US Patent 4,873,259 (United States Drug Patent) Scope, Claim Breadth, and Landscape
What is patented under US 4,873,259?
US Patent 4,873,259 claims chemical entities defined by a broad substituted heteroatom-containing scaffold (claim set 1-12), plus biological use directed to 5- and/or 12-lipoxygenase inhibition (claims 13-24) and pharmaceutical compositions for that use (claim 25).
The claims are structured around:
- A core formula (claim 1) with multiple modular substituents (R1, X, A, n, Y, Z, M).
- A secondary, narrower Markush subset (claim 2) that defines specific choices for additional variables (R5, B, W, M).
- Dependent single-point embodiments (claims 3-12; 15-21; 18-20; 22-24) that lock in particular substituent selections.
- Method of treatment claims (claim 13) and composition claims (claim 25), each tied to the same compound genus.
What is the claim 1 chemical genus scope?
Claim 1 covers “A compound of the formula” with the following variable definitions:
Core variable framework in claim 1
- R1: one of
1) hydrogen
2) C1 to C4 alkyl
3) C2 to C4 alkenyl
4) NR2 R3, where:
- R2 and R3 each independently are hydrogen, C1 to C4 alkyl, or hydroxyl
- R2 and R3 are not simultaneously hydroxyl
- X: oxygen, sulfur, SO2, or NR4, where
- R4 is hydrogen, C1 to C6 alkyl, C1 to C6 alkoyl, aroyl, or alkylsulfonyl
- A: C1 to C6 alkylene or C2 to C6 alkenylene
- n: 1 to 5
- Y: independent substitution at each occurrence, chosen from 18 categories:
1) hydrogen
2) halogen
3) hydroxy
4) cyano
5) halosubstituted alkyl
6) C1 to C12 alkyl
7) C2 to C12 alkenyl
8) C1 to C12 alkoxy
9) C3 to C8 cycloalkyl
10) C1 to C8 thioalkyl
11) aryl
12) aryloxy
13) aroyl
14) C1 to C12 arylalkyl
15) C2 to C12 arylalkenyl
16) C1 to C12 arylalkoxy
17) C1 to C12 arylthioalkoxy
18) substituted derivatives of aryl/aryloxy/aro yl/arylalkyl/arylalkenyl/arylalkoxy/arylthioalkoxy
- with substituents limited to halo, nitro, cyano, C1 to C12 alkyl, alkoxy, or halosubstituted alkyl
- Z: oxygen or sulfur
- M: hydrogen, pharmaceutically acceptable cation, aroyl, or C1 to C12 alkoyl
Immediate takeaways on genus breadth
Claim 1 is a large Markush genus that allows:
- Multiple heteroatom options in the linker/head group (X and Z).
- Variable saturation and length (A and n).
- Very wide aromatic substitution capacity through Y, including long-chain and aryl-alkyl/aryl-alkoxy/aryl-thioalkoxy patterns, plus restricted aryl substituted derivatives.
- High tolerance to functional groups on R1 via alkyl/alkenyl or secondary/tertiary amine patterns with hydroxyl allowed but restricted by “not simultaneously hydroxyl.”
From a freedom-to-operate (FTO) perspective, the claim is best viewed as a chemotype family where infringement hinges on:
1) matching the scaffold formula (as printed in the patent),
2) matching at least one allowed selection for each variable position (R1, X, A, n, Y at each occurrence, Z, M).
What is the narrowed genus subset in claim 2?
Claim 2 defines a compound of claim 1 with additional specified structural constraints:
- R5: C1 or C2 alkyl, or NR6 R7 where R6 and R7 are independently hydrogen or C1 or C2 alkyl.
- B: CH2 or CHCH3
- W: oxygen or sulfur
- M: hydrogen, pharmaceutically acceptable cation, aroyl, or C1 to C12 alkoyl
Claim 2 is therefore a subset of the claim 1 space, with:
- tighter control over one substituent group (R5),
- control over a specific backbone element (B),
- and control over another heteroatom option (W).
How do dependent claims narrow claim 1 in practice?
The dependent claims lock in specific “point” embodiments that can be used to anchor prior art comparisons or claim charts.
Claim 3-7: specific R1 and A choices
- Claim 3: R1 is CH3
- Claim 4: R1 is NH2
- Claim 5: R1 is NHCH3
- Claim 6: A is --CHCH3--
- Claim 7: A is --CH2--
Claim 8-9: specific X choices
- Claim 8: X is sulfur
- Claim 9: X is oxygen
Claims 10-12 and 11-12:
These claims recite additional fixed structures (“having the formula” with STR13/STR14/STR15). Without the embedded drawings/text of those structures, the exact substituent sets are not reproducible here. The important legal point is that they are further constrained embodiments within the already broad genus of claim 1.
What is the method-of-use claim scope?
