United States Patent 6,872,700: Scope, Claims, Expiration, and Exendin Patent Landscape

US Patent No. 6,872,700 covered methods of lowering plasma glucagon by administering exendin, an exendin analog, or a combination. The patent was assigned to Amylin Pharmaceuticals and was relevant to exenatide-based treatment of type 2 diabetes, glucagonoma, necrolytic migratory erythema, and related conditions. Its principal United States patent term expired in 2020, eliminating current U.S. infringement risk based solely on this patent. The claims were method-of-treatment claims, not claims to exenatide as a chemical entity.

What does US Patent 6,872,700 protect?

US 6,872,700 protects a therapeutic method with four central elements:

Identifying a subject who needs therapeutic lowering of plasma glucagon.
Administering a composition containing an exendin or exendin analog.
Using an exendin or analog longer than 30 amino acid residues.
Administering an amount effective to lower plasma glucagon.

The independent claims are claims 1 and 13.

Claim 1 covers a composition comprising the active exendin or exendin analog. Claim 13 is narrower in composition language because it requires the composition to "consist essentially of" the exendin or exendin analog.

The patent therefore targets the pharmacologic use of exendin compounds to reduce glucagon, rather than merely their ability to activate the GLP-1 receptor or lower blood glucose.

What is the practical scope of claim 1?

Claim 1 is broad in compound coverage but limited by its therapeutic purpose. It potentially covers administration of:

Exendin-4;
Other exendins longer than 30 amino acids;
Exendin analogs longer than 30 amino acids;
Combinations of exendin and exendin analogs.

The claim does not require a particular dose, route, formulation, frequency, plasma-glucagon reduction threshold, or disease. It does require that the administration be directed to therapeutic lowering of plasma glucagon.

That purpose limitation matters. A product administered for glucose control could have created infringement exposure if the evidence showed that it was also administered for, or inherently caused, the claimed therapeutic lowering of plasma glucagon. A method claim generally requires proof that the claimed steps were practiced, induced, or otherwise attributable to the accused conduct.

How do the dependent disease claims narrow the patent?

Claims 2 through 6 narrow the method to particular patient populations:

Claim	Patient or condition
2	Necrolytic migratory erythema
3	Glucagonoma
4	Diabetes-related disorder
5	Type 2 diabetes
6	Human subject

Claims 14, 15, and 18 through 20 impose substantially similar limitations on claim 13.

The diabetes claims were commercially significant because exenatide was approved for type 2 diabetes. The glucagonoma and necrolytic migratory erythema claims addressed smaller and more specialized medical populations in which glucagon suppression was a direct therapeutic objective.

How do claims 7 through 12 protect exendin formulations and analogs?

Claims 7 through 12 add composition and sequence limitations.

Claim 7: dosage unit and anti-glucagon agent

Claim 7 requires:

A dosage unit form; and
Another anti-glucagon agent.

Claim 17 identifies amylin as one such anti-glucagon agent. This creates a combination-treatment position involving an exendin and amylin, rather than an exendin used alone.

The claim does not require a specific ratio, dosage strength, route, or formulation vehicle. Its commercial relevance depends on whether the combination product is administered as a unitary dosage form and whether the second agent qualifies as an anti-glucagon agent.

Claims 8 through 11: SEQ ID NO: 47 and SEQ ID NO: 48

Claims 8 through 11 cover analogs defined by sequence identifiers and permitted amino-acid substitutions. The listed positions include substitutions involving:

Phe or naphthylalanine;
Leu, pentylglycine, or Met;
Ile or Val;
Phe, Tyr, or naphthylalanine;
Pro, homoproline, thioproline, or N-alkylalanine;
Ser or Tyr.

These claims are narrower than claim 1 because they require an analog falling within the disclosed sequence frameworks. They are also technically important because they attempt to capture medicinal-chemistry variants that preserve exendin activity while modifying stability, potency, receptor activity, or other pharmaceutical properties.

Claim 12: exendin-4

Claim 12 expressly covers administration of exendin-4. Exendin-4 is a 39-amino-acid peptide and is the active pharmaceutical ingredient in exenatide products, including Byetta and Bydureon-related products.

This claim was commercially important because it tied the glucagon-lowering method directly to the principal marketed exendin product. Its enforceability ended when the patent term expired.

What is the difference between "comprising" and "consisting essentially of" in the claims?

