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Patent landscape, scope, and claims summary: |
Executive summary
- US Patent 10,259,859 claims engineered SIRPα (signal-regulatory protein α) D1 variants that are tethered to Fc variants (including IgG1/IgG2/IgG4 Fc mutation sets that reduce FcγR binding and/or effector functions), plus downstream claims covering therapeutic use, combination regimens with checkpoint and other antibodies, nucleic acids/vectors/host cells, and compositions.
- The claim set is structured around (1) a tight SIRPα D1 variant sequence logic (degenerate positions and minimum “≥2” substitutions; narrower dependent sequences), (2) CD47 binding and functional constraints (e.g., KD thresholds; reduced phagocytosis/effector engagement; “not causing acute anemia” constraints), and (3) a sublicenseable modular Fc architecture (monomer or dimer Fc formats, with specific IgG Fc mutation combinations including N297A, L234A/L235A/G237A, and IgG4 effector-silencing set S228P/E233P/F234V/L235A/delG236).
- The enforceable perimeter is likely concentrated in the specific SIRPα D1 variant sequence families plus Fc mutation combinations and format constraints; generic “CD47/SIRPα axis” products with different D1 sequences, different Fc mutational cocktails, or different fusion formats may fall outside the literal claims even if they share the same mechanism.
How strong is the patent estate for US Patent 10,259,859 (SIRPα D1 variants + silenced Fc)
Direct claim strength drivers
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Sequence-defined SIRPα D1 variants
- Independent claim 1 is limited to a SIRPα D1 variant with an explicit SEQ ID NO: 49 sequence pattern and degenerate constraints (X1–X10 with specified allowed residues) plus “at least two amino acid substitutions” vs wild-type SIRPα D1 (SEQ ID NO: 1).
- Claims 3, 7, and 44 likewise anchor to variant sequence logic with explicit allowed residue sets and defined SEQ ID anchors (e.g., SEQ ID NOs: 218, 52, 47 in your text), again requiring ≥2 substitutions relative to the same wild-type reference.
- This reduces vulnerability to broad “mechanism-only” prior art while increasing knock-out risk if competitors adopt different D1 substitutions outside the enumerated families.
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Functional “quality gates”
- Claim 22 requires human CD47 binding KD < 5×10^-9 M.
- Several Fc-linked claims require reduced binding to Fcγ receptors (CD16a, CD32a/b/c, CD64; and/or C1q) and/or reduced phagocytosis.
- Claims 60–61 impose tolerability constraints: variant “does not cause acute anemia” in rodents/NHPs or humans.
- These functional gates can be powerful in infringement by narrowing the claim to variants with those performance attributes, but they also create additional proof burdens in litigation and can be attacked via measurement method disputes.
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Fc architecture modularity, but with specific mutation sets
- The independent claim 44 defines the Fc variant using a closed set of IgG1/IgG2/IgG4 mutation combinations:
- IgG1: N297A and/or L234A/L235A/G237A (and a triple set with N297A).
- IgG2: N297A and/or A330S/P331S (and a triple set with N297A).
- IgG4: S228P/E233P/F234V/L235A/delG236 (and a sextuple set adding N297A).
- Dependent claims constrain Fc binding (e.g., K_D > 5×10^-6 M for FcγR binding in certain claims).
Claim weakness drivers
- The dominant risk is not “breadth” but design-around space: a competitor can often keep SIRPα D1 function while changing the D1 substitution pattern away from SEQ ID NO families or alter fusion chemistry (e.g., different linker/Fc format, different Fc mutation cocktail, or different dimerization strategy) to avoid literal coverage.
- The “≥2 substitutions” and “degenerate X positions” are still sequence-fenced but allow many combinations. That can help the patentee capture nearby variants; it also increases the chance that at least some claimed sequences overlap with earlier disclosed engineering sets (depending on the prior art not shown in your prompt).
Which patents protect SIRPα CD47 axis therapeutics like this US 10,259,859
Your provided text contains internal claim elements but does not include:
- the patent family members (continuations/divisionals) for US 10,259,859,
- priority/filing dates,
- the assignee,
- or any citations from the prosecution history.
Under the constraints here, no external patent landscape mapping can be completed without risking inaccuracies.
What do the claims of US 10,259,859 actually cover: SIRPα D1 variant sequence + Fc silence + therapeutic methods
Claim map (what’s protected)
Polypeptide claims
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SIRPα D1 variant constructs
- Claim 1: SIRPα D1 variant = SEQ ID NO: 49 pattern with allowed residues X1–X10 and ≥2 substitutions vs wild-type SIRPα D1 (SEQ ID NO: 1).
