United States Patent 7,151,103: Flibanserin HSDD Claims, Scope, Expiration, and Patent Landscape

U.S. Patent No. 7,151,103 covered the use of flibanserin, including specified acid-addition salts, to treat female hypoactive sexual desire disorder, or HSDD. The patent issued on December 19, 2006, and its principal method-of-treatment claims reached administration of flibanserin without requiring a particular formulation, route, treatment duration, patient age, or daily dose. The patent’s enforceable term has expired, eliminating current U.S. infringement risk from practicing claims 1 through 3. Its historical importance was substantial because the claims covered the core therapeutic use later associated with Addyi.

What does U.S. Patent 7,151,103 claim?

The patent claims a therapeutic method rather than a new flibanserin molecule, manufacturing process, or dosage form.

Claim	Scope	Principal limitation
Claim 1	Broad method claim	Administering flibanserin or a pharmaceutically acceptable acid-addition salt to a female patient with HSDD
Claim 2	Salt-specific dependent claim	Limits the salt to salts formed with listed organic or inorganic acids
Claim 3	Dose-specific dependent claim	Limits administration to 0.1 to 400 mg per day

The independent claim requires four principal elements:

A female patient.
A diagnosis or condition characterized as female HSDD.
Administration of flibanserin or a pharmaceutically acceptable acid-addition salt.
A therapeutically effective amount administered to treat the disorder.

The claim does not expressly limit the method to premenopausal women, generalized HSDD, acquired HSDD, oral tablets, once-daily dosing, bedtime dosing, or the 100-mg dose used for Addyi.

How broad is claim 1 of U.S. Patent 7,151,103?

Claim 1 is broad because it captures the therapeutic use of the active compound across a wide range of administration conditions.

Active ingredient coverage

The claim covers flibanserin itself and a pharmaceutically acceptable acid-addition salt. A product containing the free base could fall within the claim. A product containing a qualifying salt could also fall within the claim if the other limitations are met.

The claim is not limited to a particular crystalline form, particle size, excipient system, release profile, tablet coating, or manufacturing method. A competing product could therefore infringe claim 1 based on its therapeutic use even if its formulation and production process differed from those used by the patent owner.

Patient population

The phrase “female patient” is broader than the FDA-approved Addyi population. FDA approved Addyi for acquired, generalized HSDD in premenopausal women when the condition causes marked distress or interpersonal difficulty and is not caused by a coexisting medical or psychiatric condition, relationship problems, or the effects of a drug or other substance [2].

Claim 1 does not expressly include all of those regulatory restrictions. Its scope could therefore reach treatment of female patients outside the approved labeling, subject to claim construction, written-description, enablement, and other validity issues.

Therapeutically effective amount

The claim requires an amount effective to treat HSDD. A purely experimental administration, an ineffective amount, or administration for a purpose unrelated to HSDD would not satisfy this limitation.

The claim does not define “therapeutically effective amount” numerically. That omission makes claim 1 broader than claim 3, but it also creates a potential factual dispute over whether a particular dose achieved the claimed therapeutic result.

Route and treatment schedule

Claim 1 does not specify:

Oral administration.
Once-daily administration.
Bedtime administration.
Continuous treatment.
A minimum treatment period.
Administration with or without food.
A particular tablet or capsule.
A particular flibanserin salt.

Those omissions increase the literal scope of the claim. They also leave greater room for disputes over the meaning of “administering” and whether a particular clinical protocol treats HSDD as opposed to merely testing the drug.

What salts are protected by claim 2?

Claim 2 identifies a closed list of acids used to form pharmaceutically acceptable flibanserin acid-addition salts.

Listed acid	Salt category
Succinic acid	Organic acid salt
Hydrobromic acid	Inorganic acid salt
Acetic acid	Organic acid salt
Fumaric acid	Organic acid salt
Maleic acid	Organic acid salt
Methanesulfonic acid	Organic acid salt
Lactic acid	Organic acid salt
Phosphonic acid	Inorganic or phosphorus-containing acid salt
Hydrochloric acid	Inorganic acid salt
Sulfuric acid	Inorganic acid salt
Tartaric acid	Organic acid salt
Citric acid	Organic acid salt
Mixtures of the listed acids	Mixed salt or salt combination

The claim text contains a typographical rendering of “methanesulfonic acid” as “methanesuiphonic acid.” The chemically recognizable term is methanesulfonic acid.

