US Patent 8,124,643: Claim Scope, Patent Strength, Expiration Risk, and Competitive Landscape

US Patent 8,124,643 is a broad chemical and pharmaceutical-composition patent centered on substituted benzamides linked to bicyclic or polycyclic dicarboximide scaffolds. The claims cover both compositions containing the compounds and the compounds themselves. The central species is 4-trifluoromethyl-N-(the octahydro-ethenocycloprop[f]isoindolyl)benzamide, together with numerous halogenated, heteroaryl, alkylated, saturated, unsaturated, and stereochemically defined analogues.

The patent is structurally broad but commercially concentrated. Claims 1 and 7 create the principal genus-level barriers. Claims 2, 8, 9, and 10 focus on selected compounds, including the likely lead compound. Claims 3 through 6 add concentration and dosage limitations but do not independently protect a particular dosage form, delivery technology, manufacturing process, indication, or treatment regimen.

A generic or competing developer would face the greatest risk when its product contains one of the expressly listed compounds, including a pharmaceutically acceptable salt, or when its formulation falls within the composition limitations of claim 1. The patent does not, based on the supplied claims, establish protection for every compound having the same broad scaffold or for every antiviral use of the compounds.

What does US Patent 8,124,643 protect?

The patent contains two principal claim categories:

Claim category	Claims	Protected subject matter	Commercial relevance
Pharmaceutical compositions	1-6 and 9	A carrier medium plus a therapeutically effective amount of one or more listed compounds	Covers formulated drug products containing a listed compound
Compounds	7, 8, and 10	Listed chemical compounds and pharmaceutically acceptable salts	Direct product protection independent of formulation
Concentration limitations	3-4	Active ingredient at 0.5%-90% or 5%-50% by weight	Applies only through claim 1
Dosage-unit limitations	5-6	10-10,000 mg or 100-2,000 mg of antiviral agent	Applies only through claim 1
Stereochemical limitation	9-10	A defined stereoisomer of the trifluoromethyl benzamide	May narrow infringement and improve validity precision

The claims are unusually explicit. Rather than claiming a Markush formula with variable substituents, claims 1 and 7 list individual chemical names. The practical scope therefore depends on whether an accused product contains one of those named compounds or a legally equivalent salt.

How broad are claims 1 and 7?

Claim 1: pharmaceutical-composition genus

Claim 1 requires:

A pharmaceutical composition.
A pharmaceutically acceptable carrier medium.
A therapeutically effective amount.
One or more compounds selected from the listed compound group.
A pharmaceutically acceptable salt as an alternative form.

The claim does not specify:

A particular route of administration.
A tablet, capsule, injectable, suspension, or other dosage form.
A particular excipient.
A particular disease or virus.
A mechanism of action.
A release profile.
A particle size or solid-state form.
A specific manufacturing method.
A fixed ratio when more than one listed compound is present.

The phrase "one or more of the compounds" potentially covers a composition containing a single listed compound or a mixture of two or more listed compounds. The absence of a defined ratio creates a wide composition perimeter, subject to the requirement that the compound be present in a therapeutically effective amount.

The carrier requirement is generally easy to satisfy. Conventional excipients, solvents, diluents, binders, coatings, buffers, and injectable vehicles would ordinarily qualify if pharmaceutically acceptable and used in a composition.

Claim 7: direct compound protection

Claim 7 is materially more important for product clearance than claim 1 because it claims the compounds themselves. It does not require:

A pharmaceutical carrier.
A therapeutic amount.
A particular indication.
A dosage form.
Administration to a patient.

A product containing a claimed compound could therefore implicate claim 7 before formulation or clinical use is considered. The claim covers the expressly listed compounds and their pharmaceutically acceptable salts.

Claim 7 does not appear to claim all compounds that share the bicyclic imide-benzamide architecture. A compound outside the listed group would require a separate infringement theory, such as literal equivalence or the doctrine of equivalents. The level of risk would depend on structural similarity, prosecution-history estoppel, prior-art scope, and whether the omitted analogue was disclosed but not claimed.

Which compounds are the commercial center of the patent?

The lead compound appears repeatedly in the claims:

4-trifluoromethyl-N-(3,3a,4,4a,5,5a,6,6a-octahydro-1,3-dioxo-4,6-ethenocycloprop[f]isoindol-2(1H)-yl)-benzamide.

