|
Patent landscape, scope, and claims: |
US Patent 6,821,987: Scope, Claims, and Patent Landscape
United States Patent 6,821,987 is a small-molecule urea patent family focused on a defined chemical scaffold (formula I, with specific sub-formulas Ia and Ib) and broad structural latitude around substituents on multiple ring systems. Claim coverage expands across: (1) the compound class itself (Markush-style ranges), (2) specific exemplified embodiments with defined substitution patterns, (3) pharmaceutical compositions, and (4) multiple therapeutic and biological methods that target angiogenesis and cancer.
What is the claim structure and what is actually covered?
Core subject matter (compound claims)
The independent compound claim is claim 1. It covers:
- “A compound represented by formula (I) or a pharmaceutically acceptable salt or solvate thereof.”
- The scaffold has a constrained core with variable substituents controlled by:
- X and Z: CH
- Y: O or S
- R1, R2, R3: H or C1-6 alkyl/alkoxy/alkenyl/alkynyl, nitro, amino, with optional halogen substitution on the alkyl/alkoxy/alkenyl/alkynyl substituents
- R4: H
- R5-R8: H, halogen, C1-4 alkyl/alkoxy, C1-4 alkylthio, CF3, nitro, amino
- R9, R10: H, C1-6 alkyl, or C1-4 alkylcarbonyl (with optional halogen substitution on the alkyl portion)
- R11: “azolyl” optionally halogen-substituted, with allowable azolyl substitution patterns limited to C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio, CF3, nitro, amino, and amino substitutions optionally by C1-4 alkyl groups
- Heteroaromatic/heterocyclic substituent group: “R14-(S)m” where R14 is a saturated or unsaturated three- to seven-membered carbocyclic or heterocyclic group, m is 0 or 1
Claim 1 is the broadest coverage lever in the patent. It is not confined to a single final API molecule; it is a parametric coverage set that can include many analogs, salts, and solvates falling within the variable definitions.
Narrower dependents (specific subset control)
Claims 2 and 3 narrow the substituent sets:
- Claim 2: restricts R1 = H, R9 = H, R10 = H
- Claim 3: defines the compound by formula (Ia):
- X = CH
- R15 and R16: C1-6 alkoxy
- R17-R20: H or a halogen, C1-4 alkyl/alkoxy/alkylthio, CF3, nitro, amino
- R21: azolyl with one of groups (i)-(iv) (defined in later claims)
Claims 4-9 further narrow R15 and R16 and constrain at least one of R17-R20 to specific substituent classes (halogen including Cl/F, alkyl, alkoxy, alkylthio/CF3/nitro/amino).
Strong sub-structural constraints via “azolyl” groups (R21)
The patent’s breadth and medicinal chemistry focus concentrate around R21, an azolyl group expressed via four specific group types:
- Group (i) through Group (iv) with a Q linker atom (O, S, or NH)
- R22 and R23: H or the same class of substituents:
- halogen, C1-4 alkyl, C1-4 alkoxy, C1-4 alkylthio, CF3, nitro, amino (with amino optionally substituted by C1-4 alkyl), C1-4 alkoxycarbonyl C1-4 alkyl, C1-4 alkylcarbonyl, or C3-5 cyclic alkyl
This construct supports both:
- general coverage for many azolyl variants, and
- explicit capture of specific azolyl embodiments in later claims.
Examples inside the claims (direct chemical recitations)
Claims 26, 54, 55, 56, and 57 recite specific urea molecules by name/form.
Notably:
- Claim 26: N-{2-chloro-4-[(6,7-dimethoxy-4-quinolyl)oxy]-phenyl}-N′-(5-methyl-3-isoxazolyl)urea
- Claim 54: N-{3-chloro-4-[(6,7-dimethoxy-4-quinolyl)-oxy]phenyl}-N′-(3-isoxazolyl)urea
- Claim 55: N-{4-[(6,7-dimethoxy-4-quinolyl)-oxy]-3-fluorophenyl}-N′-(3-isoxazolyl)urea
- Claim 56: N-{4-[(6,7-dimethoxy-4-quinolyl)-oxy]-3-fluorophenyl}-N′-(5-methyl-3-isoxazolyl)urea
- Claim 57: N-{4-[(6,7-dimethoxy-4-quinolyl)-oxy]-2-fluorophenyl}-N′-(5-methyl-3-isoxazolyl)urea
These explicit claims are important for enforcement because they lock down commercially relevant embodiments even if generic ranges are later contested.
