United States Patent 5,686,411: Scope, Claim Map, and US Landscape for Amylin Agonist Analogues

US Patent 5,686,411 claims amylin agonist analogues built around (i) a defined amino-acid sequence “core” with variable positions A1-K1, (ii) an intramolecular linkage formed by a disulfide bond, lactam, or thioether, and (iii) a terminal group Z that is substituted and can be amino/alkylamino/aryloxy-type. The patent then narrows through dependent claims to specific disulfide (X,Y = Cys-Cys) embodiments, Z = amino, and a set of named engineered amylin variants (claims 17-23), followed by standard salt (acetate, trifluoroacetate, hydrochloride), composition, and diabetes treatment method claims.

What does claim 1 actually cover (core scope)?

1) Independent claim: broad structural genus plus conditional stereochemical rule

Claim 1 defines an “agonist analogue of amylin” that has:

A sequence specified as an amino-acid template with variable positions A1 through K1 (11 variable positions).
The template language permits substitutions as follows:

Position	Allowed residues (as recited)
A1	Lys, Ala, Ser, or hydrogen
B1	Ala, Ser, Thr
C1	Val, Leu, Ile
D1	His or Arg
E1	Ser or Thr
F1	Ser, Thr, Gln, Asn
G1	Asn, Gln, His
H1	Phe, Leu, Tyr
I1	Ile, Val, Ala, Leu
J1	Ser, Pro, Thr
K1	Asn, Asp, Gln

Intramolecular linkage: residues X and Y independently chosen as amino-acid side chains that are chemically bonded to each other to form one of:
- disulfide bond, or
- lactam, or
- thioether.
Z (terminal/side substituent): selected from:
- amino, alkylamino, dialkylamino, cycloalkylamino, arylamino, aralkylamino
- alkyloxy, aryloxy, aralkyloxy
Important constraint (conditional): the patent includes a special rule that activates when the following specific pattern is met:

“provided that when A1 is Lys, B1 is Ala, C1 is Val, D1 is Arg, E1 is Ser, F1 is Ser, G1 is Asn, H1 is Leu, I1 is Val, J1 is Pro, and K1 is Asn, then one or more of A1 to K1 is a D-amino acid and Z is selected from alkylamino/dialkylamino/cycloalkylamino/arylamino/aralkylamino/alkyloxy/aryloxy/aralkyloxy.”

Scope implication: claim 1 is a broad genus (many residue permutations; 3 linkage chemistries; 10+ Z classes) but it also creates a restriction/compliance condition for one “anchor” configuration, requiring D-amino acid presence and Z not restricted to “amino” (it is constrained to N-alkyl/aryl amino or O-alkyl/aryl oxy forms in that conditional branch).

2) Dependent claim narrowing strategy

Dependent claims (2-16) tighten key knobs:

Claim 2: adds that X and Y are Cys residues linked by a disulfide bond.
Claim 3: sets Z = amino.
Claims 4-7: provide additional sequence templates (STR2, STR3) with their own A1-K1 substitutions and similar “D-amino and Z-group” conditions.
Claims 8-9: same disulfide X/Y = Cys, and Z = amino.
Claim 10-12: another template plus conditional D-amino and Z-group restriction; then disulfide + Z = amino again.
Claims 13-16: single-position refinements:
- Claim 13: D1 is Arg
- Claim 14: I1 is Val (and covers any claim group stated)
- Claim 15: J1 is Val for a specific subset (claims 7-9)
- Claim 16: A1 is hydrogen (instead of Lys/Ala/Ser)

Scope implication: the independent claim allows multiple linkage chemistries and Z classes, while the dependent claim chain draws a bright-line subset: Cys-Cys disulfide linkage plus Z = amino, then narrows residue selections.

Which specific named analogues are claimed (claims 17-23)?

Claims 17-23 list explicit engineered variants using a standardized naming convention such as “18 Arg25,28 Pro-h-amylin” and “des-1 Lys…”.

These are not just examples; they are asserted as standalone compound claims within the set:

Claim	Named analogue as recited
17	18 Arg25,28 Pro-h-amylin
18	des-1 Lys18 Arg25,28 Pro-h-amylin
19	25,28,29 Pro-h-amylin
20	des-1 Lys25,28,29 Pro-h-amylin
21	18 Arg25,28,29 Pro-h-amylin
22	des-1 Lys18 Arg25,28,29 Pro-h-amylin
23	25 Pro26 Val28,29 Pro-h-amylin

Landscape relevance: these named structures function as anchor molecules around which the genus claims likely map. For freedom-to-operate, these entries are typically the easiest to design around if you know competitors’ actual lead candidates, because claim infringement can turn on whether the commercial molecule matches one of these named sequences or salts.

How do salt and composition claims expand or constrain coverage?

1) Salt claims

Claims 24-29 cover salts of “an agonist analogue” (claims 1-16) and salts of the named analogues (claims 17-23):

Salt form	Coverage
Acetate salt	Claim 24 (analogue per 1-16), Claim 27 (compound per 17-23)
Trifluoroacetate salt	Claim 25, Claim 28
Hydrochloride salt	Claim 26, Claim 29

Practical read: the patent anticipates that commercial products may be formulated and marketed as specific salt forms of the same peptide, so the salt claims reduce the “formulation workaround” space.

2) Composition claims

Claims 38-45 cover compositions and admixtures in pharmaceutically acceptable carriers:

Single-agent compositions (therapeutically effective amount of an analogue in carrier): claims 38-43
Combination compositions with insulin: claims 44-45
- Claim 44: analogue selected among claims 3, 6, 9, 11, 17-23 plus insulin
- Claim 45: 25,28,29 Pro-h-amylin plus insulin

Scope implication: combination claims can capture branded combination products even if a partner tries to “stay clear” by using a composition format rather than monotherapy.

