US Patent 10,028,944: Pimavanserin Patent Scope, Expiration, Orange Book Status and Generic Risk

US Patent 10,028,944 covers methods of treating neuropsychiatric and affective disorders with pimavanserin, including the tartrate salt used in Nuplazid. Its strongest commercial relevance is the method-of-use coverage for psychotic depression, major depression, schizophrenia-spectrum conditions and related disorders, together with specific dose, frequency and oral-tablet limitations. The patent is expected to expire in July 2031, subject to any applicable patent-term adjustment or terminal disclaimer. It does not claim pimavanserin as a composition of matter.

What drug does US Patent 10,028,944 protect?

US 10,028,944 is directed to pimavanserin, the active pharmaceutical ingredient in Acadia Pharmaceuticals' Nuplazid. Pimavanserin is administered clinically as pimavanserin tartrate, with the labeled 34 mg pimavanserin dose corresponding to approximately 40 mg of pimavanserin tartrate.[1]

The patent's Formula (I) compound is pimavanserin. The claims cover therapeutic use rather than the compound itself.

Item	Patent-relevant information
Patent	US 10,028,944 B2
Patent holder or originating sponsor	Acadia Pharmaceuticals, Inc. and related entities
Active ingredient	Pimavanserin
Commercial product	Nuplazid
Salt covered by dependent claims	Pimavanserin tartrate
Therapeutic category	Neuropsychiatric and affective disorders
Patent type	Method-of-treatment patent
Key dose claims	15 mg, 25 mg and 50 mg tartrate; broad 0.001 mg to 50 mg range
Administration claims	Daily, once daily or twice daily
Dosage form claim	Oral unit dose, including tablets
Projected expiration	July 2031, before any applicable adjustment
FDA-approved product	Nuplazid tablets and capsules for hallucinations and delusions associated with Parkinson's disease psychosis

The current FDA-approved Nuplazid indication is narrower than the full claim set. FDA approved Nuplazid in 2016 for hallucinations and delusions associated with Parkinson's disease psychosis.[2] The patent claims extend to other neuropsychiatric conditions, including psychotic depression and major depression, whether or not those uses are approved for Nuplazid.

What are the independent and dependent claims of US 10,028,944?

Claim 1 is the principal method claim. It requires:

A patient in need of treatment.
A neuropsychiatric disease or symptom.
Administration of a therapeutically effective amount.
Pimavanserin of Formula (I), or a salt thereof.

Claim 1 is broad because it does not limit the disease to one named indication, does not require the tartrate salt, and does not prescribe a particular dose, route or dosage form.

The dependent claims narrow that coverage as follows:

Claims	Limitation
2	Schizophrenia, schizoaffective disorder, mania, behavioral disturbances associated with dementia or psychotic depression
3	Psychotic depression
4	Affective disorder, specifically major depression
5	Pimavanserin tartrate
6	Approximately 0.001 mg to approximately 50 mg of tartrate
7	Approximately 15 mg of tartrate
8	Approximately 25 mg of tartrate
9	Approximately 50 mg of tartrate
10	Daily administration
11	Once-daily administration
12	Twice-daily administration
13	Oral unit-dose formulation
14	Tablet
15	0.01 mg/kg/day to 100 mg/kg/day

Claims 7 through 9 are commercially important because they identify discrete dose embodiments. Claims 10 through 14 create a narrower package directed to repeated oral administration in a tablet or other unit-dose form.

How broad is the patent's treatment-method coverage?

The broadest coverage is in claim 1. A potential infringing use would not need to use the tartrate salt if the administered active ingredient is another salt of pimavanserin. It also would not need to follow the 15 mg, 25 mg or 50 mg dose limitations.

The breadth is reduced by several claim-construction issues:

The disease must be neuropsychiatric

The patent does not claim every use of pimavanserin. The administration must treat a neuropsychiatric disease or symptom. The dependent claims identify particular disorders, but claim 1 uses the broader category.

A generic manufacturer selling pimavanserin for Parkinson's disease psychosis could face a different analysis from a manufacturer whose label expressly includes depression, schizophrenia or another claimed condition. The central question would be whether the proposed labeling, marketing, prescribing instructions or other evidence supports the claimed method.

The compound must be administered to a patient

The claims are not directed to:

Pimavanserin as a chemical compound;
Pimavanserin tartrate as a composition;
A tablet by itself;
A manufacturing process;
A pharmaceutical composition independent of a treatment method.

The claims require actual administration to a patient. A manufacturer generally would be assessed under induced-infringement theories if its product labeling or conduct encouraged the claimed use, rather than as a direct administrator.

