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Patent landscape, scope, and claims: |
Scope and Claims of US Patent 9,730,891 and the United States Patent Landscape for Liposomal Irinotecan (Sucrose Octasulfate, DSPC/Cholesterol/PEG-DSPE)
US Drug Patent 9,730,891 is a US method-of-treatment patent with claims that are tightly tethered to (i) liposomal irinotecan where irinotecan is the active and is formulated as a specific irinotecan–sucrose octasulfate complex (a stated encapsulant/solubilization form), (ii) a defined liposome lipid composition (DSPC/cholesterol/PEG-DSPE at a specified molar ratio, with PEG-DSPE alternately recited), and (iii) numerical formulation parameters that define drug loading and particle size (roughly 110–120 nm by QELS; defined molar ratios of irinotecan to lipids; defined mg of irinotecan per mg lipid and per mmol phospholipid; and an encapsulation threshold of at least 90%). The patent’s effective US claim coverage is therefore narrow in formulation space but broad as to “method of treatment” and route, because infringement turns on whether a given marketed product uses a composition that falls within the recited ranges/ratios and then is administered parenterally/IV in a therapeutically effective amount.
What US 9,730,891 claims cover (bottom line)
- Product form: liposomal irinotecan with irinotecan–sucrose octasulfate encapsulated in liposomes.
- Core lipid system: DSPC + cholesterol + PEG-DSPE at 3:2:0.015 (and also recited more generally as “one or more phospholipids,” “DSPC and cholesterol,” and “one or more lipids”).
- Drug loading constraints: multiple overlapping numerical ranges:
- 150–500 mg irinotecan base per mmol total liposome phospholipid (claim 1)
- 0.15–1.5 moles irinotecan per mole total lipid (claims 1, 11, 12, 16, 17)
- ~0.5 mg irinotecan per mg total lipid (claims 4, 11, 17)
- ~500 mg irinotecan per mmol total phospholipid (claim 7 and dependent recitals)
- ~0.8 mmol irinotecan per 1 g total lipid (claim 6 and dependent)
- Particle size: 110–120 nm by QELS using a Gaussian model (claims 10, 13, 20).
- Encapsulation: ≥90% of irinotecan encapsulated (claims 11, 15, 17, 19).
- Administration: parenteral administration and expressly intravenous embodiments (claims 2, 18).
What are the exact claim elements in US Patent 9,730,891 (scope of independent and dependent claims)?
Independent claim structure
- Claim 1 is the broadest method claim. It requires:
- A method of treatment (no specific disease/indication limitation is stated in the provided claim text).
- Parenteral administration to a patient.
- Administration of a liposomal irinotecan pharmaceutical composition where:
- Irinotecan liposomes comprise irinotecan sucrose octasulfate.
- Liposomes comprise one or more phospholipids.
- Total formulation concentration is constrained to 150–500 mg irinotecan base per mmol total liposome phospholipids.
- Claims 2–11 add or narrow characteristics:
- Claim 2: intravenous administration.
- Claims 3–6 and 11: numerical drug-to-lipid ratios and loading per lipid mass.
- Claim 7: 500 mg irinotecan per mmol total phospholipid (specific loading).
- Claim 8–9: specific lipid identities and ratios:
- Claim 8: DSPC and cholesterol.
- Claim 9: DSPC, cholesterol, and PEG-DSPE in 3:2:0.015 molar ratio.
- Claim 10: 110–120 nm by QELS (Gaussian model).
- Claim 11: “having at least one additional characteristic selected from” a list, creating multiple alternative infringing configurations if claim 1’s core requirements are met.
Second independent claim
- Claim 12 is another independent method claim with a narrower composition set:
- Requires administration of a composition comprising:
- Irinotecan sucrose octasulfate
- Encapsulated in a liposome comprising DSPC, cholesterol, PEG2000-DSPE (PEG-DSPE) at 3:2:0.015
- ~0.15–1.5 moles irinotecan per mole total lipid
- This claim is then narrowed further by dependent claims 13–17 with particle size, loading per phospholipid, and encapsulation.
Route-specific formulation claim
- Claim 18 adds:
- intravenous administration (explicit)
- A more specific loading recital:
- ~0.5 moles irinotecan per mole total lipid
- ~500 mg irinotecan per mmol total phospholipid
- PEG2000-DSPE and lipid ratio are fixed to 3:2:0.015.
- Claims 19–20 further add encapsulation ≥90% and size 110–120 nm.
How dependent “alternative” claim language expands infringement risk
Claim 11 and claim 17 use “having at least one additional characteristic selected from the group.” In practice:
- If a product satisfies claim 1’s core constraints (irinotecan sucrose octasulfate liposomes; 150–500 mg irinotecan base per mmol phospholipid; and parenteral administration), then infringement may be triggered even if only one of the listed additional characteristics is present (for example, size 110–120 nm or ≥90% encapsulation or DSPC/cholesterol/PEG ratio depending on how the product is measured against the claim terms).
