United States Patent 11,357,731 (Deferiprone Iron Overload Tablet): Claim Scope and US Patent Landscape
What is the patented invention in US 11,357,731?
US 11,357,731 claims oral treatment of iron overload in thalassemia or sickle cell disease using a deferiprone tablet with core-level and coating-level enteric protection designed for twice daily dosing at a 1000 mg tablet strength. The claims tightly tether therapeutic effect to pharmacokinetic performance (AUCI/Cmax and Tmax in fed state) and to specific tablet architecture (enteric polymer in core + enteric coating containing enteric polymer plus excipients such as plasticizer and anti-tacking agents).
At a formulation level, the claims cover:
- 1000 mg deferiprone core plus an enteric polymer in the core (typical exemplars: HPMCAS, HPMC phthalate, PVAP, methacrylic acid copolymers)
- enteric coating with an enteric polymer plus excipients (plasticizer, anti-tacking agent) and conventional coating excipients
- pH adjusting agent in the core (claim 14 and dependent claim 17)
- glidant/anti-tacking and process-friendly excipients (colloidal silicon dioxide, talc)
- tablet dosing configuration (scored for half tablets; combinations of whole/half tablets)
- target PK windows when administered in fed state
- dose range: 50–100 mg/kg/day deferiprone
The claims are written as methods of treatment but include extensive formulation features, so the scope is constrained to treatment methods where the administered dosage form matches the claimed composition/PK attributes.
What are the independent claim structures and their practical coverage?
The claims you provided include two independent-looking method claim sets: Claim 1 (1000 mg deferiprone + enteric polymer in core + enteric coating; twice daily dosing; PK windows in fed state) and Claim 14 (same disease/indication and core 1000 mg deferiprone, but with added excipient categories: pH adjusting agent, glidant in core; coating excipients: plasticizer, anti-tacking agent; plus detailed quantitative ranges in dependent claims).
Claim 1: “twice daily” 1000 mg deferiprone enteric tablet with fed-state PK limits
Key elements:
- Oral tablet, suitable for twice daily dosing
- Core: ~1000 mg deferiprone + enteric polymer
- Enteric coating: enteric polymer
- Therapy: treating iron overload in thalassemia or sickle cell disease
- Dependents:
- transfusional iron overload (claim 2, 3)
- cardiac MRI T2* ≤ 20 ms (claim 3)
- scored tablets and half-dose administration (claims 4, 5)
- specific enteric polymer lists (claims 6, 9)
- enteric polymer content in core:
- broad: ~1% to ~20% by weight of core (claim 7)
- narrower: ~1% to ~5% by weight of core (claim 8)
- fed-state PK constraints:
- AUCI/Cmax ratio between 3.5 hours and 6.0 hours (claim 10)
- median Tmax 2.00 to 8.00 hours (claim 11)
- another AUCI/Cmax ratio window between 3.225 to 8.506 hours (claim 12)
- total daily deferiprone: 50 mg/kg to 100 mg/kg (claim 13)
Practical impact: Claim 1 is a composition-plus-performance method claim. For design-arounds, changing the excipient set or changing enteric polymer type/level alone may not avoid infringement if the resulting PK still falls inside the claimed windows. Conversely, changing PK without matching the formulation may also avoid, but the claim language suggests courts would focus on the administered tablet features and measured PK attributes.
Claim 14: core includes pH adjusting agent + glidant; coating includes plasticizer + anti-tacking
Key elements:
- Same indication and tablet architecture concept (core + enteric coating)
- Core:
- ~1000 mg deferiprone
- enteric polymer in ~1% to ~5% by weight of core
- pH adjusting agent
- glidant
- Coating:
- plasticizer
- anti-tacking agent
- enteric polymer
- Dependents narrow composition classes and add quantitative ranges for core:
- pH adjusting agent examples (claim 17)
- glidant example: colloidal silicon dioxide (claim 18)
- optional lubricants in core (claim 19)
- core quantitative breakdown (claim 20)
- coating quantitative presence (claim 23)
- explicit “example” composition (claim 24) and range version (claim 25)
- explicit numeric “typical batch” amounts (claim 27)
- Still includes daily total deferiprone range (claim 28)
- Still includes scored and half-tablet dosing (claims 29, 30)
Practical impact: Claim 14 is broader than a single preferred formulation because it covers agent classes (pH adjusting agents and plasticizers) rather than one exact recipe, but it is narrower than a generic deferiprone tablet because it requires both core-level and coating-level enteric design with specified component categories.
