United States Patent 9,375,478: Vasopressin Formulation Claims, Exclusivity, and Generic Entry Risk

U.S. Patent No. 9,375,478 protects a narrow method of treating hypotension with a defined vasopressin dosage form. The claimed product must contain vasopressin, 10 mM acetate buffer, and water; have a pH of 3.8; and deliver vasopressin at specified infusion rates. Dependent claims add chlorobutanol, rapid blood-pressure response, vasodilatory shock indications, post-cardiotomy and septic shock dosing, and titration procedures.[1]

The patent does not claim vasopressin generally, every vasopressin formulation, or every use of vasopressin for shock. Its practical value depends on whether a commercial product or proposed generic uses the claimed formulation and dosing protocol.

What does U.S. Patent 9,375,478 protect?

The independent claim combines four limitations:

Limitation	Requirement
Patient	Human who is hypotensive
Dosage form	Unit dosage form consisting essentially of vasopressin, 10 mM acetate buffer, and water
Formulation	Vasopressin concentration of about 0.01 to about 0.07 mg/mL; pH 3.8
Administration	About 0.01 to about 0.1 units of vasopressin per minute

The claim is a method-of-treatment claim. Infringement requires more than selling or manufacturing vasopressin. The accused party must practice, direct, induce, or otherwise be legally responsible for administration of a dosage form satisfying the formulation and dosing limitations.

What does "consists essentially of" mean in claim 1?

"Consists essentially of" is an intermediate transition between "comprising" and "consisting of." It generally permits additional ingredients that do not materially affect the basic and novel characteristics of the claimed formulation.

The basic formulation characteristics appear to be:

Vasopressin at the stated concentration.
A 10 mM acetate buffer.
Water.
A pH of 3.8.

The phrase creates a materiality dispute for formulations containing additional excipients. An excipient that changes stability, pH control, delivery, or another claimed formulation characteristic may be excluded. An excipient that does not materially alter those characteristics may not avoid the claim.

Claim 2 expressly permits chlorobutanol, indicating that chlorobutanol is treated as compatible with the claimed formulation. The claim language does not establish that sodium chloride, citrate, phosphate, preservatives, surfactants, or other excipients are automatically outside the claim. Each would require a formulation-specific analysis.

What are the individual claim limitations?

Claims 1 and 2: formulation and infusion-rate coverage

Claim 1 covers a concentration range of approximately 0.01 to 0.07 mg/mL. Vasopressin is commonly dosed in units rather than mass. The exact mass-to-unit conversion depends on the product specification and potency designation.

The claim also requires an infusion rate of approximately 0.01 to 0.1 units per minute. The rate limitation is important because a product may have the claimed composition but avoid literal infringement if used outside the specified administration range.

Claim 2 adds chlorobutanol. It is narrower than claim 1 and is potentially relevant to preserved multi-dose vasopressin products.

Claim 3: blood-pressure response within 15 minutes

Claim 3 requires that mean arterial blood pressure increase within 15 minutes of administration. This limitation introduces a clinical-performance element. An accused method would need evidence concerning the timing of the blood-pressure response, patient population, baseline status, and administration conditions.

The claim does not specify the magnitude of the increase. It requires an increase in mean arterial blood pressure within the stated period.

Claims 4 through 8: vasodilatory, post-cardiotomy, and septic shock

Claims 4 through 8 narrow the patient population and, in some instances, the dose range:

Claim	Condition	Administration rate
4	Vasodilatory shock	Claim 1 range
5	Post-cardiotomy shock	Claim 1 range
6	Post-cardiotomy shock	About 0.03 to 0.1 units/minute
7	Septic shock	Claim 1 range
8	Septic shock	About 0.01 to 0.07 units/minute

These claims create separate enforcement positions for different hospital protocols. A generic label directed to septic shock or post-cardiotomy shock may raise method-of-use issues even if its product composition is not independently claimed.

Claims 9 through 11: treatment duration and titration

Claims 9 to 11 cover treatment protocols:

Claim 9 requires continuing administration for about eight hours after attaining a target blood pressure.
Claim 10 requires reducing the infusion by about 0.005 units per minute after approximately eight hours.
Claim 11 requires increasing the rate by about 0.005 units per minute at 10-to-15-minute intervals if the target blood-pressure increase is not achieved.

