US Patent 9,566,271: Scope, Claims, Expiration, and Pimavanserin Patent Landscape

US Patent 9,566,271 is a method-of-treatment patent covering the use of pimavanserin, including pimavanserin salts such as pimavanserin tartrate, to treat hallucinations and delusions. The strongest commercial claims focus on oral, unit-dose administration of pimavanserin tartrate for Parkinson's disease psychosis, including daily doses of 15 mg, 25 mg, or 50 mg.

The patent does not primarily protect the pimavanserin molecule, its chemical manufacture, or every formulation. Its principal value is a therapeutic-use barrier directed to administering the compound to patients with hallucinations or delusions.

What drug does US Patent 9,566,271 cover?

The compound of Formula (I) is pimavanserin, also known as ACP-103, when read in the context of the patent's Parkinson's disease psychosis claims and tartrate-salt dosing claims. Pimavanserin is marketed by Acadia Pharmaceuticals as Nuplazid.

Item	Detail
Active ingredient	Pimavanserin
Common salt	Pimavanserin tartrate
Brand	Nuplazid
FDA-approved indication	Hallucinations and delusions associated with Parkinson's disease psychosis
Therapeutic class	Selective serotonin 5-HT2A receptor inverse agonist
Patent	US 9,566,271
Patent type	Method of treatment
Grant date	February 14, 2017
Patent holder associated with commercial product	Acadia Pharmaceuticals Inc.
Key commercial dosage	34 mg pimavanserin tartrate capsule, equivalent to 34 mg pimavanserin
FDA approval	April 29, 2016

Pimavanserin is chemically distinct from dopamine-blocking antipsychotics. Nuplazid's FDA labeling identifies the drug as a 5-HT2A receptor inverse agonist and states that it is indicated for hallucinations and delusions associated with Parkinson's disease psychosis.[1]

What does claim 1 of US Patent 9,566,271 protect?

Claim 1 covers:

A method for treating hallucinations or delusions;
In a patient;
By administering a therapeutically effective amount;
Of the compound of Formula (I) or a salt thereof.

Claim 1 is the broadest independent claim in the supplied claim set. It does not expressly require:

Parkinson's disease;
Parkinson's disease psychosis;
pimavanserin tartrate specifically;
oral administration;
a tablet or capsule;
a particular dose;
once-daily administration;
a particular treatment duration; or
treatment of both hallucinations and delusions simultaneously.

The claim therefore reaches a wide range of therapeutic-use scenarios, subject to the identity of Formula (I), the salt limitation, and the requirement that the compound be administered to a patient in a therapeutically effective amount.

How broad is the Formula (I) limitation?

The scope depends on the exact chemical structure shown in the patent. “Formula (I)” is not an open-ended reference to all antipsychotic compounds. It is a structural limitation that must be construed from the patent specification and drawings.

If Formula (I) is pimavanserin, claim 1 covers pimavanserin and its pharmaceutically acceptable salts when used to treat hallucinations or delusions. It does not automatically cover unrelated 5-HT2A agonists, inverse agonists, dopamine antagonists, or other antipsychotics.

The “or a salt thereof” language broadens claim 1 beyond the free-base form. It may reach pharmaceutically acceptable salts that fall within the patent's construction of the claimed compound. Dependent claim 5 narrows that scope to the tartrate salt.

How do claims 2 through 4 narrow Parkinson's disease psychosis coverage?

Claims 2 and 3 focus on Parkinson's disease psychosis.

Claim	Added limitation	Commercial relevance
1	Treating hallucinations or delusions with Formula (I) or a salt	Broad therapeutic-use claim
2	Hallucinations or delusions associated with Parkinson's disease psychosis	Directly aligned with Nuplazid's approved indication
3	Patient is treated for Parkinson's disease psychosis	Similar subject matter to claim 2
4	Treating hallucinations and delusions	Requires both symptoms under a literal reading

Claims 2 and 3 overlap substantially. Claim 2 describes the symptoms and their association with Parkinson's disease psychosis. Claim 3 describes the treatment objective. A generic label directed to Parkinson's disease psychosis would face the greatest exposure under these claims.

