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Patent landscape, scope, and claims: |
US Patent 8,129,385 Scope, Claim Coverage, and U.S. Patent Landscape
Executive summary
US 8,129,385 claims a structurally defined small-molecule core (a substituted “hexahydro-1-oxa-4a,8a-diaza-anthracene” scaffold) with tightly constrained variables around ring substituents, stereochemistry, halogen identity, and a specific carboxamide side chain (benzylamide bearing defined fluorinated/chlorinated patterns). Claim 1 is the broadest independent claim and is still “modular but bounded” by (i) ring A options, (ii) RX = hydrogen and R3 = hydrogen, (iii) R14 restricted to hydrogen or lower alkyl (with an optional multiparameter substitution allowance), (iv) R constrained to halogen, (v) m = 1–3, and (vi) stereochemistry limited to R/S or mixtures. Dependent claims 2–3 lock key variables further (RX, R14, R3, halogen). Claims 4–9 narrow to specific Ra and benzyl ring patterns, including explicit named stereoisomers and salt forms (notably a sodium salt). Claims 10–11 extend coverage to compositions using the enumerated compound(s), but do not add a distinct formulation technology beyond standard carrier/diluent language, which can matter for design-around and FDA label carve-outs.
Because only claim text is provided (no drug name, no specification embodiments, no priority data, no assignee, no prosecution history, no Orange Book or litigation docket), this analysis stays strictly within the claim scope you provided and does not assert timelines, expiries, ownership, or enforcement events.
What is the scope of US Patent 8,129,385 claims and what does claim 1 actually cover?
Featured-snippet answer: Claim 1 covers a family of substituted hexahydro-1-oxa-4a,8a-diaza-anthracene “compound-of-formula” structures with (a) RX = H and R3 = H, (b) R14 = H or lower alkyl (with a substituent permission set), (c) R = halogen with m = 1–3, (d) defined ring-A substitution rules, (e) specified absolute/relative stereochemistry at an asymmetric center, and (f) a pharmaceutically acceptable salt. It also supports downstream dependent claim narrowing to specific benzylamide ring patterns and named stereoisomers.
Claim 1: “modular but bounded” formula coverage
Claim 1 is written as a genus claim with multiple variable constraints:
Core structure constraints
- Ring A is defined as “R20, R21, R22, R23, R24 and R25” with each independently selected from a finite set:
- hydrogen (H)
- C1–C8 alkyl
- C6–C14 aryl-C1–C8 alkyl
- C6–C14 aryl
- alkoxy
- Stereochemistry: an asymmetric carbon marked with “*” can be R, S, or a mixture (so both single enantiomers and racemates/mixtures are inside the claim).
- RX is fixed to hydrogen.
- R3 is fixed to hydrogen.
- R is fixed to halogen.
- m is limited to 1, 2, or 3 (implying the halogen substitution pattern on the relevant substructure is limited to up to three positions as encoded by m).
Variable R14 and its substituent “permission set”
- R14 is hydrogen or lower alkyl.
- The lower alkyl at R14 “may be optionally substituted with I to 4 substituents” chosen from an enumerated list that includes:
- hydroxy, carboxy
- halogen
- halo lower alkyl / halo lower alkoxy
- lower alkyl, lower alkenyl, lower alkynyl
- cycloalkyl, cycloalkenyl
- lower alkoxy, lower alkenyloxy, lower alkoxycarbonyl
- nitro, nitroso
- amino, alkylamino, acylamino, aralkylamino
- aryl, aralkyl
- cyano, isocyano, isocyanate
- thiocyanate, isothiocyanate
- mercapto, alkylthio
- alkylsulfonyl, alkylsulfonylamino
- carbamoyl, alkylcarbamoyl
- sulfamoyl
- acyl, formyloxy, haloformyl
- (and additional sulfur and nitrogen functional group options, including hydrazino, azido, ureido, guanidino, phthalimide)
- oxo, phosphoric acid (including phosphoric acid substituted aryl/aralkyl patterns), and phosphoric-acid-functionalized alkyl groups potentially “intervened with a heteroatom”
- This part is broad on substituent types but still tethered to the narrow structural “handle” defined as R14.
