US Patent 5,807,825: Eptifibatide Claims, Patent Scope, Expiration, and Generic Risk

US Patent 5,807,825 covers methods using eptifibatide, the cyclic peptide platelet aggregation inhibitor marketed as Integrilin. Its claims are method-of-treatment claims directed to acute ischemic disorders, extracorporeal circulation, intravascular devices, and prevention of platelet aggregation or loss. The patent does not, based on the claims provided, independently claim eptifibatide as a chemical composition, a formulation, a manufacturing process, or a dosage regimen.

The patent is expired. It therefore does not create a current US patent barrier to generic eptifibatide injection, although separate patents, regulatory exclusivities, manufacturing know-how, and FDA requirements can affect market entry.

What drug does US Patent 5,807,825 protect?

The claimed platelet aggregation inhibitor is eptifibatide, also known as Integrilin.

The structural elements recited in independent claims 1, 13, and 15 identify the compound as a cyclic peptide containing:

A 3-mercaptopropionyl, or Mpr, residue.
Homoarginine, identified in the claims as Har.
Glycine.
Tryptophan.
Proline.
Cysteine amide.
A disulfide bond closing the cyclic peptide.
Physiologically acceptable acid or basic addition salts.

The claimed active ingredient corresponds to eptifibatide, whose pharmacologic activity results from inhibition of platelet glycoprotein IIb/IIIa receptors. By blocking fibrinogen-mediated platelet cross-linking, eptifibatide inhibits platelet aggregation.

The claims are narrower than a general claim to all glycoprotein IIb/IIIa inhibitors. They require the specific cyclic peptide identified by the residue sequence and disulfide arrangement.

Core chemical identity

Element	Claimed limitation
Active ingredient	Eptifibatide
Peptide type	Cyclic peptide
Key residues	Mpr-Har-Gly-Trp-Pro-Cys-amide
Ring-forming linkage	Disulfide bond
Salt coverage	Physiologically acceptable basic or acid addition salts
Primary pharmacology	Platelet aggregation inhibition
Product association	Integrilin injection

Claims 2, 14, and 16 further identify the inhibitor by the specific structural formula reproduced in the patent drawings. These dependent claims add little practical breadth because the structural limitations in the independent claims already identify eptifibatide with substantial specificity.

How many independent claims does US Patent 5,807,825 have?

The provided claim set contains three independent claims:

Claim 1 covers treatment or prevention of platelet-associated ischemic disorders.
Claim 13 covers prevention of platelet loss during extracorporeal circulation.
Claim 15 covers prevention of platelet aggregation, embolization, or consumption during extracorporeal circulation.

The remaining claims are dependent claims.

Claim group	Independent claim	Subject matter
Ischemic disorders	1	Administration to treat or prevent platelet-associated ischemia
Extracorporeal circulation	13	Contacting blood with eptifibatide to prevent platelet loss
Extracorporeal circulation and devices	15	Preventing aggregation, embolization, or consumption

The patent has 24 claims in the supplied version:

One independent claim for systemic treatment of ischemic disorders.
One independent claim for blood contact during extracorporeal circulation.
One independent claim for administration in extracorporeal circulation settings.
Twenty-one dependent claims specifying diseases, procedures, devices, or the exact peptide structure.

What medical indications are covered by the patent?

Claim 1 covers treatment or prevention of a “platelet associated ischemic disorder.” Claims 3 through 12 identify specific disorders and clinical settings.

Dependent claim	Covered condition or use
3	Thrombus formation
4	Acute myocardial infarction
5	Thrombosis following angioplasty
6	Unstable angina
7	Atherosclerosis
8	Transient ischemic attacks
9	Peripheral vascular disease
10	Restenosis following angioplasty
11	Thrombosis following carotid endarterectomy
12	Thrombosis following vascular-graft anastomosis

The claims do not require a particular dose, route, concentration, duration, patient subgroup, biomarker, or combination therapy. A product or method using a different molecule would not fall within the literal scope merely because it treats the same disease.

