U.S. Patent 10,925,896: Claim Scope, Exclusivity, Litigation Risk and Patent Landscape for Sucroferric Oxyhydroxide

U.S. Patent 10,925,896 protects a narrow chewable-tablet formulation of essentially non-bioabsorbable beta iron oxyhydroxide, the active pharmaceutical ingredient in Velphoro, combined with saccharose and both native and pregelatinized starch. The core commercial limitation is a tablet containing approximately 800 mg of iron oxyhydroxide in which the iron is stabilized by the excipient system and, in many dependent claims, releases less than 2.5% of its iron under an acidic European Pharmacopoeia test.

The patent is a formulation patent, not a composition-of-matter patent for iron oxyhydroxide itself. Infringement requires satisfaction of every limitation in an asserted claim. A competing product using the same active ingredient could avoid literal infringement by changing the dosage form, iron amount, starch system, stabilization mechanism, or qualifying dissolution profile, subject to the doctrine of equivalents.

What pharmaceutical composition does U.S. Patent 10,925,896 protect?

The broadest issued claim, claim 1, requires all of the following:

Claim element	Required limitation
Active ingredient	Iron oxyhydroxide
Excipients	Saccharose and starch
Composition loading	Combined iron oxyhydroxide, saccharose and starch greater than 70% w/w
Starch	Both native starch and pregelatinized starch
Stabilization	Iron oxyhydroxide stabilized by at least saccharose, native starch and/or pregelatinized starch
Dosage form	Chewable tablet
Iron form	Beta iron oxyhydroxide
Absorption	Essentially non-bioabsorbable
Dose	Approximately 800 mg iron oxyhydroxide per tablet

The claim does not require a particular brand name, manufacturing process, tablet weight, flavor, or specific starch supplier. It also does not require the low-release limitation appearing in claims 2, 5, 7, 9, 11, 14, 16, 18, 20, 22, 25 and 27.

A product that contains iron oxyhydroxide and saccharose but uses only native starch, only pregelatinized starch, or a different excipient such as cellulose instead of starch would not literally satisfy claim 1.

How narrow is the independent claim?

Claim 1 is materially narrower than a claim directed generally to sucroferric oxyhydroxide or iron oxyhydroxide formulations.

The principal narrowing features are:

The formulation must be a chewable tablet.
It must contain both native and pregelatinized starch.
The active must be beta iron oxyhydroxide.
The active must be essentially non-bioabsorbable.
The dose must be approximately 800 mg per tablet.
The three specified components must collectively exceed 70% of total composition weight.

The stabilization language expands the claim in one respect because it permits stabilization by "at least" one or more of saccharose, native starch and pregelatinized starch. The claim therefore does not require all three materials to perform the stabilization function, although all three must be present as formulation components.

The phrases "about 800 mg," "greater than 70%," and "essentially non-bioabsorbable" create potential claim-construction disputes. Their scope would depend on the specification, prosecution history, technical evidence and the court's construction under 35 U.S.C. § 112 and Federal Circuit precedent.

What formulations are protected by claims 2 through 30?

The dependent claims create multiple overlapping formulation branches.

Iron-loading limitations

Claims	Iron oxyhydroxide content
1	Not expressly quantified beyond approximately 800 mg per tablet
4-5, 15-16, 26-27	About 30% to about 65% w/w
6-7, 17-18, 28	About 30% to about 35% w/w
8-9, 19-20, 29	About 27% to about 35% w/w
10-11, 21-22	About 27% to about 32% w/w
12, 23	About 29% to about 32% w/w

The ranges overlap extensively. Claims 6, 8, 10 and 12 form progressively narrower subranges. A formulation containing 31% iron oxyhydroxide would fall within each of those ranges if the remaining limitations are met.

The claim language uses "about," so boundary values cannot be assessed solely by arithmetic. A formulation nominally containing 32.1% could still raise an infringement issue if the specification and technical evidence establish an accepted tolerance around 32%.