Claim 2 is narrower than claim 1 because it requires a salt formed using one of the listed acids or a mixture of those acids. A flibanserin salt formed with an acid outside the list would not fall within claim 2, although it could still fall within claim 1 if it qualified as a pharmaceutically acceptable acid-addition salt.

The claim does not appear to require a particular stoichiometric ratio, crystal form, hydration state, polymorph, or solid-state structure. It is a therapeutic-use limitation, not a detailed salt-characterization claim.

What dose range is protected by claim 3?

Claim 3 covers administration of flibanserin or a qualifying acid-addition salt in a range of 0.1 to 400 mg per day.

Under ordinary claim interpretation, the endpoints are included unless the patent provides a contrary definition. The claimed range therefore generally covers:

0.1 mg per day;
400 mg per day; and
doses between those endpoints.

The claim does not specify whether the daily dose must be given once or divided into multiple administrations. It also does not state whether the dose is based on the flibanserin free base equivalent or the total salt weight. That distinction could matter for salt products, although the claim’s ordinary pharmaceutical interpretation would focus on the administered flibanserin dose unless the patent defines the measurement differently.

The FDA-approved Addyi dose is 100 mg orally at bedtime. That dose falls within claim 3 [2]. A generic 100-mg flibanserin tablet would therefore satisfy the dose limitation when used according to the approved indication, assuming the patent were still enforceable.

When did U.S. Patent 7,151,103 expire?

U.S. Patent 7,151,103 expired in December 2020 based on the patent’s applicable statutory term. The patent issued on December 19, 2006, from an application claiming an earlier priority date associated with the flibanserin HSDD program. Patent term is generally measured from the earliest effective U.S. nonprovisional filing date for applications filed after June 8, 1995, subject to patent-term adjustment, terminal disclaimers, and other statutory provisions [3].

The practical result is:

Event	Date or status
Patent issued	December 19, 2006
Patent type	Utility patent
Core subject matter	Flibanserin treatment of female HSDD
Statutory term	Expired in December 2020
Current infringement risk	No continuing infringement liability for post-expiration practice
Historical relevance	Prior barrier to generic flibanserin and a principal Orange Book patent

The precise expiration date should be taken from the USPTO Patent Center record and the FDA Orange Book patent listing applicable to the approved product. Any patent-term adjustment or pediatric extension would need to be included in that calculation. The expiration of the underlying patent does not erase potential claims involving conduct before expiration.

What was the Orange Book status of U.S. Patent 7,151,103?

U.S. Patent 7,151,103 was listed in connection with Addyi, flibanserin tablets, the product approved under NDA 022526. Orange Book listings identify patents that the NDA holder represented as covering the drug substance, drug product, or approved method of use [1].

The patent was principally a method-of-use patent. Its claims mapped to the use of flibanserin for female HSDD, rather than to a proprietary tablet formulation or a manufacturing process.

An Orange Book listing does not independently establish patent validity or infringement. It identifies the patent information submitted by the NDA holder and affects the regulatory pathway for ANDA applicants. A generic applicant challenging the listed patent could submit a Paragraph IV certification under the Hatch-Waxman Act [4].

Because the patent has expired, it no longer creates a current statutory stay or prospective market barrier for an ANDA applicant. Historical Orange Book status remains relevant to understanding the timing of generic challenges and the commercial protection originally associated with Addyi.

What Paragraph IV challenges affected flibanserin?

A generic applicant seeking approval before expiration of an Orange Book-listed patent could file a Paragraph IV certification stating that the patent was invalid, unenforceable, or would not be infringed by the proposed generic product.

For flibanserin, the principal commercial dispute would have centered on whether a generic applicant’s proposed labeling and intended use met the limitations of claims 1 through 3. The key issues would include:

Whether the proposed labeling induced treatment of female HSDD.
Whether the product contained flibanserin or a covered acid-addition salt.
Whether the labeled dose fell within 0.1 to 400 mg per day.
Whether the patent was valid in light of prior art involving flibanserin’s known pharmacology or earlier sexual-dysfunction research.
Whether the claims were enabled across the full scope of female HSDD treatment.
Whether the patent’s priority and term were correctly calculated.

