United States Patent 5,658,929: Scope, Claims, and US Patent Landscape
What does US 5,658,929 claim?
US Patent 5,658,929 is drafted as a compound-selection patent with downstream protection on formulations containing those selected compounds. The independent claim is a Markush claim limited to specific chemical structures (shown in the claim as “##STR214##”), and the dependent claims narrow coverage to a specific subset (shown as “##STR215##”) and to corresponding pharmaceutical compositions.
Claim set provided
-
Compound Markush claim
- “A compound selected from the group consisting of: ##STR214## and pharmaceutically acceptable salts thereof.”
-
Dependent compound claim
- “A compound of claim 1 which is ##STR215##.”
-
Independent formulation claim (Markush compound + carrier)
- “A pharmaceutical composition comprising a compound of claim 1 and a pharmaceutically acceptable carrier.”
-
Dependent formulation claim (narrower compound + carrier)
- “A pharmaceutical composition comprising a compound of claim 2 and a pharmaceutically acceptable carrier.”
Scope summary (from the claim text as supplied):
- Active ingredient scope: limited to the enumerated structures in ##STR214## (plus pharmaceutically acceptable salts).
- Additional narrowing: claim 2 isolates one (or a specific set) of the ##STR214## structures identified as ##STR215##.
- Product scope: composition claims cover formulations where the only protected ingredient requirement is that the composition contains one protected compound (claim 1) or the narrower compound (claim 2), along with a generic “pharmaceutically acceptable carrier.”
How broad is the claim language?
The breadth comes from two design choices:
-
Markush “selected from the group consisting of … ##STR214##”
- Coverage attaches only to the enumerated chemical structures in the claim.
- The phrase “group consisting of” is limiting: it does not cover “substantially similar” compounds outside the enumerated set.
-
“Pharmaceutically acceptable carrier”
- This is a broad formulation placeholder. It typically covers conventional excipients, diluents, and formulation components recognized as acceptable for human administration.
- It does not require a particular route of administration, dosage form, or release profile in the claim text you provided.
Claim breadth table (based on provided claim language)
| Claim |
What must be present |
Limitation type |
Practical scope effect |
| 1 |
One of the enumerated compounds in ##STR214## + pharmaceutically acceptable salts |
Strict structure enumeration (“group consisting of”) |
Strong chemical boundary; no equivalents beyond listed structures |
| 2 |
The specific compound identified as ##STR215## |
Depends on claim 1 + narrows to a subset |
Smaller chemical set; tighter infringement analysis |
| 3 |
A composition with a claim-1 compound + pharmaceutically acceptable carrier |
Generic carrier |
Broad dosage-form and excipient coverage, assuming protected compound is present |
| 4 |
A composition with claim-2 compound + pharmaceutically acceptable carrier |
Depends on claim 2 + narrows |
Most constrained composition claim |
What is covered: salts and how does that affect infringement?
Claim 1 explicitly covers:
- “pharmaceutically acceptable salts thereof” for each enumerated compound in ##STR214##.
Implication for scope:
- A formulation (claims 3 and 4) that contains a salt of an enumerated compound can fall within claim coverage even if the free base differs in physical properties.
How does the dependent structure narrowing work?
Claim 2 is narrower by design:
- Claim 2 requires the compound to be “a compound of claim 1 which is ##STR215##.”
- That means ##STR215## is either:
- one specific member of the ##STR214## group, or
- a smaller sub-list treated as a distinct chemical identity in the claim.
Practical effect:
- If a product uses a compound in ##STR214## but not the one identified as ##STR215##, it can still potentially fall under claims 1 and 3, but not claim 2 or 4.
What does this mean for the US patent landscape?
A compound + composition structure set like this typically sits in the “core” part of a patent family for:
- substance protection (claims 1 and 2), and
- composition protection (claims 3 and 4).
Landscape map by claim-layer
| Patent-layer type |
Coverage here |
Typical competitors’ responses |
| Chemical substance |
Claim 1 and claim 2 |
Design around by using non-enumerated structures or different salt forms not covered by “pharmaceutically acceptable salts thereof” tied to enumerated compounds |
| Formulation |
Claim 3 and claim 4 |
Formulate a non-enumerated active ingredient; or if using an enumerated ingredient, negotiate/avoid based on licensing or carve-outs |
Typical freedom-to-operate (FTO) fault line
In this claim set, the primary FTO question is not carrier selection. It is:
- whether the active ingredient is one of the enumerated structures in ##STR214## (or specifically ##STR215## for the dependent claims).
If a candidate active ingredient is not literally within those enumerated structures, the claim language you supplied provides no textual hook for structural equivalence coverage.
How strong is infringement exposure under these claims?
Based on the claim structure (as provided), exposure is driven by three elements:
-
Literal active ingredient match
- Infringement of claim 1 requires the active ingredient to be one of the enumerated ##STR214## compounds or a pharmaceutically acceptable salt thereof.
-
Specific subset match for dependent claims
- Infringement of claim 2 requires the active ingredient to be the ##STR215## compound.
-
Composition presence
- Claims 3 and 4 do not require a specific formulation type in the provided text; they require that the composition contains:
- a claim-1 compound (claim 3), or
- a claim-2 compound (claim 4),
- plus a pharmaceutically acceptable carrier.
Claim-structure positioning: why it matters for enforcement
These claims are “clean” in the sense that they rely on:
- enumerated chemical structures in the claim text, and
- standard formulation language that typically does not constrain excipient choice.
That design often yields:
- clearer claim construction around whether the accused ingredient is literally one of the enumerated compounds, and
- narrower debates about whether a formulation qualifies as a “pharmaceutically acceptable” carrier.
Key Takeaways
- US 5,658,929 covers a limited set of enumerated compounds in ##STR214##, plus pharmaceutically acceptable salts, through Claim 1.
- Claim 2 narrows coverage to the specific structure shown as ##STR215##.
- Claims 3 and 4 extend protection to pharmaceutical compositions containing those compounds with a pharmaceutically acceptable carrier, without extra formulation constraints in the provided claim text.
- The central infringement and FTO boundary is whether the active ingredient is literally within the enumerated structures in ##STR214## (and specifically ##STR215## for dependent coverage).
FAQs
1) Does the patent cover any compound structurally similar to ##STR214##?
No. The claim uses “selected from the group consisting of ##STR214##,” so coverage is limited to the enumerated structures and their pharmaceutically acceptable salts.
2) Are salts covered for both the compound and composition claims?
Yes for Claim 1 (explicitly includes “pharmaceutically acceptable salts thereof”), and composition claims (3 and 4) cover compositions comprising the claimed compound(s) plus a carrier.
3) Do claims 3 and 4 require a specific dosage form (tablet, injection, etc.) based on the provided text?
No. The provided wording only requires “a pharmaceutical composition” with a “pharmaceutically acceptable carrier.”
4) If an accused product uses a compound in ##STR214## but not ##STR215##, which claims are implicated?
Claims 1 and 3 are implicated; claims 2 and 4 require the narrower ##STR215## compound.
5) What is the practical freedom-to-operate pivot point for this patent?
Identifying whether the product’s active ingredient matches one of the enumerated compounds in ##STR214## (or ##STR215## for the dependent layer).
References (APA)
[1] US Patent 5,658,929, claims 1-4 (as provided in the prompt).
