US Patent 6,693,115: Prasugrel Patent Scope, Claims, Expiration, and Generic-Entry Landscape

US Patent 6,693,115 protects specific prasugrel salt forms, pharmaceutical compositions containing those salts, and therapeutic use in thrombosis and embolism. The patent does not broadly claim every prasugrel form or every thienopyridine compound. Its strongest protection is directed to prasugrel hydrochloride and prasugrel maleate, with downstream claims covering antithrombotic treatment.

The patent issued to Sankyo Company Ltd. on February 17, 2004. Its commercial relevance is tied to prasugrel, marketed in the United States as Effient by Daiichi Sankyo and Eli Lilly. The patent estate is now expired, eliminating the principal US patent barrier created by this patent, although formulation, manufacturing, regulatory, and commercial barriers may still affect market entry.

What drug does US Patent 6,693,115 protect?

US 6,693,115 protects salt forms of prasugrel, an oral platelet P2Y12 receptor antagonist.

The compounds in claims 1 and 2 are:

Claim	Protected subject matter	Commercial identity
1	2-Acetoxy-5-(α-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine hydrochloride	Prasugrel hydrochloride
2	The corresponding maleate salt	Prasugrel maleate
3	Composition containing prasugrel hydrochloride	Drug composition
4	Composition containing prasugrel maleate	Drug composition
5-7	Disease-specific compositions for thrombosis or embolism	Therapeutic composition claims
8-15	Methods using either salt to prevent or treat thrombus- or embolus-related disease	Method-of-treatment claims

Prasugrel hydrochloride is the clinically commercialized form used in Effient. The maleate salt is claimed but is not the principal US marketed form.

What is the chemical structure covered by the patent?

The claims identify the compound through a chemically defined structure rather than through the generic name "prasugrel." The structural limitations include:

A tetrahydrothieno[3,2-c]pyridine core.
An acetoxy substituent at the 2-position.
A benzyl substituent at the 5-position.
A fluorine atom at the benzyl ring's 2-position.
A cyclopropylcarbonyl group at the alpha carbon of the benzyl substituent.
Either hydrochloride or maleate salt formation.

These limitations materially restrict claim scope. A compound that retains the prasugrel active moiety but uses a different counterion, substantially different crystalline form, or different chemical modification may fall outside claims 1 and 2, subject to claim construction and infringement analysis.

How do claims 1 and 2 define the core patent scope?

Claims 1 and 2 are composition-of-matter claims directed to two salt forms.

Claim 1: prasugrel hydrochloride

Claim 1 covers the hydrochloride salt of prasugrel. It is the most commercially significant claim because the FDA-approved product Effient contains prasugrel hydrochloride.

The claim is limited to the named chemical entity. It does not expressly claim:

Free-base prasugrel.
All pharmaceutically acceptable prasugrel salts.
Every polymorph or solvate.
Every dosage form.
Every formulation containing prasugrel.
Other P2Y12 inhibitors.
A broad genus of substituted thienopyridines.

A generic product containing prasugrel hydrochloride would implicate the claim if the active ingredient is materially the same compound and the patent remained enforceable.

Claim 2: prasugrel maleate

Claim 2 separately protects prasugrel maleate. This claim expands the patent's salt-form coverage but does not convert the patent into a broad claim over all prasugrel salts.

A product containing prasugrel maleate would face a direct composition-of-matter claim. A product containing prasugrel hydrochloride would not infringe claim 2 merely because the underlying active moiety is prasugrel.

What do claims 3 and 4 protect?

Claims 3 and 4 cover pharmaceutical compositions containing the salts in claims 1 and 2.

Claim 3 requires:

A pharmaceutically effective amount of prasugrel hydrochloride; and
A pharmaceutically acceptable carrier.

Claim 4 contains the same basic requirements for prasugrel maleate.

These claims are narrower than a pure active-ingredient claim because they require a medicament composition and a carrier. The carrier limitation may include conventional excipients used in tablets, capsules, granules, or other oral dosage forms. The claims do not specify a particular excipient, release profile, tablet strength, particle size, coating system, or manufacturing process.

What formulations are protected by claims 3 and 4?

The claims potentially cover ordinary pharmaceutical compositions containing the specified salt and a pharmaceutically acceptable carrier, including conventional oral solid dosage forms.