R and benzylamide side chain
- The claim text you provided includes “cyclo…” within the long list, but the overall structural theme becomes clear from dependent claims: the compound includes a carboxylic acid at the scaffold with a benzylamide moiety.
- Dependent claim 4 later enumerates specific benzyl ring patterns and side-chain substituents.
Salt coverage
- Claim 1 ends with “or a pharmaceutically acceptable salt thereof,” creating standard salt coverage for any salt form within “pharmaceutically acceptable” definition.
Claim 2–3: narrowing to RX = H, R14 = H, R3 = H, and specific halogen constraint
Claim 2 selects a sub-genus:
- RX = hydrogen
- R14 = hydrogen
- R3 = hydrogen
- m = 1, 2, or 3
- R is halogen
This eliminates the “R14 = lower alkyl” branch and collapses the R14 substituent complexity.
Claim 3 fixes the salt identity:
Design-around implication
- If a competitor were to use a non-sodium salt (e.g., potassium, meglumine), claim 3 would not be the best target. But claim 1 still captures “pharmaceutically acceptable salts,” depending on how a court construes “pharmaceutically acceptable” and whether non-sodium salts fall within that term.
Which specific compounds are expressly claimed in US 8,129,385 claims 4–9?
Featured-snippet answer: Claims 4–9 explicitly name multiple stereoisomeric compounds of the same core scaffold plus a benzylamide where the benzyl ring is limited to three patterns (4-fluoro, 2,4-difluoro, 3-chloro-2-fluoro) paired with defined Ra (CH3, CH(CH3)2, or CH2CH2OCH3). They also expressly claim multiple enantiomers, diastereomers, mixtures, and both freebase and salt (including a sodium salt in claim 8).
Claim 4: Ra options plus specific benzyl ring patterns
Claim 4 describes “formula (1-7)” with:
- Ra = —CH3, —CH(CH3)2, or —CH2CH2OCH3
- The phenyl ring to which it is attached is one of:
- 4-fluorophenyl
- 2,4-difluorophenyl
- 3-chloro-2-fluorophenyl
- Includes pharmaceutically acceptable salts
Scope impact
- Claim 4 is effectively a “combination claim” that pairs allowed Ra groups with only three allowed benzyl patterns. If the benzyl ring changes (e.g., 3-fluoro, 4-chloro, 2,3-difluoro) or if Ra is changed outside the three enumerations, claim 4 is not met.
Claim 5: enumerated compound list (highly specific stereoisomers)
Claim 5 lists a large set of named stereoisomers and the diastereomeric/enantiomeric variants, plus salts. The list includes multiple combinations of:
- stereochemistry at two stereogenic elements (shown in the names as (3S,9aS), (3R,9aR), (4S,9aR), (2R,9aR), etc.)
- side-chain identity such as methyl vs methoxymethyl vs ethyl vs phenyl substitution on the scaffold
- benzyl ring pattern identity (2,4-difluoro-benzylamide and/or 4-fluoro-benzylamide; and later entries also show sodium salt and 3-chloro-2-fluoro-benzylamide)
- free acid form and salt forms included by wording “and pharmaceutically acceptable salts thereof;”
From your text, Claim 5 includes (among others):
- (3S,9aS)-5-Hydroxy-3-methyl-…-carboxylic acid 2,4-difluoro-benzylamide
- (3R,9aR)-5-Hydroxy-3-methyl-…-carboxylic acid 2,4-difluoro-benzylamide
- (4S,9aR)-5-Hydroxy-4-methyl-…-carboxylic acid 2,4-difluoro-benzylamide
- (2R,9aR)-5-Hydroxy-2-methoxymethyl-…-2,4-difluoro-benzylamide
- (2S,9aR)-2-Ethyl-5-hydroxy-…-2,4-difluoro-benzylamide
- multiple entries where the benzylamide ring is 4-fluorobenzylamide
- later entries include 3-chloro-2-fluorobenzylamide for a specific scaffold stereochemistry.
Scope impact
- Claim 5 is not merely “some stereoisomers.” It is a near-complete enumerated set across multiple stereochemical combinations for those specific scaffold substitution patterns and benzyl ring types captured in Claim 4.