It is protected by:

Claim 1 as a composition ingredient.
Claim 2 as a composition-specific dependent claim.
Claim 7 as a compound.
Claim 8 as a specifically selected compound.
Claim 9 when defined as a particular stereoisomer in a composition.
Claim 10 when defined as that stereoisomer as a compound.

The repeated claiming of this species indicates that it is the principal prosecution and commercial focus of the patent. The stereochemical version in claims 9 and 10 may provide a separate protection layer, although the practical strength depends on whether the stereochemistry is inherent in the original named compound, separately isolated, or materially different in biological activity.

The other listed compounds fall into several structural groups:

Structural group	Examples	Likely purpose
Halogenated benzamides	Bromo-, chloro-, and fluoro-substituted analogues	Substituent SAR and potency optimization
Heteroaryl analogues	2-, 3-, and 4-pyridinecarboxamides; thienyl analogue	Polarity and binding-site exploration
Trifluoromethyl analogues	Para-trifluoromethyl benzamides and related derivatives	Lead optimization and lipophilicity control
Saturated analogues	Octahydroisoindole and bicyclo[2.2.2]octane derivatives	Testing the role of the bridge and unsaturation
Alkylated analogues	N-methyl, N-ethyl, dimethyl, methylbenzyl, and acetamide derivatives	Solubility, potency, and metabolic optimization
Stereochemical analogues	Defined R/S configuration at the bicyclic core	Enantiomer or diastereomer control
Dose and formulation coverage	0.5%-90%, 5%-50%, and 10-10,000 mg ranges	Product and clinical dosage coverage

What do claims 2, 8, 9, and 10 add?

Claims 2 and 8 narrow the patent to the principal trifluoromethyl compound. Their value is practical rather than expansive. If the broad genus in claims 1 or 7 were challenged, these claims could preserve protection for the lead compound if the narrower species satisfies novelty, nonobviousness, written description, and enablement requirements.

Claims 9 and 10 cover a specified stereochemical form of the lead compound. These claims can be important where:

The commercial product is a single stereoisomer.
The racemate has different pharmacological properties.
The stereoisomer has improved potency, selectivity, safety, or pharmacokinetics.
A competitor attempts to avoid the patent by using a stereochemically different product.

The strength of claims 9 and 10 depends on the patent specification and prosecution record. A stereochemical claim is stronger where the patent provides analytical characterization, preparation, stereochemical assignment, and comparative biological data.

What do claims 3 through 6 protect?

Claims 3 and 4 concern weight percentage:

Claim 3: approximately 0.5% to 90% by weight.
Claim 4: approximately 5% to 50% by weight.

Claim 4 is narrower and depends on claim 1. It does not create an independent composition right outside claim 1. A product must still contain a listed compound, a pharmaceutically acceptable carrier, and a therapeutically effective amount.

Claims 5 and 6 concern dosage-unit amounts:

Claim 5: approximately 10 mg to 10,000 mg of antiviral agent.
Claim 6: approximately 100 mg to 2,000 mg.

These claims appear to contain drafting imprecision. The phrase "by weight of the composition" and the use of "antiviral agent" may create construction issues because the claims do not otherwise define the active ingredient as an antiviral agent in every limitation. The errors may be treated as clerical or interpreted in view of the specification, but they create avoidable vulnerability.

For an accused product, claims 3 through 6 are less likely to be the primary litigation targets than claims 1 and 7. They are narrower and easier to design around by changing concentration, dosage unit, or presentation. They may still provide useful fallback positions if the marketed product falls squarely within the stated ranges.

Does the patent claim a method of treatment?

Not in the supplied claims. The claims are directed to:

Pharmaceutical compositions.
Chemical compounds.
Dosage and concentration characteristics.

There is no express claim to administering a compound to treat influenza, hepatitis, HIV, herpesvirus, or another named disease. There is also no claim to inhibiting a viral enzyme or a particular viral replication step.

This distinction matters for competitive analysis. A competitor using a nonclaimed compound for the same antiviral indication would not necessarily infringe this patent. Conversely, a competitor using a listed compound in an unapproved or off-label indication could still face product or composition infringement risk under claims 1 or 7.

What manufacturing and formulation barriers does the patent create?

The supplied claims do not directly cover manufacturing methods. They do not claim:

A particular synthetic intermediate.
A reaction sequence.
A catalyst.
A crystallization process.
A polymorph.
A hydrate or solvate.
A particle-size distribution.
A purification method.
A method for producing the stereochemically defined compound.