A Paragraph IV filing alone does not prove that litigation occurred or that the patent was invalid. The relevant sources for a complete litigation history are federal complaints, docket entries, settlement filings, FDA ANDA records, and Orange Book updates.

What patent litigation and settlements affected Addyi?

The central legal issue was the expiration of the core method-of-use patent. Once U.S. Patent 7,151,103 expired, a generic manufacturer no longer needed to avoid the claimed therapeutic method for post-expiration sales.

Publicly available product and FDA records identify Addyi as the flibanserin reference product and identify the patent as part of the product’s historical protection. Generic flibanserin subsequently entered the U.S. market after the relevant exclusivity and patent barriers had ended.

The commercial consequences were significant:

A generic could use the same active ingredient.
A generic could use a 100-mg strength corresponding to the approved product.
The generic could rely on the reference product’s clinical data through the ANDA pathway.
The expired method patent could not support a new post-2020 injunction against ordinary generic use.
Any remaining protection would have had to arise from a different unexpired patent, regulatory exclusivity, trademark, or non-patent commercial right.

No biosimilar pathway applies because flibanserin is a small-molecule drug, not a biologic.

What other patent rights could protect flibanserin?

The broader flibanserin landscape can include several patent categories beyond the claims of U.S. Patent 7,151,103.

Formulation patents

A formulation patent could claim:

A particular flibanserin salt.
A tablet or capsule composition.
Immediate-release or modified-release delivery.
Specific excipients.
Dissolution or disintegration characteristics.
Stability properties.
Food-effect mitigation.
A particular crystalline or amorphous form.

U.S. Patent 7,151,103 does not claim those features in technical detail. A later formulation patent would need independent validity, enforceability, and an unexpired term to create a present barrier.

Method-of-use patents

Later method patents could claim narrower treatment protocols, such as:

A defined premenopausal population.
A specific dosing schedule.
Treatment of acquired, generalized HSDD.
Treatment after failure of another therapy.
Administration under specified food or alcohol restrictions.
A particular clinical endpoint.

Such patents may be narrower than claim 1 but can still affect ANDA labeling if the generic product’s proposed use overlaps the patented method.

Manufacturing and process patents

Process patents could cover:

Synthesis intermediates.
Chiral resolution.
Purification.
Salt formation.
Crystallization.
Polymorph control.
Tablet manufacture.

A process patent does not automatically prevent a generic from selling flibanserin if the generic uses a noninfringing process. Process claims are therefore distinct from the product-use claims in U.S. Patent 7,151,103.

How strong was the patent estate for flibanserin?

The estate was strongest as a first-generation method-of-use position because claim 1 reached the central therapeutic concept: administering flibanserin to treat female HSDD.

Its strengths were:

Broad active-ingredient coverage.
No route limitation.
No fixed dose in the independent claim.
No requirement for a specific dosage form.
Coverage of both free base and qualifying acid-addition salts.
Direct alignment with the therapeutic indication later approved by FDA.

Its weaknesses were:

Dependence on the relatively broad and potentially contestable concept of female HSDD.
Lack of detailed clinical or dosing limitations in claim 1.
Potential enablement and written-description scrutiny across the full patient population.
Exposure to prior art concerning flibanserin’s known pharmacology and earlier sexual-dysfunction uses.
Expiration in 2020, before long-term commercial exclusivity could be sustained through the product lifecycle.

The patent was commercially valuable during the period when Addyi had no approved generic competitor. Its current blocking value is zero because the claims are expired.

How does flibanserin compare with competing female sexual-dysfunction drugs?

Flibanserin’s patent position differs from that of drugs developed for female sexual dysfunction because its commercial protection centered on chronic oral treatment of HSDD.

Product	Active ingredient	FDA status	Patent-risk profile
Addyi	Flibanserin	Approved in 2015 for acquired, generalized HSDD in premenopausal women	Core U.S. method patent expired in 2020
Vyleesi	Bremelanotide	Approved in 2019 for acquired, generalized HSDD in premenopausal women	Injectable product and method claims differ from flibanserin
Female sexual-arousal products under development	Various	Product-specific	Protection depends on formulation, delivery system, and method claims

Vyleesi is not a substitute patent estate for flibanserin. It has a different active ingredient, route of administration, dosing profile, and regulatory history. Its patents do not extend Addyi’s protection.

What generic entry risks exist for flibanserin?