Claim construction issues

The principal infringement questions would be:

Whether the administered compound is eptifibatide or a covered salt.
Whether the use is directed to one of the claimed disorders or conditions.
Whether the accused conduct involves administration to a patient or contacting blood in an extracorporeal system.
Whether the relevant indication is reasonably encompassed by “platelet associated ischemic disorder.”
Whether the accused product or method uses a structural variant outside the claimed Mpr-Har-Gly-Trp-Pro-Cys-amide sequence.

The patent does not appear to claim every use of eptifibatide. It claims the use of eptifibatide in defined therapeutic and extracorporeal-circulation contexts.

What extracorporeal uses are protected?

Claims 13 through 24 extend beyond cardiovascular treatment. They cover eptifibatide use in blood-handling systems and devices where platelet activation, platelet consumption, or thrombus formation can occur.

Claim	Application
13	Prevention of platelet loss during extracorporeal blood circulation
15	Prevention of platelet aggregation, embolization, or consumption
17	Renal dialysis
18	Cardiopulmonary bypass
19	Hemoperfusion
20	Plasmapheresis
21	Intravascular devices
22	Intraaortic balloon pumps
23	Ventricular assist devices
24	Arterial catheters

These claims are method claims, not device claims. A dialysis machine, pump, catheter, or ventricular assist device is not itself claimed. The potential infringement theory would depend on use of the device or extracorporeal circuit with the specified eptifibatide treatment.

Manufacturing and process implications

The supplied claims contain no manufacturing step. They do not cover:

Peptide synthesis.
Disulfide-bond formation.
Purification.
Lyophilization.
Sterile filling.
Container closure systems.
Injectable formulations.
Stability-enhancing excipients.
A particular concentration or dosage form.

A competitor could therefore avoid the claim set by manufacturing eptifibatide for an unclaimed purpose, although such a product could still face infringement allegations under a different patent or under induced-infringement theories if labeling promoted a covered use.

When did US Patent 5,807,825 lose exclusivity?

US Patent 5,807,825 issued on September 8, 1998. The patent is expired and cannot provide current enforceable US exclusivity.

For a patent in this issuance and filing era, the applicable term depends on the relevant US filing date, priority chain, and any patent-term adjustment or extension. The patent's enforceable term ended years before 2025. No current commercial exclusivity should be attributed to US Patent 5,807,825.

Event	Date or status
Patent issued	September 8, 1998
Current status	Expired
Current blocking effect	None from this patent
Current Paragraph IV relevance	No live challenge to an enforceable term
Patent-term extension relevance	No current enforceable term remains

Patent expiration does not eliminate historical liability for conduct occurring during the enforceable term. It also does not invalidate separate patents in the same eptifibatide portfolio.

What is the Orange Book status of Integrilin and eptifibatide?

Integrilin is the reference product associated with eptifibatide injection. The FDA-approved product is a small-molecule peptide drug supplied for intravenous use in acute coronary syndrome and percutaneous coronary intervention settings.

The Orange Book framework is relevant to approved drug applications and listed patents, but it does not revive an expired patent. Any patent listing associated with Integrilin that corresponds to US Patent 5,807,825 would have no current blocking duration after expiration.

Regulatory distinction

Patent protection and FDA exclusivity are separate rights:

Patent protection arises under Title 35 of the US Code.
New-drug exclusivity arises under the Federal Food, Drug, and Cosmetic Act.
Orange Book listing identifies patents submitted for approved drug products.
FDA approval of a generic product depends on the ANDA requirements, bioequivalence, labeling, manufacturing, and applicable patent certifications.

Eptifibatide is not a biologic under the Public Health Service Act. Biosimilar litigation and the Purple Book pathway therefore do not apply. The relevant competitor pathway is an ANDA for a generic injectable product, not a 351(k) biosimilar application.

Are there formulation patents for eptifibatide?

The claims supplied for US Patent 5,807,825 do not cover a formulation. They cover administration or blood-contact methods using the specified peptide.

