US Patent 6,140,329: Scope, Claim Structure, and U.S. Patent Landscape for Erectile Dysfunction
What does US 6,140,329 claim in scope?
US 6,140,329 is directed to methods of treating erectile dysfunction (ED) in a male animal and pharmaceutical compositions/formulations that contain a defined class of small-molecule compounds (formula (I)) and enumerated stereoisomeric species. The claims are built around (1) a broad Markush formula (I) covering variable substituents, (2) a narrower set of named individual compounds (including specific stereochemistry), and (3) composition and packaging claims (carrier/diluent; combination with another agent), plus oral administration dependencies.
Core therapeutic indication
- Erectile dysfunction
- Male animal (covering humans by standard interpretation of “male animal” in ED therapeutics)
How is “formula (I)” framed in Claim 1?
Claim 1 is the broadest “method” anchor and recites administration of a compound of formula (I) and salts and solvates, with a substitution framework:
Claim 1 (method)
- Treatment of erectile dysfunction in a male animal
- Administration of a compound of formula (I) (plus salts/solvates)
- Substituent definitions:
R0
- Hydrogen, halogen, or C1-6 alkyl
R1
- Hydrogen
- C1-6 alkyl
- C2-6 alkenyl
- C2-6 alkynyl
- haloC1-6 alkyl
- C3-8 cycloalkyl
- C3-8 cycloalkyl-C1-3 alkyl
- arylC1-3 alkyl
- heteroarylC1-3 alkyl
R2
- Optionally substituted mono-cyclic aromatic ring selected from:
- benzene, thiophene, furan, pyridine
- Or optionally substituted bi-cyclic ring:
- attached to the rest of the molecule via one of the benzene ring carbon atoms
- Fused ring A
- 5- or 6-membered ring
- saturated or partially/fully unsaturated
- contains carbon atoms and optionally one or two heteroatoms:
- O, S, N
R3
- Hydrogen or C1-3 alkyl
- Or R1 and R3 together form a 3- or 4-membered alkyl or alkenyl chain
Practical meaning for enforcement
Claim 1 is not limited to any one stereoisomer or any one aryl substituent; it captures a chemical space defined by the R-variables plus salts/solvates.
Which individual compounds are singled out?
Multiple claims (2, 3, 9, 11, 13, 14, 19, 21) enumerate specific stereodefined molecules. Two distinct “families” appear in the text you provided:
1) Two hexahydro pyrazino-pyrido-indole-1,4-diones with “(6R,12aR)” vs “(3S,6R,12aR)” stereochemistry:
- (6R,12aR)-2,3,6,7,12,12a-hexahydro-2-methyl-6-(3,4-methylenedioxyphenyl)pyrazino[2',1':6,1]pyrido[3,4-b]indole-1,4-dione
- (3S,6R,12aR)-2,3,6,7,12,12a-hexahydro-2,3-dimethyl-6-(3,4-methylenedioxyphenyl)pyrazino[2',1':6,1]pyrido[3,4-b]indole-1,4-dione
2) A broader enumerated list of cis- and (6R,12aR)-configured derivatives, including substitutions such as:
- pyridylmethyl
- dihydrobenzo[b]furan
- bromo-thienyl
- butyl-phenyl
- isopropyl-methylenedioxyphenyl
- cyclopentyl-methylenedioxyphenyl
- cyclopropylmethyl-methoxyphenyl
- chloro-methoxyphenyl
- methyl/methylenedioxyphenyl
- “octahydro” pyrrolo-bridged derivative
Claim 9 and Claim 11 expand the enumerated set to many additional structures (cis and specific stereoisomers). Claim 19 and Claim 21 similarly enumerate a smaller subset focused on (6R,12aR) stereochemistry variants.
How do the claim types stack (method vs composition vs process vs combination)?
The patent’s claim architecture follows a standard but effective ERG pattern: cover the drug substance (by formula/Markush), the use (ED method), the product (composition/formulation with carrier), and administration modality (oral).
Claim-by-claim structure (from your provided text)
Method (primary)
- Claim 1: Method of treatment using formula (I) compound(s) + salts/solvates (broad Markush)
- Claim 2: Method using two explicitly named compounds + salts/solvates
- Claim 5: Method of treating using composition of Claim 3 (effective amount)
- Claim 8: Claim 1 with oral administration
- Claim 10: Claim 9 with oral administration
- Claims 16, 17: Additional formula-based method variants, with oral dependency in Claim 17
- Claims 18-20: Further method variants and oral dependency in Claim 20
- Claims 19, 21: Method using enumerated subset compounds; Claim 21 includes a “with another diluent/carrier” structure and is a method-treatment composition path
Composition (drug product)
- Claim 3: Pharmaceutical composition for ED containing two named compounds + salts/solvates + siluent/carrier (spelling as given)
- Claim 7: Pharmaceutical formulation of Claim 6 with diluent/carrier
- Claims 11, 14, 21: Composition/formulation claims tied to enumerated compound sets
Process / formulation
- Claim 4: Process for preparing the composition of Claim 3 by formulating with diluent/carrier
Combination therapy
- Claim 6: Composition including the enumerated compound(s) plus another therapeutically active agent for simultaneous/separate/sequential use
Takeaway on legal coverage
Coverage density is high around:
- “administration” (method claims)
- “pharmaceutical composition” and “formulation” (carrier/diluent)
- “combination” (use with another active agent)
- “oral dosing” (multiple dependencies)
What is the likely “landscape” structure around this patent (scope-driven rather than database-driven)?
