US Patent 10,206,887: Claim Scope, Patent Landscape, and Generic-Entry Risk

US Patent 10,206,887 covers albumin-coated nanoparticles containing paclitaxel, other taxanes, or rapamycin, where the nanoparticles also carry a ligand capable of binding a prion protein and have a negative zeta potential. The patent is directed to targeted nanoparticle compositions rather than conventional paclitaxel or rapamycin products.

The strongest protection is concentrated in the two independent composition claims:

Claim 1: taxane nanoparticles.
Claim 12: rapamycin nanoparticles.

The claims do not require a particular treatment method, disease indication, route of administration, manufacturing process, or named commercial product. Infringement therefore turns primarily on the composition of the nanoparticles and whether all required structural and functional limitations are present.

What does US Patent 10,206,887 claim?

The patent has 21 claims organized into two parallel claim families.

Claim family	Independent claim	Active pharmaceutical ingredient	Core additional limitations
Taxane family	1	A taxane	Albumin coating, prion-protein-binding ligand, negative zeta potential
Rapamycin family	12	Rapamycin	Albumin coating, prion-protein-binding ligand, negative zeta potential

Claim 1 requires a composition comprising nanoparticles that contain:

A taxane;
Albumin coating;
A ligand capable of binding a prion protein; and
A negative zeta potential.

Claim 12 has the same architecture but replaces the taxane with rapamycin.

The dependent claims narrow the ligand, particle size, and physical presentation of the composition.

How broad is claim 1 for taxane nanoparticles?

Claim 1 is materially broader than claim 2 because it covers any taxane, subject to the other limitations. Claim 2 narrows the active ingredient to paclitaxel.

Potentially covered taxanes include paclitaxel and structurally related taxanes such as docetaxel, cabazitaxel, and other taxane derivatives, provided the accused product satisfies the albumin, ligand, zeta-potential, and nanoparticle limitations.

The claim does not expressly require:

A specific prion disease;
A specific prion isoform;
A particular ligand sequence;
A particular albumin source;
A defined ligand-to-particle ratio;
A defined drug loading;
A particular administration route;
A particular particle-production process; or
A particular particle-size range.

The absence of those limitations gives claim 1 broad composition coverage. It also creates potential validity issues if the specification does not adequately support the full scope of all taxanes, albumin coatings, ligand classes, and negative-zeta-potential formulations.

What does claim 2 add for paclitaxel?

Claim 2 narrows claim 1 to paclitaxel. A paclitaxel product remains outside claim 2 if it lacks any one of the following:

Albumin coating;
A ligand capable of binding a prion protein;
Nanoparticle structure; or
Negative zeta potential.

A conventional paclitaxel solution, liposomal paclitaxel formulation, polymeric micelle, or albumin-free nanoparticle would not satisfy claim 2 solely because it contains paclitaxel.

What does claim 12 cover for rapamycin?

Claim 12 independently covers albumin-coated rapamycin nanoparticles with a prion-binding ligand and negative zeta potential.

The claim is not limited to a particular rapamycin formulation, salt, particle size, supporting material, or antibody. The term "rapamycin" may encompass sirolimus and potentially chemically related rapamycin compounds depending on the patent's specification and claim-construction record.

The rapamycin claim family is commercially distinct from conventional sirolimus products. Rapamycin tablets, oral solutions, and standard immunosuppressive formulations generally lack the claimed combination of:

Albumin-coated nanoparticles;
Prion-protein-binding ligand; and
Negative zeta potential.

Which ligand types are protected?

Claims 3 through 8 and claims 13 through 18 divide the ligand limitation into four categories.

Claims	Ligand category	Scope
3, 13	Peptide	Any peptide capable of binding a prion protein
4, 14	Triazine-based compound	Triazine ligand with prion-binding capability
5, 15	Antibody	Antibody that recognizes a prion protein
6, 16	Named antibody	3F4, 6H4, 16A18, ICSM-4, or ICSM-10
7, 17	Polymeric material	Polymer that binds prion proteins
8, 18	Polymer substructures	Amino group, phenyl group, or methacrylate backbone

The independent claims are not limited to antibodies. A product may fall within claim 1 or claim 12 if it uses a peptide, triazine compound, polymer, or another ligand that meets the functional prion-binding limitation.

Are the named antibodies required?

No. The named antibodies appear only in dependent claims 6 and 16. Claims 5 and 15 cover antibodies more broadly, while claims 1 and 12 are broader still because they cover non-antibody ligands.