The text provided does not impose limitations on:

Immediate-release versus modified-release delivery.
Specific excipients.
Tablet coating.
Disintegrants or binders.
Dissolution profile.
Drug loading.
Particle size.
Polymorphic form.
Packaging.
Manufacturing conditions.

Accordingly, claims 3 and 4 are composition claims, not detailed formulation-platform claims. Their practical enforceability depends on whether the accused product contains the claimed salt and satisfies the effective-amount and carrier limitations.

What do claims 5 through 7 protect?

Claims 5 through 7 narrow the composition claims by adding therapeutic purpose.

Claim	Scope
5	Composition of claim 3 for prevention or treatment of thrombus- or embolization-induced disease in a warm-blooded animal
6	Composition of claim 4 for prevention or treatment of thrombosis or embolism in a human
7	Composition of claim 6 specifically for treatment of thrombosis in a human

These are purpose-limited composition claims. Claim 7 is the narrowest of this group because it requires prasugrel maleate, a human patient, and treatment of thrombosis.

The claim hierarchy creates a useful infringement structure:

A product can potentially fall within claim 3 without satisfying the disease-specific limitations in claim 5.
A product can potentially fall within claim 5 without falling within claims 6 or 7 if it is used in a nonhuman warm-blooded animal.
Claims 6 and 7 focus on human use of prasugrel maleate.
The hydrochloride-specific method claims appear separately in claims 8-11.

What do claims 8 through 15 protect?

Claims 8 through 15 are method-of-treatment claims divided between the hydrochloride and maleate salts.

Hydrochloride method claims

Claims 8-11 cover administration of prasugrel hydrochloride:

Claim 8: prevention or treatment of thrombus- or embolization-induced disease in a warm-blooded animal.
Claim 9: the animal is a human.
Claim 10: treatment of thrombosis in a human.
Claim 11: treatment of embolism in a human.

Maleate method claims

Claims 12-15 mirror the hydrochloride method claims for prasugrel maleate:

Claim 12: prevention or treatment in a warm-blooded animal.
Claim 13: the animal is a human.
Claim 14: treatment of thrombosis in a human.
Claim 15: treatment of embolism in a human.

These method claims focus on administration of a specified salt for a specified therapeutic purpose. They do not recite a dose, dosing interval, treatment duration, patient genotype, concomitant aspirin therapy, or particular cardiovascular procedure.

How strong is the patent estate for prasugrel?

US 6,693,115 was historically strong because it included direct claims to the commercially relevant active ingredient in hydrochloride form. Its principal strengths were:

Direct composition-of-matter protection.
Coverage of the marketed hydrochloride salt.
Separate protection for maleate salt.
Composition claims covering pharmaceutical products.
Method claims directed to thrombosis and embolism.
A claim structure that gave the patent holder multiple infringement theories.

Its current strength is limited by expiration. An expired composition-of-matter patent cannot block lawful manufacture or sale based solely on the former patent claims.

The patent was narrower than a broad genus patent because it did not claim all thienopyridines, all P2Y12 antagonists, or every prasugrel formulation. It also did not expressly claim a complete commercial product profile such as a specific tablet composition or manufacturing process.

When did US Patent 6,693,115 expire?

The patent issued on February 17, 2004. Its enforceable term was governed principally by the earliest effective nonprovisional filing or international filing date, subject to patent-term adjustment and any applicable patent-term extension.

Public patent records identify the patent as part of the prasugrel patent family originating from Sankyo's earlier Japanese and international filings. The patent's ordinary US term ran into the early 2020s. The commercial exclusivity period for Effient also included FDA regulatory exclusivity and other patent protection outside this patent.

The practical conclusion is:

Issue	Status
US 6,693,115	Expired
Direct composition claims	No longer enforceable as an exclusion right
Generic filing strategy	Historically subject to Paragraph IV risk; now primarily an abbreviated approval and commercial execution issue
Effient FDA approval	July 10, 2009
New chemical entity exclusivity	Expired
Patent-based exclusivity from this patent	Expired

Because patent-term calculations can be affected by patent-term adjustment, terminal disclaimers, patent-term extension, and regulatory history, the controlling date should be taken from the USPTO Patent Center record and the FDA Orange Book listing for the relevant product and patent. The patent is not a current blocking patent.

What was the Orange Book status of prasugrel and Effient?

Effient was approved by the FDA on July 10, 2009, for reducing thrombotic cardiovascular events in patients with acute coronary syndrome managed with percutaneous coronary intervention.

