establish freedom to operate in Europe or Asia. For an international LAQ824 program, national-phase patents and later continuations must be reviewed separately.

Key Takeaways

US 7,067,551 is a method patent covering substituted cinnamoyl hydroxamic acids for proliferative disorders and p21 promoter regulation.
The most important named compound is LAQ824.
Claims 6, 8 and 9 narrow to LAQ824 and selected cancer indications.
The patent does not, in the supplied claims, provide a standalone composition-of-matter claim.
It has no identified Orange Book-listed product, FDA exclusivity period or Paragraph IV litigation history.
The patent does not expressly claim formulations, polymorphs, delivery systems or manufacturing processes.
Its commercial significance depends on the statutory term and related patent family, not the 2006 issue date.
Structurally unrelated HDAC inhibitors such as vorinostat, romidepsin, belinostat and panobinostat are not automatically implicated.
Any current diligence should prioritize continuation patents, foreign counterparts, maintenance status and later LAQ824-specific formulation or process patents.

FAQs About US Patent 7,067,551 and LAQ824

Is LAQ824 the same as panobinostat?

No. LAQ824 and panobinostat are different HDAC-inhibitor molecules with different chemical structures and separate patent estates.

Does US 7,067,551 claim all HDAC inhibitors?

No. The claims cover compounds within formula (I) and specified methods of use. HDAC activity alone is not enough to place a compound within the claims.

Can a company sell a different HDAC inhibitor without infringing this patent?

Potentially, if the compound is structurally outside formula (I) and the company does not practice a claimed method. Structural and use-specific analysis is required.

Does the patent cover LAQ824 salts?

Yes. The supplied claims expressly include pharmaceutically acceptable salts of the claimed compounds.

Does an expired patent still matter for LAQ824 development?

It can remain relevant to historical rights, family analysis, claim interpretation and freedom-to-operate diligence. It does not create a current enforceable barrier after expiration, subject to any related unexpired patent.

References

United States Patent and Trademark Office. (2006). US Patent No. 7,067,551, substituted cinnamides as histone deacetylase inhibitors. U.S. Department of Commerce.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.
U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.
Marks, P. A., & Breslow, R. (2007). Dimethyl sulfoxide to vorinostat: Development of the first histone deacetylase inhibitor. Nature Biotechnology, 25(1), 84-90.
Atadja, P. (2009). Development of the pan-DAC inhibitor panobinostat (LBH589): Successes and challenges. Cancer Letters, 280(2), 233-239.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1318980	⤷ Start Trial	CA 2015 00068	Denmark	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	92890	Luxembourg	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	15C0086	France	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	300778	Netherlands	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	1590070-7	Sweden	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	122015000098	Germany	⤷ Start Trial
European Patent Office	1318980	⤷ Start Trial	CR 2015 00068	Denmark	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,067,551

Summary for Patent: 7,067,551