"Therapeutically effective amount" is functional

The claims do not require a single fixed dose in claim 1. The amount must be sufficient to treat the disease or symptom. This functional language may create disputes over clinical effect, patient population and whether a particular dose falls within the claim.

Claims 6 through 9 provide more concrete dose limitations but use "about," which permits a range around the stated values. The legal scope of "about 15 mg," "about 25 mg" and "about 50 mg" would depend on the specification, prosecution history and technical evidence.

What formulations are protected by US 10,028,944?

The patent has limited formulation coverage. Claim 13 covers pimavanserin tartrate formulated for oral administration as a unit dose, and claim 14 narrows that coverage to a tablet.

The patent does not appear to provide a broad, formulation-specific composition claim covering all Nuplazid excipient combinations. Its formulation protection is tied to the treatment method. A product would need to be:

Pimavanserin tartrate;
Formulated for oral administration;
Provided as a unit dose or tablet; and
Used in a claimed neuropsychiatric treatment method.

This is weaker than a formulation patent that claims a tablet composition regardless of use. It also leaves potential design-around questions involving capsules, liquid formulations, non-unit-dose products, alternative salts or different dosing instructions.

Does the patent protect the 34 mg Nuplazid dose?

Not directly in the text supplied. The claims expressly identify approximately 15 mg, 25 mg and 50 mg of pimavanserin tartrate, rather than 34 mg of pimavanserin base.

Because Nuplazid's labeled dose is expressed as pimavanserin equivalent, the patent analysis requires conversion between the active-moiety amount and the tartrate-salt amount. The 34 mg pimavanserin dose corresponds to approximately 40 mg of pimavanserin tartrate. That amount is within the broad range in claim 6 but is not the specific 15 mg, 25 mg or 50 mg embodiments in claims 7 through 9.[1]

The most relevant claims for the labeled product are therefore claim 1 and the broader salt, dosage and daily-administration claims, rather than the specific 15 mg, 25 mg or 50 mg claims.

What is the patent expiration date for US 10,028,944?

The ordinary 20-year patent term is calculated from the earliest effective nonprovisional filing date in the relevant family. Public patent records associate US 10,028,944 with a July 2011 priority date, producing a nominal expiration in July 2031.[3]

Milestone	Date or period
Earliest relevant priority	July 2011
Patent grant	July 24, 2018
Nominal 20-year term end	July 2031
Possible adjustment	Patent-term adjustment may alter the final date
Pediatric extension	No extension should be assumed without a confirmed FDA pediatric-exclusivity record
Regulatory exclusivity	Distinct from patent term and expired before the patent term

The operative expiration date should be taken from the USPTO patent record and the FDA Orange Book listing in effect for the relevant product and dosage form. Patent expiration can differ from a simple priority-date calculation because of patent-term adjustment, terminal disclaimers, disclaimers of term or patent-family relationships.

What is the Orange Book status of US 10,028,944?

US 10,028,944 has been associated with the Nuplazid patent estate and is relevant to FDA-listed patent protection for pimavanserin products. Orange Book listings identify patents that the sponsor represents as covering an approved drug, its formulation or an approved method of use.[4]

An Orange Book listing does not establish validity or enforceability. It places the patent within the FDA abbreviated-new-drug-application framework. A generic applicant seeking approval before patent expiration may address the listing through:

Paragraph III certification, accepting approval after expiration;
Paragraph IV certification, alleging that the patent is invalid, unenforceable or not infringed; or
A section viii statement, where the applicant omits the patented method from its labeling.

The practical scope depends on how FDA lists the patent. A method-of-use listing can be vulnerable to a section viii carve-out if the generic can market the product without the patented indication. That route becomes less effective if the approved label contains a use that cannot be cleanly separated from the claimed method or if the sponsor asserts induced infringement based on the proposed labeling.

When does Nuplazid lose exclusivity?

Nuplazid's regulatory exclusivity and patent exclusivity have different timelines.

Exclusivity category	Relevance to Nuplazid
New chemical entity exclusivity	Delayed certain ANDA submissions for five years from the 2016 approval
Orphan-drug exclusivity	Parkinson's disease psychosis approval received orphan-drug treatment; the scope is tied to the approved orphan indication
Patent exclusivity	Extends into the late 2020s and early 2030s depending on the patent
US 10,028,944	Nominally expires in July 2031
Generic approval	Can occur before patent expiration if patents are invalidated, not infringed, settled or carved out

FDA approved Nuplazid on April 29, 2016.[2] The five-year NCE period would have restricted ordinary ANDA filing until 2021, subject to FDA's specific regulatory determination. That regulatory barrier did not eliminate the later patent barriers.