The Orange Book historically listed patents associated with Effient, including patents covering prasugrel and related product protection. US 6,693,115 was the key patent directed to prasugrel salt forms and their antithrombotic use.

Orange Book analysis should distinguish among:

Listed patents for the approved product.
Drug substance patents.
Drug product or formulation patents.
Method-of-use patents.
Patent expiry dates.
Any pediatric exclusivity.
Whether a listed patent remains active.

The regulatory listing does not itself extend an expired patent. An Orange Book patent must be analyzed with its current legal status and applicable term.

Which companies challenged prasugrel exclusivity?

Prasugrel generic entry was pursued through the ANDA pathway, which generally requires certification against Orange Book patents under section 505(j)(2)(A)(vii) of the Federal Food, Drug, and Cosmetic Act.

Potential certification pathways included:

Paragraph I: no patent information listed.
Paragraph II: listed patent had expired.
Paragraph III: applicant would wait for patent expiration.
Paragraph IV: listed patent was invalid, unenforceable, or would not be infringed.

The supplied information does not identify a complete, verified docket list of all Paragraph IV filers or settlements associated with US 6,693,115. The patent's expiration means that historical Paragraph IV activity no longer determines present US entry rights.

A generic applicant's current risk assessment would focus on:

Remaining unexpired Orange Book patents.
Approved labeling.
Formulation differences.
Salt or polymorph identity.
Manufacturing patents.
ANDA approval status.
Any litigation involving later-listed patents.

What generic launch risks exist for prasugrel?

The principal patent-based risk from US 6,693,115 has ended. Generic launch risk therefore shifts from this patent to regulatory and commercial factors.

Regulatory risks

A prasugrel ANDA must demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug. The applicant must address:

Active ingredient identity.
Strength.
Dosage form.
Route of administration.
Labeling.
Impurity profile.
Stability.
Manufacturing controls.
Bioequivalence.

Legal risks

Possible legal issues can still arise from:

Later-expiring Orange Book patents.
Formulation or polymorph patents.
Manufacturing-process patents.
Improper Paragraph IV notice.
Induced infringement based on product labeling.
Product-specific exclusivity.
Patent litigation involving a different patent family.

Commercial risks

Prasugrel competes with established antiplatelet therapies, particularly clopidogrel and ticagrelor. A generic entrant must account for:

Price erosion.
Hospital and payer formulary control.
Existing generic clopidogrel competition.
Clinical preference for ticagrelor in particular patient populations.
Bleeding-risk considerations.
Brand retention by Effient.
Authorized or branded-generic strategies.

How does the prasugrel patent estate compare with clopidogrel and ticagrelor?

Drug	Principal mechanism	Historical brand	Patent position	Generic or competing status
Prasugrel	Irreversible P2Y12 inhibition	Effient	Core compound protection expired	Generic entry is legally more feasible
Clopidogrel	Irreversible P2Y12 inhibition	Plavix	Core patents expired earlier	Broad generic competition
Ticagrelor	Reversible P2Y12 inhibition	Brilinta	Later-generation patent estate; product and use patents historically important	Generic-entry timing depends on remaining patents and regulatory exclusivity

Prasugrel's core patent position was stronger than a typical formulation-only estate because US 6,693,115 claimed the active pharmaceutical salt directly. That advantage ended when the patent expired. Clopidogrel has a longer-established generic market, while ticagrelor has had a later and more complex exclusivity profile.

What manufacturing and intellectual-property barriers remain?

US 6,693,115 does not claim a manufacturing process in the 15 claims provided. It therefore does not directly block a process for preparing prasugrel unless the process necessarily produces or uses the claimed salt in an infringing context, and the patent is no longer enforceable in any event.

Current manufacturing barriers may include:

Control of stereochemistry.
Purity and impurity specifications.
Salt formation.
Crystallization.
Particle-size control.
Stability of the acetoxy group.
Scale-up reproducibility.
Supply of qualified starting materials.
Process patents in other jurisdictions.
Know-how not disclosed in expired patent claims.

The patent's composition claims do not automatically cover every process used to manufacture prasugrel hydrochloride. Process infringement requires the relevant process claims in a separate patent.

What is the geographic coverage of US Patent 6,693,115?

US 6,693,115 provides rights only under US patent law. It does not directly control:

European Union manufacture or sale.
Japan.
Canada.
China.
India.
Other national markets.