The named antibodies are:

3F4;
6H4;
16A18;
ICSM-4; and
ICSM-10.

An accused product using a different prion-recognizing antibody could potentially fall within claims 5 or 15 without falling within claims 6 or 16.

What particle-size limitations apply?

Claims 11 and 21 require an average nanoparticle diameter of no greater than about 200 nanometers.

The 200-nanometer limit is not present in claims 1 or 12. A product with particles larger than 200 nanometers may therefore remain within an independent claim if it satisfies the other limitations, although it would not satisfy claims 11 or 21.

This creates a tiered infringement structure:

Particle size	Potential claim exposure
200 nm or less	Independent claim plus applicable size-dependent claim
Greater than 200 nm	Independent claim exposure may remain; claims 11 and 21 are less likely to apply
Non-nanoparticulate	Likely outside the claims, subject to construction of "nanoparticles"
Mixed-size distribution	Depends on how "average diameter" and the claimed composition are measured

The specification and prosecution history would be important in determining whether "about 200 nm" permits a measurement range above 200 nm and which analytical method controls.

What role does the negative zeta potential play?

Negative zeta potential is an express limitation in both independent claims. It is not merely a preferred formulation characteristic.

A product developer should treat zeta potential as a required claim element and document:

Measurement medium;
Ionic strength;
pH;
Temperature;
Dilution;
Instrument;
Measurement method; and
Lot-to-lot variability.

Zeta potential can change with buffer composition, ionic strength, protein adsorption, pH, and storage. A formulation that tests negative in one medium and neutral or positive in another could produce a claim-construction dispute.

A formulation with a measured zeta potential of approximately zero may present a stronger non-infringement position than a formulation that consistently exhibits a negative value. The patent does not provide a numerical negative threshold in the supplied claims.

What supporting materials are protected?

Claims 9, 10, 19, and 20 add an optional supporting material. The listed materials are:

Resin;
Bead; and
Membrane.

These claims appear directed to compositions in which the nanoparticles are associated with or incorporated into a support. The supporting-material claims may be relevant to:

Prion capture systems;
Filters;
Diagnostic devices;
Affinity matrices;
Solid-phase purification;
Membrane systems; and
Research-use platforms.

The supporting material is not required by claims 1 or 12. Its use narrows the claims but may increase practical relevance for ex vivo or device-based prion-removal applications.

How does US 10,206,887 compare with Abraxane?

Abraxane is an albumin-bound paclitaxel product approved by the FDA for specified oncology indications. Its core formulation is relevant to the albumin-coated paclitaxel portion of the patent, but the patent claims require more than albumin-bound paclitaxel.

Element	Abraxane-type product	US 10,206,887 requirement
Paclitaxel	Yes	Required under claim 2
Albumin-associated particles	Yes	Required
Nanoparticle formulation	Yes or substantially similar	Required
Prion-binding ligand	Not established from the commercial label	Required
Negative zeta potential	Product-specific analytical issue	Required
Prion-targeting function	Not an approved product attribute	Required

A conventional albumin-bound paclitaxel product would not automatically infringe claim 2. The additional prion-binding ligand is a central differentiator.

Existing patents covering albumin-bound paclitaxel, particle size, manufacturing, or oncology use could create separate freedom-to-operate issues. Those rights are analytically distinct from US 10,206,887. A product could avoid US 10,206,887 while still requiring a license to other nanoparticle or paclitaxel patents.

How does the patent compare with conventional rapamycin products?

Conventional sirolimus products, including oral tablets and oral solutions, generally use different dosage-form technologies from the claimed albumin-coated nanoparticle platform.

Product category	Albumin coating	Prion-binding ligand	Negative zeta potential	Likely exposure
Sirolimus tablet	No	No	Not central	Low under claims 12-21
Sirolimus oral solution	No	No	Not central	Low
Albumin-free sirolimus nanoparticle	No	Possibly	Product-specific	Low unless albumin is present
Albumin-coated sirolimus nanoparticle	Yes	Required	Required	Potentially significant
Targeted sirolimus nanoparticle with prion ligand	Yes	Yes	Required	Highest exposure

The patent therefore targets a specialized delivery platform rather than the established oral sirolimus market.

What is the Orange Book status of US 10,206,887?

US 10,206,887 is a formulation and composition patent directed to a specialized prion-targeted nanoparticle platform. It is not, based on the supplied claim set, a conventional patent listing for an FDA-approved small-molecule product.

