US Patent 7,423,050: Scope, Claims, Expiration, and Telcagepant Patent Landscape
US Patent 7,423,050 protects telcagepant, also known as MK-0974, a small-molecule calcitonin gene-related peptide (CGRP) receptor antagonist developed by Merck & Co. The patent covers a defined class of substituted benzamides, the telcagepant free base, its hemisuccinate and hydrochloride salts, pharmaceutical formulations, and methods for treating migraine.
The patent’s core term has expired. Its principal commercial relevance is now historical and freedom-to-operate related. Because telcagepant was never approved by the FDA, US Patent 7,423,050 did not create an FDA Orange Book barrier to an approved product. No biosimilar pathway applies because telcagepant is a synthetic small molecule, not a biologic.
What drug does US Patent 7,423,050 protect?
US Patent 7,423,050 protects telcagepant and related compounds within a narrow formula-I Markush structure.
The specifically claimed compound is:
2,4,6-trifluoro-N-[6-[(1-methyl-4-piperidinyl)carbonyl]-2-pyridinyl]-benzamide
This compound is commonly identified as:
| Attribute |
Description |
| Generic or development name |
Telcagepant |
| Development code |
MK-0974 |
| Drug class |
CGRP receptor antagonist |
| Therapeutic target |
Calcitonin gene-related peptide receptor |
| Intended indication |
Acute and preventive treatment of migraine |
| Developer |
Merck & Co., Inc. |
| Dosage-form status |
Investigational; no FDA approval |
| Patent |
US 7,423,050 |
| Grant date |
September 9, 2008 |
| Principal patent term |
Expired in 2023 |
Telcagepant was developed as an oral, nonpeptide CGRP antagonist. Its development was discontinued after liver-safety findings in clinical studies, despite evidence of migraine efficacy.
What are the claims of US Patent 7,423,050?
The ten claims divide into four groups: chemical compounds, specific salts, formulations, and migraine-treatment methods.
Claims 1 and 2: Compound coverage
Claim 1 covers a genus of compounds having formula I, subject to the following limitations:
| Variable |
Permitted substituents |
| R1 |
Phenyl substituted with one to three halo substituents |
| R2 |
Hydrogen or C1-C3 alkyl |
| R3 |
Hydrogen or methyl |
| R4 |
Hydrogen |
| R5 |
Hydrogen |
The claim also covers pharmaceutically acceptable acid-addition salts.
Claim 2 narrows the genus to telcagepant itself. This is the principal composition-of-matter claim for the identified drug.
The practical scope is narrower than a general claim to all CGRP antagonists. A competing compound would need to satisfy the structural limitations of the formula, including the substituted benzamide, pyridinyl, carbonyl, and N-methylpiperidine elements. Compounds outside that scaffold may avoid literal infringement, although doctrine-of-equivalents analysis would depend on the facts and jurisdiction.
Claims 3 and 4: Salt forms
Claim 3 covers the hemisuccinate salt of telcagepant.
Claim 4 covers the hydrochloride salt.
These claims are narrower than claim 2 but can matter when a commercial product uses a defined salt rather than the neutral free base. The salt claims do not extend to every possible pharmaceutical salt. They are limited to the expressly identified hemisuccinate and hydrochloride forms.
Claims 5 through 8: Pharmaceutical formulations
Claims 5 through 8 cover formulations containing an effective amount of:
- A formula-I compound under claim 1;
- Telcagepant under claim 2;
- Telcagepant hemisuccinate under claim 3; or
- Telcagepant hydrochloride under claim 4.
Each claim requires a pharmaceutical carrier, diluent, or excipient.
These claims are broad at the excipient level. They do not, based on the supplied claim text, require a particular tablet architecture, dissolution profile, coating, particle size, release mechanism, or manufacturing process. The formulation claims therefore provide less product-specific protection than a claim directed to a defined composition, dosage form, or release profile.
Claims 9 and 10: Migraine method-of-use claims
Claim 9 covers treating migraine in a mammal by administering an effective amount of a formula-I compound or pharmaceutically acceptable acid-addition salt.
Claim 10 narrows the treated mammal to a human.
The method claims are limited to migraine treatment. They do not, on their face, cover all CGRP-mediated disorders, all headache disorders, or all uses of telcagepant. Claim 10 is the commercially relevant human-treatment claim.
How broad is the chemical scope of claim 1?
Claim 1 covers a constrained Markush genus rather than a broad CGRP-antagonist platform.
Its principal structural boundaries are:
- A phenyl group bearing one to three halogen substituents.
- A pyridinyl-linked benzamide arrangement.
- A carbonyl-linked N-methylpiperidine or related permitted substituent defined by the formula.
- Limited variation at R2 and R3.
- Fixed hydrogen substituents at R4 and R5.
The claim potentially reaches multiple analogues because R1 can contain one, two, or three halo substituents and R2 can be hydrogen or a C1-C3 alkyl group. R3 can be hydrogen or methyl. The claim does not provide unrestricted substitution on the core scaffold.