The underlying international patent family may contain counterpart patents with different claims, prosecution histories, expiry dates, and legal status. A global prasugrel freedom-to-operate review must examine each national family member separately.

Patent rights are territorial. Expiration in the United States does not establish expiration or invalidity in another jurisdiction.

What litigation and settlement issues matter now?

The relevant litigation questions are:

Whether any case concerning US 6,693,115 remains pending.
Whether a court entered a final judgment affecting validity, enforceability, or infringement.
Whether a settlement delayed generic entry beyond the patent term.
Whether later patents were asserted against prasugrel products.
Whether an ANDA applicant obtained a Paragraph IV judgment or approval.

Based on the patent's expired status, US 6,693,115 is unlikely to present a current litigation-based barrier to a prasugrel hydrochloride generic. Historical settlements may remain commercially relevant only if they affected launch timing, market entry commitments, or damages.

What is the revenue exposure associated with this patent?

Effient generated meaningful revenue for Daiichi Sankyo and Eli Lilly during its protected commercial period. The patent's economic value was concentrated in the period when prasugrel hydrochloride was protected and before competing P2Y12 therapies and generics reduced pricing pressure.

Revenue exposure from US 6,693,115 is now historical rather than forward-looking:

Period	Economic effect of the patent
Pre-approval	Supported protection of the prasugrel salt and development asset
2009 to early generic-entry period	Protected the commercial product and supported premium pricing
After patent expiry	Direct patent contribution to US exclusivity ended
Current period	Revenue depends on brand persistence, generic competition, and remaining product rights

The patent should not be valued as a current standalone US exclusivity asset. Its residual value lies in historical litigation records, family prosecution, technical disclosure, and any foreign counterpart rights that remain active.

Key Takeaways

US 6,693,115 is a prasugrel patent.
Claim 1 protects prasugrel hydrochloride, the salt used in Effient.
Claim 2 protects prasugrel maleate.
Claims 3 and 4 cover pharmaceutical compositions containing those salts.
Claims 5-7 add disease and patient-use limitations.
Claims 8-15 cover administration for prevention or treatment of thrombosis, embolism, and related thrombus-induced disease.
The patent does not broadly claim all prasugrel salts, all formulations, or all P2Y12 inhibitors.
The patent has expired and is not a current US blocking right.
Generic risk now depends principally on FDA approval, remaining listed patents, formulation differences, manufacturing rights, and commercial execution.
Foreign counterpart patents require separate jurisdiction-by-jurisdiction analysis.

FAQs About US Patent 6,693,115 and Prasugrel

Does US Patent 6,693,115 cover Effient?

Yes. Claim 1 covers prasugrel hydrochloride, the active salt in Effient. Claims 3 and related claims also address pharmaceutical compositions and antithrombotic use.

Does the patent cover prasugrel free base?

The claims provided do not expressly claim prasugrel free base. They claim the hydrochloride and maleate salts.

Can a generic manufacturer sell prasugrel hydrochloride after expiration?

Expiration of US 6,693,115 removes the patent's direct exclusion right. The manufacturer must still obtain FDA approval and address any other unexpired patents or regulatory exclusivities.

Is prasugrel maleate marketed in the United States?

The commercially important US product is prasugrel hydrochloride. The patent separately claims prasugrel maleate, but the provided claims do not establish commercial approval or marketing of that salt.

Does the patent protect a specific prasugrel tablet formulation?

Not specifically. Claims 3 and 4 require a pharmaceutical composition containing the claimed salt and a pharmaceutically acceptable carrier, but they do not recite a detailed excipient system, coating, dissolution profile, or manufacturing process.

References

Daiichi Sankyo Co., Ltd. (2004). US Patent No. 6,693,115, 2-acetoxy-5-(alpha-cyclopropylcarbonyl-2-fluorobenzyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine derivatives. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2009). Effient (prasugrel hydrochloride) prescribing information. FDA.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book. FDA.
U.S. Patent and Trademark Office. (n.d.). Patent Center: US Patent No. 6,693,115. USPTO.
U.S. Food and Drug Administration. (n.d.). Abbreviated new drug application submissions and patent certifications under the Hatch-Waxman Act. FDA.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Japan	2000-205396	Jul 06, 2000
Japan	2000-266780	Sep 04, 2000

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	346071	⤷ Start Trial
Austria	398624	⤷ Start Trial
Australia	2001267916	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,693,115

Summary for Patent: 6,693,115