Details for Patent: 7,910,605

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Summary for Patent: 7,910,605

Title:	Non-imidazole alkylamines as histamine H3- receptor ligands and their therapeutic applications
Abstract:	Use of a compound of formula (A), wherein: W is a residue which imparts antagonistic and/or agonistic activity at histamine H3-receptors when attached to an imidazole ring in 4(5) position; R1 and R2 may be identical or different and represent each independently a lower alkyl or cycloalkyl, or taken together with the nitrogen atom to which they are attached, a saturated nitrogen-containing ring (i) as defined, a non-aromatic unsaturated nitrogen-containing ring (ii) as defined, a morpholino group, or a N-substituted piperazino group as defined for preparing medicaments acting as antagonists and/or agonists at the H3-receptors of histamine.
Inventor(s):	Jean-Charles Schwartz, Jean-Michel Arrang, Monique Garbarg, Jeanne-Marie Lecomte, Xavier Ligneau, Walter G. Schunack, Holger Stark, Charon Robin Ganellin, Fabien Leurquin, Sigurd Elz
Assignee:	Bioprojet SC
Application Number:	US11/478,682
Patent Claim Types: see list of patent claims	Use;

United States Patent 7,910,605: Claim Scope, Expiration, Orange Book Status, and Pitolisant Patent Landscape

U.S. Patent No. 7,910,605 protects methods of treating cognitive symptoms with histamine H3 receptor-inhibiting compounds. Its commercially important species is pitolisant, also known as 1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine. The patent is directed to cognitive disorders, particularly attention, wakefulness, and memory symptoms associated with Alzheimer disease, rather than narcolepsy.

The patent’s core protection is narrow in therapeutic purpose but broad in chemical scope under claim 1. Claim 2 materially narrows that scope to pitolisant and its permitted stereochemical and salt forms. Claims 3 through 6 further limit the indication and pharmaceutical salt.

Based on the patent’s filing date, the standard 20-year term ran from December 13, 2004, producing a base expiration date of December 13, 2024, subject to any patent-term adjustment or extension reflected in the USPTO record. The patent is not a biologic patent and does not create biosimilar exclusivity. It is a small-molecule method-of-use patent.

What does U.S. Patent 7,910,605 cover?

U.S. Patent 7,910,605 covers administering specified H3 receptor-inhibiting compounds to treat symptoms associated with cognitive disorders. The patent’s disclosed commercial compound is pitolisant, the active ingredient in Wakix.

Patent element	Scope
Patent number	U.S. 7,910,605
Patent type	Pharmaceutical method-of-use patent
Core receptor target	Histamine H3 receptor
Principal compound	Pitolisant
Key product	Wakix
Core symptoms	Attention, wakefulness, and memory disorders
Alzheimer limitation	Added by claim 3
Elderly-patient limitation	Added by claim 4
Covered salts	Hydrochloride, hydrobromide, hydrogen maleate, and hydrogen oxalate
Standard term basis	20 years from December 13, 2004
Base expiration	December 13, 2024, before any applicable adjustment
Principal commercial assignee	Bioprojet-related patent interests

The patent does not claim every H3 antagonist in every medical use. It claims a defined chemical genus when used to treat the specified cognitive symptoms.

What is the scope of claim 1 in Patent 7,910,605?

Claim 1 is an open-ended treatment claim requiring four principal elements:

1. A patient with symptoms associated with a cognitive disorder.
2. The symptoms must involve attention, wakefulness, or memory.
3. The administered compound must inhibit H3 receptor activity.
4. The compound must fall within formula IIa as structurally defined in the patent.

The chemical definition includes a saturated nitrogen-containing ring with four or five ring atoms, corresponding in practical terms to certain pyrrolidine or piperidine derivatives. The claimed molecule also requires:

• An AII chain of three methylene units.
• An oxygen atom in the X'' position.
• A BII chain containing three carbon atoms.
• A phenyl group at YII.
• An unsubstituted or substituted phenyl ring, with a broad list of permitted substituents.

The substituent list includes halogens, trifluoromethoxy, trifluoromethyl, nitro, sulfonamide, alkyl, alkenyl, alkynyl, alkoxy, aryloxy, aldehyde, ketone, sulfone, acetal, alcohol, oxime, hydrazide, and related groups.

The claim therefore combines a relatively specific molecular architecture with a broad phenyl-substitution Markush definition. A product would need to satisfy both the structural limitations and the claimed treatment purpose.

How broad is the formula IIa Markush claim?

Claim 1 has meaningful genus breadth because it covers multiple ring systems, phenyl substitutions, optical forms, racemates, diastereoisomers, enantiomers, and pharmaceutically acceptable salts. The claim is not limited to pitolisant.

