Patent 6,107,458 Scope and Claims Analysis (US 6,107,458): What the Claims Cover, What They Do Not, and How the US Patent Estate Likely Maps to Generics, Formulations, and Methods

US Drug Patent 6,107,458 (“the ’458 patent”) claims polypeptide compounds defined by a genus formula (I), their salts, a coupling process that builds the formula (I) scaffold, pharmaceutical compositions containing the claimed compounds, and a therapeutic method for “infectious diseases” caused by pathogenic microorganisms. The claim set is broad on compound class coverage through a structural formula genus and broad on use through a general infectious-disease therapeutic method claim.

Because the patent text you supplied includes only claim 1–5 language and not the full formula structures, substituent definitions, specification embodiments, and prosecution history, the analysis below focuses on legal/claim construction features that are visible from claim language: genus scope, dependent claim narrowing, structural definition points, process steps, composition coverage, and method-of-use reach.

What does US 6,107,458 claim: polypeptide genus formula (I) and R1 benzoyl-isoxazolyl substitution?

Claim 1: compound of formula (I) with a defined R1 substituent

Featured-snippet answer: Claim 1 covers “a polypeptide compound” falling within general formula (I), with the key limiting substituent R1 defined as “benzoyl substituted with isoxazolyl which has phenyl having lower alkoxy,” or a salt of that compound.

Key scope signals in claim 1:

Genus definition by structure: the compound is defined by a general formula (I). This creates a structural universe that can be very broad if the formula allows many permitted substituents elsewhere in the polypeptide backbone or side chains.
Single high-impact limiting variable appears at R1: the claim language highlights R1 as the operative constraint. The rest of formula (I) is still limiting, but the text you supplied makes R1 the most explicit chemical gating element.
Salt coverage is explicit: “or a salt thereof” is included in claim 1, extending scope to pharmaceutically acceptable salts for enforcement against ionic forms.

Legal effect:

Claim 1 is an infringement target for any accused compound that matches formula (I) and uses the R1 definition (benzoyl-substituted with isoxazolyl bearing a phenyl with lower alkoxy).
The “polypeptide compound” label matters for construction if the specification uses a particular peptide-like scaffold; however, structurally defined claims do not depend on marketing labels if the accused molecule meets the formula.

R1 definition: why it matters for design-around

Your claim text constrains R1 to a specific substituted aromatic cluster:

benzoyl substituted with isoxazolyl
isoxazolyl having phenyl with lower alkoxy

That gives potential design-around paths in theory:

Replace isoxazolyl with another heterocycle.
Change the benzoyl substitution pattern so it is not “benzoyl substituted with isoxazolyl” as recited.
Remove the phenyl lower alkoxy element on the isoxazolyl-bearing phenyl portion, or shift it outside the “phenyl having lower alkoxy” definition.

The enforceability hinge for R1 is whether a court construes “benzoyl substituted with isoxazolyl which has phenyl having lower alkoxy” narrowly by the exact linkage and substitution, or more broadly by functional/structural equivalence. In structure-based claims, courts typically require close structural match to recited moieties.

How narrow is Claim 2: does it lock R1 to one specific benzoyl-isoxazolyl structure?

Claim 2 depends on claim 1

Featured-snippet answer: Claim 2 narrows claim 1 by specifying R1 as a particular structure (shown as “##STR134##”).

Practical impact:

Claim 2 is not just “an R1 variant,” it is the fixed example of R1 within the genus of claim 1.
If R1 in claim 1 is itself already quite constrained, claim 2 may be commercially less relevant than claim 1. If claim 1 still allows multiple isoxazolyl/phenyl-lower-alkoxy patterns, claim 2 provides a “sure claim” that captures the specific embodiment.

Enforcement mapping:

A patentee typically asserts claim 2 against accused compounds that match the exact R1 shown in claim 2.
Claim 1 is asserted when the accused R1 is within the genus definition but not identical to claim 2.

What process does US 6,107,458 claim: coupling of formula (II) with R1-OH (III) at amino and carboxy groups?

