US Patent 4,517,181 (Synthetic GH-Releasing Peptides): Scope of Claims and US Patent Landscape
US 4,517,181 claims synthetic peptide and peptide-fragment structures defined by specific residue constraints, plus composition and method-of-use claims centered on stimulating pituitary release of growth hormone (GH). The patent’s practical scope is driven by (i) whether a candidate peptide’s key residues match the defined positions and (ii) whether claims cover biologically active fragments and nontoxic salts. The landscape around this patent typically clusters on GH-releasing peptides and analogs, with claim pressure on sequence variants, terminal forms (free acid vs amide), salt forms, and method-of-use in mammals and farm/nonhuman animals.
What exactly does US 4,517,181 claim: peptide sequences, fragments, salts, and terminal variants?
Short answer: The patent claims a synthetic peptide defined by a structured sequence formula with constrained amino acids at defined positions, including biologically active fragments that trigger pituitary GH release, plus nontoxic salts, plus pharmaceutical compositions and methods for GH stimulation and anabolic effects.
1) Claim 1: core structural genus (sequence-defined peptide/fragments)
Claim 1 is the broadest independent claim you provided. It recites:
- A synthetic peptide having a formula (sequence shown in the patent, not reproduced in your message text).
- Variables and constraints:
- R is OH or NH2 (implies termini-related substitution, commonly reflecting terminal group identity such as carboxylic acid vs carboxamide).
- R34 is Ser or Ala
- R38 is Arg or Ser
- R40 is Ala or Arg
- R41 is Arg, Arg-Ala, Arg-Ala-Arg, or Arg-Ala-Arg-Leu
- Coverage includes:
- A fragment of such peptide that is biologically active to effect GH release
- A nontoxic salt of the peptide or peptide fragment
Scope implications:
- The claim is a genus claim over a family of analogs defined by a residue-position grammar.
- It is also functionally anchored through “biologically active to effect the release of GH.” That phrase can expand infringement theories beyond exact full-length sequence, as long as the accused peptide fragment still performs the GH-release function.
2) Dependent claims narrow specific residue combinations
Your dependent claim set progressively locks in particular residue selections and terminal R forms.
- Claim 2: R34 = Ser, R38 = Arg, R40 = Ala
- Claim 3: Claim 2 plus R41 = Arg-Ala-Arg-Leu
- Claims 4 and 5: Claim 3 plus R is NH2 or OH
- Claims 8 and 17-20: composition claims that also lock in selected R41 and terminal forms
Scope implications:
- These claims capture specific members of the genus (including at least one member with R41 = Arg-Ala-Arg-Leu and carboxyl terminus variants via R = OH vs NH2, depending on how R maps to the terminal group in the patent drawings/formula).
3) Method-of-use claims: GH release and anabolic acceleration
- Claim 6: method of stimulating GH release in mammals by administering an effective amount of the peptide of claim 1.
- Claim 7: method of improving muscle mass in nonhuman animals by administering an amount effective to accelerate anabolism.
- Claims 9-13: method claims specifically reciting administering the peptide having the sequence shown in the patent (plus fragments biologically active to effect GH release by pituitary), including:
- Claim 10: GH release in nonhuman animals
- Claim 11: growth in farm animals via anabolism
- Claim 12: carboxyl terminus free acid or amide
- Claim 13: combination with pharmaceutically acceptable liquid or solid carrier for stimulating GH release in humans
Scope implications:
- You have separate functional buckets:
- Pituitary GH release in mammals
- Anabolic effects (muscle mass/growth) in nonhuman animals, including farm animals
- Methods are likely to be implicated by both clinical formulations and veterinary/admin use (assuming the administration practice matches the claim).
4) Pharmaceutical composition claims
- Claim 8: pharmaceutical composition comprising peptide of claim 1 in an amount effective to stimulate GH release in humans, plus a pharmaceutically acceptable liquid or solid carrier.
- Claims 17-20: composition claim tied to a specific sequence with R41 options and biologically active fragments, plus carrier, and with additional limitations on terminal forms (amide vs free acid).
Scope implications:
- Composition claims are typically broad on carriers and dosage presentation, but narrow on:
- the peptide identity (via defined sequence constraints)
- terminal form
- biologically active fragments
5) Fragment coverage is explicit and potentially broad
- Claim 1: covers “a fragment … biologically active to effect the release of GH.”
- Claim 14: covers “biologically active fragment of the 40-residue peptide including the N-terminal sequence thereof.”
- Claim 17: covers fragments biologically active to effect GH release by the pituitary.
Scope implications:
- “Biologically active” is the hinge for infringement:
- if a shorter peptide still triggers GH release, the patent’s fragment concept can be asserted even when the full-length sequence is not used.
How broad is the claim construction: what does the “formula” really mean for infringement?
Short answer: The patent’s breadth is governed by the residue-position constraints (R34, R38, R40, R41) and terminal variable R. The fragment and function qualifiers expand coverage to active fragments, not only the full-length peptide.
Residue-position grammar (key to infringement risk)
A competitor peptide is most at risk if it satisfies these position rules simultaneously:
- Position 34: Ser or Ala
- Position 38: Arg or Ser
- Position 40: Ala or Arg
- Position 41: a specific arginine-rich pattern:
- Arg
- Arg-Ala
- Arg-Ala-Arg
- Arg-Ala-Arg-Leu
And terminal variable:
- R is OH or NH2 (maps to terminal chemical identity; and dependent claims and composition claims separately call out free acid vs amide).
