United States Drug Patent 7,579,321: Claim Scope, Expiration, and Desmopressin Patent Landscape

U.S. Patent No. 7,579,321 covers low-dose desmopressin regimens intended to postpone urination while limiting the duration and intensity of antidiuresis, with an associated reduction in hyponatremia risk. The patent is a method-of-treatment patent, not a composition-of-matter patent. Its core limitations are dose, administration route, pharmacodynamic duration, plasma concentration, urine osmolality, patient counseling, and urinary indication.

The patent presents substantial historical relevance to short-acting desmopressin products, but its practical exclusionary value depends on patent-term status, claim construction, the accused product’s delivered dose and pharmacodynamic profile, and whether the patent was listed for a relevant FDA-approved product.

What does U.S. Patent 7,579,321 protect?

The patent protects administering desmopressin at a relatively low systemic exposure to achieve a short antidiuretic effect. The principal inventive concept is a limited-duration treatment window intended to reduce fluid-retention-related hyponatremia.

The independent claims divide into four claim groups:

Claim group	Independent claim	Core limitation
Low-dose treatment with hyponatremia-risk objective	1	No more than about 2 ng/kg, specified nonoral routes, antidiuretic effect lasting no more than about four to six hours
Urine-osmolality endpoint	8	Urine osmolality above about 300 mOsm/kg for less than about five hours
Very-low-dose nonintranasal treatment	19	No more than about 1 ng/kg through transdermal, intradermal, transmucosal, or conjunctival administration, with a four-to-six-hour effect
Intranasal treatment	20	No more than about 2 ng/kg by intranasal administration

Claims 2 through 7, 9 through 18, and 21 narrow those independent claims through additional dose, concentration, route, counseling, indication, and pharmacodynamic limitations.

The patent does not broadly claim every use of desmopressin for nocturia, enuresis, or incontinence. Infringement requires satisfaction of the specific limitations in at least one asserted claim.

How do the independent claims differ?

Claim 1: low dose, limited duration, and reduced hyponatremia risk

Claim 1 requires:

A patient;
Induction of voiding postponement;
A stated objective of reducing the risk of hyponatremia;
Delivery of desmopressin to the bloodstream;
A dose of no more than about 2 ng/kg;
Intranasal, transdermal, intradermal, transmucosal, or conjunctival administration; and
An antidiuretic effect lasting no more than approximately four to six hours.

The claim is narrow in several respects. It does not cover oral administration. It also requires a pharmacodynamic duration, not merely a prescribed dose. A product that delivers 2 ng/kg or less but produces antidiuresis for more than six hours may fall outside the literal scope of claim 1.

The phrase “while reducing the risk” is likely to be litigated as a functional or intended-result limitation. The claim may require the claimed regimen to achieve the stated risk-reduction objective, rather than merely reciting a physician’s purpose.

Claim 8: urine osmolality as the central endpoint

Claim 8 is broader in route and does not expressly require the hyponatremia-risk limitation. It requires administration of enough desmopressin to produce urine osmolality above approximately 300 mOsm/kg for less than approximately five hours.

This claim shifts infringement analysis from dose and route to a measurable physiological result. It may be relevant to formulations that use different nominal doses but produce the claimed urine-osmolality profile.

The principal evidentiary issue is measurement. An infringement case would likely require pharmacokinetic and pharmacodynamic testing showing:

Urine osmolality rises above 300 mOsm/kg;
The elevation persists for less than five hours; and
The result is attributable to the accused desmopressin administration.

Claim 19: very-low-dose nonintranasal administration

Claim 19 requires no more than approximately 1 ng/kg and excludes intranasal administration. It is directed to transdermal, intradermal, transmucosal, or conjunctival delivery.

This claim is commercially significant for alternative delivery systems. A transdermal patch, microneedle product, buccal formulation, or ocular delivery system could implicate claim 19 if it reaches the bloodstream at the specified dose and produces the required four-to-six-hour antidiuretic effect.

