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United States Patent 10,081,671 (Cell, Antibody, and Vectors for RSV F Antigenic Region II/A): Claims 1-17 Claim Scope, Likely Novelty, and US Patent Landscape

Executive summary:
US Patent 10,081,671 claims engineered antibody constructs/fragments (typically IgG1) and producing cells/expression vectors defined by a specific heavy/light CDR set that binds RSV F antigenic region II/A with sub‑nanomolar affinity (>1×10⁻⁹ M) and includes glycoengineering (glycans lacking fucose and xylose, with non-human N-glycans). Claims also narrow to expression in non–β-lymphocytes and to manufacturing platform cells (plant/CHO/HEK) plus several activity and pairing constraints (CDRs from different β-lymphocytes; heavy/light can originate from different patients; neutralization of RSV strains resistant to palivizumab).

The practical threat landscape for this patent is shaped by (i) RSV F antigenic region II/A epitope coverage, (ii) CDR sequence-specific antibody composition risk, (iii) glycan-deficient Fc manufacturing strategies (fucose/xylose knockout in plant/CHO/HEK backgrounds), and (iv) platform genericability (cells/vectors can be copied without using the same antibody sequences if an alternative binder is used). Without the full specification and prosecution history, only the claim text can be analyzed; claim-determinative positions are driven by the exact CDR amino-acid sequences and the fucose/xylose-deficient glycan requirement, plus explicit RSV functional/epitope recitations.

What claims are covered by US Patent 10,081,671 for RSV F II/A antibodies?

Featured snippet answer: The patent covers cells, antibodies/fragments, and expression vectors that encode and express antibody variable regions with fixed heavy CDR1/2/3 sequences (GASINLYD / GYISGST / ARDVGWGPQYYYGLDV) and fixed light CDR1/2/3 sequences (HSVQSTS / GGS / QQSDRSPPIT). The constructs must target RSV F antigenic region II/A with affinity >1×10⁻⁹ M, and dependent claims require IgG1 and glycans lacking fucose and xylose plus non–β-lymphocyte expression in specified hosts (plant/CHO/HEK) via nucleic acid vectors.

Claim 1: Core infringement “hook”

Claim 1 is a composite, multiple-constraint claim:

Cell type constraint: “wherein the cell is other than a beta lymphocyte.”
Genetic/sequence constraint:
- First cDNA encodes a heavy chain variable region containing three specified heavy CDR sequences.
- Second cDNA encodes a light chain variable region containing three specified light CDR sequences.
Functional/epitope constraint (via dependent claims, but the structure points to it): Claim 1 itself sets structure; dependent claim 5 ties to RSV F II/A binding and affinity.
Product constraint: the cell produces an antibody construct or fragment comprising the heavy and light variable regions.

Implication: literal infringement is most straightforward when all CDR sequences match and the construct is expressed in a non‑β-lymphocyte cell.

Claim 2: Host cell narrowing

Claim 2 limits cell embodiments to plant cells, CHO, and HEK. This can matter if a competitor uses another mammalian line (e.g., NS0, HEK293 variants not treated as “HEK” in claim construction, or engineered invertebrate systems).

Claim 3: Glycoengineered glycan limitation

Claim 3 adds: “N-glycan is a non-human N-glycan.” This excludes fully “human glycoforms” if interpreted strictly. It also creates a manufacturing-specific limitation.

Claim 4: Heavy/light CDR origin from different β-lymphocytes

This is a biological origin constraint: CDRs are sourced from different β-lymphocytes. If the patent is being used for commercial antibody engineering, this constraint can be bypassed by making the same CDR sequences via recombinant approaches not tied to “different β-lymphocytes,” depending on how strictly “originate from” is construed.

Claim 5: RSV F II/A binding and affinity

Claim 5 limits the antibody/fragment to bind RSV F antigenic region II/A with affinity >1×10⁻⁹ M. This is the key functional constraint for the antibody.

Implication for risk: an antibody that uses the same CDR sequences but has weaker affinity could avoid literal infringement; an antibody that binds II/A with stronger affinity but uses different CDRs can avoid literal infringement but could still face doctrine-of-equivalents arguments depending on jurisdiction and claim construction.

Claim 6: Isotype

Claim 6 requires the antibody construct or fragment is IgG1. If a competitor uses IgG2/IgG4 or a non-IgG Fc scaffold, it may not fall under this dependent claim.

Claims 7-9: Expression vector and specific nucleotide embodiments

Claim 7 covers cells with one or more expression vectors containing the first and second cDNA sequences.
Claim 8 requires stable transfection and adaptation.
Claim 9 is a specific nucleotide embodiment:
- heavy variable region cDNA is SEQ ID NO: 2, or
- light variable region cDNA is SEQ ID NO: 4.

Implication: Claims 7-8 expand infringement beyond “antibody possession” to engineering/manufacturing conduct. Claim 9 narrows to specific nucleotide sequences.

Claims 10-11: Patient-derived pairing and resistance phenotype

Claim 10: light and heavy CDR sequences originate from different antibodies produced by an RSV patient.
Claim 11: neutralizes at least one RSV strain resistant to palivizumab.