Functional fragment coverage
Even if full-length analogs differ, the patent still reaches:
- fragments that retain GH-releasing biological activity
- fragments of a “40-residue peptide” that include the N-terminal sequence
Nontoxic salt coverage
This is standard in peptide patents but matters for:
- formulation salt selection
- label claims that use salts or counterions
- generic or follow-on peptides that try to differentiate by salt form
Which specific claim sets are most valuable for enforcement: sequence member claims vs method claims?
Short answer: The highest leverage typically comes from (i) claim 1 for broad genus coverage, (ii) composition claims for marketed product infringement, and (iii) fragment claims when competitors use shorter GH-releasing peptide fragments.
Priority buckets by enforcement posture
-
Composition product risk (high)
- Claim 8
- Claims 17-20
Composition claims are usually easier to attack in product litigation because the accused product contains the claimed peptide.
-
Method risk (medium to high)
- Claim 6, 9-13
Method claims can be enforced against prescribing and administration practices, but are often harder depending on evidence and jurisdiction.
-
Genus and member coverage (high)
- Claim 1 + key dependent narrowing claims like claim 3 (R41 = Arg-Ala-Arg-Leu)
If an accused peptide matches the constrained residues, claim 1 is a strong anchor.
What other US patents likely exist in the GH-releasing peptide landscape around 4,517,181?
Short answer: The surrounding landscape for GH-releasing peptides in the US typically includes patents covering:
- other analogs of the same GH-releasing peptide family
- positional substitutions (including Arg-rich C-termini)
- terminal modifications (free acid vs amide)
- formulation-specific patents (carriers, depot systems, stability)
But: You have not provided the application number, assignee, earliest priority date, or a list of related patents. Without those identifiers, a complete, accurate US patent landscape cannot be produced.
Orange Book status: does US 4,517,181 map to an FDA-approved drug listed in the Orange Book?
Short answer: This cannot be determined from the information provided. Mapping requires the FDA application (NDA/BLA) and the specific listed patent record.
Patent expiration and exclusivity: when would US 4,517,181 likely lose enforceability?
Short answer: This cannot be calculated accurately without:
- the filing date(s) and any priority dates
- whether the claims qualify for any extension mechanisms
- whether there are terminal disclaimers
Your prompt includes only claim text, not bibliographic data.
Paragraph IV or biosimilar risk: is there a generic challenge pathway tied to this patent?
Short answer: This depends on whether the claimed peptides are used in an approved, currently marketed reference product and whether the patent is listed for that product in the Orange Book. No such mapping can be completed from the provided data.
Commercial and litigation relevance: what product design choices would steer around 4,517,181?
Short answer: Around this patent, design-around strategies usually focus on breaking one of the claim predicates:
- changing residue constraints at positions 34, 38, 40, or C-terminal residue pattern at 41
- using fragments that either:
- do not include the N-terminal sequence required by fragment claims, or
- are not biologically active to effect pituitary GH release
- using terminal forms not covered by R and terminal definitions (free acid vs amide)
- using salt forms arguably outside “nontoxic” characterization (though courts often treat “nontoxic salt” as a broad exclusion that is evidence-dependent)
Because claim 1 and dependent claims are defined by residue-position grammar and functional activity, the most direct risk-reduction is to alter at least one of the constrained residues or C-terminal Arg-rich segment patterns so the peptide cannot fall within the defined genus.
Key Takeaways
- US 4,517,181 is a GH-releasing peptide patent with sequence-defined genus coverage (claims 1-5) anchored on residue-position constraints at R34, R38, R40, and R41, plus terminal identity (R = OH or NH2) and nontoxic salts.
- The patent explicitly covers biologically active peptide fragments, including fragments of a 40-residue peptide containing the N-terminal sequence, which expands scope beyond full-length sequences.
- Enforcement leverage is strongest where an accused product is a pharmaceutical composition containing the claimed peptide (claims 8 and 17-20), followed by method-of-use claims for pituitary GH release and anabolic effects in humans/nonhuman and farm animals (claims 6, 7, 9-13).
- Designing around the patent most plausibly requires changing at least one of the constrained residues or the Arg-rich C-terminal patterns at the position corresponding to R41, or ensuring the candidate fragment is not within the “biologically active” fragment concept.
- A complete US landscape (related patents, assignees, expiration timeline, Orange Book listings, and litigation/Paragraph IV or biosimilar posture) cannot be produced from the claim text alone.
FAQs
1. What is the key structural feature that determines whether a GH-releasing peptide falls under claim 1 of US 4,517,181?
Residue-position constraints: R34 (Ser/Ala), R38 (Arg/Ser), R40 (Ala/Arg), and R41 (Arg or Arg-Ala patterns up to Arg-Ala-Arg-Leu), plus terminal R (OH or NH2) and inclusion of biologically active fragments or nontoxic salts.
2. Do the claims cover peptide fragments shorter than the full sequence?
Yes. Claim 1 and multiple dependent claims cover fragments that are biologically active to effect GH release, including fragments of a 40-residue peptide that include the N-terminal sequence.
3. Are both free-acid and amide terminal forms covered?
Yes. The claims explicitly include carboxyl terminus free acid or amide through terminal-related limitations (R = OH or NH2 and the method/composition terminal form recitations).
4. Which claim types are most likely to be implicated by a marketed drug product: composition or method claims?
Composition claims (claim 8; claims 17-20) are typically more directly implicated because they attach to a pharmaceutical composition containing the claimed peptide, while method claims depend on administration/use evidence.
5. Can competitors avoid infringement by selecting a different salt form?
The patent covers nontoxic salts of the peptide or fragments, so salt selection alone may not avoid infringement if the salt is still considered “nontoxic” and the underlying peptide sequence falls within the claim constraints.
References (APA)
- United States Patent 4,517,181. “Synthetic peptides and methods for stimulating growth hormone release.” (Claim text as provided in prompt).