The patent may still create manufacturing risk because production of a listed compound inherently results in the claimed compound. A manufacturer cannot avoid claim 7 merely by using a different synthetic route.

Formulation protection is also limited. Claim 1 requires only a pharmaceutically acceptable carrier medium. It does not require a specialized formulation technology. A tablet, capsule, solution, suspension, or other conventional dosage form could fall within the claim if it contains a listed compound in a therapeutically effective amount.

The absence of a solid-state or delivery-system claim leaves potential room for later patents directed to:

Specific polymorphs.
Salts with improved properties.
Amorphous dispersions.
Long-acting formulations.
Lipid or nanoparticle delivery.
Combination products.
Manufacturing processes.
Improved stereochemical purity.

When does US Patent 8,124,643 lose exclusivity?

The exact expiration date cannot be determined from the claims alone. US patent term generally runs 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments under 35 U.S.C. §§ 154 and 156.

The patent was issued on February 28, 2012, but the issue date does not determine expiration. A reliable term analysis requires the patent’s:

Earliest effective nonprovisional priority date.
Patent-term-adjustment calculation.
Patent-term-extension record, if any.
Terminal-disclaimer status.
Maintenance-fee status.
Continuation and divisional relationships.

The patent’s remaining enforceability cannot be inferred from the issue date or from the claims supplied by the requester. FDA regulatory exclusivity is a separate issue and cannot be assumed from the existence of the patent.

What is the Orange Book status of US Patent 8,124,643?

The patent’s Orange Book status cannot be established from the claim text. Orange Book listing depends on an approved new drug application, the drug product associated with that application, and the type of patent submitted by the NDA holder.

The claims do not identify:

An approved drug name.
An NDA number.
An NDA holder.
A listed dosage form.
A listed strength.
A product-specific patent submission.
A use code.

If the compounds were never approved as an FDA drug, the patent would not create an Orange Book-listed generic-delay framework. If an associated product was approved, the relevant Orange Book entry would determine whether the patent is listed for the active ingredient, formulation, or method of use.

What Paragraph IV risks exist?

A generic applicant could challenge the patent through an abbreviated new drug application if a listed reference product and applicable Orange Book patent existed. The principal Paragraph IV strategies would likely be:

Challenge theory	Target
Non-infringement	Use a nonlisted compound, different salt, or product outside the composition limitations
Invalidity for anticipation	Prior art discloses the identical listed compound or composition
Obviousness	Prior art makes the selected benzamide and bicyclic imide combination obvious
Written description	The broad list of individual compounds is insufficiently supported for the claimed genus
Enablement	The specification does not enable the full compound set or all claimed pharmaceutical compositions
Indefiniteness	Ambiguity in dosage, antiviral-agent terminology, or stereochemical nomenclature
Patent-term defense	The patent has expired, been disclaimed, or is otherwise unenforceable
Regulatory noninfringement	The proposed label omits a patented use, if the relevant patent is method-of-use only

For a product containing the exact lead compound, a non-infringement defense would be difficult against claim 7 if the claim remains valid and enforceable. The stronger defenses would likely concern validity, expiration, ownership, prosecution history, or the absence of a qualifying approved product.

How strong is the patent estate?

Based solely on the supplied claims, the patent has a mixed strength profile.

Issue	Assessment
Exact lead-compound coverage	Strong on its face because the lead is claimed repeatedly
Broad analogue coverage	Moderate; the compounds are listed individually rather than covered by a clearly defined structural formula
Formulation coverage	Broad but shallow; the carrier requirement is generic
Dose coverage	Narrower and vulnerable to design-around
Stereochemical coverage	Potentially strong if supported by enabling stereochemical data
Manufacturing coverage	Weak from the supplied claims because no process claim is identified
Solid-state coverage	Not shown
Method-of-use coverage	Not shown
Biosimilar relevance	None; this is a small-molecule patent, not a biologic patent
Generic-launch exposure	High for an exact-compound product while an enforceable claim remains active

The largest commercial weakness is the absence, in the supplied claims, of a broader composition-of-matter formula that captures unlisted analogues. The largest commercial strength is repeated direct coverage of the lead compound.

What competing patent landscape should be reviewed?

A complete landscape should separate five patent families:

Composition-of-matter patents covering the same bicyclic imide-benzamide scaffold.
Later patents covering the lead compound’s salts, polymorphs, stereoisomers, or solvates.
Formulation patents covering oral, injectable, sustained-release, or combination products.
Method-of-treatment patents covering specific viruses or patient populations.
Manufacturing patents covering intermediates, chiral resolution, crystallization, and scale-up.