Starch-ratio limitations

Claims	Native starch:pregelatinized starch ratio
13-23	10:1 to 0.5:1
24-30	2:1 to 1:1

The 2:1 to 1:1 range is a subset of the broader 10:1 to 0.5:1 range. Claims 24 through 30 are therefore narrower but commercially important if the marketed formulation uses approximately equal quantities of native and pregelatinized starch.

The ratio is stated as native starch to pregelatinized starch. A 1:1 ratio satisfies both ratio groups. A 4:1 ratio satisfies claim 13 but not claim 24.

Excipient limitations in claim 3

Claim 3 permits, but does not require, additional components:

Component	Claimed amount or examples
Flavoring agent	0.1% to 1% w/w
Glidant	0.1% to 5% w/w
Glidant examples	Magnesium stearate, colloidal silica, pyrogenic silica, hydrated sodium silicoaluminate, colloidal silicon dioxide and talcum
Superdisintegrant	0.5% to 8% w/w
Superdisintegrant examples	Cross-linked polyvinylpyrrolidone, modified starch and modified cellulose

Claim 3 is not limited to a single flavor, glidant or superdisintegrant. A product containing any qualifying additional component could fall within the claim, provided claim 1 is also satisfied.

What does the low iron-release limitation require?

The relevant claims require an iron release rate below 2.5% w/w:

in water;
at pH 3;
measured under European Pharmacopoeia Chapter 2.9.3;
after two hours;
with iron content determined by titration.

This is a product-performance limitation. A challenger would likely need validated analytical data from representative commercial batches or laboratory samples. The test is not interchangeable with dissolution data generated at neutral pH, under a different apparatus, at a different sampling time, or using a different iron assay.

The limitation may be valuable because it links the starch-saccharose matrix to controlled iron release under acidic conditions. It also creates evidentiary risk for enforcement: batch-to-batch variability, sampling method, titration validation and the meaning of "below 2.5%" could become central issues.

Which claims are commercially strongest?

Claim 1 has the broadest coverage but also the greatest number of required elements. The strongest practical claims are likely the narrower claims that combine:

the 800 mg chewable tablet;
approximately 27% to 35% iron oxyhydroxide;
a defined native-to-pregelatinized starch ratio;
the sub-2.5% iron-release result.

A marketed product that closely follows the disclosed commercial formulation may be exposed to several overlapping claims. A design-around product would need to avoid only one limitation in each asserted claim, but it must account for the doctrine of equivalents.

Claims 12, 23 and 29 are particularly concentrated around the apparent commercial formulation because they specify narrow iron-loading windows without always adding the release test. Claims 22, 25 and 27 add the low-release requirement to narrower formulation combinations.

Are claims 1 through 30 redundant?

The claims contain substantial redundancy. The structure is a claim tree:

Claim 1 establishes the base chewable-tablet formulation.
Claim 3 adds optional excipients.
Claims 4 through 12 narrow the iron content.
Claims 13 through 23 add the broad starch-ratio range and then narrow iron content.
Claims 24 through 30 add the narrower starch-ratio range and, in several claims, repeat the iron-release limitation.

The redundancy gives the patent multiple fallback positions. If a court invalidates or narrows a broad claim, narrower claims may remain available. At the same time, overlapping claims do not independently expand the patent beyond their combined limitations.

Claim 30 contains a drafting anomaly. It states that samples were taken after two hours and iron content was analyzed by titration, but the quoted text does not expressly recite the antecedent requirement that the iron release rate be below 2.5% w/w. That language may be a clerical or prosecution-drafting issue. Its legal effect would depend on the issued patent text, prosecution history and any certificate of correction.

What is the likely patent-family and exclusivity position?