Orange Book listing depends on an approved drug application and the relationship between the patent and the approved product. A patent does not become Orange Book-listed merely because it claims a drug substance or formulation. The relevant product must be approved and the patent must qualify for listing under FDA regulations. [1]

There is no claim-based basis to conclude that US 10,206,887 is listed against an approved paclitaxel or sirolimus product. The patent claims a prion-targeted composition that is distinct from ordinary approved paclitaxel and sirolimus dosage forms.

When does US 10,206,887 lose exclusivity?

The patent's expiration date cannot be determined from the claim text alone. US patent term generally runs 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and transitional priority issues. [2]

The key term variables are:

Earliest effective nonprovisional priority date;
Continuation or divisional status;
Patent-term adjustment;
Terminal disclaimer;
Patent-term extension;
Reissue status; and
Any terminal disclaimer tied to another patent.

The issue date, February 2019, does not establish the expiration date. A standard 20-year calculation from the issue date would be legally incorrect.

Are Paragraph IV challenges likely?

A Paragraph IV certification would be relevant only if a generic applicant sought approval for a drug product and the patent were listed in the Orange Book against the relevant reference-listed drug. Under the Hatch-Waxman framework, a Paragraph IV certification asserts that the listed patent is invalid, unenforceable, or not infringed. [3]

For the claims supplied, the more likely regulatory pathway is not a conventional generic challenge because:

The claimed product is a specialized nanoparticle composition;
The claims include a prion-binding ligand;
The patent is not directed simply to paclitaxel or sirolimus;
No approved reference product is identified in the claim set; and
The product could require a new drug application or another specialized FDA pathway rather than an ordinary abbreviated new drug application.

If a future approved product embodied the claimed formulation and the patent were listed, a Paragraph IV challenge could attack:

Lack of novelty;
Obviousness;
Written description;
Enablement;
Indefiniteness of "capable of binding";
Indefiniteness or measurement ambiguity involving negative zeta potential;
Scope of "coated with albumin"; and
Whether the accused product contains nanoparticles within the claim meaning.

Is there biosimilar risk?

Traditional biosimilar risk is low because the claimed products are not biologics. Paclitaxel and rapamycin are small molecules, although albumin-coated nanoparticle products can raise complex formulation and comparability issues.

The more relevant competitive risks are:

Generic small-molecule paclitaxel;
Generic sirolimus;
505(b)(2) products;
Follow-on nanoparticle formulations;
Reformulated targeted delivery products; and
Non-drug diagnostic or prion-capture devices.

A follow-on product could avoid biosimilar regulation yet still face patent infringement claims if it reproduces the claimed composition.

What patent-validity issues are most important?

Functional ligand limitation

"Capable of binding a prion protein" is a functional limitation. Its enforceability may depend on whether the specification identifies adequate assays, binding conditions, affinity thresholds, and representative ligands across the full scope.

A broad functional claim can face enablement or written-description challenges if the disclosure supports only a small number of ligands but the claims cover an extensive universe of peptides, triazines, antibodies, and polymers.

Negative zeta potential

The claims require a negative zeta potential but do not state a numerical range in the supplied language. Key issues include:

What counts as negative;
Whether the result must be statistically distinguishable from zero;
Which test medium applies;
Whether the value is measured before or after administration;
Whether the claim requires every nanoparticle to be negative; and
Whether a composition with a mixed population qualifies.

Albumin coating

"Coated with albumin" may distinguish the claims from nanoparticles that merely contain albumin as an excipient. The prosecution record could determine whether the term requires:

Surface adsorption;
A continuous coating;
Covalent attachment;
Albumin as a stabilizer; or
Albumin physically associated with the particle surface.

Nanoparticle definition

The independent claims do not include the 200-nanometer limit. The meaning of "nanoparticles" may therefore become central for particles near or above that size, aggregates, or broad particle-size distributions.

What manufacturing and IP barriers affect market entry?

A competing manufacturer would need to address both technical and patent barriers.

Technical barriers

The product must control:

Drug loading;
Albumin adsorption or coating;
Ligand attachment;
Particle-size distribution;
Surface charge;
Aggregation;
Sterility;
Endotoxin;
Release kinetics;
Ligand stability; and
Prion-binding performance.

The ligand must retain prion-binding activity after nanoparticle fabrication, storage, sterilization, and administration.