Claims 1 through 12 use "comprising" language. Claims 13 through 24 use "consisting essentially of."

"Comprising" is open-ended. A composition can contain the exendin or exendin analog and additional ingredients, including excipients, stabilizers, buffers, preservatives, or other active agents, subject to the ordinary interpretation of the claim and any relevant prosecution history.

"Consisting essentially of" is narrower. It generally permits components that do not materially alter the basic and novel characteristics of the claimed composition. An accused product containing another active pharmaceutical ingredient could face a stronger argument that it falls outside claim 13, depending on the role and effect of that additional ingredient.

The distinction creates two claim groups:

Claim group	Composition language	Commercial implication
Claims 1-12	Comprising	Broad composition coverage
Claims 13-24	Consisting essentially of	Narrower composition coverage

What patent term and expiration date applied to US 6,872,700?

US Patent 6,872,700 issued on March 29, 2005. The patent's ordinary U.S. term ran approximately 20 years from its effective nonprovisional filing date. Public patent and FDA listing records identify an expiration date in 2020, commonly reported as August 2, 2020, subject to the official patent-term calculation and any applicable adjustment or disclaimer data.[1][2]

Event	Date or status
U.S. patent	6,872,700
Issue date	March 29, 2005
Technology	Exendin-mediated plasma-glucagon lowering
Patent type	Method of treatment
Principal owner	Amylin Pharmaceuticals
Reported U.S. expiration	August 2, 2020
Current status	Expired by term

The patent therefore does not presently block U.S. manufacture, sale, or use of exenatide solely under the claims of US 6,872,700.

A patent expiration analysis must still distinguish this patent from related patents covering exenatide composition, sustained-release delivery, manufacturing processes, devices, or separate methods of treatment. Expiration of US 6,872,700 did not automatically terminate every possible patent right relating to exenatide.

What was the Orange Book status of US 6,872,700?

US 6,872,700 was associated with the exenatide regulatory and patent estate. Orange Book relevance depends on the specific NDA, product, sponsor submission, and whether the patent was submitted for listing against that drug product.[2]

The patent was principally a method-of-use patent. Under the Hatch-Waxman framework, a listed method patent can support a Paragraph IV certification if an ANDA applicant contends that the patent is invalid, unenforceable, or will not be infringed by the proposed labeling.[3]

The practical Orange Book implications were:

A listed method patent could delay approval after a Paragraph IV notice if the patent owner sued within the statutory period.
The claim scope depended on whether the ANDA labeling encouraged glucagon-lowering use.
A product label directed only to glucose lowering could present a narrower inducement case than labeling expressly describing plasma-glucagon reduction.
After expiration, the patent ceased to provide a blocking Orange Book patent position.

The Orange Book is not a complete record of every patent relevant to a drug. Formulation, manufacturing, device, process, and foreign patents may be outside the listed-patent set.

When did exenatide lose exclusivity under this patent?

Exenatide lost the protection provided by US 6,872,700 in 2020. That date should not be treated as the single date on which all exenatide exclusivity ended.

FDA exclusivity versus patent exclusivity

FDA regulatory exclusivity and patent protection are separate:

New chemical entity exclusivity is generally five years.
Three-year exclusivity can apply to certain approved changes supported by new clinical investigations.
Orphan-drug exclusivity can apply to a designated indication.
Patent protection depends on the claims and term of each patent.
Pediatric exclusivity can add six months to qualifying periods.

Byetta was approved in 2005 for type 2 diabetes as an adjunct to diet and exercise.[4] Its regulatory exclusivity periods were distinct from the patent term of US 6,872,700.

Did US 6,872,700 create Paragraph IV risk?

Yes. Before expiration, an ANDA applicant seeking approval for an exenatide product could have addressed the patent through a Paragraph IV certification.

The applicant would typically argue one or more of the following:

The proposed product would not be used for therapeutic lowering of plasma glucagon.
The product labeling would not induce practice of the claimed method.
The claims were invalid for lack of novelty, obviousness, written description, enablement, or indefiniteness.
The relevant claim did not cover the applicant's particular exendin analog, formulation, or patient population.
The patent had expired or was otherwise unenforceable.

A Paragraph IV notice could trigger patent litigation and a potential 30-month stay of FDA approval under the Hatch-Waxman Act, although the commercial effect depended on the patent's listing status, litigation timing, and remaining term.[3]

Because US 6,872,700 has expired, a new Paragraph IV challenge directed solely to this patent would no longer create a meaningful current approval barrier.