Claim 13 claims:
- “A method for inhibiting 5- and/or 12-lipoxygenase activity in a mammal”
- by administering a therapeutically effective amount
- of a compound of claim 1
Claims 15-21 mirror dependent compound locks applied to the method:
- Claim 15: R1 is CH3
- Claim 16: R1 is NH2
- Claim 17: R1 is NHCH3
- Claim 18: A is --CHCH3--
- Claim 19: A is --CH2--
- Claim 20: X is sulfur
- Claim 21: X is oxygen
Claims 14 and 22-24 narrow the method to additional specific formula blocks:
- Claim 14: method claim where the compound has the same structured constraints as claim 2 (R5, B, W, M).
- Claims 22-24: method where the compound has fixed structures (STR17/STR18/STR19).
Claim 25: composition scope
Claim 25:
- “A pharmaceutical composition for inhibiting 5- and/or 12-lipoxygenase”
- with a pharmaceutical carrier
- and a therapeutically effective amount of a compound of claim 1.
This is a typical use-driven composition claim: non-drug carrier plus drug amount.
How broad is infringement risk across the claim set?
In terms of risk mapping, the claims fall into two layers:
1) Chemical infringement (claims 1-12)
Any product that matches the claim 1 formula and substituent selections can fall inside the genus, regardless of intended use (subject to how the formula is interpreted in the issued patent).
2) Use infringement (claims 13-25)
Even if a compound is made, if it is used to inhibit 5- and/or 12-lipoxygenase via administration, the method and composition claims can be triggered.
Practical consequence:
- A single optimized analog that still fits the variable lattice for X, R1, A, n, Y, Z, M can land in the claim set even if it is “chemically distinct” from a competitor’s marketing lead.
- Conversely, if a competitor’s series substitutes outside the defined variables (or changes the scaffold in a way that breaks the printed formula), it can avoid literal scope.
What is the likely patent landscape shape around this disclosure?
Based on the claim structure alone, US 4,873,259 presents a landscape characterized by:
- A dominant genus claim (claim 1) with extensive Markush options.
- A secondary constrained subset (claim 2) that often functions as a “fallback” and can support additional enforceable coverage if the full genus is attacked.
- A use layer (claims 13-25) that binds biological intent to the compound genus.
From an enforcement standpoint, the strongest handles are typically:
- claim 1 genus match to a specific competitor analog,
- claim 2 subset match to a competitor’s “lead-like” series member,
- method/composition claims if clinical or label-like disease targeting is aligned to lipoxygenase inhibition.
From an R&D planning standpoint, this structure usually drives two competitive outcomes:
- Analog strategy within the lattice (to stay inside or around depending on who you are).
- Scaffold redesign strategy outside the lattice (to break the chemical definition).
What claim elements are the highest-leverage decision points for FTO?
Within the claim 1 variable list, the elements that most often determine “inside vs outside” in practical patent screens are:
- X and Z (heteroatom definitions): oxygen/sulfur/SO2/NR4 and oxygen/sulfur. Changing heteroatom identity can break literal scope quickly.
- A and n (linker length/saturation): C1-C6 alkylene or C2-C6 alkenylene; n = 1-5. These drive scaffold conformation and structural identity.
- Y substitution domain: extremely broad. This reduces design freedom for avoiding infringement unless the substitution pattern itself is coupled to the scaffold (for example, if the competitor cannot match the number or positions of Y occurrences).
- R1 (amine/aliphatic substitution with restricted hydroxyl pairing): the hydroxyl restriction on NR2R3 is a distinctive gating rule.
Key takeaways
- US 4,873,259 has a broad claim 1 genus built on variable definitions for R1, X, A, n, Y, Z, and M, with very wide substitution latitude through Y.
- The patent adds a subset in claim 2 (R5, B, W, M) that can function as a practical fallback for enforcement.
- Claims 13-25 convert the chemical genus into functional coverage via 5- and/or 12-lipoxygenase inhibition and extend that to methods and pharmaceutical compositions.
- For FTO and competitive design, the most leverage points are X/Z heteroatom choices and A/n scaffold identity; Y substitution breadth is so wide that it often does not provide a clean avoidance path by itself.
FAQs
1) Does US 4,873,259 cover only specific lipoxygenase indications?
The claims are not limited to a named disease. They cover methods of inhibiting 5- and/or 12-lipoxygenase activity in a mammal.
2) Is the chemical coverage limited to one lead compound?
No. Claim 1 is a large Markush genus across multiple substituent classes, and dependent claims enumerate specific embodiments.
3) Can infringement occur through a method even if compound identity is the same?
Yes. Claim 13 and claim 25 impose use-based coverage for administration of claim 1 compounds to inhibit 5- and/or 12-lipoxygenase.
4) Which variables most constrain redesign to avoid the claim?
X, Z, A, and n tend to be higher-impact because they define core structural identity and heteroatom/linker placement.
5) Does claim 2 matter if you are analyzing claim 1 coverage?
Yes. Claim 2 defines a narrower structural subset with specified choices (R5, B, W, M) that can survive scenarios where broader genus coverage becomes harder to apply.
References
[1] U.S. Patent 4,873,259, “(claims as provided by user text): compounds of the formula; inhibitors of 5- and/or 12-lipoxygenase; pharmaceutical compositions.”