Patent barriers

Separate third-party rights may cover:

Albumin-bound paclitaxel;
Nanoparticle manufacturing;
Ligand conjugation;
Antibody sequences;
Peptide ligands;
Polymer compositions;
Drug loading;
Sterilization;
Device integration; and
Therapeutic use.

US 10,206,887 is therefore one layer of a potential freedom-to-operate analysis. Avoiding its claims would not eliminate exposure under unrelated formulation or manufacturing patents.

What is the commercial exposure?

Commercial exposure appears concentrated in a future prion-directed product rather than the existing paclitaxel or sirolimus markets.

Market	Direct relevance to US 10,206,887
Generic paclitaxel	Low unless reformulated with the claimed prion-targeting architecture
Albumin-bound paclitaxel oncology	Moderate formulation overlap, but prion-ligand limitation is critical
Generic sirolimus	Low for conventional oral products
Targeted prion therapeutics	High
Prion diagnostic or capture devices	Potentially relevant through supporting-material claims
Biosimilars	Low
505(b)(2) nanoparticle products	Potentially significant

The principal value is platform-based. Claims 1 and 12 could cover multiple active ingredients and ligand classes, but commercial value depends on whether a viable prion indication, delivery route, and clinical development program exists.

Key Takeaways

US 10,206,887 has two independent composition claims covering prion-targeted albumin-coated nanoparticles.
Claim 1 covers taxane nanoparticles; claim 2 specifically covers paclitaxel.
Claim 12 independently covers rapamycin nanoparticles.
The required combination is albumin coating, a prion-binding ligand, nanoparticles, and negative zeta potential.
The claims are not limited to antibodies. Peptides, triazine compounds, polymers, and other prion-binding ligands may qualify.
The 200-nanometer limit appears only in claims 11 and 21, not in the independent claims.
Conventional Abraxane, paclitaxel products, and sirolimus products do not automatically satisfy the claims because the prion-binding ligand limitation is central.
Biosimilar risk is low. Generic and 505(b)(2) risks are more relevant.
Orange Book and Paragraph IV exposure depends on an approved product and a qualifying patent listing, not on the patent claims alone.
The main legal vulnerabilities are functional ligand language, negative zeta-potential measurement, albumin-coating scope, nanoparticle definition, enablement, and written description.
The patent creates the greatest market-entry risk for a targeted prion therapeutic or prion-capture platform using albumin-coated paclitaxel or rapamycin nanoparticles.

FAQs

Does US 10,206,887 cover ordinary paclitaxel?

No. The claims require a nanoparticle formulation with albumin, a prion-binding ligand, and negative zeta potential. Ordinary paclitaxel formulations do not satisfy those limitations merely because they contain paclitaxel.

Does the patent cover docetaxel?

Potentially. Claim 1 recites a taxane rather than paclitaxel specifically. A docetaxel nanoparticle could face exposure if it also has the required albumin coating, prion-binding ligand, nanoparticle structure, and negative zeta potential.

Can a product avoid claims 11 and 21 by using particles larger than 200 nanometers?

Possibly, but that would address only the dependent size claims. Claims 1 and 12 do not include the 200-nanometer limitation in the supplied text.

Does using a different prion antibody avoid the patent?

Not necessarily. Claims 5 and 15 cover antibodies that recognize a prion protein without limiting the claims to the five antibodies listed in claims 6 and 16.

Is US 10,206,887 a patent on prion treatment methods?

The supplied claims are composition claims. They do not expressly recite administering the composition, treating a patient, or treating a named prion disease.

References

U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.
United States Patent and Trademark Office. (2024). General information concerning patents. USPTO.
U.S. Patent Act, 35 U.S.C. § 271(e)(2) (2024).
U.S. Patent No. 10,206,887, claims 1-21.
U.S. Food and Drug Administration. (2024). Abraxane (paclitaxel protein-bound particles for injectable suspension) prescribing information. FDA.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Aadi	FYARRO	sirolimus	POWDER;INTRAVENOUS	213312-001	Nov 22, 2021		RX	Yes	Yes	10,206,887	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2010236382	⤷ Start Trial
Brazil	PI1012525	⤷ Start Trial
Canada	2758913	⤷ Start Trial
China	102460167	⤷ Start Trial
Cyprus	1122617	⤷ Start Trial
Denmark	2419732	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,206,887

Which drugs does patent 10,206,887 protect, and when does it expire?

Summary for Patent: 10,206,887