Claim 20: intranasal administration

Claim 20 is directed specifically to intranasal delivery at no more than approximately 2 ng/kg. Unlike claim 1, it does not expressly require an antidiuretic duration of four to six hours or recite reduction of hyponatremia risk in the final limitation.

Its potentially broader scope makes claim construction important. The claim requires administration “so as to produce an antidiuretic effect,” but it does not specify a maximum effect duration. Claims 20 and 21 therefore create a separate intranasal claim pathway.

What dependent claims add to the patent scope?

Claims	Added limitation	Commercial relevance
2, 21	No more than about 1 ng/kg	Captures ultra-low systemic exposure
3	Advising fluid restriction after administration	Links treatment to patient counseling
4	Advising that no water should be taken after administration	More restrictive counseling requirement
5, 18	Nocturia, PNE, or incontinence	Defines target urinary disorders
6, 15	Maximum plasma/serum concentration of about 10 pg/mL	Pharmacokinetic limitation
7, 16	Maximum plasma/serum concentration of about 5 pg/mL	More stringent exposure limitation
9, 20	Intranasal administration	Relevant to nasal sprays and nasal drops
10	Transdermal administration	Relevant to patches and skin delivery
11	Intradermal administration	Relevant to microneedle and injection-based systems
12	Transmucosal administration	Relevant to buccal, sublingual, and related systems
13	Conjunctival administration	Relevant to ocular delivery
14	100 to 2,000 ng total desmopressin	Defines an absolute administered amount
17	No more than about 2 ng/kg	Converts claim 8 into a dose-limited regimen

Claims 6, 7, 15, and 16 are particularly important for product comparison. A generic or reformulated product could avoid a dose limitation in some circumstances but still encounter a concentration limitation if clinical testing demonstrates plasma or serum desmopressin levels within the claimed range.

What formulations and delivery systems are protected?

The patent claims treatment methods rather than a specific excipient system. The claimed routes include:

Intranasal delivery;
Transdermal delivery;
Intradermal delivery;
Transmucosal delivery; and
Conjunctival delivery.

The claims therefore do not depend on a particular buffer, preservative, tablet matrix, patch adhesive, permeation enhancer, or device design. A competing formulation can use different excipients and still raise infringement issues if its use satisfies the claimed patient, dose, route, and pharmacodynamic parameters.

The patent does not expressly claim oral tablets or orally disintegrating tablets in the supplied claims. That distinction matters because later desmopressin products, including sublingual products, may rely on separate formulation and dosing patents.

When does U.S. Patent 7,579,321 lose exclusivity?

U.S. Patent No. 7,579,321 was issued on August 25, 2009. Its term is governed by the earliest effective nonprovisional filing or priority date, subject to patent-term adjustment, terminal disclaimers, and any applicable statutory extensions. Public family records associate the patent with an early-2000s priority chain, placing the ordinary patent term in the 2023-2025 period rather than the late 2020s.

The legally operative expiration date is the date recorded in USPTO patent-term records, not simply the issue date plus 20 years. If the patent expired before a proposed launch, it cannot ordinarily block a new product on the basis of patent infringement, although separate unexpired continuation, formulation, device, or method-of-use patents may remain relevant.

Exclusivity issue	Assessment
Composition-of-matter protection	Not provided by the supplied claims
Method-of-treatment protection	Yes
Route-specific protection	Yes
Pharmacokinetic protection	Yes
Pharmacodynamic protection	Yes
Manufacturing-process protection	Not provided by the supplied claims
Orange Book status	Cannot be determined from the patent claims alone
Biosimilar exclusivity	Not applicable; desmopressin is a peptide drug, not an FDA-reference biologic for the biosimilar pathway
Generic launch impact	Depends on current patent-term status and other unexpired patents

What is the Orange Book status of U.S. Patent 7,579,321?