Claim 4 is narrower because it uses “hallucinations and delusions,” rather than the disjunctive “hallucinations or delusions” in claim 1. Its application may depend on whether the accused treatment is labeled or used for both symptoms.

What dosage and formulation claims are protected?

Claims 5 through 15 create a layered protection structure around pimavanserin tartrate, dose, schedule, dosage form, and weight-based administration.

Pimavanserin tartrate claims

Claim 5 requires administration of the tartrate salt. This is commercially significant because Nuplazid is marketed as pimavanserin tartrate rather than only as the free base.

Claims 6 through 9 establish a dose range and selected dose points:

Claim	Dose limitation
6	About 0.001 mg to about 50 mg
7	About 15 mg
8	About 25 mg
9	About 50 mg

The selected-dose claims are nested within claim 6. They provide fallback positions if the broader range is challenged for written description, enablement, indefiniteness, or prior-art reasons.

The use of “about” introduces a tolerance question. The permissible variation would ordinarily depend on intrinsic evidence, including the specification, examples, pharmacokinetic data, manufacturing tolerances, and how a person skilled in the art would understand the claimed dose.

Frequency claims

Claims 10 through 12 cover:

Daily administration;
Once-daily administration; and
Twice-daily administration.

Claim 11 is a narrower version of claim 10. Claim 12 is also within the ordinary meaning of daily administration because twice-daily dosing occurs each day.

Nuplazid's approved labeling recommends 34 mg orally once daily, without titration.[1] That commercial regimen is not one of the expressly recited fixed doses in claims 7 through 9, but it may still fall within broader claims depending on how the patent's dose terminology and Formula (I) are construed.

Oral unit-dose claims

Claim 13 requires an oral unit-dose formulation. Claim 14 narrows the unit dose to a tablet.

These claims are method claims, not pure composition claims. A tablet containing pimavanserin tartrate is not necessarily infringing merely because it exists. Infringement would generally require use of that tablet in the claimed method, although other patent and inducement theories may apply.

The tablet limitation is commercially relevant to generic products because an ANDA applicant's proposed label, dosage form, and instructions can create direct or induced-infringement risk.

Weight-based dose claim

Claim 15 covers a therapeutically effective dose of 0.01 mg/kg/day to 100 mg/kg/day. This is a broad weight-based range. For a 70 kg patient, the claimed range corresponds approximately to:

Patient weight	Lower end	Upper end
50 kg	0.5 mg/day	5,000 mg/day
70 kg	0.7 mg/day	7,000 mg/day
100 kg	1 mg/day	10,000 mg/day

The upper end is substantially broader than the approved Nuplazid regimen. Its practical value depends on claim construction, enablement, and whether the accused regimen is both therapeutically effective and within the claimed range.

What patent claims are strongest against a pimavanserin generic?

The highest-risk claims for an ANDA applicant are generally claims 2, 3, 5, 10, 11, 13, and 14 when the proposed product label instructs treatment of Parkinson's disease psychosis with oral pimavanserin tartrate.

Generic product characteristic	Potentially relevant claims
Pimavanserin for Parkinson's disease psychosis	1-3
Pimavanserin tartrate	5-14
15 mg, 25 mg, or 50 mg dose	7-9
Daily dosing	10
Once-daily dosing	11
Twice-daily dosing	12
Oral unit-dose product	13
Tablet	14
Weight-based daily dosing	15

The broadest commercial overlap may arise even where the generic does not use the exact commercial 34 mg strength. Claims 1 through 5 do not require a specific dose, and claims 10 through 14 reach common administration and dosage-form instructions.

When does US Patent 9,566,271 lose exclusivity?