How broad is the chemical scope of excipients?
Enteric polymer scope
Both independent claim pathways use enteric polymers, with dependent claims listing multiple candidates.
- Claim 6 (core enteric polymer) examples:
HPMCAS, HPMC phthalate, polyvinyl acetate phthalate, methacrylic acid copolymers and derivatives; combinations
- Claim 9 (coating enteric polymer) examples: similar list with additional derivative concepts
- Claim 16 also uses the same core list concept
Claim 21 expands coating enteric polymer exemplars further:
HPMCAS, HPMC phthalate, PVAP, methacrylic acid copolymers, cellulose acetate phthalate, cellulose acetate trimellitate, shellac, zein, derivatives, combinations.
Enteric polymer amount
- Claim 7: core enteric polymer about 1% to 20% by weight of core
- Claim 8: core enteric polymer about 1% to 5% by weight of core
- Claim 14 already locks core enteric polymer to ~1% to 5% by weight of core
This matters for design-around: enteric polymer type may be substituted, but polymer levels are constrained by the claim family.
pH adjusting agents and glidants (Claim 14 family)
- Claim 17 pH adjusting agent examples:
meglumine, metal oxides, metal hydroxides, basic salts of weak acids, combinations
- Claim 18 glidant:
colloidal silicon dioxide
Lubricants (claim 19): magnesium stearate, calcium stearate, stearic acid, sodium stearyl fumarate, talc.
Coating plasticizers and anti-tacking
- Claim 22 plasticizer examples:
diethyl phthalate, citrate esters, polyethylene glycol, glycerol, acetylated glycerides, acetylated citrate esters, dibutyl sebecate, castor oil, combinations
- Claim 24 coating exemplifies an “anti-tacking” component via talc (claim 24 includes talc in coating)
- The independent Claim 14 explicitly requires an anti-tacking agent in the coating (but the dependent claims you provided do not list a single exhaustive set beyond examples like talc).
What is the scope around dosing, tablet splitting, and twice daily use?
- Twice daily suitability is embedded in Claim 1: tablet is “suitable for twice daily dosing.”
- Claim 4 includes administration as one or more whole or half tablets (splitting allowed).
- Claim 5 specifies tablet can be scored to facilitate breakage into half tablets.
- Claims 29–30 repeat scored tablet and half/whole administration in the Claim 14 family.
Interpretive consequence: A manufacturer selling a 1000 mg scored enteric deferiprone tablet intended for BID regimens, where physicians titrate via half tablets, aligns closely with the claim design.
What are the key performance constraints (PK) that materially narrow the claim?
Claims 10–12 in the Claim 1 family tie infringement to measured fed-state parameters:
- AUCI/Cmax ratio between 3.5 hours and 6.0 hours when the 1000 mg tablet is administered in the fed state (claim 10)
- median Tmax between 2.00 and 8.00 hours in the fed state (claim 11)
- another AUCI/Cmax ratio formulation: 3.225 to 8.506 hours when administered in fed state (claim 12)
Design and litigation impact:
- If a generic competitor’s formulation yields fed-state PK outside one of these windows, that can be an exclusion path even if the excipient categories match.
- If the competitor stays within these windows, changing excipient identities may not help if the claim construction reads “enteric polymer” broadly enough to capture substitutes.
Who is covered (patient phenotype scope)?
- Base indication: thalassemia or sickle cell disease (Claim 1 and Claim 14)
- Iron overload type: transfusional iron overload (claims 2 and 15)
- Additional subgroup: **cardiac MRI T2* ≤ 20 ms** (claim 3)
The T2* condition adds a stronger phenotype and can create a narrower slice of coverage for enforcement actions aimed at high-risk cardiac iron overload populations.