How broad is claim 1 versus the later formulas (Ia and Ib)?
Breadth comparison table
| Claim layer |
Coverage expression |
Key narrowing controls |
Practical scope |
| Claim 1 |
Formula (I) with Markush-like substituent variable definitions |
Y = O or S; R4 = H; broad R1-R11 definitions; R14-(S)m limited to C3-7 ring groups |
Broad chemical class coverage across multiple substitution dimensions |
| Claim 3 (via Ia) |
Formula (Ia) |
R15/R16 = C1-6 alkoxy; R17-R20 restricted to specific small substituent sets; R21 restricted to defined azolyl group families (i)-(iv) |
Medium breadth: still large but focused on the azolyl + quinoline/aryl substitution pattern |
| Claim 23 (via Ib) |
Formula (Ib) |
fixes MeO = methoxy; X = CH; limits R17-R18-R19; R21 restricted to (i)-(iv); R18/R17/R19 substitution constraints |
Narrower subset within the already narrowed Ia region |
| Claims 26, 54-57 |
explicit urea molecules |
exact aryl halogen position and exact isoxazolyl substitution |
Narrowest, highest-evidentiary weight for enforcement |
What does the patent cover in therapy: methods and compositions?
Pharmaceutical composition claim
- Claim 27: “A pharmaceutical composition comprising the compound according to claim 1 or a pharmaceutically acceptable salt or solvate thereof as an active ingredient.”
This is a straightforward formulation capture. It ties compositions to claim 1 coverage.
Treatment and biological function methods (multiple indications)
The patent includes broad “method of treatment” and “method of inhibiting angiogenesis” claims:
- Claim 28: treat a disease selected from:
- diabetic retinopathy
- chronic rheumatism
- psoriasis
- atherosclerosis
- Claim 29: “method for inhibiting the angiogenesis of blood vessels” by contacting vascular endothelial cells
- Claim 30: treat Kaposi’s Sarcoma
- Claim 31: treat malignant tumor, lung tumor
- Claim 32: treat malignant tumor, colon tumor
Enforcement impact of method claims
- Method claims increase leverage for downstream developers because they can be asserted without matching every structural analog, as long as the accused product contains a covered compound and is used in the claimed therapeutic method context.
- The angiogenesis method (claim 29) is mechanistically phrased and can be useful for regulatory presentations and clinical claims.
Which dependent claims create enforceable “islands” within the structure space?
Claims 10-23 use R21 group definitions as the principal structure islands. Then claims 24-25 and 33-38 further restrict Q and substituent positions on the azolyl ring.
R21 group specificity (claims 10-23)
Exemplified R21 options by further constraints
- Claim 24: for R21 = group (iii), Q = S
- Claim 25: R22 and R23 are H/H or H/alkyl
Special-case claim series focused on isoxazolyl
- Claim 36: “wherein R11 represents optionally substituted isoxazolyl”
- Claim 39: “wherein R21 represents optionally substituted isoxazolyl”
- Claims 37-38: Q = O; R22 = C1-4 alkyl; R23 = H; and R22 can be methyl
These claims align strongly with the recited exemplars that use isoxazole/isoxazolyl urea substituents.
What is the scope implied by the explicit example molecules?
The explicitly recited urea molecules establish:
- a quinoline-oxy aryl ether core with 6,7-dimethoxy-4-quinolyl as the oxy-substituted heteroaryl moiety
- an anilide urea linkage with varying halogen substitution on the phenyl (2-F, 3-F, 3-Cl, 2-F, etc.)
- an N′ substituent on urea derived from isoxazole:
- either 3-isoxazolyl or 5-methyl-3-isoxazolyl
For portfolio and landscape purposes, those fixed elements mean the patent’s commercially salient region is centered on:
1) 6,7-dimethoxy-4-quinoline oxygenated aryl urea derivatives, and
2) isoxazolyl urea N′ substitution patterns, especially methyl at the 5-position.
Patent landscape: what to check around 6,821,987 (and why this matters)?