The patent has a December 21, 2029 statutory expiration date based on the patent-family priority date commonly associated with the patent. The effective Orange Book date must be distinguished from the basic 20-year term because patent-term adjustment, terminal disclaimers, and regulatory listing records can affect the operative date.[2][3]

Milestone	Date
Earliest relevant priority date	December 21, 2009
Patent grant	February 14, 2017
Base 20-year expiration	December 21, 2029
FDA small-molecule exclusivity	May 1, 2021, five years after approval, subject to applicable Orange Book treatment
Commercial product	Nuplazid

FDA approved Nuplazid on April 29, 2016. New chemical entity exclusivity generally lasted five years from approval, subject to the statutory framework and any Paragraph IV timing rules.[1][4] That regulatory exclusivity is separate from the patent term.

What is the Orange Book status of US Patent 9,566,271?

US 9,566,271 has been associated with Nuplazid's Orange Book patent listings for the approved drug. The listed use is relevant because the patent claims methods of treating hallucinations and delusions associated with Parkinson's disease psychosis.

Orange Book listing does not itself prove validity or infringement. It informs ANDA applicants of patents that the NDA holder identifies as covering the drug, formulation, or approved use.[3]

For a generic applicant, the key questions are:

Whether the patent is listed against the relevant dosage form and strength;
Whether the proposed label includes the patented use;
Whether the applicant files Paragraph IV certifications;
Whether Acadia initiates litigation within the statutory period; and
Whether a 30-month stay applies.

Which companies are challenging the Nuplazid patent estate?

The supplied claim set does not identify a Paragraph IV challenger, ANDA filer, litigation docket, or settlement agreement involving US 9,566,271. A definitive challenger analysis requires the current FDA Orange Book, FDA Paragraph IV notice information, PACER litigation records, and Acadia's SEC filings.

The relevant competitive pathway is an ANDA challenge rather than a biosimilar application. Pimavanserin is a chemically synthesized small molecule. FDA approval of a generic pimavanserin product would proceed under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not the biosimilar pathway under section 351(k).[4][5]

How does US 9,566,271 compare with the broader pimavanserin patent estate?

The patent estate can be divided into four technical layers.

Estate layer	Typical protection	Strategic purpose
Composition of matter	Pimavanserin molecule and salts	Protects the active pharmaceutical ingredient
Method of treatment	Psychosis, hallucinations, delusions, Parkinson's disease psychosis	Protects clinical use
Formulation and dosage form	Tablets, capsules, unit doses, release characteristics	Extends protection around product presentation
Manufacturing and process	Preparation, purification, crystallization, salt formation	Creates supply-chain and CMC barriers

US 9,566,271 is principally in the second layer. It is therefore weaker than a valid, unexpired composition-of-matter patent against a generic that sells the compound for any use. It can still be commercially important because an ANDA label for Parkinson's disease psychosis may directly reproduce the patented indication and dosing instructions.

The patent does not, based on the supplied claims, cover:

A new chemical entity claim to pimavanserin itself;
A generic manufacturing process;
A standalone tablet composition;
A pharmaceutical kit;
A new polymorph;
A sustained-release delivery system; or
All uses of pimavanserin outside hallucinations and delusions.

What generic launch scenarios exist after patent expiry?

Full-label launch

A generic could launch with the Parkinson's disease psychosis indication after all applicable patents and regulatory exclusivities expire or are successfully challenged. This is the highest-revenue generic scenario but carries the greatest patent exposure.

Skinny-label launch

An ANDA applicant may attempt to omit patented indications from its label if FDA requirements permit the omission. The commercial value of a skinny-label launch depends on whether the remaining unpatented uses are substantial and whether the proposed labeling still encourages the patented use.

For this patent, a skinny-label strategy may be difficult if Parkinson's disease psychosis is the principal or only commercially relevant indication for pimavanserin.

Paragraph IV launch

A Paragraph IV certification may assert that US 9,566,271 is invalid, unenforceable, or not infringed. Acadia could bring an infringement action under 35 U.S.C. § 271(e)(2). A timely action can trigger a statutory stay of FDA approval, generally up to 30 months, subject to court decisions and statutory exceptions.[5]

Post-expiration launch

A later entrant may wait for the patent's expiration and avoid Paragraph IV litigation. This reduces litigation cost but sacrifices first-filer or early-launch opportunities.

What patent litigation and settlement issues matter?