What exactly does “irinotecan sucrose octasulfate” require for infringement?
The claim language explicitly requires irinotecan sucrose octasulfate in the irinotecan liposomes. For infringement analysis, this functions as a composition-of-encapsulant element:
- A court/PHOSITA will typically treat this as requiring that the drug in the liposome is the irinotecan–sucrose octasulfate complex (not just irinotecan free base or irinotecan in an unrelated salt form).
- The patent then layers drug loading and encapsulation requirements on top.
Practical effect for competitive products
- A competitor that uses liposomal irinotecan with a different complexing/encapsulation form (if it truly is different from sucrose octasulfate complex) is pushed toward design-around potential, even if DSPC/cholesterol/PEG and size are similar.
- A competitor that uses irinotecan sucrose octasulfate but outside the loading/size ranges still may evade specific dependent claims, but independent claim 1 can still catch formulations meeting its loading floor and ceiling.
What liposome composition is covered (DSPC/cholesterol/PEG-DSPE) and what non-covered alternatives exist?
Fixed sub-combination
- Claims 9, 12, 18 specify DSPC + cholesterol + PEG2000-DSPE (PEG-DSPE) with a molar ratio of 3:2:0.015.
Partially covered sub-combination
- Claim 8 covers DSPC and cholesterol (without requiring PEG at the specified molar ratio in the provided text).
- Claim 1 also allows “one or more phospholipids” and does not explicitly require PEG, unless the infringement theory relies on dependent claim limitations.
Size requirement
- Many dependent claims and “alternative characteristic” lists require 110–120 nm.
Practical reading
- A formulation with DSPC/cholesterol but no PEG-DSPE can still fall into the scope if claim 1 is satisfied and the infringement theory relies on claim 1 + the appropriate alternative additional characteristic (where PEG is not required).
- Conversely, formulations with the right PEG ratio but with wrong encapsulated complex or wrong drug loading can fall outside.
How do the drug loading numbers constrain the patent’s coverage (mg/mmol phospholipid, moles/moles lipid, and mmol/g lipid)?
US 9,730,891 uses overlapping quantitative constructs. That matters because competitor product characterization can align with one metric while missing another.
Key numeric thresholds and ranges from the provided claims
| Claim element / metric |
Claimed value(s) in provided text |
Notes on infringement sensitivity |
| Irinotecan base per mmol total phospholipid |
150–500 mg/mmol (claim 1) |
A ceiling and floor: a competitor outside the range can reduce risk for claim 1 |
| Irinotecan per total lipid (moles/moles) |
0.02–5 (claim 3) and 0.15–1.5 (claims 1, 11, 12, 16, 17) |
Very broad independent coverage via claim 1 + dependent constraints; narrower subrange in claim 12/16 |
| Irinotecan per total lipid mass |
0.5 mg/mg (claims 4, 11) |
A single “about” value is typically narrower than a range but still tolerant of measurement uncertainty |
| Irinotecan per mmol total phospholipid |
~500 mg/mmol (claim 7 and claim 14/18 recitals) |
Dependent constraints can be avoided by moving away from ~500 mg/mmol |
| mmol irinotecan per 1 g lipid |
~0.8 mmol/g (claim 6 and 11(e)) |
Another “about” anchor that could be design-around by adjusting loading |
| mmol-based loading in claim 1’s statement |
“150–500 mg irinotecan base per mmol total liposome phospholipids” |
Total phospholipids may be measured differently depending on assay approach |
| Encapsulation |
≥90% encapsulated (claims 11, 15, 17, 19) |
If a competitor achieves lower encapsulation, it can attempt to avoid those dependent limitations, but claim 1 could still be infringed if claim 11/17 is not needed |
| Size |
110–120 nm (claims 10, 13, 20) |
Avoidable by changing formulation to shift size distribution |
Key point
Even if a competitor evades “about 0.5 mg/mg” and “about 500 mg/mmol,” the independent claim 1 can still capture compositions that meet its 150–500 mg/mmol phospholipid requirement, plus the other core compositional element (irinotecan sucrose octasulfate) and the administration method.
What particle size and measurement method is required (QELS, Gaussian model)?
Dependent claims 10, 13, and 20 require:
- Volume-averaged mean liposome size of about 110–120 nm
- Determined by quasi-elastic light scattering (QELS) using a Gaussian model
Scope impact
- If a competitor’s formulation yields a size distribution outside that window, or if reporting uses a different modeling approach rather than the Gaussian model as recited, it may be a path to reduce claim capture for those dependent limitations.
But claim 11 and 17 allow “at least one” from a list that includes the size limitation. So size avoidance must consider whether the product satisfies other alternative additional characteristics that do not require the 110–120 nm window.
How is “method of treatment” defined, and does it cover all indications?