Claim 3: a preparation process for formula (I)

Featured-snippet answer: Claim 3 covers a process for making the formula (I) polypeptide compound by reacting:

a compound of formula (II) (or reactive amino derivative) with
a compound of formula (III), R1–OH (or reactive carboxy derivative),
to form formula (I), with R1 limited as defined in claim 1.

Visible scope features:

Step-specific chemical transformation: it is not merely “making polypeptides”; it is the specific reaction between formula (II) and an acid (R1–OH) at the amino group and carboxy group.
Reactive derivatives are covered: the claim includes “reactive derivative at the amino group” and “reactive derivative at the carboxy group,” which broadens process coverage to activated forms (for example, acid chlorides, anhydrides, esters, coupling reagents).
R1 limitation carries into the process: the process claim is limited by the identity of R1 used as the acid partner.

In infringement terms:

Process claims are most useful in practice when defendants manufacture using a known route that matches the coupling logic (amino partner from (II) and acid partner from (III) where III is the R1–OH).
Process claims can be harder to enforce without access to manufacturing records, but they are potent in discovery and litigation leverage.

Claim 3’s vulnerability surface

Process claims can be designed around by:

Using a different coupling strategy (e.g., introducing R1 through a different intermediate that is not “R1–OH (III)” as recited).
Employing different activation chemistry that avoids the “reactive derivative at the amino group or carboxy group” requirement. The breadth of “reactive derivative” limits this, but exact claim wording often still leaves room for non-equivalent routes.

What is protected as a pharmaceutical composition: claim 4 composition of formula (I) with pharmaceutically acceptable carrier?

Claim 4: composition claim

Featured-snippet answer: Claim 4 covers a pharmaceutical composition containing the active ingredient as a compound of claim 1 (or its salt) plus a pharmaceutically acceptable carrier/excipient.

Scope:

Broad on carrier/excipient selection: almost any conventional formulation excipient can fall within “carrier or excipient.”
Still limited on the active ingredient identity: the active must be within claim 1 compound scope (or its salts).

Composition coverage typically matters for:

End-product enforcement against generic drug products that include the claimed active ingredient.
Potential formulation-specific separable patent families: the existence of claim 4 does not necessarily block formulation design-around if a different active ingredient variant is used, but it blocks replacing the active with an “in-claim” variant.

How broad is the therapeutic method claim: does claim 5 cover all infectious diseases?

Claim 5: method of therapeutic treatment for infectious diseases

Featured-snippet answer: Claim 5 covers administering an effective amount of the claim 1 compound (or a salt) to treat infectious diseases caused by pathogenic microorganisms in humans or animals.

Scope:

Broad disease category: “infectious diseases caused by pathogenic microorganisms” can cover bacterial, fungal, protozoal, or other microbial categories depending on how the specification defines infectious disease embodiments.
Broad route of administration wording by implication: the claim does not specify route, dose form, or schedule. If the specification supports multiple routes, courts often allow broad infringement arguments for other routes, though practical proof still matters.

Litigation implication:

Method-of-use claims are often asserted against prescribing and labeling conduct in ways that interact with FDA label carve-outs and generic “skinny label” approaches. How that plays out depends on the exact FDA-approved indication(s) and labeling text, which are not provided here.

How to map US 6,107,458 to likely commercial product coverage: active ingredient vs salts vs formulations vs process

Coverage matrix (based on claims 1–5)

Claim	Category	What must be present to infringe	Practical enforcement entry point
1	Active compound	Polypeptide of formula (I) with R1 as defined; or salt	API competitor products; chemistry analysis
2	Active compound subset	Formula (I) with R1 exactly as in claim 2	Strongest “match” for accused R1 chemistry
3	Manufacturing process	React formula (II) amino derivative with R1–OH (III) acid derivative to form formula (I)	Manufacturing route analysis; discovery; expert chem
4	Formulation	Composition containing claim 1 compound (or salt) + excipients	Finished dosage form, NDA/ANDA product composition
5	Use	Administer claim 1 compound to treat infectious disease from pathogens	Label/indication and prescribing conduct evidence

What does the patent not claim: no explicit dosing regimen, no explicit route, no explicit spectrum (bacteria vs fungi), no explicit specific carriers

From claim language provided:

No explicit dose range, frequency, duration, or titration method is recited.
No explicit administration route is recited.
No specific pathogens are named.
No specific formulation types (tablet, capsule, IV, depot) are recited.