The principal commercial issue is therefore not loss of FDA NCE exclusivity. It is whether an ANDA applicant can obtain approval through a Paragraph IV challenge, a section viii carve-out or a settlement that permits an agreed launch date.

Which patents form the broader pimavanserin patent estate?

US 10,028,944 is one component of a broader estate. Public FDA and patent records identify several categories of pimavanserin protection:

Patent category	Typical subject matter	Commercial function
Core compound patents	Pimavanserin and related chemical structures	Protect the active molecule
Salt patents	Pimavanserin tartrate and related solid forms	Protect the marketed salt
Use patents	Parkinson's disease psychosis and other neuropsychiatric conditions	Protect approved or pipeline indications
Dosing patents	Dose, frequency and patient-selection regimens	Extend method-of-use coverage
Formulation patents	Tablets, unit doses and pharmaceutical compositions	Protect the marketed presentation
Manufacturing patents	Synthesis, intermediates and purification	Create supply-chain barriers

The core compound patent generally has greater strategic value than a late-filed method patent because it can block substantially all commercial uses of the active ingredient. US 10,028,944 is more dependent on indication and labeling. Its value increases where the approved label includes a claimed use or where the sponsor can prove that generic labeling encourages that use.

How strong is the patent estate for pimavanserin?

The estate is stronger as a layered portfolio than as a standalone reliance on US 10,028,944.

Strengths

The patent covers the active ingredient used in Nuplazid.
Claim 1 is broad as a method claim.
The claims include both broad neuropsychiatric treatment language and named disorders.
Dependent claims cover the tartrate salt, oral unit-dose administration and tablet presentation.
The estate includes separate patents that may cover the compound, salt, formulation or approved use.
A generic may face multiple certification and litigation issues rather than a single patent dispute.

Weaknesses

US 10,028,944 is not a composition-of-matter claim.
The claim requires a neuropsychiatric treatment use.
A section viii carve-out may be available for uses outside the patented indication.
The specific dose claims do not map exactly onto the labeled 34 mg pimavanserin dose when expressed as active moiety.
Method claims require proof tied to administration, prescribing, labeling or encouragement.
Validity challenges can target written description, enablement, anticipation, obviousness and claim construction.

The most material litigation risk concerns the relationship between the proposed generic label and the patented method. A generic label limited to an unpatented use may reduce induced-infringement exposure. A label that recites or encourages a claimed depression, schizophrenia or other neuropsychiatric use would create greater risk.

Which companies are challenging Nuplazid patents?

Pimavanserin has attracted ANDA activity from generic-drug manufacturers, and Acadia has disclosed patent litigation and Paragraph IV activity in its SEC filings. The relevant defendants and applicants can change as ANDAs are filed, amended, transferred or settled.

The most important diligence source is the FDA Orange Book combined with PACER or district-court dockets for each asserted patent. Company disclosures should be read with the patent number and dosage form because a case involving a core compound patent presents a materially different risk from a case involving only a method-of-use patent.[5]

A Paragraph IV filing does not mean that a generic will launch. Acadia may obtain a 30-month stay, preliminary relief, a judgment upholding the patent, a settlement with a delayed entry date or a settlement allowing an earlier launch under specified conditions.

What patent litigation affects US 10,028,944?

The relevant legal mechanisms are:

Paragraph IV litigation

A generic applicant certifies that an Orange Book patent is invalid, unenforceable or not infringed. The sponsor may sue within 45 days, triggering a statutory stay of FDA approval for up to 30 months, subject to court action and statutory exceptions.[6]

Section viii carve-out

An applicant may omit a patented method from its labeling if the remaining indications are independently approvable. This is the most direct design-around path for a method-of-use patent.

Induced infringement

Even after a carve-out, the sponsor may argue that the generic's label, promotional activity, distribution or product design encourages use of the patented method. The strength of that argument depends on the final label and evidence of intended use.

Settlement agreements

A settlement may establish a licensed entry date, restrictions on launch, a supply arrangement or other commercial terms. FTC review and antitrust scrutiny remain relevant, particularly where payment-for-delay concerns arise.[7]

What generic launch scenarios exist for pimavanserin?

