US Patent 9,572,856 (Method for Refractory Hypotension Using Angiotensin II With Vasopressors): Claims Scope and US Patent Landscape
US Patent 9,572,856 claims a specific clinical method: treating refractory hypotension in humans by administering angiotensin II at a defined infusion rate while the patient is already receiving a vasopressor, with explicit coverage for vasopressin and catecholamines (including norepinephrine with a numeric dosing threshold). The claim set is narrow in the sense that it requires both (i) the rate of angiotensin II and (ii) the concurrent vasopressor identity during administration. For freedom-to-operate (FTO), the key question is not generic angiotensin II use, but whether the angiotensin II infusion is performed at or near ~20 ng/kg/min in combination with a listed vasopressor class, including specific dosing ranges for infusion duration and (for one dependent claim) norepinephrine rate.
What does US Patent 9,572,856 claim for refractory hypotension using angiotensin II + vasopressors?
Core independent claim (Claim 1) covers:
- Population/condition: “a human patient suffering from refractory hypotension”
- Therapy: administer angiotensin II
- Timing context: administer while the patient is receiving a vasopressor
- Angiotensin II dosing: at a rate of about 20 ng/kg/min
- Concurrent vasopressor requirement: vasopressor is vasopressin or a catecholamine
This claim structure creates a “combination during co-therapy” hook. Infringement is driven by contemporaneous use: angiotensin II dosing is performed while a patient is on an eligible vasopressor regimen.
Dependent claims add bounded dosing parameters:
- Claim 2: angiotensin II infusion over ~1 to ~7 hours
- Claim 3: infusion over ~2 to ~6 hours
- Claim 4: infusion over ~3 to ~5 hours
- Claim 5: vasopressor is a catecholamine (narrows Claim 1)
- Claim 6: catecholamine is norepinephrine
- Claim 7: norepinephrine administered at >15 mcg/min
- Claim 8: vasopressin is the vasopressor
Claim scope in operational terms (what has to be true)
A practicing clinician or protocol-based R&D team is squarely within the literal structure if the method includes all of the following:
- Refractory hypotension diagnosis (as defined clinically in the record)
- Angiotensin II infusion at ~20 ng/kg/min
- Co-administration with a vasopressor
- Vasopressor is vasopressin or catecholamine
- If relying on the norepinephrine-dependent coverage: norepinephrine infusion rate >15 mcg/min
- If the method includes defined infusion duration windows, additional narrowing occurs, but those are still within the independent coverage because the dependent claims sit “on top of” Claim 1’s required elements
Practical implication: protocol mismatch risk
If angiotensin II infusion deviates materially from ~20 ng/kg/min (even if clinically similar), the method claim can fall out of literal coverage depending on what “about” means under claim construction. The claims are not just “angiotensin II for refractory hypotension”; they require a dosing-rate anchor.
How do the dependent claims narrow claim 1 (infusion duration and vasopressor specifics)?
Infusion duration windows (Claims 2–4)
- 1 to 7 hours (Claim 2)
- 2 to 6 hours (Claim 3)
- 3 to 5 hours (Claim 4)
These duration elements are likely protocol-driven. Many clinical regimens use multi-hour titrated infusions; these windows concentrate coverage around common infusion durations while still requiring the specific rate in Claim 1.
Vasopressor identity and type (Claims 5, 6, 8)
- Catecholamine limitation (Claim 5)
- Norepinephrine limitation (Claim 6)
- Vasopressin limitation (Claim 8)
The independent claim already allows either vasopressin or catecholamines, but the dependent claims establish additional infringement pathways for narrower fact patterns.
Norepinephrine dosing threshold (Claim 7)
- Norepinephrine rate >15 mcg/min is the most quantifiable narrowing element beyond the angiotensin II infusion rate.
For enforcement and FTO, the existence of clinical protocols that keep norepinephrine at or under 15 mcg/min during angiotensin II co-therapy could be a factual design-around if other claim elements are also met. Conversely, protocols that exceed that threshold likely face direct risk.
What is the legal claim structure and infringement theory for US 9,572,856?
Method-of-treatment claim elements
US method claims for medical use typically raise enforcement questions around:
- who performs the steps (prescriber, hospital pharmacy protocol, nursing administration)
- whether “administering” is practiced as a combined clinical pathway
- whether “while the patient is receiving a vasopressor” is satisfied by concurrent administration
Claim 1 is written so that a single treatment episode can satisfy all elements if the healthcare provider follows the regimen and the patient is on an eligible vasopressor during angiotensin II dosing.
Typical infringement proof touchpoints
- dosing records: angiotensin II infusion rate (ng/kg/min) and duration
- medication administration records: vasopressor selection and dosing
- clinical documentation supporting “refractory hypotension”
- synchronization: timestamps establishing “while the patient is receiving” the vasopressor
How strong is the patent estate for angiotensin II in refractory hypotension in the US?
A credible “estate strength” assessment requires mapping to the US patent family and related continuations/divisionals, plus Orange Book listings if any, and litigation history. No additional patent numbers, family members, assignees, filing dates, or prosecution history are provided in the input; therefore, an accurate estate-wide strength analysis cannot be produced without inventing missing data.
What can be concluded from the claim text alone:
- The claim is tightly coupled to combination co-therapy with vasopressors.
- The numeric anchors (about 20 ng/kg/min; infusion duration ranges; norepinephrine >15 mcg/min) limit breadth but increase enforceability where protocols match.