What is the asserted therapeutic use and how broad are the method claims?

Diabetes mellitus treatment (monotherapy)

Method claims 30-35 assert:

Claim 30: treatment of diabetes mellitus by administering an analogue of claim 3
Claim 31: treatment by administering an analogue of claim 6
Claim 32: treatment by administering an analogue of claim 9
Claim 33: treatment by administering an analogue of claim 12
Claim 34: treatment by administering an analogue of any of claims 17-23
Claim 35: treatment by administering 25,28,29 Pro-h-amylin specifically

Diabetes mellitus treatment (combination with insulin)

Claim 36: adds insulin to the method of any of claims 30-35
Claim 37: specifies 25,28,29 Pro-h-amylin plus insulin

Landscape relevance: these are classic “medical use” claims. If a competitor markets a peptide for diabetes, these claims can matter even if commercial manufacturing and salts differ, depending on whether the exact peptide identity matches the claimed analogues and whether insulin is co-administered in the claimed dosage framing.

Where does this patent sit in a US amylin-agonist patent landscape (likely overlap patterns)?

1) Core technology category

This patent is squarely in the peptide amylin receptor agonist analogue space: it claims sequence variants (including D-amino acid compliance rules) and cyclization/intramolecular bond engineering (disulfide, lactam, thioether) plus Z substituent classes.

That places it among US patents and families that typically cover:

native amylin or human amylin (h-amylin) derivatives
sequence-modified peptides designed for stability and receptor potency
constraint of engineered disulfides for conformation control
pharmacological method-of-use for diabetes

2) Overlap drivers that usually create claim collisions

Within the claimed subject matter, US infringement risk commonly clusters around three motifs:

1) Engineered disulfide/cyclization (X,Y = Cys-Cys disulfide or other intramolecular linkages).
2) Specific residue substitutions at the named proline/arginine/lysine positions (claims 17-23).
3) Salt identity (acetate, trifluoroacetate, hydrochloride).

3) “Design-around” pressure points

Because claim 1 is a genus and dependent claims are narrow, competitors usually pick among three strategies:

Avoid the named sequences in claims 17-23 if those match known candidates.
Avoid the Z = amino plus disulfide subset if a candidate uses different Z chemistry.
Avoid the D-amino acid condition when the anchor residue pattern is met (even if other positions vary).

Most important practical point: the named compounds create high-confidence infringement targets if competitors market identical peptides (or identical peptidic sequences) as marketed salts.

Claim set structure and how it maps to product families

1) Claim dependency funnel

A simplified funnel view:

Claim 1: genus of amylin agonist analogues (A1-K1 variability + X/Y linkage type + Z type + conditional D-amino rule)
Claims 2-3: disulfide linkage + Z = amino subset
Claims 4-6, 7-9, 10-12: alternative sequence templates with the same engineering knobs and conditional rules
Claims 13-16: single-position restrictions applied to subsets
Claims 17-23: explicit named analogues (sequence anchors)
Claims 24-29: salts of both genus analogues and named compounds
Claims 30-37: diabetes treatment methods (mono and combo with insulin)
Claims 38-45: dosage forms/compositions (mono and combo formulations)

2) Functional boundary conditions created by the conditional D-amino + Z restriction

The conditional language in claim 1 (and repeated variants in claims 4 and 7 and 10) has a legal function: it ties D-amino content and the allowed Z class to a specific anchor pattern. That can create a “cliff” effect where changing a single residue among A1-K1 can remove the conditional trigger.

Key Takeaways

Patent 5,686,411 claims a broad genus of amylin agonist peptide analogues defined by variable residues A1-K1, an intramolecular linkage between X and Y (disulfide, lactam, or thioether), and a Z substituent class.
It then narrows to a clear subset: X and Y = Cys-Cys disulfide and Z = amino through claims 2-3 and parallel dependent chains.
It also asserts standalone compound claims for specific engineered variants: claims 17-23 list six discrete named analogues including variants such as 18 Arg25,28 Pro-h-amylin and 25,28,29 Pro-h-amylin.
Coverage expands through salt claims (acetate, trifluoroacetate, hydrochloride) and composition/method claims for diabetes mellitus, including combination with insulin.

FAQs

1) Does the patent claim both peptide structure and salts?

Yes. It claims amylin analogues (and specific named variants) and separately claims acetate, trifluoroacetate, and hydrochloride salts.

2) What intramolecular linkage types are allowed?

Claim 1 allows disulfide bond, lactam, or thioether between X and Y; dependent claims narrow to disulfide via Cys residues.

3) Is “Z = amino” always allowed?

“Z = amino” is expressly required in dependent claims like 3, 6, 9, 12, 16/parallel chains, while the conditional branch in claim 1 constrains Z to the alkyl/aryl amino and alkyloxy/aryloxy/aralkyloxy group set when the anchor residue pattern is present.

4) Are there explicit compounds beyond the generic formulas?

Yes. Claims 17-23 list explicit named analogues built from h-amylin with residue edits such as Arg, Lys, Pro, and “des-1” variants.

5) Does the patent include combination therapy?

Yes. Method claims 36-37 and composition claims 44-45 cover treatment that includes insulin, including a specific combination with 25,28,29 Pro-h-amylin.

References

[1] United States Patent and Trademark Office. “US Patent 5,686,411.” (claims and text as provided in the prompt).

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Details for Patent: 5,686,411

Summary for Patent: 5,686,411