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Patent landscape, scope, and claims: |
United States Patent 4,859,692 (Drug Patent): Claims Scope, Claim Construction, and U.S. Landscape
US Patent 4,859,692 is a composition-of-matter patent with layered scope: (i) a broad Markush-style genus defined by Formula Ia (claim 1), (ii) narrowing enumerations in dependent claims (claims 2-5, 8-11), (iii) a further defined “indole derivative” sub-genus through Formula IIa (claims 7-8), and (iv) explicit downstream coverage for pharmaceutical compositions and methods targeting leukotriene activity (claims 12-16), plus salt forms (claims 17).
The strongest commercial relevance is that the independent claim 1 is not directed to a single molecule. It covers a large set of indole-containing benzoyl sulfonamide structures with variable linker/connectivity rules, multiple substituent families, and multiple options for acidic groups that can be incorporated as salts.
What does claim 1 cover in plain chemical-legal terms?
Core structure logic
Claim 1 requires a compound of Formula Ia with substituent variables constrained as follows:
Finally, claim 1 covers pharmaceutically acceptable salts.
Legal character
Claim 1 is drafted as a classic Markush genus around a specific scaffold. The scope is large, but it is not open-ended. It is bounded by:
- the required scaffold connectivity implicit in Formula Ia,
- the permitted variable sets (Ra, Rb/Rc, Rd, R1, W, R2, Q, A1, A2, M),
- and the allowed acid functionalities.
This makes claim 1 the centerpiece for enforcement against any U.S.-sold generic or alternative that remains inside the genus.
How do dependent claims narrow scope (and where do they create “islands” of easier proof)?
Claim 2: enumerated exemplars create a more tractable claim set
Claim 2 narrows the genus by selecting from explicit lists:
- R1: limited to a set of specific alkyl and aryl-alkyl groups including benzyl, substituted benzyls (4-chloro, 4-CF3, 4-methyl), alpha-fluorobenzyl, alpha-methoxybenzyl, several cycloalkyl/alkyl variants including cyclohexen-4-yl
- R2: hydrogen, fluoro, chloro, bromo, methyl, methoxy
- R3: methyl, isopropyl, butyl, cyclopentyl, phenyl and selected phenyls (4-chloro, 4-methyl, 2-methyl, naphthyl, thien-2-yl, 6-chloropyrid-3-yl)
- Ra: H or methyl
- Rb/Rc: H each or combined unsaturation (tightens to the “unsaturation together with existing bond” condition)
- Rd: limited to enumerated families including:
- H, methyl, ethyl, propyl, butyl, pentyl, hexyl
- allyl, propargyl
- several substituted carboxy/carbamoyl/alkoxycarbonyl-bearing motifs (e.g., carboxymethyl, carboxyethyl, N-ethylcarbamoylmethyl, N,N-dimethylcarbamoylmethyl)
- cyclopentyl/cyclopropylmethyl and selected benzyl/cyano-benzyl options
- A1: methylene or ethylene
- A2: direct linkage or methylene
- Q: m-phenylene or p-phenylene with optional fluoro/chloro/hydroxy/methyl/methoxy/trifluoromethyl
- W: oxy, imino, thio, or direct linkage
Practical effect: claim 2 defines a smaller universe than claim 1 but still remains broad because each enumerated variable list is still large.
Claim 3 and 4: additional tightening around selected preferred chemistry
- Claim 3 picks particular subsets of claim 2 (e.g., R2 = H; Q has hydroxy/methoxy options only; W limited to oxy, imino, direct linkage).
- Claim 4 sets the explicit connectivity condition: Rb and Rc together with the existing C-C bond form an unsaturated linkage.
These dependent constraints are important because they create distinct sub-genus boundaries. In litigation, proving infringement can turn on whether the accused structure uses the “Rb/Rc unsaturated” embodiment.
Where does claim 7-8 create a distinct sub-genus (Formula IIa)?
Claim 7: switches to an “indole derivative” framing
Claim 7 states claim 4 “consisting of an indole derivative” of Formula IIa.
Even without the full structural depiction in the text excerpt, it does two things structurally:
- it locks the scaffold to an indole derivative embodiment;
- it ties the Markush variability to Formula IIa’s specific region.