When does US Patent 9,572,856 expire and how much exclusivity time remains?
No filing date, priority date, or patent term adjustment information is provided. Without those inputs, an expiration timeline cannot be calculated without speculation.
What prior art and obviousness risks affect US 9,572,856’s validity?
A complete validity-risk view requires:
- the patent’s priority date
- the full specification disclosure
- actual prosecution history and claim amendments
- identified references in office actions
None of those are included. The claims themselves suggest likely factual overlap with:
- earlier angiotensin II investigational regimens
- co-administration frameworks for vasopressors in refractory hypotension
But identifying specific anticipatory references or obviousness combinations would require external patent/publication data not present in the input.
What generic entry risks exist if angiotensin II is used off-label with vasopressors?
This is a method-of-treatment patent. For generic or biosimilar entry risk, the key determinant is whether the generic product is marketed for the claimed use and whether clinicians administer it in a manner that meets all elements.
Claim 1’s constraints shift the risk from “any angiotensin II use” to “angiotensin II at ~20 ng/kg/min while on vasopressin or a catecholamine.” If clinical practice protocols differ materially (angiotensin II rate not near 20 ng/kg/min, or vasopressor selection excluded, or norepinephrine at ≤15 mcg/min for the dependent pathway), the risk profile changes by fact pattern.
What patent-limited design-arounds target angiotensin II infusion rate, duration, or vasopressor selection?
Design-around levers embedded in the claim text
- Change vasopressor class (avoid vasopressin and catecholamines) would avoid the “vasopressor is vasopressin or a catecholamine” limitation, but such regimens may not be clinically standard.
- Keep norepinephrine at ≤15 mcg/min could reduce risk for Claim 7 while still potentially leaving Claim 1 and Claims 2–6, 8 exposure.
- Use angiotensin II infusion rate materially away from ~20 ng/kg/min could reduce literal risk, but “about” can capture ranges depending on claim construction.
- Adjust infusion duration outside 1–7 hours would potentially avoid dependent claims 2–4; however, Claim 1 does not require a duration window, only rate.
“Protocol change” is not the same as “no infringement”
Even if you avoid the dependent claims, Claim 1 remains unless at least one element is eliminated.
How does US 9,572,856 compare with other angiotensin II patents for hypotension and vasopressor co-therapy?
A side-by-side comparison requires other patents’ claim language and families. None are provided. A comparison cannot be generated without inventing specific competing patent numbers or claim elements.
What is the Orange Book status of angiotensin II for refractory hypotension and how does it relate to 9,572,856?
Orange Book linkage requires:
- drug product identifiers (NDC/RLD)
- Orange Book patent listing record for the product
- whether US 9,572,856 is listed and in what patent type (method-of-use, formulation, etc.)
- any Orange Book exclusivity
No product identifier or Orange Book listing data is supplied.
How do biosimilar or generic pathways affect enforcement of method claims like 9,572,856?
The enforcement logic for method-of-use claims typically targets the use, not the molecule formulation. That means:
- even if a generic product is approved, liability can hinge on whether clinicians follow the claimed method.
- if a product’s label or supporting clinical materials drive adherence to the claimed regimen, risk increases.
- if clinical use drifts to non-claimed dosing protocols, actual exposure depends on treatment facts.
A pathway analysis requires data on label indications, dosing instructions, and any FDA label references to co-therapy with vasopressors, which are not included.
Key Takeaways
- Claim 1 is a combination co-therapy method claim: angiotensin II ~20 ng/kg/min given to refractory hypotension patients while they receive a vasopressor that is vasopressin or a catecholamine.
- Claims 2–4 add angiotensin II infusion duration bands (~1–7h, ~2–6h, ~3–5h).
- Claims 5–8 set vasopressor identity limits, including norepinephrine and vasopressin.
- Claim 7 adds a second numeric anchor: norepinephrine >15 mcg/min.
- The claim set is narrower than blanket angiotensin II for hypotension, but it is potentially enforceable when real-world protocols match the numeric dosing and co-therapy criteria.
FAQs
1) Does US 9,572,856 cover angiotensin II monotherapy for hypotension?
No based on the provided claim text; Claim 1 requires angiotensin II administration while the patient is receiving a vasopressor, with the vasopressor limited to vasopressin or a catecholamine.
2) What element is most important for potential infringement risk under Claim 1?
The combination of angiotensin II infusion rate (~20 ng/kg/min) and concurrent vasopressor identity (vasopressin or catecholamine) during treatment.
3) If angiotensin II is infused for 6 hours, is Claim 2 or Claim 3 implicated?
Yes if the infusion rate is also ~20 ng/kg/min and the vasopressor requirement is met. Claim 2 covers ~1–7h; Claim 3 covers ~2–6h.
4) Does keeping norepinephrine at 10 mcg/min avoid all claims?
It avoids Claim 7 specifically, but it does not automatically avoid Claim 1 (which does not require norepinephrine >15 mcg/min). Whether it avoids infringement depends on satisfying or not satisfying Claim 1’s rate and co-therapy requirements.
5) Can a protocol that uses vasopressin instead of catecholamines still infringe?
Yes. Claim 1 expressly includes vasopressin, and Claim 8 depends on vasopressin as the vasopressor.
References
- US Patent 9,572,856 claims as provided in the prompt.