Scenario	Likely commercial result
All core and method patents survive	No unrestricted generic entry before the last enforceable patent expires
Generic wins a core patent challenge	Early entry becomes possible, subject to remaining patents
Generic wins only a method patent challenge	Entry may still be blocked by compound, salt or formulation patents
Section viii carve-out succeeds	Generic may enter for non-patented uses
Settlement reached	Entry occurs on the agreed date and terms
Patent expires in 2031	Broad entry becomes more likely unless another valid patent remains

The highest-risk scenario for Acadia is a successful challenge to a core active-ingredient or salt patent combined with a viable section viii strategy against method patents. The lower-risk scenario is an intact compound or salt patent that blocks commercial supply regardless of the indication in the generic label.

Is there biosimilar risk for pimavanserin?

No. Pimavanserin is a small-molecule drug, not a biologic. FDA approval of a competing product would proceed through the ANDA pathway for a generic drug, not the section 351(k) biosimilar pathway.

The relevant risks are:

ANDA Paragraph IV challenges;
Label carve-outs;
Invalidity or noninfringement decisions;
Authorized-generic arrangements;
Settlement-based entry;
Patent expiration.

How does US 10,028,944 compare with a core compound patent?

Issue	US 10,028,944	Core compound patent
Claim type	Method of treatment	Composition of matter
Requires a disease indication	Yes	Usually no
Requires administration	Yes	No
Covers all commercial uses	No	Often substantially broader
Carve-out potential	Meaningful	Limited
Relevance to Nuplazid label	Depends on use	Direct
Generic vulnerability	Label and inducement disputes	Chemical invalidity, infringement and expiration
Strategic value	Lifecycle and indication protection	Primary market exclusivity

US 10,028,944 is best viewed as a lifecycle patent. It can extend protection around specific therapeutic uses and dosing practices, but it does not replace a valid core compound or salt patent.

Key Takeaways

US 10,028,944 covers pimavanserin treatment methods, including use of pimavanserin tartrate.
Claim 1 is broad but requires treatment of a neuropsychiatric disease or symptom.
Claims 2 through 4 target schizophrenia-spectrum disorders, psychotic depression and major depression.
Claims 6 through 14 add salt, dose, frequency and oral-tablet limitations.
The patent does not claim pimavanserin as a composition of matter.
The nominal expiration date is in July 2031, subject to the official USPTO term calculation.
Nuplazid's regulatory exclusivity expired or became non-dispositive before the principal patent term ends.
Generic applicants face Paragraph IV, section viii and induced-infringement strategies.
Pimavanserin has generic risk, not biosimilar risk.
The commercial strength of US 10,028,944 depends heavily on the Orange Book listing, approved indications, generic labeling and the survival of Acadia's core compound and salt patents.

FAQs

Does US 10,028,944 cover pimavanserin tartrate itself?

No. The claims cover administering pimavanserin tartrate in specified treatment methods. They do not claim the salt as a standalone composition.

Does a generic pimavanserin tablet automatically infringe US 10,028,944?

No. Infringement depends on the proposed use, label, dosage instructions and evidence of encouragement. A generic may seek to omit patented uses from its labeling.

Is psychotic depression an FDA-approved Nuplazid indication?

No. Psychotic depression appears in the patent claims, but FDA's approved Nuplazid indication is Parkinson's disease psychosis.

Does the 34 mg Nuplazid dose fall within the patent's dose claims?

The labeled 34 mg dose is expressed as pimavanserin active moiety. It corresponds to roughly 40 mg of pimavanserin tartrate, which falls within the broad tartrate range but is not the specific 15 mg, 25 mg or 50 mg claim embodiment.

Can a generic launch before July 2031?

Yes, if it prevails in patent litigation, obtains a successful labeling carve-out, reaches a settlement permitting entry, or relies on a patent that does not block its proposed product and use.

References

U.S. Food and Drug Administration. (2024). Nuplazid (pimavanserin tartrate) prescribing information.
U.S. Food and Drug Administration. (2016). FDA approves first drug to treat hallucinations and delusions associated with Parkinson's disease.
U.S. Patent and Trademark Office. (2018). U.S. Patent No. 10,028,944, Methods for treating neuropsychiatric disorders.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
Acadia Pharmaceuticals Inc. (2024). Annual report on Form 10-K.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations, Appendix C: Paragraph IV patent certifications.
Federal Trade Commission. (2013). Pay-for-delay: How drug company pay-offs cost consumers billions.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	407117	⤷ Start Trial
Austria	512136	⤷ Start Trial
Australia	2004206886	⤷ Start Trial
Brazil	PI0406591	⤷ Start Trial
Canada	2512639	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,028,944

Summary for Patent: 10,028,944