Claim 8: enumerated IIa embodiments
Claim 8 enumerates three families:
- M = carboxy, Rd = methyl, propyl, 2-methoxyethyl, N-ethylcarbamoylmethyl, cyclopentyl
- M = --CO.NH.SO2 R4 with R4 = phenyl, and Rd = H, methyl, 2-methoxyethyl, N-ethylcarbamoylmethyl
- M = --CO.NH.SO2 R4 with R4 = 2-methylphenyl, and Rd = methyl, N,N-dimethylcarbamoylmethyl
Practical effect: claim 8 creates proof-friendly boundaries because it narrows both the acidic group class (carboxy vs sulfonamide-acidic residue) and the Rd variants in each branch.
What do claims 9-11 do: they lock specific molecules (species claims)
Claims 9-11 are essentially species enumerations tied to compound names that map onto the genus/sub-genus:
- Claim 9 lists eight specific compounds (a)-(h), each as a benzenesulphonamide-containing N-[...]-benzoyl indole derivative with defined substitution patterns and explicit Rd-like substituents such as:
- cyclopentyloxycarbonylamino
- cyclopentylureido
- 2-cyclopentylacetamido
- combinations with 1-methylindole and 3-methoxybenzoyl
- and includes both free acid and pharmaceutically acceptable salts.
- Claim 10 selects one of the listed species:
- N-[4-[5-(2-cyclopentylacetamido)-1-methylindo-3-ylmethyl]-3-methoxybenzoyl]-benzenesulphonamide
- Claim 11 selects another listed species:
- N-[4-[5-(cyclopentyloxycarbonyl)amino-1-methylindol-3-ylmethyl]-3-methoxybenzoyl]-2-methylbenzenesulphonamide
Practical effect: these are the “hardest” enforceable hooks because they directly name/define molecules. A direct match to any of these structures is infringement without relying on broad Markush interpretations.
Downstream claim coverage: composition and method of use (leukotriene antagonism)
Claims 12-13: pharmaceutical composition
- Claim 12: “A pharmaceutical composition having leukotriene antagonist properties” with:
- pharmaceutically effective amount of a claim 1 compound
- non-toxic pharmaceutically acceptable diluent/carrier
- Claim 13: composition can be “liquid or powdered aerosol”
This gives formulation protection tied to the active class.
Claims 14-16: method of use
- Claim 14: method for “antagonizing one or more of the actions of leukotrienes in a living mammal” by administering an effective amount.
- Claim 15: treatment of “allergic diseases, inflammatory diseases, endotoxic conditions or traumatic shock conditions.”
- Claim 16: specifically “treatment of allergic asthma.”
In enforcement, the key question becomes whether the accused product’s labeling or actual use aligns with these method claims, and whether the active ingredient falls within claims 1/2/3/4 (composition claims) or within the species of claims 9-11.
Claim 17: salts
Claim 17 explicitly covers “a salt of a compound claimed in any of claims 1-4 and 7-10.”
This extends protection to salt forms for the relevant sub-genus and the indole derivative embodiments.
How to map the claim scope to a patent landscape strategy
Without external bibliographic data, the U.S. patent landscape here is treated strictly as a scope-and-claim analysis of what would fall inside or outside this patent. The following analysis is designed for infringement screening and freedom-to-operate triage based on claim features.
Feature checklist for “inside claim 1”
A candidate structure is likely inside claim 1 if it satisfies, at minimum:
- It has the required scaffold corresponding to Formula Ia:
- indole-like core implied by later claims (7-8), but claim 1 itself already defines a benzoyl-linked sulfonamide framework via Q and acidic group M
- It uses an allowable:
- acidic group M = carboxy or 1H-tetrazol-5-yl or acylsulphonamide residue --CO.NH.SO_m R3 (m=1/2)
- The amidic radical R1.L-- fits:
- R1.W.CO.--NH-- or R1.W.CS.NH--
- Substitution rules for:
- Ra (H or C1-4 alkyl)
- Rb/Rc (both H or unsaturation formed together with existing C-C bond)
- Rd (H/C1-10 alkyl with optional substituents or alternate ring/phenylalkyl groups as defined)
Feature checklist for “inside the tighter corridors”
- Inside claim 2: in addition to claim 1, variables must match the enumerated lists for R1/R2/R3/Rd/A1/A2/Q/W.
- Inside claim 3: further restricts R2 = H; limits R3 to phenyl or 2-methylphenyl; Ra = H; and narrows Q and W choices.
- Inside claim 4: fixes the unsaturation embodiment.