- Claim 3: SEQ ID NO: 218 pattern (more “free” positions) with ≥2 substitutions.
- Claim 7: SEQ ID NO: 52 pattern with ≥2 substitutions (plus additional degenerate constraints).
- Claim 44: expanded combinatorial “EEX…KPS (SEQ ID NO: 47)” D1 variant logic with allowed residues X1–X31 and ≥2 substitutions vs wild-type SEQ ID NOs: 1 to 10 reference.
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Fc domain inclusion and format
- Claim 23: Fc domain monomer linked to N- or C-terminus; Fc can be IgG1/IgG2/IgG4 region.
- Claim 26: specific Fc mutation lists (closed set).
- Claim 28–31: Fc dimer architecture and additional polypeptide provisions (including variable domain targeting cell surface proteins, including cancer cells).
- Claim 44: Fc variant is explicitly selected from a closed list of IgG1/IgG2/IgG4 Fc mutation combinations, with EU Kabat numbering.
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Binding and effector-silencing functional constraints
- Claim 22: CD47 binding KD threshold (< 5×10^-9 M).
- Claim 27: reduced phagocytosis vs wild-type IgG Fc.
- Claims 47–51, 48–50: ablated/reduced binding to Fcγ receptors or C1q; and/or K_D thresholds indicating reduced receptor engagement.
- Claim 60–61: “does not cause acute anemia” in rodent/NHP and humans.
Method claims
- Claim 63: method of treating disease/disorder by administering the polypeptide described in the independent structure (D1 variant + Fc variant selected from the closed mutation set).
- Claim 64–66: disease categories include cancer, autoimmune, inflammatory; includes broad lists of cancer types and autoimmune/inflammatory indications.
- Claims 67–81 etc.: specifies SIRPα sequences via SEQ ID NOs: 98–104, 107–113, 116–122, 135–137, and then permits combinations with antibodies and explicitly enumerated antibodies (anti-HER2, anti-CD20, PD-1/PD-L1, etc.).
- Claims 69–73: combination therapy with at least one additional agent; includes antibody + non-antibody therapeutic options.
- Claims 77–78: narrows representative antibody list for combination regimens.
- Claims 79–87 etc.: explicit examples with named clinical antibodies (cetuximab, necitumumab, pembrolizumab, nivolumab, ipilimumab, durvalumab-class equivalents not listed here, daratumumab, belimumab, bevacizumab, denosumab, panitumumab, ramucirumab, etc.) and corresponding SEQ ID polypeptide inclusion lists.
Platform claims
- Claim 113–116: isolated nucleic acid encoding claim 44 polypeptide; vector; host cell; method of production.
- Claim 117: pharmaceutical composition comprising polypeptide + pharmaceutically acceptable carrier.
Optimization/modification add-ons (composition architecture)
- Claim 37–39: optional HSA (SEQ ID NO: 12) with specified substitutions (C34S or K573P) and optional HSA-incorporating polypeptide sequences.
- Claim 40–41: optional albumin-binding peptide (SEQ ID NO: 160; “DICLPRWGCLW”).
- Claim 42–43: optional PEG polymer joined to cysteine substitution.
When does exclusivity end for therapies covered by US 10,259,859
The prompt does not provide:
- grant date, priority date(s),
- whether patent term adjustment applies,
- whether there are terminal disclaimers,
- any applicable FDA exclusivity (NCE/Biologic exclusivity, 7/10-year rules),
- Orange Book/NDA/BLA linkage.
No accurate exclusivity timeline can be produced under the “no incomplete answer” constraint.
What generic or biosimilar entry risks exist if competitors target CD47/SIRPα constructs
You can infer claim-proximity risks from the modularity:
- Competitors that keep the same SIRPα D1 sequence families (SEQ ID NO: 49/218/52/47 families and dependent SEQ ID lists) and the same Fc mutation cocktails (N297A, L234A/L235A/G237A, IgG4 “S228P/E233P/F234V/L235A/delG236” and optional N297A addition) face the highest literal infringement risk.
- Competitors can reduce risk by:
- substituting SIRPα D1 outside the enumerated allowed residue sets and/or outside dependent SEQ ID anchors,
- using an Fc with different effector-silencing mutations not captured by the closed lists,
- shifting to a different fusion format that does not meet “monomer linked” vs “Fc dimer comprising two monomers” definitions.
However, without the patent family and prosecution history, no litigation-ready freedom-to-operate assessment can be produced here.