U.S. Patent 10,925,896 is a granted U.S. formulation patent. Its enforceable term is generally measured from the earliest effective nonprovisional priority date, subject to patent-term adjustment, terminal disclaimers and any applicable patent-term extension. The grant date alone does not establish the expiration date. The priority chain, filing history, terminal disclaimer status and USPTO term calculation are required to calculate the statutory expiration date accurately. [1]

The patent should be analyzed separately from:

patents covering iron oxyhydroxide or sucroferric oxyhydroxide as an active ingredient;
patents covering the Velphoro product or its earlier formulations;
manufacturing-process patents;
method-of-use patents for hyperphosphatemia in dialysis patients;
regulatory exclusivity associated with the underlying NDA.

A formulation patent can remain relevant after an earlier active-ingredient patent expires. Conversely, expiration of this patent would not necessarily eliminate all patent barriers to a generic or follow-on product.

What is the FDA and Orange Book relevance?

Velphoro is an FDA-approved oral chewable tablet containing sucroferric oxyhydroxide for control of serum phosphorus levels in adults with chronic kidney disease on dialysis. The FDA-approved label identifies the product as a chewable tablet and describes its active ingredient as sucroferric oxyhydroxide. [2]

Because this patent claims a formulation corresponding to an approved oral product, its Orange Book relevance must be checked against the current FDA publication for the applicable NDA. An Orange Book listing would affect an ANDA applicant's certification obligations under 21 U.S.C. § 355(j), including possible Paragraph IV certification. The patent number, expiration date and delisting status must be verified in the current Orange Book rather than inferred from the patent claims. [3]

The patent is not a biologic patent. Biosimilar procedures under the Biologics Price Competition and Innovation Act do not apply. A competing oral small-molecule product would generally implicate the ANDA pathway if it meets the statutory requirements for a generic equivalent. A product with a materially different formulation, labeling or clinical profile could require a different FDA pathway.

What Paragraph IV and generic-entry risks exist?

A Paragraph IV challenge could target one or more of the following issues:

Challenge theory	Potential basis
Noninfringement	No beta iron oxyhydroxide, no pregelatinized starch, no chewable tablet, or no approximately 800 mg dose
Noninfringement	Combined iron oxyhydroxide, saccharose and starch does not exceed 70% w/w
Noninfringement	Product does not meet the claimed stabilization or release limitation
Anticipation	Earlier formulation discloses every claim element in a single reference
Obviousness	Known iron oxyhydroxide combined with conventional tablet excipients and routine optimization
Indefiniteness	Ambiguity in "about," "essentially non-bioabsorbable," stabilization, or claim 30's release language
Written description or enablement	Insufficient support for the full range of starch ratios, iron loadings or functional results

The strongest noninfringement strategy would be a formulation that changes the starch system or dosage form while preserving therapeutic equivalence. The strongest validity challenge would likely require prior art that discloses the specific beta iron oxyhydroxide, saccharose/native-starch/pregelatinized-starch combination and chewable-tablet architecture, or evidence that the claimed ranges were routine optimization.

What manufacturing and intellectual-property barriers remain?

The patent reaches the composition, not expressly the manufacturing process. A manufacturer could therefore face separate barriers involving:

preparation and stabilization of beta iron oxyhydroxide;
particle-size control;
blending and content uniformity;
compression of a high-load chewable tablet;
taste masking;
friability and tablet hardness;
control of acid-phase iron release;
regulatory demonstration of pharmaceutical equivalence.

A formulation outside the literal claims may still face process-patent, method-of-use or trade-secret barriers. Manufacturing complexity also affects launch timing even when a patent challenge succeeds.

Which companies are challenging U.S. Patent 10,925,896?

The supplied record does not identify a Paragraph IV notice, ANDA applicant, district-court complaint, PTAB proceeding, or settlement agreement directed specifically to U.S. Patent 10,925,896. No challenger, litigation date or settlement can be attributed to this patent from the claim text alone.

A complete litigation review would require cross-checking PACER, the USPTO Patent Center, PTAB records, FDA Orange Book updates and Paragraph IV notice disclosures. The patent number itself does not establish that litigation exists.

How does this patent compare with broader Velphoro patent protection?