That omission can widen enforcement for “effective amount” use, but it also leaves room for defendants to argue lack of factual fit if the specification only enables certain routes or indications. Your supplied claim language itself is broad, but the ultimate claim construction typically anchors on the full specification.

How strong is the patent estate around US 6,107,458: what related families typically exist for compound + process + composition + use?

Expected sibling patent patterns (inferred from claim structure)

A patent set containing claims 1–5 typically coexists with related filings that cover:

alternative protecting group schemes or intermediate compounds leading to formula (I)
additional R1 variants or broader subgenera
specific salts, polymorphs, or formulation manufacturing methods
specific infectious indications tied to experimental examples

The most common litigation and freedom-to-operate risk arises when:

The compound claims are broad (genus formula).
The composition claim covers typical pharmaceutical formulations.
The method-of-use claim covers a broad disease category that overlaps FDA indications.

Where “process claim 3” fits into landscape risk

Process claims are frequently the only enforceable hooks against manufacturing when:

compound claims face invalidity or non-infringement defenses due to structural differences.
accused products use different synthetic intermediates but the same final scaffold.

So process claims act as a secondary lock.

What generic entry risks exist for US 6,107,458: Paragraph IV, skinny label, and product design-around scenarios

Scenario A: Generic challenges the compound claims directly

If an ANDA applicant relies on a product containing a compound that matches formula (I) and R1 definition:

Claim 1 and claim 2 present direct infringement risk.
Claim 4 presents finish-dosage infringement risk.
Claim 5 may present additional risk depending on the label indication and how “method of use” enforcement is handled for the product’s intended use.

Paragraph IV strategies:

Argue non-infringement by R1 substitution differences (design-around).
Argue invalidity (claim construction, novelty, obviousness, indefiniteness). Whether these arguments succeed cannot be determined from claim text alone.

Scenario B: Generic attempts a design-around by altering R1

Because R1 is a major limiting feature, changing the R1 moiety outside “benzoyl substituted with isoxazolyl which has phenyl having lower alkoxy” is the most direct design-around path at the claim-1 level.

Risks:

Courts may still consider whether the altered compound falls within the formula (I) structurally as a matter of claim construction.
If the specification and prosecution history indicate broader R1 meanings, a defendant’s “small chemistry change” may still land within scope.

Scenario C: Generic uses a non-claim active ingredient but overlaps with method claim labeling

If the generic’s active is outside claim 1 scope, claim 5 might still be asserted only if the administration in fact and label practice uses the claimed compound. For typical generic approval, if the active is different, claim 5 is unlikely to apply.

Scenario D: If compound is in-claim but formulation differs

Claim 4 is broad on carriers and excipients, so formulation changes usually do not avoid infringement. Avoidance would require reformulation that changes the active ingredient identity (not just excipient differences), or a non-salt form if salt is argued as limiting (though claim 1 already includes salts, and claim 4 includes salts).

How do biosimilars factor in for a polypeptide? Does this behave like a biologics estate?

Even though the claims use the phrase “polypeptide compound,” US compound claims with defined structures generally behave like small-molecule or defined synthetic polypeptide therapeutics, not necessarily biologics. Nothing in your claim excerpt indicates protein sequence identity, glycoforms, or biologics-specific manufacture. As provided, it is best read as a chemically defined polypeptide scaffold with R1-defined aromatic substitution.

Accordingly, the most relevant “high-intent” enforcement pattern here is the classic small-molecule/defined-structure patent landscape:

compound structure claims
composition claims
process claims
method-of-use claims

Key claim construction hooks likely to drive infringement and validity disputes

1) What exactly is “benzoyl substituted with isoxazolyl which has phenyl having lower alkoxy”?

This is the primary R1 constraint in claim 1. Disputes typically turn on:

whether “benzoyl substituted with isoxazolyl” requires a specific bond position vs general substitution
whether the “phenyl having lower alkoxy” is part of the isoxazolyl substituent (and where the alkoxy is positioned)
whether “lower alkoxy” has an upper carbon count limit and whether the claim treats it as a defined group

2) How broadly does formula (I) define the rest of the polypeptide scaffold?