Implication: These are two additional “origin/phenotype” constraints. They can either provide robustness (if valid) or become design-around vectors (if competitors can neutralize palivizumab-resistant RSV without matching the “patient origin” language).

Claims 12-14: Fc glycan knockout (fucose and xylose) + non-human N-glycans

Claim 12 requires glycans lacking fucose and xylose.
Claim 13 extends to antibody compositions.
Claim 14 specifies glycans are non-human N-glycans.

Implication: This creates a manufacturing and Fc glycosylation barrier. Many bioprocesses can alter glycosylation, but if a competitor achieves standard mammalian glycoforms (including fucose), the dependent claims may not be met.

Claim 15: Recognition of epitopes in specified regions (SEQ ID NO: 23/24)

This claim ties the antibody recognition to epitope regions defined by SEQ ID NO: 23 or SEQ ID NO: 24.

Implication: This is an alternative epitope definition to “RSV F II/A” in claim 5. If claim 15 covers the same epitope as II/A, it strengthens scope clarity; if II/A and SEQ ID 23/24 don’t map identically, competitors could argue mismatch.

Claims 16-17: Expression vector variants

Claim 16 covers an expression vector with two nucleic acids encoding the heavy and light variable regions. Claim 17 adds that nucleic acids are cDNA or ties CDR origin to different β-lymphocytes.

How strong is the patent estate around RSV F antibodies and palivizumab-resistant strains?

Featured snippet answer: US 10,081,671 is structurally a CDR-sequence-defined antibody patent plus manufacturing and glycoengineering dependent limitations. Its strength hinges on (i) enforceability of sequence-specific antibody claims, (ii) validity of epitope/affinity assertions as limiting features, and (iii) whether prior art already disclosed the same CDR set or equivalent II/A-binding antibodies with similar glycosylation traits.

What prior art is most likely to be cited against CDR-defined RSV F antibodies

Based on typical RSV F antibody patent practice, the most relevant prior art categories are:

Sequence-defined RSV F antibodies (especially palivizumab-mimics and II/A binders)
Escape/resistance antibodies targeting II/A or related epitopes
Fc glycoengineering platforms producing afucosylated and/or afucosylated/xylose-lacking IgG
Expression in non–β-lymphocytes with recombinant heavy/light variable region pairing
Method-of-making and vector claims combining two nucleic acids encoding heavy/light variable domains

Because US 10,081,671 includes explicit CDR amino-acid sequences, an obviousness attack must usually show either:

the exact CDRs were known, or
the CDRs were routine to derive from known antibodies or epitope scaffolds with a predictable result meeting the affinity and binding constraints, and
dependent glycosylation constraints are disclosed or would be obvious.

Sequence-specific claims usually raise validity friction

Exact CDR amino-acid sequences create a narrower net than broader “recognizes RSV F II/A” claims. That tends to reduce overlap with prior art that only shares epitope class but not the specific CDRs. The flip side is that if the same CDRs appear in earlier filings, the patent can become vulnerable.

What does the CDR sequence set imply about design-around options?

Featured snippet answer: The clearest design-around is to change any of the required CDR sequences (heavy CDR1/2/3 or light CDR1/2/3). Secondary design-arounds include using different host cell types, avoiding fucose/xylose-lacking glycans, changing isotype away from IgG1, or producing glycoforms that retain fucose and/or xylose.

Primary design-around levers

CDR mutation/substitution: altering even one required CDR sequence should avoid literal infringement.
Different variable region framework with different CDRs, while still binding II/A, could avoid literal claim 1/13.
Isotype swap: avoids claim 6 (IgG1).
Glycoform changes:
- If the product retains fucose or xylose, dependent claims 12/14 fail.
Non-covered expression system: claim 2 narrows to plant/CHO/HEK.

Secondary levers that may or may not work depending on claim construction

CDR origin phrasing (different β-lymphocytes/patient antibodies). If a competitor’s engineering history does not map neatly to “originates from,” it may attempt to argue non-meet of that limitation.
Vector specifics: avoid SEQ ID NO: 2 / SEQ ID NO: 4 to dodge claim 9.

What other patents likely intersect with US 10,081,671’s subject matter?

Featured snippet answer: The intersection set is typically not just “more antibodies,” but rather platform and process patents that handle (i) non-human N-glycan glycoengineering, (ii) engineered CHO/plant expression, and (iii) RSV F antigen targeting. The strongest overlap risk comes from any patent that independently claims the same II/A-binding antibody architecture or the same glycoengineered Fc phenotype for IgG.

High-probability patent families that intersect

RSV F antigen-binding antibodies (palivizumab derivatives and resistance-escape antibodies)
Antibody Fc glycoengineering:
- afucosylation (L-fucose removal) and
- xylose depletion (XylT1-related or plant-specific N-glycan trimming pathways)
Recombinant expression systems for antibody production in CHO/HEK and plant platforms
Stable transfection / expression vector constructions with two-nucleic-acid heavy/light architectures
Epitope mapping frameworks referencing RSV F region II/A and adjacent residues

What can be concluded from the claim text alone

The patent is not limited to a single antibody product; it covers a family defined by CDRs (and then further limited by glycan phenotype and IgG1, depending on claim).
It is also not limited to a single manufacturing method, but dependent claims push toward particular host categories and stable expression.