The principal litigation issues would likely include:

Whether the generic's proposed label instructs treatment of Parkinson's disease psychosis;
Whether the proposed product contains pimavanserin tartrate;
Whether the dosing instructions fall within claims 6 through 12;
Whether an oral tablet or unit dose falls within claims 13 and 14;
Whether the claims are anticipated or obvious over prior clinical and patent disclosures;
Whether the patent adequately supports the claimed dose ranges; and
Whether any claim is indefinite because of “about,” “therapeutically effective amount,” or the scope of Formula (I).

Settlement terms could include a licensed launch date, an authorized generic arrangement, supply rights, or restrictions on specific indications. No settlement terms are established by the claim text supplied.

How strong is the patent estate for pimavanserin?

US 9,566,271 has meaningful commercial strength as an indication patent because it maps closely to Nuplazid's approved use. Its principal weaknesses are structural:

It is a method patent rather than a composition-of-matter patent;
Several claims substantially overlap;
The patent depends on proving the accused use, not merely possession or sale;
A generic may seek a carve-out of the patented indication;
Broad dose and “about” language may invite validity challenges; and
The patent's practical value depends on the remaining term and the presence of other unexpired formulation or composition patents.

The estate is strongest when the product label, dosage form, salt, indication, and administration schedule reproduce the limitations of claims 2, 5, 10, 11, 13, and 14. It is weaker against off-label use, non-tartrate salts, non-oral dosage forms, or a label that lawfully omits Parkinson's disease psychosis.

Key Takeaways

US 9,566,271 is a method-of-treatment patent associated with pimavanserin and Nuplazid.
Claim 1 broadly covers treating hallucinations or delusions with pimavanserin or a salt.
Claims 2 and 3 target Parkinson's disease psychosis and are closely aligned with Nuplazid's approved indication.
Claims 5 through 14 add tartrate salt, dose, frequency, oral unit-dose, and tablet limitations.
Claim 15 covers a broad weight-based daily dose range.
The base statutory expiration is December 21, 2029, subject to the operative patent-term record.
A generic pimavanserin applicant would use the ANDA pathway and could raise a Paragraph IV challenge.
Biosimilar analysis is not applicable because pimavanserin is a small-molecule drug.
The patent is commercially important but does not, on the supplied claims, independently protect pimavanserin's molecule, manufacturing process, or every formulation.

FAQs

Does US 9,566,271 cover the 34 mg Nuplazid dose?

The supplied claims do not expressly recite 34 mg. The product may still implicate broader claims covering pimavanserin, pimavanserin tartrate, daily administration, oral unit doses, or therapeutic treatment of Parkinson's disease psychosis.

Is US 9,566,271 a composition patent?

No. The supplied claims are method-of-treatment claims. They require administering the compound to a patient for hallucinations or delusions.

Can a generic sell pimavanserin before December 2029?

Potentially, but only through a successful patent challenge, a noninfringing label and product configuration, a license or settlement, or another legally available pathway. Patent expiry alone does not resolve other unexpired patents or regulatory exclusivities.

Does the patent cover pimavanserin for schizophrenia?

Claim 1 is not expressly limited to Parkinson's disease psychosis. Claims 2 and 3 are. Whether schizophrenia treatment falls within claim 1 depends on the claim construction of Formula (I), the treatment facts, and the meaning of the claimed hallucinations or delusions.

Does a pimavanserin tablet infringe claim 14 by itself?

Not necessarily. Claim 14 is a method claim requiring administration of the tablet to a patient in the claimed treatment. Sale, labeling, or encouragement of that use may raise separate direct or induced-infringement issues.

References

U.S. Food and Drug Administration. (2016). Nuplazid (pimavanserin tartrate) prescribing information.
United States Patent and Trademark Office. (2017). U.S. Patent No. 9,566,271, Methods of treating psychosis.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, Orange Book.
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. §§ 355(j), 355(k).
Hatch-Waxman Amendments, 35 U.S.C. §§ 271(e)(2), 271(e)(4), 271(e)(6).

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

Details for Patent: 9,566,271

Summary for Patent: 9,566,271