Its practical breadth is reduced by the required combination of:

• A three-carbon linker before the ether oxygen.
• An ether linkage.
• A second three-carbon chain.
• A saturated nitrogen-containing ring.
• A phenyl terminus with the listed substitution options.
• Use for attention, wakefulness, or memory disorders.

A structurally related H3 antagonist lacking the exact chain lengths, ether placement, ring structure, or phenyl limitation should fall outside literal infringement of claim 1. Infringement under the doctrine of equivalents would depend on prosecution history, the importance of the numerical chain-length limitations, and whether the accused structure was surrendered during examination.

What does claim 2 protect?

Claim 2 narrows claim 1 to 3-(4-chlorophenyl)propyl-3-piperidinopropyl ether, which is pitolisant, together with its pharmaceutically acceptable salts and stereochemical forms.

The compound is commonly represented as:

1-{3-[3-(4-chlorophenyl)propoxy]propyl}piperidine

Claim 2 is the commercially relevant claim because it identifies the active ingredient used in Wakix. It does not require the Alzheimer disease limitation in claim 3. A party practicing pitolisant for another claimed symptom category could therefore face claim 2 if the use falls within claim 1.

The principal limitations are:

• Pitolisant must be administered.
• The administration must be for a symptom category covered by claim 1.
• The amount must be effective to inhibit H3 receptor activity.
• The claim covers the specified pharmaceutical salts and stereochemical forms through its dependency on claim 1.

What do claims 3 through 6 add?

What does claim 3 cover?

Claim 3 limits the treatment to attention, wakefulness, and/or memorization disorders associated with Alzheimer disease. This is narrower than claim 1 because the underlying cognitive disorder must be Alzheimer disease.

A treatment for narcolepsy, idiopathic hypersomnia, or another wakefulness disorder would not satisfy claim 3 unless the patient also has the Alzheimer-related condition specified in the claim.

What does claim 4 cover?

Claim 4 further limits claim 3 to symptoms occurring in aged persons. It is the narrowest disease-population claim in the patent.

The term “aged persons” may create claim-construction issues because the claim does not establish a numerical age threshold. Courts would likely examine the specification, prosecution record, ordinary meaning, and the clinical context of the patent.

What do claims 5 and 6 cover?

Claims 5 and 6 limit the compounds to particular salts:

• Hydrochloride
• Hydrobromide
• Hydrogen maleate
• Hydrogen oxalate

Claim 5 depends from claim 1. Claim 6 depends from claim 2 and therefore focuses on pitolisant in one of those salt forms.

A generic developer using pitolisant free base would not necessarily infringe claims 5 or 6, but it could still implicate claim 2 if the selected form falls within claim 2’s broader salt language.

When does Patent 7,910,605 lose exclusivity?

The patent’s standard term is calculated from the U.S. nonprovisional filing date of December 13, 2004. On that basis, the base expiration date is December 13, 2024. Patent-term adjustment could alter the effective expiration date if granted by the USPTO.

Event	Date
U.S. filing	December 13, 2004
U.S. patent grant	March 22, 2011
Standard 20-year term	December 13, 2024
Core protected subject matter	Cognitive-disorder treatment using H3 antagonists
Regulatory product associated with compound	Wakix, pitolisant
Relevant exclusivity type	Patent protection, not biologic exclusivity

Any patent-term extension under 35 U.S.C. § 156 would need to be separately confirmed against the regulatory product and patent record. A patent-term extension is distinct from FDA marketing exclusivity and can extend only eligible patent claims.

What is the FDA and Orange Book status?

Wakix was approved by the FDA on August 14, 2019, for the treatment of excessive daytime sleepiness or cataplexy in adult patients with narcolepsy. The active ingredient is pitolisant hydrochloride. The FDA later expanded the labeled population to include pediatric patients in the applicable age range.

The FDA Orange Book distinguishes patents that claim the approved drug, formulation, or approved method of use from patents directed to unrelated or unapproved indications. Patent 7,910,605 is directed to cognitive disorders and Alzheimer-related symptoms. Those indications are not the principal FDA-approved Wakix indication.

Accordingly, the patent’s commercial relevance to the approved Wakix label depends on whether the patent was submitted and accepted for Orange Book listing against the approved indication. A cognitive-disorder method patent does not automatically qualify for listing merely because it covers the same active ingredient.

Regulatory issue	Assessment
FDA-approved drug	Wakix
Active ingredient	Pitolisant hydrochloride
Approved therapeutic area	Narcolepsy-related excessive daytime sleepiness and cataplexy
Patent 7,910,605 subject matter	Cognitive disorders and Alzheimer-related symptoms
Small-molecule or biologic	Small molecule
Biosimilar pathway	Not applicable
ANDA relevance	Depends on listed patents and the proposed label
Paragraph IV exposure	Depends on Orange Book-listed patents for the approved product

The key distinction is between patent coverage of pitolisant as a compound or product and patent coverage of a particular cognitive-disorder use.

