United States Patent 7,491,691: Claims, Scope, and U.S. Patent Landscape

What does US 7,491,691 actually claim?

US 7,491,691 is a peptide-centric IP position that ties specific proline/hydroxyproline-containing short peptides to “bone and/or cartilage development-stimulating” activity, then expands coverage into compositions and delivery formats (carriers, adjunct agents, local and systemic routes, and implant/matrix embodiments).

Claim 1: Core inventive concept (peptide sequence + functional use)

Claim 1 is an isolated bone and/or cartilage development-stimulating peptide selected from a defined set of sequences. It is further limited by residue chemistry for P (proline) or P* (hydroxyproline).

Key structural limits in Claim 1:

Peptide identity is determined by membership in a closed list of named sequences (SEQ ID NOs. 1-20, but not all numbers appear to be used; Claim text lists SEQ ID NOs 1-5, then 7-20 with gaps).
P is proline or hydroxyproline variant P* is hydroxyproline.
Functional limitation: the peptide “stimulates bone and/or cartilage development.”

Dependent claims: narrow to specific sequences and broaden to use and formulation

Dependent claims do two things: (i) lock Claim 1 down to particular sequences, and (ii) broaden beyond peptide identity into biology, formulations, and delivery.

Sequence-specific dependent claims: Claims 2-20 map to individual sequences in the Claim 1 list (e.g., Claim 2 = NGLPGPIGP* (SEQ ID NO. 1); Claim 3 = PGPIG (SEQ ID NO. 7); Claim 14 = GPRGRTGDA (SEQ ID NO. 13), etc.).
Biology and assays: Claims 21-26 specify stimulation of bone cells/cartilage cells and formation of bone/cartilage; Claim 25 includes “a response in vitro, ex vivo and/or in vivo.”
Formulation: Claim 27 adds a pharmaceutically acceptable carrier.
Adjunct agents: Claim 28 adds a long list of combination co-ingredients spanning osteoconductive materials (calcium salts), growth factors (BMPs, FGFs, PDGFs, TGFs, IGFs), and hormones/cytokine signaling molecules.
Administration and delivery: Claims 29-33 cover:
- systemic vs local administration,
- a broad list of systemic routes,
- local injection and implant-based administration,
- coating/filling/dispersal within an implant matrix,
- granular/powdered biomaterial format.

Practical claim footprint (what is covered)

At a high level, US 7,491,691 covers:

Specific peptide sequences (short, defined by SEQ ID NO list).
Use by function (bone/cartilage development stimulation).
Pharmaceutical compositions containing those peptides.
Combinations with numerous bone/cartilage-active agents.
Delivery modalities ranging from systemic administration to implant coatings/matrices and particulate formats.

How strong is the “peptide list” limitation?

The strongest structural feature is the closed list of enumerated sequences. That tends to reduce invalidity exposure versus open-ended “variants” or broad homology claims.

However, the listed sequences are:

short (many are 4-10 residues; some are longer but still typical “bioactive peptide” lengths),
compositionally simple with repeating motifs (e.g., P/PG/GPIG patterns appear multiple times),
and include both proline (P) and hydroxyproline (P*) placements.

This matters because, in the prior art space, it is common to find:

fragments of extracellular matrix proteins,
collagen- or bone-related peptide fragments,
short chemotactic or signaling peptides with similar motifs.

The patent’s enumerated list helps, but if those specific sequences were already disclosed as bone/cartilage active peptides, the functional limitation may not rescue novelty.

Where the claim is most vulnerable: functional language tied to known motifs

The functional limitation in Claim 1 is “bone and/or cartilage development-stimulating.” In practice, many prior art references claim similar biological outcomes for peptides derived from collagen or other extracellular matrix proteins.

If the prior art includes even one disclosure of:

the exact sequences in the Claim 1 list and
a demonstrated or credible teaching of bone/cartilage stimulation (or osteogenic/chondrogenic activity),

then novelty and nonobviousness risk rises quickly.