- Inside claim 7-8: must correspond to Formula IIa indole derivatives and use M/Rd combinations from claim 8’s enumerated branches.
- Inside claim 9-11: must match one of the named species.
Infringement “fault lines”
Design-around is most likely to succeed by changing one of these fault-line features:
- Acid functionality M: switching away from carboxy, 1H-tetrazol-5-yl, or the specified acylsulphonamide residue family would push the molecule outside claims 1-4 and 7-10.
- Amidic radical pattern (R1.W.CO.--NH-- vs R1.W.CS.NH--): altering the core amidic chemistry so it no longer matches the CO-NH or CS-NH motif would eliminate coverage.
- Rb/Rc unsaturation requirement: if claim 4’s unsaturation embodiment is required (via dependency), deleting that exact connectivity would matter.
- W linker identity: oxy/thio/imino/direct-link rules create another boundary.
- A1/A2 connectivity: direct link vs methylene/vinylene changes may move the structure outside the permitted A1/A2.
US patent 4,859,692: claim scope summary by hierarchy
Claim coverage matrix
| Claim |
Type |
Scope driver |
Practical enforceability |
| 1 |
Genus |
Formula Ia Markush variables (Ra, Rb/Rc, Rd, R1, W, R2, Q, A1, A2, M) |
Broad; depends on Markush interpretation |
| 2 |
Narrower genus |
Enumerated lists for R1/R2/R3/Rd/A1/A2/Q/W |
Medium-broad; proof via substitution set matching |
| 3 |
Further narrower |
Select subsets: R2 = H; R3 = phenyl/2-methylphenyl; Q options limited; W limited |
Better-defined corridor |
| 4 |
Connector constraint |
Rb/Rc together form unsaturated linkage |
Critical if accused structure depends on this feature |
| 7 |
Sub-genus |
“Indole derivative” Formula IIa |
Scaffold-locked; simpler mapping |
| 8 |
Enumerated species sub-genus |
M/Rd enumerations under IIa |
Proof-friendly branching |
| 9 |
Species list |
Eight explicitly named compounds |
High; direct mapping |
| 10-11 |
Species subset |
Select two species from claim 9 list |
Highest clarity |
| 12-13 |
Formulation |
Leukotriene antagonist composition with carrier |
Tied to active-in-claim |
| 14-16 |
Method of use |
Leukotriene antagonism and disease indications |
Depends on product label/use and active coverage |
| 17 |
Salt |
Salts of compounds in claims 1-4 and 7-10 |
Extends coverage to salt variants |
Key Takeaways
- Claim 1 is a large Markush genus around a specific indole-benzoyl sulfonamide framework with constrained variable sets, especially the acidic group M and the amidic radical R1.W.CO.--NH-- / R1.W.CS.NH--.
- Claims 2-5 narrow the genus using explicit enumerations and connectivity rules (notably the Rb/Rc unsaturated linkage).
- Claims 7-8 lock the scope into an indole derivative sub-genus (Formula IIa) and enumerate allowed M/Rd combinations.
- Claims 9-11 are species-level protection for eight named molecules, with two singled out.
- Claims 12-16 extend protection to leukotriene-antagonist pharmaceutical compositions and methods for allergic and inflammatory indications, including allergic asthma.
- Claim 17 extends coverage to salts for the relevant sub-genus/species sets.
FAQs
1) Which claim is the main infringement target for composition coverage?
Claim 1 is the central composition-of-matter claim, covering the widest genus of Formula Ia embodiments and their pharmaceutically acceptable salts.
2) What structural element most reliably narrows the scope across the whole claim set?
The acidic group M definition is the most global constraint, because it is required across claim 1 and then further specialized in claims 7-8 and species listings in claims 9-11.
3) Do claims 9-11 function like independent claims or species lists tied to the genus?
They function as species lists captured as dependent claims within the genus-to-species hierarchy. Each listed molecule is covered as a distinct protected embodiment.
4) Are leukotriene antagonism and specific indications protected as composition claims or method claims?
They are protected as method-of-use claims in claims 14-16, and as a composition in claims 12-13 tied to leukotriene antagonist properties.
5) What is the key design-around lever most likely to move a candidate outside the patent?
Changing the molecule so it no longer matches one of the claim’s required families, especially the amidic radical pattern (CO-NH or CS-NH with permitted W) or the acidic group M family.
References
[1] U.S. Patent 4,859,692 (claims as provided in prompt text).
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