What is the Orange Book status of US 10,081,671 and how does that affect generic entry?

No reliable determination can be made from the provided claim text alone. Patent landscape and FDA listings require the Orange Book drug-product and patent list, which cannot be derived here without specific product identifiers.

What patent expiration timeline matters for this US patent?

No reliable determination can be made from the provided claim text alone. Expiration depends on:

application filing dates,
continuations/divisionals,
PTA (patent term adjustment),
terminal disclaimers,
any life-of-the-patent reduction scenarios.

The claim text does not include filing/priority data.

How would a competitor test infringement risk under US 10,081,671?

Featured snippet answer: A competitor would compare (1) the heavy and light variable region CDR amino-acid sequences against the required sequences, (2) whether the antibody binds RSV F II/A with >1×10⁻⁹ M affinity, (3) the isotype (IgG1), and (4) glycosylation profile lacking both fucose and xylose if operating under dependent claims.

Infringement mapping matrix (claim-to-feature)

Claim	Required technical features	Most sensitive to design-around
1	Cell (non–β-lymphocyte) producing antibody with exact heavy CDRs (SEQ ID 8-10) and light CDRs (SEQ ID 14-16)	Any CDR mismatch; host cell class
2	Host cell is plant/CHO/HEK	Using other expression systems
3	Non-human N-glycan	Human-like glycoforms or different glycosylation
4	CDRs originate from different β-lymphocytes	Engineering provenance language
5	Binds RSV F II/A with affinity >1×10⁻⁹ M	Using a different binder/scaffold or weaker affinity
6	IgG1	Isotype swap
7	Expression vectors encode the two cDNAs	Avoiding vector architecture (hard to avoid in manufacturing)
8	Stable transfection/adapted expression	Transient expression strategy
9	Heavy cDNA is SEQ ID NO:2 and/or light cDNA is SEQ ID NO:4	Avoid exact nucleotide sequences
10	Heavy/light originate from different antibodies in an RSV patient	Engineering/provenance constraints
11	Neutralizes palivizumab-resistant RSV strain(s)	Escape from phenotype; may still bind II/A
12	Glycans lacking fucose and xylose	Preserving fucose/xylose in Fc glycan
13-15	Antibody/fragments with same CDRs; glyco phenotype; epitope mapping	Glycan changes; CDR changes; epitope region mismatch
16-17	Expression vector with specific cDNA encoding and CDR provenance	Avoid exact nucleotide and provenance limitations

What are the key litigation and licensing issues implied by these claim types?

Featured snippet answer: The claim set is built to support both (i) composition-of-matter enforcement (antibody defined by CDRs and epitope/affinity) and (ii) manufacturing/production leverage (cells/vectors, stable transfection, glycosylation phenotype). This pattern tends to drive licensing disputes over both product identity and manufacturing glyco profile.

Likely negotiation fault lines

Do competing CDR sequences map exactly?
Does the product carry the required glyco phenotype (no fucose and no xylose)?
Is the binding claim satisfied (II/A region + affinity threshold)?
Are there non-β-lymphocyte production differences that change claim meeting? (Dependent claims help enforce process constraints.)

Key Takeaways

US 10,081,671 claims engineered RSV F antigenic region II/A antibodies defined by fixed heavy and light CDR amino-acid sequences, produced in non–β-lymphocyte systems via nucleic acids/vectors.
Dependent claims add narrow but material constraints: IgG1, glycans lacking fucose and xylose, non-human N-glycans, and host cell categories (plant/CHO/HEK).
The strongest design-around is changing any CDR sequence; secondary risk management includes altering isotype and avoiding the fucose/xylose-deficient glycoforms.
The effective “infringement surface” spans both end-product antibody and the recombinant manufacturing setup (cells and expression vectors), making it likely to influence licensing and litigation strategy.

FAQs

Can a competitor infringe US 10,081,671 by making the same CDR sequences in a different host cell line than plant/CHO/HEK?
If an antibody matches the CDR sequences but retains fucose or xylose in Fc glycans, which dependent claims become non-actionable?
How does swapping IgG1 to another Fc isotype affect claim coverage under US 10,081,671?
Does using transient expression instead of stable transfection reduce exposure under the vector/cell dependent claims?
If an antibody binds RSV F II/A but with affinity below 1×10⁻⁹ M, does that avoid dependent claim 5?

References

US Patent 10,081,671. (Claims provided in the prompt).

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Swedish Orphan Biovitrum Ab (publ)	SYNAGIS	palivizumab	For Injection	103770	June 19, 1998	10,081,671	2035-10-29
Swedish Orphan Biovitrum Ab (publ)	SYNAGIS	palivizumab	Injection	103770	July 23, 2004	10,081,671	2035-10-29
>Applicant	>Tradename	>Biologic Ingredient	>Dosage Form	>BLA	>Approval Date	>Patent No.	>Expiredate

Patent: 10,081,671

Summary for Patent: 10,081,671