Without a live citation pull of the full U.S. family members, continuations, and related filings, the most reliable landscape assessment you can do from the claim text alone is scope adjacency: identify the likely competitive design-around and the likely follow-on claim positions.
1) Likely competitive overlap zones
From the claim language, infringement risk clusters where products or candidates fall into:
- Same ED indication (method-of-use claims)
- Same compound scaffold class (formula (I) Markush)
- Same specific stereoisomer set (enumerated “named compounds”)
- Same delivery modality (oral administration dependencies)
- Same formulation carrier class (composition claims are broad: “pharmaceutically acceptable diluent or carrier”)
2) Likely design-around levers (based on the claim text)
A competitor could attempt to move outside coverage by changing at least one of the claim anchors:
- Chemical space shift: leaving formula (I) by changing substituent classes so R0/R1/R2/R3 fall outside the defined ranges (especially R2 aromatic/bicyclic constraints and the fused ring A heteroatom set)
- Stereochemical divergence: for products that rely on Claim 2 / Claim 9 / Claim 19 enumerations, avoiding those specific stereoisomers can reduce risk for those narrower claims, while Claim 1 may still capture some variants within formula (I)
- Form factor: changing route of administration alone may not avoid Claim 1, but it can target the oral-dependent dependent claims (Claims 8, 10, 17, 20) if the marketing route is non-oral
- Combination composition: Claim 6/13 capture combination therapy where “another therapeutically active agent” is present. Monotherapy that omits combination may reduce exposure to those combination claims while still leaving method/composition claims
3) How the Markush breadth changes the landscape
Claim 1’s Markush definition is broad enough that many “nearby” analogs can still fall into formula (I) unless the modifications violate at least one of:
- permissible R0 halogen/C1-6 alkyl
- permissible R1 substituent families (alkyl, alkenyl, alkynyl, cycloalkyl, aryl-alkyl, heteroaryl-alkyl)
- permissible aromatic/bicyclic choice for R2 and the attachment geometry
- fused ring A size (5 or 6), saturation state, and heteroatom count/type
- chain constraint in R3 (including R1-R3 cyclization into 3- or 4-membered chain)
In other words, the “escape hatch” is chemical, not just stereochemical, because the broad method claim is not stereochemically limited in the provided text.
What does the oral administration dependency imply competitively?
Multiple dependent claims explicitly require oral administration:
- Claim 8: Claim 1 administered orally
- Claim 10: Claim 9 administered orally
- Claim 17: Claim 16 administered orally
- Claim 20: Claim 18 administered orally
From an infringement-risk perspective, this means:
- Oral dosing aligns strongly with the claim set.
- Non-oral routes can reduce exposure to these dependent claims, but Claim 1’s independent method coverage remains unless the competitor also exits formula (I).
How do combination claims expand the product-development risk?
Claim 6 and Claim 13 both cover combination with another therapeutically active agent for ED, with “simultaneous, separate, or sequential” use.
This matters commercially because:
- Many ED regimens in pipelines consider add-on therapy, including PDE5 inhibitor combinations, alpha-blocker combinations, or lifestyle-adjunct regimens.
- The claim language is product-agnostic regarding the “another therapeutically active agent,” meaning most ED-active adjuncts could satisfy it if the composition includes the enumerated scaffold compound(s).
What are the enforceable “claim boundaries” in plain terms?
Enforceable boundaries
- ED use: method and composition claims are tethered to treating erectile dysfunction.
- Compound boundaries:
- broad: formula (I) plus salts/solvates (Claim 1; also formula variants in Claims 15-16)
- narrow: enumerated compounds with specified stereochemistry (Claims 2, 9, 19 and corresponding composition claims)
- Product boundaries:
- includes pharmaceutical composition/formulation with standard diluent/carrier terms
- Route boundary (for dependent claims):
- oral administration in Claims 8, 10, 17, 20
Key Takeaways
- US 6,140,329 is centered on ED treatment using a defined chemical scaffold: a broad Markush “formula (I)” method (Claim 1) plus many explicit stereoisomer enumerations (Claims 2, 9, 19).
- The patent has a full coverage stack: method-of-treatment, composition/formulation, process, combination therapy, and oral administration dependencies.
- From a landscape standpoint, the main design-around lever is chemical space (violating formula (I) constraints), not merely stereochemistry, because the independent method claim is Markush-defined.
- Oral dosing directly maps to multiple dependent claims, raising risk for oral ED products unless the drug is outside formula (I).
- Combination regimens are explicitly covered for “another therapeutically active agent,” so combination strategies must be screened against the enumerated compound sets.
FAQs
1) What is the broadest claim in US 6,140,329 from the provided text?
Claim 1, which covers a method for ED by administering any compound of formula (I) (plus salts/solvates) with R0/R1/R2/R3 defined by the Markush ranges.
2) Does US 6,140,329 require a specific stereoisomer to be infringed?
Not for Claim 1, because it is Markush-driven in the provided text. Stereochemical specificity becomes central in the narrower enumerated-compound claims such as Claim 2, Claim 9, and Claim 19.
3) Are pharmaceutical composition and method claims both present?
Yes. The patent includes composition claims (e.g., Claims 3, 11, 14, 21) alongside method-of-treatment claims (e.g., Claims 1, 2, 5, 9, 19, 21).
4) Does the patent cover oral administration?
Yes, through multiple dependent claims: Claims 8, 10, 17, and 20.
5) Is combination therapy with another ED active covered?
Yes. Claim 6 and Claim 13 include compositions for simultaneous, separate, or sequential use with another therapeutically active agent in treating ED.
References
[1] US Patent 6,140,329 (claims provided in the prompt text).