Claim 6: single stereoisomer family explicitly claimed
Claim 6 focuses on:
- (4R,9aS)-5-Hydroxy-4-methyl-6,10-dioxo-…-2,4-difluoro-benzylamide
- plus an enantiomer, diastereomer, and mixtures
- plus pharmaceutically acceptable salts
This is a narrower independent-style dependent claim that ensures a litigation plaintiff can point to a specific “anchor” compound even if other enumerated entries face claim-construction limits.
Claim 7–9: the “(4R,9aS)” anchor and sodium salt
- Claim 7: compound is exactly (4R,9aS)-5-hydroxy-4-methyl-…-2,4-difluoro-benzylamide or a pharmaceutically acceptable salt.
- Claim 8: the sodium salt of that exact compound.
- Claim 9: repeats the free (or generic pharmaceutically acceptable salt) for the same (4R,9aS) compound.
Scope impact
- Claim 8 can be a primary hook for enforcement if a product uses the sodium salt form.
Do the claims cover pharmaceutical compositions or only the active compound?
Featured-snippet answer: Yes. Claims 10 and 11 cover pharmaceutical compositions comprising the (4R,9aS) compound or a compound of any one of the listed claims, plus a conventional pharmaceutically acceptable carrier or diluent.
Claim 10: composition anchor to (4R,9aS) compound
- A pharmaceutical composition comprising:
- (4R,9aS)-5-hydroxy-4-methyl-…-2,4-difluoro-benzylamide
- or pharmaceutically acceptable salt
- with pharmaceutically acceptable carrier/diluent
Claim 11: composition using any compound in claims 1, 5, 6, 7, 8, 9, or 4
- A pharmaceutical composition comprising:
- a compound according to any one of claims 1, 4, 5, 6, 7, 8, 9
- plus pharmaceutically acceptable carrier/diluent
Claim strength note (construction, not validity)
- The composition claims are “standard carrier” language. They do not appear to claim:
- specific excipient percentages
- release profiles (immediate vs extended)
- particle size or crystallinity
- solid-state form (polymorphs/solvates)
So the composition scope is likely broad as to dosage form type, but narrow as to formulation innovation.
What is the practical patent coverage breadth: genus vs enumerated stereoisomers and salt?
Coverage map by claim type
| Claim |
Role |
What it captures |
Main narrowing levers |
| 1 |
Genus |
Family of formula compounds with constrained ring substituent options, RX=H, R3=H, R=halogen, m=1–3, stereochemistry R/S/mixtures, R14=H or lower alkyl with optional substitutions, salt |
Fixes RX and R3 to H; restricts R to halogen; limits m; bounds ring A substituent classes |
| 2 |
Narrow genus |
Claim 1 with RX=H, R14=H, R3=H, R=halogen, m=1–3 |
Removes R14≠H branch |
| 3 |
Salt-specific |
Sodium salt of claim 1-compound |
Salt identity |
| 4 |
Genus with explicit benzyl ring patterns |
Specific Ra groups and only 3 benzyl ring substitution patterns; salts |
Ra restricted to 3 options; benzyl ring restricted to 3 patterns |
| 5 |
Enumerated stereoisomer list |
Large set of named stereoisomers across specific scaffold substitutions and benzyl patterns |
Must match enumerated structures |
| 6 |
Narrow anchor |
(4R,9aS)-…-2,4-difluoro-benzylamide family plus enantiomer/diastereomer/mixtures and salts |
Anchors to one scaffold substitution set |
| 7 |
Anchor |
Same as claim 6 but closer to a single compound definition |
Anchor stereochemistry and substitution |
| 8 |
Salt-specific anchor |
Sodium salt of (4R,9aS)-…-2,4-difluoro-benzylamide |
Sodium salt only |
| 9 |
Anchor |
(4R,9aS) compound (and pharmaceutically acceptable salt) |
Anchor stereochemistry |
| 10 |
Composition |
Composition containing the (4R,9aS) compound/salt + carrier |
Requires that active |
| 11 |
Composition |
Composition with a compound falling within claims 1/4/5/6/7/8/9 + carrier |
Requires active to be within those claim sets |
How could competitors design around based on claim structure (without assuming validity or prosecution)?