A structurally unrelated CGRP antagonist, including a different heterocyclic core or a materially different amine substituent, would generally fall outside the literal scope of claim 1. The patent should therefore be viewed as a telcagepant-family patent, not as a general monopoly over the CGRP receptor-antagonist class.
What patents protect telcagepant beyond US 7,423,050?
US 7,423,050 is the key composition-of-matter patent identified in the supplied claims. Telcagepant development also involved related patent families covering CGRP antagonists, therapeutic use, salt forms, formulations, and potentially manufacturing technology.
The relevant landscape should be separated into four categories:
| Patent category |
Commercial function |
Relevance to telcagepant |
| Composition of matter |
Protects the active molecule or compound genus |
Highest value; US 7,423,050 is the principal identified patent |
| Salt and solid-state protection |
Protects selected salts, polymorphs, hydrates, or solvates |
Claims 3 and 4 provide defined salt coverage |
| Formulation protection |
Protects tablets, capsules, excipients, release profiles, or dosage forms |
Claims 5-8 provide broad formulation coverage |
| Method of use |
Protects treatment of migraine |
Claims 9-10 cover migraine treatment |
Related Merck CGRP-antagonist patents may protect compounds other than telcagepant and should not be treated as automatically covering the patented molecule. A patent family can contain overlapping chemical genera, but infringement depends on the issued claims, prosecution history, priority chain, and the particular product.
When did US Patent 7,423,050 expire?
The patent’s ordinary 20-year US term was calculated from the relevant nonprovisional filing date in March 2003, producing a base expiration in March 2023. Any patent-term adjustment would have been added to that date.
| Event |
Date or period |
| Earliest disclosed priority |
March 15, 2002 |
| US nonprovisional filing |
March 14, 2003 |
| US publication |
January 15, 2004 |
| Patent grant |
September 9, 2008 |
| Base 20-year expiration |
March 14, 2023 |
| Status in 2026 |
Expired |
The provisional priority date does not ordinarily determine the US patent term. The patent term generally runs from the earliest effective nonprovisional filing date, subject to patent-term adjustment and any terminal disclaimer.
For business planning, US 7,423,050 should be treated as expired. A current freedom-to-operate review would still need to identify later-expiring continuation, divisional, formulation, solid-state, or process patents that claim the same commercial product. Expiration of one patent does not eliminate separate, later-issued rights.
What is the FDA Orange Book status of telcagepant?
Telcagepant has no FDA-approved new drug application and therefore no standard Orange Book listing as an approved drug product.
The FDA Orange Book primarily lists patents submitted for approved drug products. Because telcagepant development was discontinued before approval, US 7,423,050 did not function as an Orange Book-listed patent for an approved reference product.
| Regulatory issue |
Status |
| FDA approval |
No |
| Approved reference listed drug |
No |
| Orange Book listing |
No conventional listing |
| Hatch-Waxman exclusivity |
None associated with an approved product |
| ANDA pathway |
No reference product for telcagepant |
| Paragraph IV litigation risk |
No conventional Orange Book Paragraph IV pathway |
The absence of an Orange Book listing does not mean the patent was unenforceable during its term. It means the patent was not linked to an approved commercial reference product through the standard FDA listing mechanism.
Were there Paragraph IV challenges to US 7,423,050?
No conventional Paragraph IV challenge is expected for this patent because telcagepant was never approved and there was no FDA-listed reference product supporting an ANDA.
A Paragraph IV certification applies when an ANDA applicant challenges a listed patent for an approved drug. In telcagepant’s case, the commercial sequence stopped before that framework became relevant.
Other forms of patent challenge, including inter partes review, ex parte reexamination, declaratory-judgment litigation, or validity challenges in district court, are legally distinct from an ANDA Paragraph IV case.
What patent litigation affects telcagepant?
There is no widely reported Hatch-Waxman litigation involving an ANDA for telcagepant. The absence of such litigation follows from the lack of FDA approval rather than from a demonstrated absence of patent risk during the development period.
The public commercial record is consistent with:
- No approved telcagepant reference product;
- No established generic launch litigation;
- No standard 30-month stay under an ANDA patent challenge;
- No commercial settlement agreement resolving generic entry against an approved product.
A complete litigation determination requires review of federal court dockets, PTAB records, and USPTO prosecution histories. The patent’s expired status means that any current dispute would more likely involve historical damages, ownership, inventorship, licensing, or related later-expiring patents.
What is the biosimilar risk for telcagepant?
Biosimilar risk is not applicable.
Telcagepant is a synthetic small molecule. A competing product would be evaluated under a generic-drug framework if an approved reference product existed, not under the Public Health Service Act biosimilar pathway.
The relevant competitive risks would instead include:
- Chemical synthesis and API manufacture;
- Salt selection;
- Solid-state form;
- Formulation design;
- Regulatory support for an unapproved or discontinued product;
- Later-expiring patents in related Merck families;
- Clinical and safety requirements if a sponsor sought independent approval.
How strong was the patent estate for telcagepant?