Potentially separate formulation rights could address:

Concentration and pH.
Sterile aqueous solutions.
Preservative-free presentations.
Container and vial configurations.
Infusion compatibility.
Stability during storage.
Manufacturing controls for peptide oxidation and disulfide integrity.

Those subjects must be analyzed separately from the claims of US Patent 5,807,825. A generic eptifibatide manufacturer would typically assess the full patent family, Orange Book listings, FDA labeling, product specifications, and any formulation or process patents before launch.

Are method-of-use patents relevant to generic eptifibatide?

Yes. US Patent 5,807,825 is principally a method-of-use patent.

Its method claims target two commercial categories:

Cardiovascular and ischemic indications.
Extracorporeal circulation and intravascular-device applications.

An ANDA applicant seeking approval for the same indications could face a Paragraph IV certification if a relevant unexpired method patent were listed in the Orange Book. Because US Patent 5,807,825 is expired, it should not independently support a current Paragraph IV dispute.

A generic applicant may also use a “section viii” statement to omit a patented indication from labeling when an unexpired method-of-use patent remains listed for another indication. That strategy is not necessary for this expired patent, but it is relevant to any later or related eptifibatide method patent.

Which companies challenged or commercialized eptifibatide?

Eptifibatide was developed and commercialized through the Integrilin program, associated with COR Therapeutics and later Schering-Plough. Schering-Plough subsequently became part of Merck through the 2009 merger.

The commercial landscape has historically included:

COR Therapeutics, as the original developer.
Schering-Plough, as the major commercial partner and later owner.
Merck, following the Schering-Plough merger.
Generic injectable manufacturers seeking ANDA approval after patent and exclusivity barriers declined.

The relevant competitive product category is narrow. Eptifibatide competes pharmacologically with other intravenous glycoprotein IIb/IIIa inhibitors, particularly abciximab and tirofiban, but those products are not covered by the eptifibatide-specific compound limitations in US Patent 5,807,825.

How does the eptifibatide patent estate compare with competing drugs?

Drug	Drug class	Administration	Relationship to US 5,807,825
Eptifibatide	Cyclic peptide GP IIb/IIIa inhibitor	Intravenous	Directly identified by the claims
Tirofiban	Small-molecule GP IIb/IIIa inhibitor	Intravenous	Outside the claimed peptide structure
Abciximab	Monoclonal antibody fragment	Intravenous	Outside the claimed peptide structure
Clopidogrel	Oral P2Y12 inhibitor	Oral	Outside the claimed mechanism and structure
Cangrelor	Intravenous P2Y12 inhibitor	Intravenous	Outside the claimed structure

The patent is strong against literal use of eptifibatide for a covered indication during its term because the active ingredient is structurally specific. It is weak against design-around products using different platelet inhibitors. It also provides no composition, formulation, or manufacturing protection based on the supplied claims.

What generic launch risks exist?

The principal current risks are commercial and regulatory rather than based on US Patent 5,807,825.

Patent risk

The patent is expired. It should not prevent launch of a generic eptifibatide product.

Regulatory risk

Generic manufacturers must establish:

Pharmaceutical equivalence.
Bioequivalence or an appropriate FDA-supported basis.
Sterility and injectable-product quality.
Consistent peptide identity and purity.
Control of oxidation, aggregation, and disulfide-related impurities.
Adequate labeling and approved-use alignment.

Manufacturing risk

Eptifibatide is a peptide drug rather than a conventional low-complexity small molecule. Manufacturing controls can affect:

Correct sequence assembly.
Stereochemical purity.
Disulfide cyclization.
Removal of deletion sequences.
Residual reagents.
Endotoxin levels.
Sterile filtration and filling.
Long-term solution stability.

These barriers may limit the number of credible suppliers even when patent protection has ended.

Commercial risk

Eptifibatide is an acute-care injectable with demand concentrated in hospitals and cardiovascular centers. Pricing pressure from generic entry can be significant, but the addressable market is narrower than for chronic oral antiplatelet drugs. Hospital contracting, reliable sterile supply, and inclusion in purchasing systems may matter more than brand recognition.