Dependent claims increase breadth, not selectivity

Several dependent claims broaden scope without adding strong structural constraints:

Claim 21-24 add cell types and outcomes.
Claim 25 adds “in vitro, ex vivo and/or in vivo.”
Claim 28 adds an extremely broad combination agent set.
Claims 29-33 broaden routes and delivery formats, especially implant-based delivery.

From a patentability perspective, these formulation and method-of-administration features can be easier to find in prior art (carriers, growth factors, implant coatings, local injection paradigms), making them less helpful in differentiating from earlier disclosures once the peptide identity is compromised.

How does Claim 28 affect validity and freedom-to-operate?

Claim 28’s combination list is wide, covering established classes like:

osteogenic/osteoinductive factors (BMPs),
cytokine/growth factor systems (FGF, PDGF, TGF, IGF),
endocrine signaling molecules (calcitonin, estrogen, estradiol, parathyroid hormone),
and multiple bone remodeling agents (bisphosphonic acids, sodium fluoride, vitamin K).

This kind of claim structure creates two distinct consequences:

Invalidity risk: Combination disclosures (peptide + carrier + one or more osteogenic co-factors) can be found as “standard” in this therapeutic area.
Enforcement ambiguity: Even if the peptide is protected, proving that an accused product uses a claimed combination agent “selected from the group consisting of … mixtures thereof” could create evidentiary complexity in infringement analysis.

Implant and coating claims (Claims 31-33): likely strongest enforcement hooks, weakest differentiators

Claims 31-33:

require local administration via injection or implant,
define peptide presentation “as a coating, filling or dispersed within a matrix of said implant,”
and allow granular/powdered biomaterial compound.

This aligns with common orthopedic product architectures (bone void fillers, scaffold coatings, implant surface functionalization). That makes these claims potentially easier to design around if the peptide itself is not protected strongly, but they can be strong enforcement hooks if the peptide is uniquely protected and used on a compatible implant format.

Patent landscape analysis: what typically dominates this field

The bone/cartilage peptide IP landscape in the U.S. is usually driven by three clusters:

Matrix-derived peptides
- Short collagen or extracellular matrix fragments claimed for osteogenic/chondrogenic stimulation.
- Often overlap in sequence motifs (proline/hydroxyproline and glycine-rich patterns).
Peptide analogs and variants
- Prior art often lists sequences and then includes substitution/hydroxyproline placement as part of “variant” families.
- If prior art discloses these peptides with P-to-P* modifications, US 7,491,691’s proline/hydroxyproline distinction may be insufficient.
Compositions and delivery platforms
- Broad claims on carriers, scaffolds, implants, and growth factor co-administration are common.
- These typically narrow patentability to whether the peptide identity itself is novel/nonobvious and whether the specific sequences were not previously disclosed.

Given your provided claim set, the decisive question for the landscape is whether those exact sequences were disclosed earlier (in U.S. patents or non-patent literature that is prior art under U.S. standards). If they were, the rest of the claim package becomes much easier to challenge.

Landscape map by claim element (where others likely sit)

A. Peptide identity (Claim 1 and 2-20)

Competitive IP risk is concentrated around:
- identical sequence disclosures,
- disclosures of those sequences as collagen/cell-activity peptides,
- disclosures of P/hydroxyproline placement producing the same named sequences.

B. Functional use (Claim 1 and 21-26)

Competitive activity often appears as:
- in vitro assays with osteoblast/chondrocyte markers,
- ex vivo or in vivo bone defect models,
- claims that peptides stimulate differentiation or extracellular matrix production.

C. Formulation and co-ingredients (Claim 27-28)

Competitive IP is typically easier to find:
- pharmaceutically acceptable carriers,
- bone graft substitute components (calcium salts),
- growth factor/cytokine co-therapy strategies.

D. Routes and implants (Claim 29-33)

Competitive IP is typically broad:
- implant coatings, fillers, scaffold dispersions,
- particulate formats and local delivery methods.