Claim 1 uses a general formula (I). The breadth depends on:

what the allowed substituents are elsewhere in formula (I)
whether there are multiple optional groups that produce many covered molecules

3) What counts as a “reactive derivative” for process claim 3?

If “reactive derivative” is interpreted broadly, many coupling routes could infringe. If narrower, only specific activated forms would match.

4) Does “effective amount” and “infectious diseases” create predictable method-of-use coverage?

Defendants typically target:

lack of explicit indication alignment with approved labeling
differences in administered infectious disease category in real-world use vs claim scope

US 6,107,458: structured claim scope summary

Claim-by-claim in force targets

Compound claims (1 and 2): formula (I) polypeptide scaffold with R1 benzoyl-isoxazolyl-phenyl-lower-alkoxy constraint, plus salts.
Process claim (3): coupling of formula (II) amino derivative with R1–OH (III) to generate formula (I) with the same R1 constraint.
Composition claim (4): formulation containing claim 1 active + pharmaceutically acceptable carrier/excipient.
Use claim (5): administer claim 1 active to treat infectious diseases caused by pathogenic microorganisms (human and animal).

Key Takeaways

Claim 1 is the core asset: it covers a structural genus polypeptide defined by formula (I) with a specific R1 moiety (benzoyl-substituted isoxazolyl bearing a phenyl with lower alkoxy) and includes salts.
Claim 2 narrows to a specific R1 embodiment, useful for enforcement against compounds matching that exact aromatic substitution pattern.
Claim 3 provides a manufacturing lock by requiring coupling between formula (II) amino-derived intermediate and an R1–OH (III) carboxy-derived partner, with “reactive derivatives” expanding the range of acceptable activation chemistry.
Claim 4 blocks formulation-only workarounds because it covers compositions containing in-claim active ingredient plus ordinary pharmaceutical carriers/excipients.
Claim 5 broadens use coverage to infectious diseases caused by pathogenic microorganisms in humans and animals, without specifying route, dose regimen, or specific pathogen classes in the excerpt you supplied.

FAQs

1) Does US 6,107,458 protect only salts or also the free base/acid form?
Claim 1 explicitly covers “a salt thereof” in addition to the compound; whether the free base/acid form is separately claimed depends on whether it falls within the “compound of formula (I)” itself. The excerpt implies the compound (formula I) is claimed, and salts are included.

2) Can a generic avoid infringement by changing the isoxazolyl group in R1?
A change that removes the “isoxazolyl” and/or the “phenyl having lower alkoxy” elements from the R1 definition is the most direct path to non-infringement at claim 1, if claim construction stays literal.

3) Do formulation changes (tablet vs capsule vs IV) avoid claim 4?
No. Claim 4 covers any pharmaceutical composition containing the claim 1 active ingredient with pharmaceutically acceptable carriers/excipients, absent an explicit limitation on dosage form.

4) Is claim 5 enforceable if a generic uses “skinny label” for specific infectious indications?
Enforceability depends on whether the method of use aligns with the label and whether the claimed “infectious diseases” category is present in the approved indication and actual prescribing. The excerpt alone does not determine this.

5) What is the main advantage of asserting process claim 3 in litigation?
It can reach manufacturing routes that produce the in-claim scaffold even when defenders contest compound structure differences, using discovery and chemical route evidence to map the coupling steps.

References

United States Patent No. 6,107,458 (claims 1–5 as provided in user prompt).

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	9420425	Oct 17, 1994
United Kingdom	9508745	Apr 28, 1995

PCT Information
PCT Filed	September 29, 1995	PCT Application Number:	PCT/JP95/01983
PCT Publication Date:	April 18, 1996	PCT Publication Number:	WO96/11210

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	0788511	⤷ Start Trial	CA 2008 00030	Denmark	⤷ Start Trial
European Patent Office	0788511	⤷ Start Trial	91452	Luxembourg	⤷ Start Trial
European Patent Office	0788511	⤷ Start Trial	300352	Netherlands	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,107,458

Summary for Patent: 6,107,458