The post-expiration generic-entry risk is high because the principal method patent no longer blocks commercial competition.

A generic flibanserin launch can rely on:

The same active pharmaceutical ingredient.
A 100-mg tablet strength.
FDA’s ANDA pathway.
Bioequivalence rather than repeat efficacy trials.
The absence of a live core method patent.
The absence of biosimilar-specific regulatory barriers.

Remaining commercial risks are more likely to involve market demand, prescriber adoption, safety labeling, reimbursement, distribution, and brand loyalty than patent enforcement. The approved labeling includes important warnings concerning hypotension, syncope, alcohol, and CYP3A4 inhibitors [2]. Those labeling requirements can affect generic commercialization but do not recreate the expired patent right.

What is the geographic coverage of U.S. Patent 7,151,103?

The patent protected the claimed method in the United States only. It did not directly control treatment methods practiced in Europe, Canada, Japan, or other jurisdictions.

Foreign counterparts may have had different:

Claim language.
Grant dates.
Opposition outcomes.
Patent-term adjustments.
Supplementary protection certificates.
Expiration dates.
Orange Book or national-listing treatment.

A U.S. patent cannot establish infringement for conduct occurring entirely outside the United States. Geographic analysis therefore requires separate review of the international patent family and each jurisdiction’s national-phase prosecution history.

Key Takeaways

U.S. Patent 7,151,103 claimed treatment of female HSDD with flibanserin or a qualifying acid-addition salt.
Claim 1 was broad and did not require the Addyi 100-mg dose, oral tablets, bedtime administration, or the current FDA-labeled patient restrictions.
Claim 2 covered salts formed with 13 listed acids or mixtures of those acids.
Claim 3 covered daily doses from 0.1 mg through 400 mg.
The patent’s U.S. term expired in December 2020.
The patent was historically important to Addyi’s Orange Book protection but is no longer a current U.S. market barrier.
Flibanserin is a small-molecule drug, so biosimilar rules do not apply.
Current competitive exposure is driven primarily by generic entry and commercial execution, not by enforcement of Patent 7,151,103.

FAQs About U.S. Patent 7,151,103 and Flibanserin

Can a generic manufacturer sell flibanserin after Patent 7,151,103 expired?

Yes. Expiration removed the patent-based prohibition arising from claims 1 through 3, subject to any separate unexpired patent, regulatory requirement, or lawful labeling restriction.

Does Patent 7,151,103 cover the Addyi tablet formulation?

Not as a detailed formulation claim. It covers the therapeutic administration of flibanserin or a qualifying salt. It does not require a specific excipient, tablet design, release profile, or manufacturing process.

Does the patent cover flibanserin use in men?

The claims expressly require treatment of a female patient. Treatment of a male patient would not satisfy that express limitation.

Does a salt outside the listed acids infringe claim 2?

Not necessarily. Claim 2 is limited to the listed acids and mixtures. A different pharmaceutically acceptable salt could still raise claim 1 issues, but it would not satisfy claim 2 solely because it is a salt.

Does FDA approval extend the patent term for flibanserin?

FDA approval does not automatically extend a patent. Patent-term extension, pediatric exclusivity, and regulatory exclusivity are separate legal mechanisms governed by different statutes and records. The core U.S. patent term for Patent 7,151,103 ended in December 2020.

References

U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
U.S. Food and Drug Administration. (2015). Addyi (flibanserin) prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/
United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term information. https://www.uspto.gov/patents/laws/patent-term-adjustment
21 U.S.C. § 355(j), Abbreviated applications for new drugs; Paragraph IV certifications.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Sprout Pharms	ADDYI	flibanserin	TABLET;ORAL	022526-001	Aug 18, 2015		RX	Yes	Yes	7,151,103	⤷ Start Trial				USE OF FLIBANSERIN OR A PHARMACEUTICALLY ACCEPTABLE ACID ADDITION SALT THEREOF TO TREAT HYPOACTIVE SEXUAL DESIRE DISORDER (HSDD)	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	01125020	Oct 20, 2001

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	037109	⤷ Start Trial
Argentina	077480	⤷ Start Trial
Austria	327757	⤷ Start Trial
Australia	2002333894	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,151,103

Which drugs does patent 7,151,103 protect, and when does it expire?

Summary for Patent: 7,151,103