What litigation and settlement issues affect this patent?

US Patent 5,807,825 is no longer capable of supporting a prospective injunction against generic eptifibatide use. Any historical Paragraph IV case would have been relevant only during the patent's enforceable term.

No current settlement should be treated as extending the patent's term. A settlement involving another patent, another patent family member, regulatory exclusivity, or a different Integrilin listing would require separate analysis. Expiration of this patent does not establish that every eptifibatide-related patent has expired, but it removes this patent as a current blocking right.

How strong is the patent estate based on the supplied claims?

Attribute	Assessment
Compound specificity	High
Method-of-use breadth	Moderate
Disease coverage	Broad within platelet-associated ischemia
Extracorporeal-use coverage	Broad across listed systems
Formulation protection	None apparent
Manufacturing protection	None apparent
Design-around vulnerability	High through alternative antiplatelet agents
Current enforceability	None because the patent is expired
Biosimilar relevance	None
Generic relevance	Historical only for this patent

The patent had meaningful historical value because it linked a defined therapeutic molecule to high-value cardiovascular uses and extracorporeal circulation. Its present value is primarily documentary and freedom-to-operate related.

Key Takeaways

US Patent 5,807,825 covers methods using eptifibatide, the active ingredient in Integrilin.
The patent has three independent method claims and 24 claims in the supplied claim set.
Claim 1 covers ischemic disorders including myocardial infarction, unstable angina, angioplasty-related thrombosis, restenosis, transient ischemic attacks, and peripheral vascular disease.
Claims 13 through 24 cover extracorporeal circulation, dialysis, cardiopulmonary bypass, hemoperfusion, plasmapheresis, and intravascular devices.
The patent does not claim a general class of GP IIb/IIIa inhibitors.
The supplied claims do not cover formulations, manufacturing methods, devices themselves, or dosing schedules.
The patent is expired and does not create current US exclusivity.
Eptifibatide is a small-molecule peptide drug, so biosimilar rules do not apply.
Current generic risk is centered on injectable-product quality, manufacturing, FDA approval, and commercial supply rather than this expired patent.
Separate formulation, process, continuation, or Orange Book-listed patents must be evaluated independently.

Frequently Asked Questions

Is US Patent 5,807,825 a composition-of-matter patent for eptifibatide?

No. The supplied claims are method claims. They require use of the specified cyclic peptide in treatment, extracorporeal circulation, or intravascular-device contexts.

Does US Patent 5,807,825 cover tirofiban or abciximab?

No. The claims require the eptifibatide peptide structure. Tirofiban is a different small molecule, and abciximab is an antibody fragment.

Can a generic company launch eptifibatide after this patent expired?

This patent does not prevent launch. The applicant must still satisfy FDA requirements and evaluate any separate unexpired patent, formulation right, regulatory exclusivity, or litigation risk.

Does the patent cover dialysis machines or ventricular assist devices?

No. It covers use of eptifibatide in connection with extracorporeal circulation or specified intravascular devices. The devices themselves are not claimed.

Is eptifibatide subject to biosimilar approval?

No. Eptifibatide is regulated as a drug product. A generic competitor would generally use the ANDA pathway rather than the 351(k) biosimilar pathway.

References

U.S. Patent and Trademark Office. (1998). U.S. Patent No. 5,807,825.
U.S. Food and Drug Administration. (2019). Integrilin (eptifibatide) injection prescribing information.
U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations.
35 U.S.C. § 154. Patent term.
21 U.S.C. § 355. New drug applications and abbreviated applications.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0477295	⤷ Start Trial	SPC/GB99/046	United Kingdom	⤷ Start Trial
European Patent Office	0477295	⤷ Start Trial	C990043	Netherlands	⤷ Start Trial
European Patent Office	0477295	⤷ Start Trial	51/1999	Austria	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 5,807,825

Summary for Patent: 5,807,825