Critical assessment of claim architecture (novelty and nonobviousness pressure points)

1) Strong: enumerated sequences reduce overbreadth

The peptide is selected from a specific set of sequences. This is a meaningful constraint compared with generic “peptide comprising motif” claims.

2) Weak: functional outcomes can be reused from prior disclosures

If any of the sequences were known for similar activity, the “bone/cartilage development-stimulating” functional language becomes a standard translation rather than a new technical teaching.

3) Mixed: P vs P* constraint is chemically meaningful but may not be dispositive

Hydroxyproline placement is a legitimate variation class, but in collagen-related peptide prior art, hydroxyproline may already appear in the exact same locations due to collagen’s known composition.

4) Broad formulation and administration clauses can be attacked post-peptide invalidation

Even if the peptide is novel, broad downstream claims can be narrowed by interpretation or challenged if prior art already used those delivery concepts with similar agents.

Claim scope summary table (what each element does)

Claim element	What it covers	Scope impact	Main risk vector
Claim 1 peptide list	Closed list of specific peptide sequences (SEQ ID NO. 1-5, 7-20) with P/P* defined	High specificity	Prior art disclosure of exact sequences + similar activity
Claim 21-26 biology	Bone/cartilage cells, formation of bone/cartilage, and in vitro/ex vivo/in vivo response	Broad functional translation	Functional similarity already taught for same peptides
Claim 27 composition	Peptide + pharmaceutically acceptable carrier	Typical	Carriers alone rarely distinguish art
Claim 28 co-agent list	Adds many standard osteogenic agents	Very broad	Combination strategies already known
Claims 29-33 delivery	Systemic routes and implant coatings/fillers/matrices/particulates	Broad practical use	Local delivery and implant integration are common platform claims

Key takeaways for R&D and investment decisions

US 7,491,691 is structurally peptide-defined (enumerated sequences), but its functional and formulation breadth is wide (cells, outcomes, assays, carriers, co-agents, and delivery).
The patent’s enforceability and validity hinge on whether the enumerated sequences were already disclosed in U.S. prior art as bone/cartilage-active peptides. If yes, downstream breadth becomes less defensible.
Combination and delivery claims (especially implant matrix/coating and adjunct osteogenic agents) are likely to be easy to replicate in the market and may already exist as generic strategies, shifting differentiation back to peptide novelty/nonobviousness.
For freedom-to-operate and product design, the design-around path typically focuses on peptide identity (avoid the listed sequences) and on delivery formats that can remove overlap with implant coating/filling claims where peptide identity is not safely constrained.

FAQs

1. What is the single most important claim limitation in US 7,491,691?
The peptide identity in Claim 1: the peptide must be one of the explicitly listed sequences defined by SEQ ID NOs and P/P* constraints.

2. Do the dependent claims materially narrow the patent?
Sequence-dependent claims (2-20) narrow to specific peptides, but many dependent claims broaden via biological outcomes, assay contexts, carriers, co-agent lists, and administration routes.

3. Are the co-ingredient combinations (Claim 28) likely to be a validity anchor?
They are more likely to be an enforcement and claim coverage lever than a validity anchor, because the listed co-agents are broadly standard across orthopedic/biologic regeneration technologies.

4. What delivery embodiments are explicitly covered?
Local injection and implant-based delivery, including peptide coatings, filling within an implant, or dispersal in an implant matrix; also granular or powdered biomaterial formats.

5. Where should competitors focus to reduce overlap?
Avoiding the enumerated peptide sequences and then evaluating whether any remaining peptide-adjacent sequences are also taught in the prior art as bone/cartilage-active.

References

[1] United States Patent 7,491,691 (as provided in claim text).

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Takeda Pharmaceuticals U.s.a., Inc.	NATPARA	parathyroid hormone	For Injection	125511	January 23, 2015	7,491,691	2023-05-02
>Applicant	>Tradename	>Biologic Ingredient	>Dosage Form	>BLA	>Approval Date	>Patent No.	>Expiredate

Patent: 7,491,691

Summary for Patent: 7,491,691