Chemical-space design-around levers visible from the claim language
-
Change the benzyl ring substitution pattern
Claims 4 and the explicit enumerations in 5 heavily point to:
- 4-fluorophenyl
- 2,4-difluorophenyl
- 3-chloro-2-fluorophenyl
If the benzylamide uses a different ring substitution pattern not included in the explicit lists, it is the cleanest visible route around claims 4 and 5-style enumerations.
-
Change RX or R3 away from hydrogen
Claim 1 fixes RX = H and R3 = H. Introducing substituents at those defined positions can fall outside claim 1’s literal scope.
-
Use non-halogen for R
Claim 1 fixes R to halogen and m ≤ 3. A non-halogen substituent at that position is an immediate literal carve-out (if structurally feasible while retaining pharmacology).
-
Avoid the claimed salt form (sodium)
Claim 3 and claim 8 are sodium-specific. A product using a different salt does not avoid claim 1 or 7/9 if they include “pharmaceutically acceptable salts,” but it can remove clean salt-specific hooks.
-
Change Ra away from the enumerated options in claim 4
Claim 4 limits Ra to CH3, isopropyl (CH(CH3)2), or CH2CH2OCH3. If the analog changes that group, claim 4 can be missed while still potentially falling under claim 1 (depending on how Ra maps into claim 1’s “ring A” and “R” variables in the full specification’s formula numbering).
Practical enforcement posture implied by claim set
- The claim set is structured so that:
- broad chemical coverage sits in claim 1 (with fixed RX/R3 and halogen R constraints)
- a product-specific enforcement hook sits in the named (4R,9aS) compound and its sodium salt
- composition claims follow the active definitions rather than covering unique formulation technologies
What “patent landscape” can be inferred from this single patent’s claim scope?
With only the claims provided for US 8,129,385, the only landscape conclusions that can be stated are structural:
- The patent likely protects a compound series and a composition using that compound series, with a strong emphasis on stereoisomer coverage and a salt form (sodium).
- The breadth is high enough to cover multiple stereochemical variants of the same scaffold and the benzylamide ring patterns enumerated.
- There is no visible claim language in the provided excerpt covering:
- specific polymorphs/solvates
- manufacturing methods
- dosing regimens
- therapeutic use or method-of-use indications
Any landscape conclusions about those areas cannot be made from the excerpt.
Key Takeaways
- Claim 1 is the core genus but is bounded by fixed positions (RX = H, R3 = H), halogen-only constraint for R, and m = 1–3, with a defined ring-A substitution class and defined stereochemistry.
- Claims 4–5 provide the practical enforcement backbone by enumerating permissible benzylamide ring substitution patterns (4-F, 2,4-di-F, 3-Cl-2-F) and multiple named stereoisomers.
- Claims 7–9 and 8 are high-leverage targets around the specific (4R,9aS)-…-2,4-difluoro-benzylamide and its sodium salt.
- Composition claims 10–11 are conventional-carrier claims tied to the active, with no visible formulation-specific restrictions in the provided text.
FAQs
-
Does US 8,129,385 claim both enantiomers and racemic mixtures?
Yes. Claim 1 includes stereochemistry at the marked asymmetric carbon as R, S, or mixtures, and multiple dependent claims enumerate enantiomer/diastereomer variants.
-
Is the sodium salt of the (4R,9aS) compound separately protected?
Yes. Claims 3 and 8 separately capture sodium salt coverage, with claim 8 specifically reciting the sodium salt of the (4R,9aS)-…-2,4-difluoro-benzylamide.
-
Are changes to the benzyl ring substituents likely to avoid claim 4 and the enumerated claim 5 entries?
Yes, based on the explicit limitation in claim 4 to 4-fluoro, 2,4-difluoro, or 3-chloro-2-fluoro benzyl rings and the corresponding enumerations in claim 5.
-
Can a compound with RX not equal to hydrogen still fall under claim 1?
No. Claim 1 sets RX = hydrogen, and claim 2 further locks RX to hydrogen while also setting R14 = hydrogen and R3 = hydrogen.
-
Do the composition claims require a specific dosage form or special excipients?
No. Claims 10 and 11 require only a pharmaceutically acceptable carrier/diluent with the defined active compound/salt.
References
- United States Patent US 8,129,385 (claims provided in prompt text).
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