Quantitative composition snapshots that likely anchor enforcement
The dependent claims include explicit composition examples and quantitative formulations, which usually become focal points in validity and infringement analyses.
Core composition in ranges (Claim 20)
Core contains:
- (i) ~1000 mg deferiprone
- (ii) enteric polymer: ~1% to ~5% by weight of core
- (iii) pH adjusting agent: ~2% to ~8%
- (iv) glidant: ~0.1% to ~0.5%
- (v) lubricant: ~0.5% to ~2%
Core composition example (Claim 24)
- Deferiprone: ~1000 mg
- HPMCAS: ~1% to ~5% by weight of core
- Magnesium oxide
- Colloidal silicon dioxide
- Magnesium stearate
Core composition ranges (Claim 25)
- Deferiprone: ~1000 mg
- HPMCAS: ~1% to ~5%
- Magnesium oxide: ~2% to ~8%
- Colloidal silicon dioxide: ~0.1% to ~0.5%
- Magnesium stearate: ~0.5% to ~2%
Coating weight fraction
- Enteric coating about 0.5% to 2% of total tablet weight (claims 23 and 26)
Numeric “batch-like” formulation (Claim 27)
- Deferiprone: ~1000 mg
- HPMCAS: ~25 mg to ~35 mg
- Magnesium oxide: ~40 mg to ~60 mg
- Colloidal silicon dioxide: ~5 mg
- Magnesium stearate: ~15 mg to ~20 mg
These numeric ranges provide concrete targets for both generic design-around efforts and for enforcement by claim mapping.
What does the claim architecture imply for infringement risk?
Highest-risk competitor design region
A generic or follow-on developer faces highest risk if it:
- uses a 1000 mg deferiprone enteric tablet intended for BID
- contains enteric polymer in the core at ~1% to ~5% (at least within the Claim 14 family; within 1% to 20% for Claim 1 dependent)
- includes pH adjusting agent + glidant in the core with glidant as colloidal silicon dioxide
- includes plasticizer + anti-tacking agent + enteric polymer in the coating
- achieves fed-state PK AUCI/Cmax and Tmax inside the claimed windows
Lower-risk paths
A developer can reduce claim mapping alignment by altering one of the following structural anchors:
- omit enteric polymer in the core (Claim 1 requires it)
- omit required coating enteric polymer (Claim 1 and Claim 14 require it)
- shift tablet so it is not “suitable” for BID dosing at 1000 mg strength
- design PK outside the claimed fed-state windows (claims 10–12)
- replace required excipient categories in a way that is no longer covered by the claim’s class language (for example, if the pH adjusting agent and plasticizer are outside the listed options and cannot be captured by “selected from the group” language)
US patent landscape: how to think about related claims and blocking positions
The information provided is restricted to the claim text for US 11,357,731. A complete, numbered landscape anchored to publication numbers, assignees, and related families cannot be produced from the record provided.