These claims are narrower and more dependent on the actual prescribing instructions. Their commercial relevance is greatest where a product label, hospital protocol, or clinical order set directs the specified titration steps.

How does the patent compare with a typical Vasostrict formulation?

Vasopressin injection products are generally administered intravenously for vasodilatory shock, including septic shock and post-cardiotomy shock. FDA labeling for Vasostrict identifies vasopressin as the active ingredient and describes dosing, dilution, warnings, and administration instructions.[2]

A comparison against a typical commercial vasopressin product requires analysis of the following variables:

Issue	Relevance to Patent 9,375,478
Vasopressin concentration	Must fall within approximately 0.01 to 0.07 mg/mL
Buffer	Must include 10 mM acetate buffer
pH	Must be 3.8
Preservative	Chlorobutanol supports claim 2 if other limitations are met
Patient	Must be hypotensive under claim 1
Indication	Septic or post-cardiotomy shock activates dependent claims
Rate	Must fall within the applicable units-per-minute range
Titration	Claims 9 through 11 require the specified duration or rate adjustments

A product concentration stated in units per milliliter cannot be compared conclusively with the mass-per-milliliter limitation without the applicable potency conversion. The formulation record, certificate of analysis, label, and manufacturing specifications control that analysis.

What is the Orange Book status of U.S. Patent 9,375,478?

Patent 9,375,478 has been associated with the Vasostrict vasopressin product in FDA patent-listing materials and commercial patent databases. The relevant Orange Book inquiry is whether the patent remains listed for the applicable NDA and whether the listing covers the approved product, an approved method of use, or both.[3]

The principal regulatory implications are:

Regulatory issue	Impact
Listed patent	An ANDA applicant may need a Paragraph IV certification or a certification that approval will be delayed
Method-of-use listing	A generic may attempt a section viii carve-out for a patented indication
Formulation limitation	A product formulation that differs materially may support a non-infringement position
Patent expiration	Approval timing and launch risk depend on the listed expiration date and any applicable pediatric or patent-term adjustment
Label content	A carved-out label may still create induced-infringement exposure if promotional conduct or instructions direct use of the patented method

Publicly reported Orange Book data have identified a January 2035 expiration date for this patent family. The operative date for regulatory planning is the current FDA listing together with the USPTO patent-term record.[3][4]

The patent itself does not create FDA exclusivity. FDA regulatory exclusivity and patent exclusivity are separate rights. Any new-drug exclusivity associated with the underlying vasopressin product must be assessed independently from the patent term.

When does vasopressin lose exclusivity?

The principal patent barrier associated with U.S. Patent 9,375,478 is expected to run to approximately January 2035 based on reported Orange Book expiration information. That date does not necessarily mean that no generic can enter earlier.

Earlier entry can occur through:

A successful Paragraph IV challenge.
A settlement granting an authorized or licensed launch date.
A non-infringing formulation.
A label carve-out that removes the patented method of use.
An ANDA approved after the listed patent is no longer an approval barrier but before commercial litigation is resolved.
A licensed product or authorized generic arrangement.

The patent does not block every vasopressin product. It presents the strongest barrier to products matching the acetate-buffered, pH 3.8 formulation and using the specified dosing methods.

What Paragraph IV challenges and patent litigation affect the product?

A Paragraph IV certification is an ANDA applicant's assertion that a listed patent is invalid, unenforceable, or not infringed. The claim text alone does not establish whether a particular generic applicant has filed a Paragraph IV certification, whether the NDA holder filed a timely suit, or whether a court entered a judgment or settlement.

For this patent, likely litigation issues include:

Issue	Legal significance
pH of 3.8	A formulation outside the claimed pH limitation may support non-infringement
10 mM acetate	The identity and concentration of the buffer are central claim limitations
"About" ranges	The parties may dispute the scope of approximately 0.01 to 0.07 mg/mL and the rate ranges
Unit dosage form	The parties may dispute whether a diluted infusion bag, vial, syringe, or compounded preparation is the claimed dosage form
"Consists essentially of"	Additional excipients may create an infringement and claim-construction dispute
Method-of-use labeling	A generic label may be challenged if it directs septic-shock or post-cardiotomy use
Titration instructions	Claims 9 through 11 may be asserted against detailed dosing protocols

A product applicant can face different exposure for product composition, induced infringement, contributory infringement, and direct infringement by healthcare providers. The absence of a formulation claim in the asserted patent would not eliminate method-of-use exposure.