A patent number is not automatically an Orange Book-listed patent. FDA listing is tied to a specific approved drug application and generally concerns patents claiming the drug substance, drug product, or an approved method of use. The patent’s method claims could be relevant to Orange Book listing if they cover an approved use and were submitted by the NDA holder, but the claims alone do not establish that listing.

The relevant desmopressin products have included:

Product	Drug	Regulatory category	Patent relevance
DDAVP and generic desmopressin products	Desmopressin acetate	Small-molecule/peptide drug products	Earlier products and route-specific formulations
Noctiva	Desmopressin acetate	FDA-approved nasal spray for nocturia	Low-dose intranasal and safety-related patent landscape
Nocdurna	Desmopressin acetate	FDA-approved sublingual tablet for nocturia	Separate sublingual formulation and method patents

FDA labeling for desmopressin products emphasizes fluid restriction and the risk of hyponatremia, directly corresponding to the safety objective reflected in claims 1, 3, and 4.[2][3]

Which companies and products are most relevant?

Ferring Pharmaceuticals is the central innovator associated with modern low-dose desmopressin products, including Nocdurna. Avadel Pharmaceuticals commercialized Noctiva after acquiring rights associated with the low-dose intranasal product. Generic manufacturers have marketed desmopressin tablets, nasal products, and other presentations, subject to product-specific FDA approvals and patent certifications.

The competitive landscape is divided by delivery route:

Route	Principal commercial issue	Likely patent focus
Intranasal	Rapid systemic delivery and dose control	Claims 1, 9, 20, and 21; later nasal patents
Sublingual/transmucosal	Low-dose absorption and formulation performance	Claim 12 and separate sublingual formulation patents
Oral tablet	Established desmopressin use, generally outside supplied claim routes	Formulation, dosage, and method patents outside this patent
Transdermal/intradermal	Controlled delivery and short exposure	Claim 19 and delivery-device patents
Conjunctival	Specialized administration route	Claims 11, 13, and 19

What Paragraph IV challenges and litigation affect this patent?

The supplied claim set does not establish whether a generic manufacturer filed a Paragraph IV certification against this patent. A Paragraph IV certification is product- and NDA-specific. It requires a generic applicant to assert that a listed patent is invalid, unenforceable, or will not be infringed.

For this patent, a Paragraph IV challenge would likely focus on:

Whether the accused product reaches the claimed dose in ng/kg;
Whether “about” permits variation around 1 or 2 ng/kg;
Whether the product produces the required four-to-six-hour effect;
Whether urine osmolality exceeds 300 mOsm/kg for less than five hours;
Whether the route is legally “transmucosal” or another claimed route;
Whether a physician or label provides the claimed fluid-restriction advice;
Whether the claims are enabled across all listed routes; and
Whether the claims are indefinite because of functional duration and approximate numerical limits.

Patient-counseling claims 3 and 4 are weaker as standalone commercial barriers because infringement depends on what is advised to the patient. They may have value against an approved label that expressly directs fluid restriction or avoidance of water.

No conclusion that a particular generic has infringed or challenged U.S. 7,579,321 follows from the claims alone. Litigation and settlement analysis must be tied to a specific NDA, ANDA, product, and court docket.

How strong is the patent estate for low-dose desmopressin?

The patent’s strength is mixed.

Stronger features

Multiple independent claim formats;
Coverage of intranasal and nonintranasal delivery;
Dose limits expressed both as ng/kg and absolute nanograms;
Plasma and serum concentration claims;
Urine-osmolality claims;
Direct linkage to nocturia, PNE, and incontinence;
Safety-related counseling limitations.

Vulnerable features

Numerical terms use “about,” creating claim-construction disputes;
Duration limitations require clinical or laboratory proof;
Plasma concentration limits may vary with assay methodology and sampling time;
Urine osmolality can be affected by hydration, renal function, age, and concomitant therapy;
The claims are method claims and require a qualifying treatment event;
Enablement and written-description arguments may arise across five different administration routes;
The stated hyponatremia-risk limitation may create a causation or results-based dispute.