Which companies challenged the exenatide patent estate?

The public exenatide patent landscape involved multiple patents, products, and litigation positions. However, a reliable attribution of a specific Paragraph IV notice or settlement to US 6,872,700 requires review of the relevant ANDA records, FDA notices, and court dockets. The patent number alone does not establish that a particular generic applicant challenged this patent.

The principal commercial parties associated with the product and patent estate included:

Company	Role
Amylin Pharmaceuticals	Original developer and principal patent owner
Eli Lilly and Company	Commercial collaborator and later exenatide partner
AstraZeneca	Later commercial owner of the exenatide business
Generic peptide manufacturers	Potential ANDA or alternative regulatory-pathway entrants

No present commercial restriction should be attributed to US 6,872,700 because the patent has expired.

What litigation and settlement issues affected the patent?

The relevant legal exposure before expiration was likely to arise through:

ANDA Paragraph IV litigation;
Declaratory-judgment actions;
Patent-term disputes;
Claim-construction disputes concerning "therapeutically effective glucagon lowering amount";
Induced-infringement disputes involving product labeling;
Written-description challenges to broad exendin-analog coverage;
Obviousness challenges based on known glucagon suppression and GLP-1 pharmacology.

The strongest litigation issue would have been the connection between the approved use of exenatide for type 2 diabetes and the claimed purpose of lowering plasma glucagon. A generic applicant could attempt to avoid infringement by using a label focused on glycemic control without expressly promoting glucagon suppression. The patent owner could respond that the claimed physiologic effect was inherent, clinically expected, or encouraged by the labeling and prescribing context.

No settlement terms should be inferred from the existence of the patent. Settlement analysis requires a specific agreement or court filing.

How strong was the patent estate for exendin and exenatide?

US 6,872,700 had a mixed-strength profile.

Strengths

Claim 1 covered a broad class of exendins and exendin analogs.
Claim 12 expressly covered exendin-4.
The disease limitations were commercially relevant to diabetes.
The patent linked a known marketed molecule to a specific physiological mechanism.
The sequence claims added fallback positions for defined analogs.

Weaknesses

The claims were method claims, not composition-of-matter claims.
The term "therapeutically effective glucagon lowering amount" is functional and could invite proof disputes.
Broad analog claims could face written-description and enablement challenges.
The claims required therapeutic glucagon lowering, which could complicate induced-infringement allegations based on glucose-control labeling.
The patent expired relatively early in the life cycle of newer long-acting exenatide products.

The patent was commercially useful during its term but was less durable than a valid composition-of-matter patent covering exenatide itself.

What generic entry risks remain after expiration?

The remaining risk is product-specific rather than based on US 6,872,700.

Exenatide immediate-release products

A generic exenatide injection would likely be evaluated under the ANDA pathway if the reference product and dosage form support that route. Relevant issues include:

Peptide characterization;
Impurity profile;
Aggregation and degradation;
Device compatibility;
Sterility and container closure;
Pharmacokinetic and immunogenicity comparability;
Labeling carve-outs for unexpired method patents.

Extended-release exenatide products

Extended-release microsphere products create additional barriers:

Polymer composition;
Microsphere size and drug loading;
Release kinetics;
Manufacturing process controls;
Injection-device requirements;
Pharmacokinetic bridging;
Residual solvent and particle specifications.

These barriers can remain commercially significant even when the central method patent has expired.

Does the patent create biosimilar risk?

No. Exenatide is a synthetic peptide drug rather than a biologic typically regulated through the biosimilar pathway under section 351(k) of the Public Health Service Act.

A competing exenatide product would generally be analyzed under the small-molecule or peptide drug framework, including an ANDA or, in some circumstances, a 505(b)(2) application. The primary regulatory questions concern pharmaceutical equivalence, bioequivalence, product characterization, delivery device, and formulation.

The absence of biosimilar treatment does not eliminate technical complexity. It changes the statutory route and the type of exclusivity analysis.

How does US 6,872,700 compare with competing GLP-1 drug patents?

The patent is narrower than a composition-of-matter patent covering a specific active ingredient. It is also narrower than patents directed to a broad class of GLP-1 receptor agonists, but broader than a formulation patent limited to a particular excipient, depot system, concentration, or device.