How strong is the patent estate for vasopressin?

Patent 9,375,478 is commercially meaningful but technically narrow.

Strengths

It covers both composition and administration.
The claimed pH, buffer, concentration, and rate provide multiple infringement hooks.
The dependent claims track recognized clinical settings.
Chlorobutanol coverage may align with a preserved commercial formulation.
Titration claims may affect labeling and hospital protocols.

Weaknesses

The claim requires a specific acetate-buffered formulation.
A design-around may be possible through a different buffer, pH, concentration, preservative system, or dosage form.
The method claims depend on actual clinical use.
Claims 9 through 11 require detailed treatment behavior that may not appear in a generic label.
The word "about" can create both infringement and validity disputes.
The patent does not claim the vasopressin molecule itself.

The estate is stronger against a copy of the commercial formulation and its labeled dosing instructions than against a materially different vasopressin presentation.

What formulations are protected by the patent?

The protected formulation profile is:

Vasopressin or a pharmaceutically acceptable salt.
Approximately 0.01 to 0.07 mg/mL vasopressin.
10 mM acetate buffer.
Water.
pH 3.8.
Optionally chlorobutanol under claim 2.

Potential design-around strategies include:

Design-around	Main risk
Different buffer, such as phosphate or citrate	May avoid the literal acetate limitation
Different acetate concentration	May avoid the 10 mM limitation, subject to claim construction
Different pH	May avoid the pH 3.8 limitation, subject to the meaning of "about"
Concentration outside the claimed range	May avoid literal infringement
Different preservative system	May avoid claim 2 but not claim 1
Different label or use instructions	May reduce method-of-use exposure
Different dosage form	May raise a dispute over the "unit dosage form" limitation

A design-around is not established merely by changing one excipient. The complete formulation must be evaluated against every limitation, including the "consists essentially of" language.

Are biosimilars relevant to vasopressin?

No. Vasopressin is a synthetic peptide drug, not a biologic subject to the biosimilar pathway under section 351(k) of the Public Health Service Act. Competitive entry would generally proceed through an ANDA or another applicable small-molecule drug pathway, depending on the reference product and dosage form.[5]

The relevant competitors are generic vasopressin injection manufacturers, not biosimilar developers. Regulatory competition will focus on pharmaceutical equivalence, bioequivalence or other applicable approval requirements, formulation differences, labeling, manufacturing controls, and patent certifications.

Which companies can challenge the patent estate?

Potential challengers include manufacturers seeking approval for generic vasopressin injection, contract manufacturers supporting ANDA applicants, and companies developing alternative presentations. The commercial relevance of any challenger depends on:

Whether the proposed formulation falls within the acetate and pH limitations.
Whether the ANDA label includes patented indications.
Whether the applicant uses a Paragraph IV certification.
Whether the NDA holder files an infringement action.
Whether a settlement restricts launch timing.
Whether the applicant can obtain a non-infringement opinion or pursue a label carve-out.

A competitor with a different formulation may have a stronger pathway than an applicant seeking to reproduce the reference product exactly.

What manufacturing and intellectual-property barriers remain?

Manufacturing barriers are separate from patent scope. Vasopressin products require controlled peptide manufacture, potency testing, sterility assurance, preservative control, container-closure compatibility, and stability data. The claimed pH and acetate system may be difficult to reproduce while maintaining stability and acceptable injection characteristics.

The principal IP barriers are:

The formulation limitation in claim 1.
The chlorobutanol limitation in claim 2.
Clinical-use claims for vasodilatory, septic, and post-cardiotomy shock.
Label-based exposure under induced-infringement theories.
Additional patents or regulatory protections associated with the reference product or related formulations.

A freedom-to-operate review should separate formulation infringement from label and clinical-use exposure. It should also review continuation and divisional patents in the same family, because a later patent may contain broader or differently structured claims.

How does Patent 9,375,478 affect generic launch scenarios?

Launch scenario	Patent risk
Exact formulation and full reference label	High
Same formulation with patented indications	High method-of-use risk
Same active ingredient, different buffer	Lower risk under this patent, subject to equivalents
Different pH outside the claimed range	Lower literal-infringement risk
Septic-shock use omitted from label	Reduced but not necessarily eliminated risk
Post-cardiotomy use omitted from label	Reduced claim 5 and claim 6 exposure
Titration language omitted	Reduced claims 9 through 11 exposure
Authorized generic or license	Commercial entry may occur under negotiated terms
Entry after patent expiry	Lowest patent risk from this patent

The highest-risk generic is an exact or near-exact copy of a commercial vasopressin injection that uses the claimed acetate buffer, pH, concentration, and labeled infusion rates.