The strongest practical claims are likely claims 8, 17, 20, and 21 when a product’s pharmacodynamic profile and delivered dose are well characterized. Claims 3 and 4 are more dependent on prescribing information and patient instructions.

What generic launch risks exist?

A generic desmopressin launch faces three separate patent questions:

Whether U.S. 7,579,321 remained unexpired at the proposed launch date;
Whether the generic product’s approved labeling instructs use within the claimed route, dose, and safety parameters; and
Whether later patents cover the specific formulation, device, sublingual technology, nasal delivery system, or approved indication.

A product can avoid this patent by using a different route, dose, indication, or labeled duration, but that strategy may trigger separate patents or reduce regulatory substitutability. A section viii carve-out may be relevant where only a patented method of use is listed and the noninfringing label omits that use.[4]

Key Takeaways

U.S. 7,579,321 is a method patent for low-dose, short-duration desmopressin treatment.
Its core technical parameters are approximately 1-2 ng/kg, plasma concentrations of no more than 5-10 pg/mL, urine osmolality above 300 mOsm/kg for less than five hours, and an antidiuretic effect lasting approximately four to six hours.
The patent covers intranasal, transdermal, intradermal, transmucosal, and conjunctival administration, but the supplied claims do not cover oral administration.
Claims 1, 8, 19, and 20 are the principal infringement pathways.
The patent does not provide composition-of-matter or manufacturing-process protection.
Its remaining commercial relevance depends on the recorded USPTO expiration date and any later continuation or related formulation patents.
FDA approval, Orange Book listing, Paragraph IV activity, litigation, and settlement status are product- and application-specific.
Biosimilar analysis is generally inapplicable because desmopressin products are not analyzed through the FDA biosimilar pathway.

FAQs About U.S. Patent 7,579,321

Does U.S. Patent 7,579,321 cover Nocdurna?

It may be relevant to low-dose desmopressin treatment concepts, but the supplied claims do not specifically claim Nocdurna’s sublingual tablet formulation. Separate product and formulation patents must be reviewed.

Does the patent cover generic desmopressin tablets?

The supplied claims generally do not reach ordinary oral tablets because the principal route limitations are intranasal, transdermal, intradermal, transmucosal, or conjunctival. A specific sublingual or transmucosal product may require separate analysis.

Is desmopressin a biologic subject to biosimilar competition?

No. Desmopressin is a synthetic peptide drug and is generally regulated through the drug approval framework rather than the FDA biosimilar pathway under section 351(k) of the Public Health Service Act.

Can a generic avoid the patent by changing the dose?

A different dose can avoid a dose-limited claim, but only if the product also avoids every other limitation of the asserted claim. Pharmacodynamic, plasma-concentration, route, indication, and labeling limitations may remain relevant.

Why is hyponatremia important in the patent claims?

Desmopressin increases water reabsorption through antidiuretic activity. Excessive duration or exposure can increase water retention and hyponatremia risk. The patent claims a regimen intended to provide urinary symptom control with shorter antidiuretic activity, while the FDA labels emphasize fluid restriction and sodium-risk management.[2][3]

References

United States Patent and Trademark Office. (2009). U.S. Patent No. 7,579,321, Methods for inducing voiding postponement using desmopressin.
U.S. Food and Drug Administration. (2017). Noctiva (desmopressin acetate) nasal spray prescribing information.
U.S. Food and Drug Administration. (2018). Nocdurna (desmopressin acetate) sublingual tablet prescribing information.
U.S. Food and Drug Administration. (2023). Approved drug products with therapeutic equivalence evaluations.
21 U.S.C. § 355. [Federal Food, Drug, and Cosmetic Act provisions governing abbreviated applications and patent certifications].

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	0210397.6	May 7, 2002

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Argentina	039092	⤷ Start Trial
Argentina	039794	⤷ Start Trial
Argentina	107948	⤷ Start Trial
Austria	333886	⤷ Start Trial
Australia	2002337419	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,579,321

Summary for Patent: 7,579,321