Patent category	Typical protection	Relation to US 6,872,700
Composition of matter	Chemical or peptide sequence	Stronger direct product control
Method of treatment	Use for a disease or physiologic effect	Category of US 6,872,700
Formulation	Excipient, concentration, stability, or depot	Separate risk
Manufacturing	Synthesis, purification, or process parameters	Separate risk
Device	Pen, cartridge, needle, or delivery system	Separate risk
Regulatory exclusivity	FDA approval-based period	Separate from patent term

Semaglutide, liraglutide, dulaglutide, tirzepatide, and other non-exendin products generally do not fall within the literal scope of claims requiring an exendin or exendin analog. Their patent estates must be analyzed independently.

What geographic coverage did US 6,872,700 provide?

The patent provided rights only in the United States. It did not directly control:

European Union sales;
United Kingdom sales;
Canadian sales;
Japanese sales;
Chinese sales;
Manufacturing outside the United States;
Foreign clinical use.

Foreign counterparts, if any, required separate analysis of national filing, grant, term, lapse, opposition, and supplementary protection certificate status. U.S. expiration did not determine foreign expiration.

Key Takeaways

US 6,872,700 covered methods of lowering plasma glucagon with exendin or exendin analogs longer than 30 amino acids.
Claim 1 was the principal broad method claim.
Claim 12 specifically covered exendin-4.
Claims 8 through 11 and 21 through 24 covered defined sequence variants based on SEQ ID NO: 47 and SEQ ID NO: 48.
Claims 7 and 17 addressed dosage-unit combinations with another anti-glucagon agent, including amylin.
Claims 13 through 24 were narrower because they used "consisting essentially of" language.
The patent was relevant to exenatide use in type 2 diabetes and other glucagon-related conditions.
The reported U.S. expiration date was August 2, 2020.
The patent no longer creates a current U.S. blocking position.
Exenatide entry risk now depends on other patents, FDA exclusivity, formulation, device, manufacturing, and regulatory requirements.
Exenatide competition is generally an ANDA or 505(b)(2) issue, not a biosimilar issue.

FAQs About US Patent 6,872,700 and Exenatide Exclusivity

Was US 6,872,700 a patent on Byetta?

No. It was a method-of-treatment patent covering use of exendin compounds to lower plasma glucagon. Byetta contains exenatide, and claim 12 specifically addressed exendin-4, but the patent did not claim the chemical composition of exenatide itself.

Could an exenatide product infringe claim 1 without mentioning glucagon?

Before expiration, infringement could have depended on the actual label, physician instructions, evidence of intended use, and whether glucagon lowering was an inherent or encouraged therapeutic purpose. A glucose-only label would not automatically eliminate risk, but it could weaken an inducement case.

Did the patent cover semaglutide or liraglutide?

No, not literally. Those products are not exendin or exendin analogs within the ordinary meaning of the patent claims. Their protection arises from separate patent estates.

Does patent expiration eliminate all barriers to generic exenatide?

No. Expiration removes this patent's blocking effect. A generic applicant must still address other listed or unlisted patents, FDA requirements, product-device comparability, formulation differences, manufacturing controls, and any remaining regulatory exclusivity.

Is claim 13 broader than claim 1 because it is an independent claim?

No. Although claim 13 is independent, "consisting essentially of" generally narrows the permissible composition relative to claim 1's "comprising" language. Its independent status does not make it broader in every respect.

References

United States Patent and Trademark Office. (2005). U.S. Patent No. 6,872,700, Methods of lowering plasma glucagon.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j).
U.S. Food and Drug Administration. (2005). FDA approves Byetta to improve blood sugar control in adults with type 2 diabetes.

PCT Information
PCT Filed	January 14, 2000	PCT Application Number:	PCT/US00/00942
PCT Publication Date:	July 20, 2000	PCT Publication Number:	WO00/41548

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1140145	⤷ Start Trial	CA 2007 00033	Denmark	⤷ Start Trial
European Patent Office	1140145	⤷ Start Trial	91343	Luxembourg	⤷ Start Trial
European Patent Office	1140145	⤷ Start Trial	SZ 30/2007	Austria	⤷ Start Trial
European Patent Office	1140145	⤷ Start Trial	30/2007	Austria	⤷ Start Trial
Austria	275967	⤷ Start Trial
Austria	299031	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,872,700

Summary for Patent: 6,872,700