What is the revenue exposure from the patent?

The patent's economic value is tied to the U.S. market for vasopressin injection used in intensive-care and perioperative settings. Revenue exposure is not determined by the patent alone. It depends on:

The reference product's U.S. net sales.
Generic price erosion after entry.
The number of approved generic competitors.
Hospital contracting and supply availability.
Whether a generic can launch with a non-infringing formulation.
The timing and terms of any settlement.
Whether shortages limit substitution.

A formulation-specific patent can preserve pricing only if it blocks practical generic substitution. If competitors can obtain approval with a different buffer or label, the patent may provide less commercial protection than its expiration date suggests.

Key Takeaways

U.S. Patent 9,375,478 covers a narrow vasopressin treatment method tied to a specific formulation and infusion protocol.
The core formulation requires approximately 0.01 to 0.07 mg/mL vasopressin, 10 mM acetate buffer, water, and pH 3.8.
Chlorobutanol is covered by dependent claim 2.
The patent reaches hypotension associated with vasodilatory shock, including septic and post-cardiotomy shock.
Claims 9 through 11 cover eight-hour continuation and specified titration procedures.
The reported Orange Book expiration date is approximately January 2035.
The patent does not cover vasopressin generally and does not create biosimilar exclusivity.
Generic risk is highest for an exact copy of the reference formulation and labeled use instructions.
The most credible design-around paths involve changing the buffer, pH, concentration, dosage form, or label.
Paragraph IV, litigation, settlement, and continuation-patent analysis must be assessed separately from the claim language.

FAQs

Does Patent 9,375,478 cover all vasopressin injections?

No. It covers methods using a specific vasopressin formulation, pH, buffer, concentration range, and infusion rate.

Can a generic avoid the patent by using a phosphate buffer?

A phosphate-buffered product may avoid the literal acetate-buffer limitation, but the complete formulation and any doctrine-of-equivalents theory would require separate analysis.

Does claim 2 require chlorobutanol for infringement?

No. Claim 1 does not require chlorobutanol. Claim 2 adds chlorobutanol as an additional limitation and is infringed only when the narrower formulation is used.

Are septic-shock methods separately protected?

Yes. Claims 7 and 8 specifically address septic shock, with claim 8 narrowing the infusion rate to approximately 0.01 to 0.07 units per minute.

Can a generic omit patented indications from its label?

A section viii label carve-out may reduce method-of-use exposure, but it does not automatically eliminate infringement risk if the product, labeling, promotional conduct, or distribution practices direct the patented use.

References

United States Patent and Trademark Office. (2016). U.S. Patent No. 9,375,478, vasopressin formulations and methods of use thereof.
U.S. Food and Drug Administration. (n.d.). Vasostrict (vasopressin injection) prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
United States Patent and Trademark Office. (n.d.). Patent Center: U.S. Patent No. 9,375,478.
U.S. Food and Drug Administration. (2020). Applications covered by section 505(b)(2).

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Ph Health	VASOSTRICT	vasopressin	SOLUTION;INTRAVENOUS	204485-001	Apr 17, 2014	AP	RX	Yes	Yes	9,375,478	⤷ Start Trial				TO INCREASE BLOOD PRESSURE IN ADULTS WITH VASODILATORY SHOCK (E.G., POST-CARDIOTOMY OR SEPSIS) WHO REMAIN HYPOTENSIVE DESPITE FLUIDS AND CATECHOLAMINES	⤷ Start Trial
Ph Health	VASOSTRICT	vasopressin	SOLUTION;INTRAVENOUS	204485-002	Dec 17, 2016	AP	RX	Yes	Yes	9,375,478	⤷ Start Trial				TO INCREASE BLOOD PRESSURE IN ADULTS WITH VASODILATORY SHOCK (E.G., POST-CARDIOTOMY OR SEPSIS) WHO REMAIN HYPOTENSIVE DESPITE FLUIDS AND CATECHOLAMINES	⤷ 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

Details for Patent: 9,375,478

Which drugs does patent 9,375,478 protect, and when does it expire?

Summary for Patent: 9,375,478