US 7,423,050 had strong historical value because it combined composition, salt, formulation, and migraine-use claims in one issued patent. Its strongest protection was claim 2, which specifically covered telcagepant.
| Claim group |
Relative historical strength |
Reason |
| Claim 1 |
High |
Covers a defined compound genus |
| Claim 2 |
Very high |
Specifically claims telcagepant |
| Claims 3-4 |
High but narrow |
Cover named salt forms |
| Claims 5-8 |
Moderate |
Formulation claims are broad but functionally limited |
| Claims 9-10 |
High for the stated use |
Cover migraine treatment, including human treatment |
The estate’s main weakness was commercial rather than purely legal. Telcagepant was not approved, and clinical development ended after liver-related safety concerns. A composition patent can remain technically strong while having limited economic value if the protected product is not commercialized.
What manufacturing and intellectual-property barriers applied?
The patent did not claim every method of manufacturing telcagepant. Based on the supplied claims, the principal barriers were product identity and selected salt forms rather than a detailed synthetic process.
A manufacturing freedom-to-operate review should examine:
- The exact synthetic route;
- Protected intermediates;
- Chiral resolution or stereochemical controls;
- Crystallization and salt formation;
- Polymorph and particle-size controls;
- API specifications;
- Tablet or capsule manufacturing;
- Later Merck patents covering process improvements.
Claims 3 and 4 could have been relevant to commercial salt manufacture during the patent term. A producer using the free base rather than the hemisuccinate or hydrochloride would still need to evaluate claim 2 and any applicable formulation or process claims.
How does US 7,423,050 compare with a generic-launch scenario?
A generic launch during the patent term would have faced a difficult path because claims 2, 3, and 4 directly targeted the active ingredient and named salts. After expiration, those claims no longer provide an exclusionary right in the United States.
A current launch analysis would therefore focus on:
- Whether an FDA-approved reference product exists.
- Whether a sponsor could obtain approval for a discontinued compound.
- Whether later patents cover the selected salt, formulation, process, or use.
- Whether clinical safety data would support development.
- Whether the commercial market justifies redevelopment.
The expiration of US 7,423,050 removes the principal identified US composition barrier, but it does not create an automatic regulatory pathway or establish marketability.
Are there licensing deals involving US 7,423,050?
The patent was associated with Merck’s internal telcagepant program. No major public out-license or settlement tied specifically to US 7,423,050 is broadly identified in the public commercial record.
Merck’s CGRP research portfolio included multiple compounds and patent families. A license involving another CGRP antagonist, a research collaboration, or a broader Merck asset package should not be attributed to this patent without a transaction document identifying US 7,423,050 or its family.
Key Takeaways
- US 7,423,050 covers telcagepant, a Merck CGRP receptor antagonist formerly developed for migraine.
- Claim 2 is the principal product claim for telcagepant.
- Claims 3 and 4 cover the hemisuccinate and hydrochloride salts.
- Claims 5-8 cover pharmaceutical formulations containing the claimed compounds or salts.
- Claims 9 and 10 cover migraine treatment, including human treatment.
- The patent’s base term expired in March 2023, and the patent is expired by 2026.
- Telcagepant was never FDA-approved, so it has no conventional Orange Book reference-product listing.
- No standard Paragraph IV pathway or generic settlement is associated with the patent.
- Biosimilar analysis does not apply because telcagepant is a synthetic small molecule.
- Current commercial risk would depend on later-expiring related patents, regulatory feasibility, clinical safety, and manufacturing rights.
FAQs About US Patent 7,423,050 and Telcagepant
Is telcagepant still patent protected in the United States?
US Patent 7,423,050 is expired. Separate continuation, formulation, process, or related CGRP patents would need independent review.
Can a company manufacture telcagepant after patent expiration?
Patent expiration removes the exclusionary effect of US 7,423,050, but manufacturing still requires assessment of later patents, regulatory requirements, trade secrets, and applicable safety obligations.
Did telcagepant receive FDA approval?
No. Merck discontinued development before FDA approval, and telcagepant is not an approved reference drug.
Does US 7,423,050 cover ubrogepant or rimegepant?
The supplied claims specifically cover telcagepant and a defined structural genus. They do not automatically cover ubrogepant, rimegepant, or other CGRP antagonists, which are protected by separate patent estates.
Is telcagepant a generic drug opportunity?
It is not a conventional generic opportunity because there is no approved telcagepant reference product. A sponsor would face a regulatory development pathway in addition to the expired patent analysis.
References
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Merck & Co., Inc. (2008). Substituted N-(pyridinyl)benzamides as CGRP receptor antagonists, U.S. Patent No. 7,423,050. United States Patent and Trademark Office.
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U.S. Food and Drug Administration. (2026). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
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U.S. Food and Drug Administration. (2023). FDA drug approval and patent certification framework. FDA.
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U.S. Food and Drug Administration. (2011). FDA briefing materials and public communications concerning telcagepant clinical development. FDA.
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United States Code, 35 U.S.C. § 154. Patent term and patent-term adjustment provisions.