Does Patent 7,910,605 create a Paragraph IV barrier?

A Paragraph IV challenge is relevant only if the patent is listed in the Orange Book for the reference product and the generic applicant certifies that the listed patent is invalid, unenforceable, or not infringed.

Patent 7,910,605 would be most vulnerable to a Paragraph IV challenge if:

• It remained listed for the relevant approved product.
• The generic applicant’s proposed label included the patented cognitive use.
• The patent remained unexpired.
• The applicant relied on a certification directed to the patent claims.

A generic applicant using a labeling strategy that omits the patented Alzheimer-related indication could argue that it does not induce infringement of claims 3 and 4. Claims 1 and 2 are broader in treatment purpose, so the scope of a permissible “skinny label” would depend on how the FDA label and prescribing information describe wakefulness, attention, memory, and H3 receptor activity.

The patent’s expiration substantially reduces its current Paragraph IV significance. Later Wakix patents, rather than this cognitive-disorder patent, are more likely to determine generic launch timing for the approved narcolepsy product.

Which patents are more important for Wakix generic entry?

Wakix’s commercial patent estate is likely to include separate families directed to:

• Pitolisant composition of matter.
• Treatment of narcolepsy.
• Excessive daytime sleepiness.
• Cataplexy.
• Dosage regimens.
• Pediatric use.
• Formulations and solid forms.
• Manufacturing and purification.

Patent 7,910,605 is principally an older use patent for cognitive disorders. It should be separated from later patents that may cover the FDA-approved narcolepsy indication.

Patent category	Relevance to generic entry
Compound patent	Highest if unexpired and listed
Narcolepsy method patent	High for a full-label generic
Formulation patent	High if the generic uses the claimed dosage form
Dosage patent	Variable; depends on proposed regimen
Alzheimer method patent	Limited unless the label includes that use
Manufacturing patent	Relevant to supply chain and process design, but usually not an ANDA listing barrier
Pediatric-use patent	Relevant if the generic seeks pediatric labeling
Solid-form patent	Relevant if the generic uses the protected crystalline or salt form

What are the main validity and enforcement risks?

Written description and enablement

The formula IIa genus covers numerous substitutions and stereochemical variants. A validity challenge could argue that the specification does not adequately describe or enable the full breadth of the Markush genus, particularly if the disclosure provides limited examples relative to the claimed chemical space.

The patentee would rely on the common structural features, shared H3 pharmacology, and examples demonstrating representative compounds. The strength of the claim would depend on the number and diversity of disclosed examples and the predictability of H3 antagonist activity across the genus.

Indefiniteness

Potential issues include:

• The scope of “effective to inhibit H3 receptor activity.”
• The meaning of “lower alkyl.”
• The boundary of “aged persons.”
• The chemical interpretation of the formula and chain definitions.
• Whether the incorporated structural language provides a sufficiently definite claim boundary.

The treatment endpoint is functional but commonly used in pharmaceutical method claims. The more substantial risk is likely to involve chemical definition and claim dependency rather than the general requirement for an effective amount.

Obviousness

A challenger could combine known H3 antagonists with prior art describing treatment of attention, memory, wakefulness, or Alzheimer-related symptoms. The patentee would argue that the specific compound class and clinical use were not predictable and that the prior art did not provide a reasonable expectation of success.

Claim 2 may be stronger than the broad genus claims against a purely chemical obviousness challenge if pitolisant’s specific therapeutic profile was not disclosed or suggested. It remains vulnerable if the prior art disclosed pitolisant or a close structural analog together with the claimed cognitive use.

Induced infringement

Because the claims are method claims, enforcement against a manufacturer would usually focus on induced infringement or contributory infringement rather than direct infringement by the manufacturer. Marketing materials, prescribing information, clinical studies, and distribution practices would be relevant to whether the manufacturer encouraged the patented use.

How does Patent 7,910,605 compare with biosimilar and generic protection?

Pitolisant is a small molecule. The relevant regulatory pathway is an ANDA, not a biosimilar application under the Public Health Service Act.

Issue	Pitolisant	Biologic
Regulatory pathway	ANDA	351(k) biosimilar application
Orange Book	Applicable	Not the principal patent listing system
Paragraph IV	Applicable	No direct equivalent
Biosimilar interchangeability	Not applicable	Potentially applicable
Main IP risks	Compound, method, formulation, dosage, process patents	Composition, manufacturing, formulation, use patents

The absence of biosimilar risk does not eliminate market-entry risk. Generic pitolisant applicants must still address listed patents, FDA exclusivity, label carve-outs, and potential litigation.