1) Family and continuation risk
Given that US 6,821,987 is a multi-claim compound patent with broad Markush language, landscape diligence typically focuses on:
- earlier priority filings that define the scaffold and early examples
- later continuations or divisionals that may capture:
- narrower positional isomer subsets (e.g., 2-F vs 3-F vs 3-Cl)
- specific azolyl variants (isoxazolyl vs oxazolyl vs thiazolyl)
- new formulation or method-of-use coverage (angiogenesis, lung/colon tumor, Kaposi’s sarcoma)
Even without viewing the full bibliographic record here, the internal claim architecture indicates there are multiple patentable “planes” (compound breadth, azolyl variants, and method-of-use breadth). Those are classic targets for continuation practice.
2) Freedom-to-operate (FTO) pinch points
For an accused product or pipeline candidate, FTO risk concentrates on matching:
- Core scaffold corresponding to formula (I)/(Ia)/(Ib) structural relationships
- Y = O or S, and the specific aryl/heteroaryl oxy linkage pattern
- The urea nitrogen substituents:
- N′ must fall within R11 azolyl or R21 group families
- The aryl halogen pattern on the phenyl ring (claims 26, 54-57 show multiple halogen positional embodiments)
If a competitor changes the N′ heterocycle off the defined azolyl families (e.g., swaps to a non-azolyl amide substituent), it can move outside R11/R21 definitions, depending on the exact structure mapping to formula (I).
3) Method-of-use entry points
If a competitor’s clinical development aims at angiogenesis inhibition or the enumerated indications (diabetic retinopathy, psoriasis, Kaposi’s sarcoma, lung/colon tumors), method-of-use claims become relevant even if the chemical entity is within or close to coverage.
Where a competitor uses a covered compound, the method language in claims 28-32 can be a direct enforcement vector.
Claim-by-claim enforcement map (highest to lowest priority)
- Claim 1 (formula I, salts/solvates): broad chemical class anchor.
- Claim 3 (formula Ia): narrows the class but keeps significant substitution freedom.
- Claims 10-22: define the azolyl families and ring types that likely correspond to commercial exemplars.
- Claim 23 (formula Ib): a further narrowed path that still retains R21 generality.
- Claims 24-25, 33-38, 36-39, 40-51, 52-53: additional constraint islands on Q, R22/R23, and halogen positions.
- Claims 26, 54-57: explicitly recited embodiment molecules with the highest practical claim certainty.
Key Takeaways
- US 6,821,987 claims a urea-based small-molecule class defined by formula (I), with broad Markush-style latitude on substituents (R1-R11) and explicit coverage of salts and solvates.
- Coverage narrows through formula (Ia) and formula (Ib), with the most commercially aligned variability centered on R21/R11 azolyl and aryl halogen substitution patterns.
- The patent extends beyond compounds into pharmaceutical compositions and multiple method-of-treatment/use claims, including angiogenesis inhibition and specific indications (diabetic retinopathy, chronic rheumatism, psoriasis, atherosclerosis, Kaposi’s sarcoma, lung and colon tumors).
- Enforcement focus typically concentrates on whether an accused product matches the core scaffold and N′-azolyl urea substituent definitions and whether the product is used for any of the claimed method-of-use contexts.
FAQs
1) Does the patent claim salts and solvates as part of the protected subject matter?
Yes. Claim 1 and its downstream coverage repeatedly include “pharmaceutically acceptable salt or solvate thereof.”
2) What is the most important substituent group for structural scope?
R11 in claim 1 and R21 in claims 3/10-23 are the azolyl-variant drivers. They define the allowed azolyl ring types and substituent patterns.
3) Which dependent claims most directly lock down commercial embodiments?
Claims 26 and 54-57 recite specific urea molecules by name, tying protection to exact halogen positions on the phenyl ring and specific isoxazolyl substitution patterns.
4) Are method-of-use claims limited to one indication?
No. Claims include diabetic retinopathy, chronic rheumatism, psoriasis, atherosclerosis, angiogenesis inhibition, Kaposi’s sarcoma, and malignant tumors including lung and colon.
5) Can the patent protect a pharmaceutical composition even if the formulation is new?
Claim 27 protects a pharmaceutical composition containing a compound of claim 1 (or its salts/solvates) as the active ingredient.
References
[1] United States Patent 6,821,987, claims 1-57 (as provided).
More… ↓
⤷ Start Trial
|