The provided claim text defines:
- “A method of treatment” via administration of the composition to a patient.
- No explicit indication is recited in the text shown.
Claim consequence
- If the formulation falls within the claimed composition and is administered parenterally/IV as claimed, infringement exposure is tied to clinical use in practice rather than indication-specific claim wording.
When would US 9,730,891 expire and how does that drive generic or biosimilar timing?
No filing date, priority date, or patent term information is provided in the prompt, so expiration timing cannot be stated from the information available here.
What is the “patent estate” likely to look like around US 9,730,891 for liposomal irinotecan?
US 9,730,891 is a method-of-treatment patent with narrow formulation parameters. In a typical liposome platform, related estates often include:
- formulation patents defining lipid composition (DSPC/cholesterol/PEG-DSPE),
- encapsulation/drug loading and particle size patents,
- manufacturing/process patents defining how irinotecan sucrose octasulfate is incorporated,
- and method-of-use patents if specific administration schedules or indication-specific dosing is included.
However, the prompt provides no bibliographic data for other US patents in the same family (assignee, priority, continuations, CIP/divisional relationships) and no sister patent numbers. Without that, a complete estate mapping in the US cannot be produced.
What generic-entry risks exist for liposomal irinotecan in the presence of a method-of-treatment patent like 9,730,891?
Because the claims are method-of-treatment, a generic manufacturer can face:
- infringement by clinical administration: if a substituted product’s liposomes satisfy all claimed composition constraints and it is administered in the accused manner.
- Formulation design-around as the primary lever: the claim’s multiple numerical anchors make it sensitive to changes in loading ratios and particle size.
Most actionable design-around levers embedded in the claim text
- Avoid irinotecan sucrose octasulfate complex use (if possible while maintaining a working product).
- Move the drug loading so it falls outside the 150–500 mg/mmol phospholipid requirement for claim 1 and/or outside the dependent ~500 mg/mmol/0.5 mg/mg/0.8 mmol/g values.
- Shift particle size outside 110–120 nm (where dependent limitations apply).
- Reduce encapsulation below ≥90% (where dependent limitations apply).
- Alter PEG-lipid architecture away from 3:2:0.015 (where those dependent independent claims apply, especially claim 12 and 18).
Orange Book status, FDA reference product, and litigation/Paragraph IV posture
No FDA labeling, Orange Book listing, listed patents for the relevant NDC/RLD, or litigation docket data is provided in the prompt. A precise statement of Orange Book status, FDA pathways, and any Paragraph IV challenges cannot be produced from the available information.
Key Takeaways
- US 9,730,891 is a narrow formulation-linked method-of-treatment patent: infringement depends on parenteral/IV administration of a liposomal irinotecan composition using irinotecan sucrose octasulfate plus specific lipid/PEG architecture and quantitative loading and size parameters.
- Claim 1 provides the main coverage core via 150–500 mg irinotecan base per mmol total phospholipid and irinotecan sucrose octasulfate liposomes, with infringement potentially expanded via “at least one” additional characteristic in claim 11.
- Claims 12 and 18 tighten the scope to DSPC/cholesterol/PEG2000-DSPE at 3:2:0.015 and defined irinotecan-to-lipid loading targets.
- Dependent claims create multiple design-around paths: particle size (110–120 nm), encapsulation (≥90%), and specific loading metrics (including ~500 mg/mmol phospholipid and ~0.5 mg/mg total lipid).
- A full US patent landscape (family mapping, expiration, Orange Book listing, litigation, settlement) cannot be finalized from the information provided.
FAQs
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Does US 9,730,891 require a specific indication or disease state in the provided claim text?
No indication is stated in the claim language provided; the claims cover “a method of treatment” by administration of the specified composition.
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Can a product avoid infringement by changing liposome size outside 110–120 nm?
It may avoid dependent limitations that require 110–120 nm, but claim 11/17 “at least one additional characteristic” structure means size avoidance must be evaluated alongside other listed characteristics.
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Is PEG-DSPE mandatory for infringement under all claims?
Not from the provided text: claim 8 recites DSPC and cholesterol, and claim 1 broadly covers “one or more phospholipids.” PEG-DSPE at 3:2:0.015 is explicitly required in claims 9, 12, and 18.
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Which is the most critical claim element to avoid: irinotecan sucrose octasulfate or lipid composition?
The complex is a core element in claim 1 and claim 12: avoiding irinotecan sucrose octasulfate use is a more direct route than adjusting only lipid composition, which many claims still allow through “one or more lipids/phospholipids.”
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What formulation parameter is most likely to be litigated: encapsulation, drug loading, or particle size?
All three appear in dependent limitations. Drug loading and phospholipid-normalized thresholds are central to claim 1 and claim 12/18, while particle size and ≥90% encapsulation frequently appear as additional characteristic constraints.
References
- United States Patent No. 9,730,891 (claims provided in prompt).
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