What geographic protection does the patent provide?

U.S. Patent 7,910,605 provides rights only in the United States and its territories under U.S. patent law. Corresponding applications may exist in Europe and other jurisdictions, but foreign family members have separate claims, terms, prosecution histories, and legal status.

A U.S. patent can block U.S. manufacture, importation, sale, offer for sale, or use of the claimed method under 35 U.S.C. § 271. It does not block manufacture or sale solely outside the United States unless the conduct has a U.S. statutory nexus.

What manufacturing and licensing barriers remain?

The patent does not primarily claim a manufacturing process. A manufacturer could therefore avoid this patent through a noninfringing process while still facing separate composition, formulation, salt, or method patents.

Commercial barriers may include:

• Access to pitolisant active pharmaceutical ingredient.
• Control of the preferred hydrochloride form.
• Regulatory exclusivity.
• Listed Wakix patents.
• Product-specific labeling restrictions.
• Contractual licensing arrangements.
• Trade secrets involving purification, crystallization, or scale-up.

Publicly documented licensing or settlement terms specifically allocating rights under Patent 7,910,605 should not be assumed from commercial relationships involving Wakix or pitolisant. Patent ownership, product commercialization rights, and regulatory sponsorship can be held by different entities.

Key Takeaways

• Patent 7,910,605 is a cognitive-disorder method patent centered on H3 receptor inhibition.
• Claim 1 covers a broad chemical genus constrained by defined linkers, an ether group, a saturated nitrogen ring, and a substituted phenyl group.
• Claim 2 specifically covers pitolisant and is the commercially important claim.
• Claims 3 and 4 narrow the use to Alzheimer-related cognitive symptoms and aged persons.
• Claims 5 and 6 cover specified pitolisant or genus-member salts.
• The patent’s base 20-year term ran from December 13, 2004, to December 13, 2024, subject to any USPTO patent-term adjustment or extension.
• The patent is not a biosimilar barrier.
• Its relevance to Wakix generic entry depends on Orange Book listing and whether a proposed generic label includes the patented cognitive use.
• Later pitolisant patents directed to narcolepsy, formulations, dosage regimens, pediatric use, and manufacturing are likely to be more important for current commercial exclusivity.
• The principal validity risks are genus enablement, written description, obviousness, chemical definiteness, and the relationship between the claimed cognitive indication and the FDA-approved label.

FAQs About U.S. Patent 7,910,605

Does Patent 7,910,605 cover Wakix?

It covers pitolisant, the active ingredient in Wakix, when used for the claimed cognitive-disorder symptoms. It does not automatically cover every use of Wakix, including every FDA-approved narcolepsy use.

Is Patent 7,910,605 a composition-of-matter patent?

No. It is a method-of-treatment patent. Claim 2 identifies pitolisant, but the claim requires administration for a covered therapeutic purpose.

Can a generic pitolisant product avoid this patent?

Potentially. A generic may avoid infringement by using a noninfringing label that excludes the patented cognitive use, provided the resulting labeling and promotional conduct do not induce the claimed treatment.

Does the patent cover pitolisant hydrochloride?

Yes. The claims cover pharmaceutically acceptable salts, and claims 5 and 6 expressly identify hydrochloride among the permitted salts.

Does the patent block pitolisant manufacture outside the United States?

No. The patent is territorial. It can affect U.S.-connected manufacturing, importation, sale, or use, but it does not independently control purely foreign activity.

Is a license required to commercialize pitolisant after patent expiration?

Not because of the expired term of Patent 7,910,605 alone. A commercial launch must still address any other unexpired patents, FDA exclusivity, regulatory requirements, and separate contractual or trade-secret restrictions.

References

1. U.S. Patent and Trademark Office. (2011). U.S. Patent No. 7,910,605, Methods of treating cognitive disorders using H3 receptor antagonists. U.S. Department of Commerce.

2. U.S. Food and Drug Administration. (2019). Wakix (pitolisant hydrochloride) prescribing information. FDA.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

4. U.S. Code, 35 U.S.C. § 154. Patent term.

5. U.S. Code, 35 U.S.C. § 156. Extension of patent term.

6. U.S. Code, 35 U.S.C. § 271. Infringement of patent.

7. U.S. Code, 21 U.S.C. § 355. New drug applications and abbreviated new drug applications.

Drugs Protected by US Patent 7,910,605

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

Foreign Priority and PCT Information for Patent: 7,910,605

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
	98401944	Jul 29, 1998
	98403351	Dec 31, 1998

International Family Members for US Patent 7,910,605

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1428820		300832	Netherlands
European Patent Office	1428820		122016000073	Germany
European Patent Office	1428820		93229	Luxembourg
European Patent Office	1428820		CA 2016 00042	Denmark