How does US 10,259,859 compare with other CD47-blockade strategies (mechanism vs effector silencing)
What is distinctive in this patent
- The claims are not “anti-CD47 antibody” claims. They are SIRPα D1 variant-Fc constructs designed to:
- retain CD47 engagement (KD threshold),
- but reduce Fc-mediated effector functions by using Fc mutations that ablate/reduce Fcγ receptor binding and/or C1q binding,
- and claim tolerability via “no acute anemia” constraints.
Implication for competition
- Products built on a different “scaffold” (e.g., anti-CD47 antibody formats) are conceptually different and may not map to this claim set at all unless they incorporate an SIRPα D1 variant sequence defined here.
Are the claims vulnerable to invalidity arguments like anticipation or obviousness
No prior art references are provided in the prompt. Under the constraints, a detailed novelty/obviousness invalidity analysis with named prior patents cannot be performed reliably.
What is the regulatory status or Orange Book status of US 10,259,859
The prompt does not identify:
- the drug product name,
- the NDA/BLA number,
- any FDA labels,
- the Orange Book listing status (if applicable),
- pediatric exclusivity or interchangeability.
No status mapping can be completed without producing potentially incorrect details.
Key patent-coverage vectors inside the claims (useful for claim-charting)
Below are the recurring “elements” that drive both infringement mapping and design-around:
| Coverage element |
Claim anchors in your text |
Design-around leverage |
| SIRPα D1 variant sequence family |
Claims 1, 3, 7, 44 (SEQ ID NO: 49, 218, 52, 47; degenerate X-position constraints; ≥2 substitutions vs wild-type SEQ ID NO: 1 or 1–10) |
Switch to D1 substitution patterns outside allowed X-position sets or outside dependent SEQ ID sequences |
| CD47 binding strength |
Claim 22 (<5×10^-9 M) |
Use lower-affinity variants (if permitted by the intended mechanism) |
| Fc mutation cocktail (IgG1/IgG2/IgG4 effector-silencing) |
Claim 26; Claim 44 closed list; claims 47–51; 48–50 |
Use alternative Fc mutations not in the closed sets; use different numbering/mutation mapping approach not covered |
| FcγR and C1q binding reduction |
Claims 27, 47–51, 48–50 |
Keep Fc effector engagement but claim-functional tests could fail if any are required |
| Acute anemia “does not cause” |
Claims 60–61 |
Use variants with known anemia signals in preclinical/clinical data, or dispute assay equivalence |
| Fc format |
Claims 23 (monomer), 28–29 (dimer), 52 (Fc dimer with two monomers selected from closed lists) |
Change format from monomer/dimer definitions, or use heterodimers not matching claim definitions |
| Combination therapy methods |
Claims 63–66, 68–78, 79–107 |
Different regimen or exclusion of specific antibody examples may reduce method-claim alignment |
Key Takeaways
- US 10,259,859 is centered on a specific class of SIRPα D1 engineered variants (sequence-defined with degenerate residue logic and dependent SEQ IDs) fused to Fc variants that are functionally effector-silenced through defined IgG1/IgG2/IgG4 mutation sets.
- The claim set is strongest where infringement requires (a) the SIRPα D1 variant sequence family and (b) the specific Fc mutation cocktail and format, plus where functional thresholds like CD47 binding affinity and reduced phagocytosis/FcγR engagement are provable.
- The biggest practical risk for competitors is that small sequence changes or different Fc mutations could fall outside literal claim coverage, but the modular breadth in SIRPα D1 degeneracy and the closed Fc mutation sets still provide substantial nearby coverage if the designs remain within the enumerated families.
FAQs
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Do the claims require an Fc-silenced construct or can a wild-type Fc satisfy coverage?
The enumerated Fc mutation sets in the Fc variant-dependent claims require specific IgG1/IgG2/IgG4 mutation combinations.
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Are CD47 binding affinity thresholds required for all polypeptide claims?
The KD threshold is explicitly stated in a dependent claim (claim 22) tied to the polypeptide of the SIRPα D1 variant.
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Can the same SIRPα D1 variant be used with a heterologous Fc if it is not one of the closed mutation combinations?
Claim 44 and related dependent claims define Fc selection from a closed list of mutation configurations.
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Does the patent cover only polypeptides, or also nucleic acids and manufacturing?
The claims include isolated nucleic acids, vectors, host cells, and production methods.
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Do the method claims limit the disease category or drug combinations?
The method claims are broad on indication (cancer, autoimmune, inflammatory) and allow combination regimens with enumerated antibodies and other therapeutic agents.
References
(No external sources were cited because the prompt provided only the claim text and did not include the patent’s bibliographic record, family members, prosecution history, FDA product linkage, or prior-art citations.)
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