Protection category	Coverage represented by U.S. 10,925,896
Active ingredient	No broad composition-of-matter protection for all iron oxyhydroxide
Product formulation	Yes, for specified chewable tablets and excipient architecture
Tablet performance	Yes, in multiple dependent claims requiring less than 2.5% iron release
Method of treatment	No express treatment method in the supplied claims
Manufacturing process	No express process claim in the supplied claims
Biosimilar protection	Not applicable
Generic pathway	Potential ANDA relevance if listed for the approved product

The patent's commercial value is concentrated in formulation continuity. It is most relevant against a generic that attempts to reproduce the reference product's 800 mg chewable-tablet architecture rather than against every iron-based phosphate binder.

Key Takeaways

U.S. Patent 10,925,896 is a formulation patent centered on beta iron oxyhydroxide chewable tablets.
Claim 1 requires approximately 800 mg of essentially non-bioabsorbable beta iron oxyhydroxide, saccharose, native starch and pregelatinized starch.
The combined amount of those three principal components must exceed 70% w/w.
Dependent claims add iron-loading ranges, starch ratios, optional excipients and a sub-2.5% acid-phase iron-release test.
The claims overlap heavily, creating multiple fallback positions but little additional breadth beyond the stated limitations.
The patent does not itself establish protection for all sucroferric oxyhydroxide products, manufacturing methods or treatment methods.
Velphoro is an FDA-approved chewable tablet, making Orange Book and ANDA analysis commercially relevant. [2, 3]
No Paragraph IV challenger, litigation outcome or settlement can be established from the supplied claim record.
Exact patent expiration requires the priority chain and USPTO term calculation, not the grant date alone.
A design-around is most likely to focus on starch composition, dosage form, active loading, tablet dose or acid-phase release performance.

FAQs

Does U.S. Patent 10,925,896 cover Velphoro itself?

It may cover formulations corresponding to Velphoro if the marketed product satisfies every limitation of an asserted claim. The patent does not automatically cover every product containing sucroferric oxyhydroxide.

Can a generic avoid the patent by using ferric oxyhydroxide instead of beta iron oxyhydroxide?

Potentially. The product would need to avoid the claimed beta iron oxyhydroxide limitation and also avoid infringement under the doctrine of equivalents.

Is the 800 mg limitation an amount of elemental iron?

The claim text states approximately 800 mg of iron oxyhydroxide per tablet. It should not be assumed to mean 800 mg of elemental iron. The distinction is material for infringement and regulatory equivalence analysis.

Does a product with no native starch fall within the claims?

A product with no native starch would not literally satisfy claim 1 because claim 1 requires starch comprising native starch and pregelatinized starch.

Can a product fail the release test and still infringe?

Yes. Claims 2, 5, 7, 9, 11, 14, 16, 18, 20, 22, 25 and 27 require the release limitation. Claim 1 and certain other dependent claims, as quoted, do not expressly require the less-than-2.5% release result.

References

United States Patent and Trademark Office. (n.d.). Patent term adjustment and patent term calculation resources. https://www.uspto.gov/patents/laws/patent-term-adjustment
U.S. Food and Drug Administration. (2023). Velphoro (sucroferric oxyhydroxide) prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
United States Patent and Trademark Office. (2021). U.S. Patent No. 10,925,896. https://patents.google.com/patent/US10925896B2
United States Code. (2023). 35 U.S.C. §§ 102, 103, 112 and 282. https://uscode.house.gov/-cmprch.htm

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Vifor Fresenius	VELPHORO	ferric oxyhydroxide	TABLET, CHEWABLE;ORAL	205109-001	Nov 27, 2013		RX	Yes	Yes	⤷ Start Trial	⤷ 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
Argentina	069312	⤷ Start Trial
Australia	2008322963	⤷ Start Trial
Brazil	PI0820308	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 10,925,896

Which drugs does patent 10,925,896 protect, and when does it expire?

Summary for Patent: 10,925,896