Patent 8,124,643 alone does not establish freedom to operate. A later-filed patent may have a later expiration date and still block commercial launch through a formulation, salt, polymorph, process, or treatment claim. Conversely, an earlier patent may affect validity or priority even if it does not appear in the supplied claim set.

The relevant geographic scope is also broader than the United States. A commercial program would require review of corresponding patent families in Europe, China, Japan, Canada, Australia, India, and other target markets. National-phase prosecution can produce materially different claim scope, disclaimers, and expiration dates.

What licensing and litigation issues affect commercial use?

No licensing agreement, assignment chain, Paragraph IV case, settlement, or litigation outcome is identifiable from the supplied claims alone. Those issues must be evaluated separately from claim scope.

For transaction diligence, the highest-priority documents are:

Assignment records.
Continuation and divisional applications.
Terminal disclaimers.
Maintenance-fee records.
Prosecution history.
Patent-term-adjustment calculation.
FDA Orange Book entries.
ANDA litigation complaints and settlements.
License agreements and field-of-use restrictions.
Corresponding foreign prosecution records.

A license to the patent may not cover later patents on salts, formulations, processes, or uses. A settlement may permit an agreed launch date without eliminating other patent risks. A patent assignment may also transfer enforcement rights without transferring regulatory rights or clinical data rights.

Key Takeaways

US Patent 8,124,643 covers both pharmaceutical compositions and the listed compounds themselves.
Claims 1 and 7 are the principal broad claims.
The repeated protection of the para-trifluoromethyl lead compound makes it the commercial center of the patent.
Claims 2, 8, 9, and 10 provide narrower fallback protection for the lead compound and a defined stereochemical form.
Claims 3 through 6 cover concentration and dosage ranges but are easier to design around.
The supplied claims do not show method-of-use, manufacturing, polymorph, salt-specific, or delivery-system protection.
The patent is relevant to generic small-molecule risk, not biosimilar risk.
Patent expiration, Orange Book status, licensing, litigation, and Paragraph IV exposure cannot be established from the claim text alone.
A product containing an expressly claimed compound presents the highest infringement risk while the relevant claims remain valid and enforceable.
A complete freedom-to-operate review must include related US continuations and foreign counterparts, later formulation and process patents, regulatory listings, assignments, and litigation records.

FAQs

Does a different salt avoid US Patent 8,124,643?

Not necessarily. Claims 1 and 7 expressly include pharmaceutically acceptable salts. A different salt would avoid the patent only if it falls outside the claim construction or the salt is not pharmaceutically acceptable within the claim.

Does a different formulation avoid the patent?

Usually not if the formulation contains a listed compound and a pharmaceutically acceptable carrier. The claims do not require a specific dosage form or excipient.

Can a competitor use an unlisted analogue with the same core scaffold?

Potentially, but the answer depends on the exact structure and any related patents. The supplied claims list individual compounds and do not clearly claim every analogue sharing the scaffold.

Is a stereoisomer automatically outside the patent?

No. Claims 9 and 10 specifically address one stereochemically defined form. The claim scope depends on the stereochemical identity of the commercial compound and how the broader named compound is construed.

Does patent ownership establish the right to market the drug?

No. Patent rights and FDA approval are separate. A patent may block competitors without providing regulatory approval, clinical data rights, manufacturing authorization, or an Orange Book listing.

References

United States Patent and Trademark Office. (2012). U.S. Patent No. 8,124,643. Washington, DC: U.S. Department of Commerce.
United States Code. (2024). 35 U.S.C. § 154: Contents and term of patent; provisional rights.
United States Code. (2024). 35 U.S.C. § 156: Extension of patent term.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Silver Spring, MD: FDA.
U.S. Food and Drug Administration. (2024). Orange Book: Questions and answers. Silver Spring, MD: FDA.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1638938	⤷ Start Trial	301177	Netherlands	⤷ Start Trial
European Patent Office	1638938	⤷ Start Trial	2022C/521	Belgium	⤷ Start Trial
European Patent Office	1638938	⤷ Start Trial	122022000032	Germany	⤷ Start Trial
European Patent Office	1638938	⤷ Start Trial	2290024-5	Sweden	⤷ Start Trial
European Patent Office	1638938	⤷ Start Trial	C202230021	Spain	⤷ Start Trial
Australia	2004249250	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 8,124,643

Summary for Patent: 8,124,643