What can be said from the claim content alone
US 11,357,731 is positioned as a formulation and dosing method patent for deferiprone in thalassemia/sickle cell iron overload, centered on:
- enteric polymer strategy (core and coating)
- high-strength 1000 mg tablet dosing and splitting
- fed-state PK performance windows
- pH adjusting agent and excipient package for enteric behavior
This places the patent in the area where US challenges typically arise through:
- formulation non-infringement (different excipients, different enteric polymer types, different coating architecture)
- PK differences (if not meeting the fed-state ratios)
- invalidity arguments tied to prior art describing enteric deferiprone formulations or enteric coated high dose iron chelator tablets
Claim-by-claim scope map (condensed)
| Claim |
Core requirements |
Coating requirements |
Patient/clinical constraints |
Dosing/PK constraints |
| 1 |
1000 mg deferiprone + enteric polymer |
enteric coating with enteric polymer |
thalassemia or sickle cell; iron overload; tablet BID suitable |
fed-state AUCI/Cmax windows; fed-state Tmax window; daily dose range (via dependents) |
| 2 |
same |
same |
transfusional iron overload |
n/a |
| 3 |
same |
same |
transfusional iron overload; cardiac MRI T2* ≤ 20 ms |
n/a |
| 4 |
same |
same |
same |
whole/half tablet administration |
| 5 |
same |
same |
same |
scored tablet |
| 6 |
core enteric polymer limited to listed classes |
n/a |
n/a |
n/a |
| 7 |
enteric polymer in core ~1% to ~20% |
n/a |
n/a |
n/a |
| 8 |
enteric polymer in core ~1% to ~5% |
n/a |
n/a |
n/a |
| 9 |
n/a |
coating enteric polymer limited to listed classes |
n/a |
n/a |
| 10 |
n/a |
n/a |
n/a |
fed-state AUCI/Cmax 3.5–6.0 hours |
| 11 |
n/a |
n/a |
n/a |
fed-state median Tmax 2.00–8.00 hours |
| 12 |
n/a |
n/a |
n/a |
fed-state AUCI/Cmax 3.225–8.506 hours |
| 13 |
n/a |
n/a |
n/a |
total daily dose 50–100 mg/kg |
| 14 |
1000 mg deferiprone + enteric polymer (~1% to ~5%) + pH adjusting agent + glidant |
coating: plasticizer + anti-tacking agent + enteric polymer |
thalassemia or sickle cell; iron overload |
n/a |
| 15 |
same |
same |
transfusional iron overload |
n/a |
| 16 |
enteric polymer in core limited to listed classes |
n/a |
n/a |
n/a |
| 17 |
pH adjusting agent limited to listed classes |
n/a |
n/a |
n/a |
| 18 |
glidant is colloidal silicon dioxide |
n/a |
n/a |
n/a |
| 19 |
optional lubricant limited to listed classes |
n/a |
n/a |
n/a |
| 20 |
core composition quantified (polymer, pH agent, glidant, lubricant) |
n/a |
n/a |
n/a |
| 21 |
n/a |
enteric polymer in coating expanded list |
n/a |
n/a |
| 22 |
n/a |
plasticizer limited to listed classes |
n/a |
n/a |
| 23 |
n/a |
coating ~0.5%–2% of tablet |
n/a |
n/a |
| 24 |
example core with HPMCAS, magnesium oxide, colloidal silicon dioxide, magnesium stearate |
example coating (triethyl citrate, talc, titanium dioxide, methacrylic acid copolymer) |
n/a |
n/a |
| 25 |
quantified example core ranges |
n/a |
n/a |
n/a |
| 26 |
n/a |
coating ~0.5%–2% |
n/a |
n/a |
| 27 |
quantified example amounts |
n/a |
n/a |
n/a |
| 28 |
n/a |
n/a |
n/a |
daily dose 50–100 mg/kg |
| 29 |
scored tablet and split dosing |
n/a |
n/a |
whole/half tablets |
| 30 |
n/a |
n/a |
n/a |
whole/half tablet combinations |
Key Takeaways
- US 11,357,731 claims method-of-treatment using an oral 1000 mg deferiprone enteric tablet designed for twice daily dosing, with enteric polymer in both the core and the enteric coating.
- The Claim 1 family adds fed-state PK performance windows tied to AUCI/Cmax and Tmax, which narrows practical infringement to products that match both formulation and measured performance.
- The Claim 14 family adds a structured excipient package: pH adjusting agent and glidant in the core (with colloidal silicon dioxide exemplified) and plasticizer plus anti-tacking plus enteric polymer in the coating.
- The highest enforcement leverage is in the claims that combine: 1000 mg strength + enteric architecture (core and coating) + quantitative excipient ranges + fed-state PK windows + split dosing capability.
- A complete numbered US patent landscape (related families, continuations, assignees, and challenge history) cannot be produced from the claim text alone.
FAQs
-
Does US 11,357,731 cover any deferiprone use in thalassemia?
No. It covers iron overload treatment specifically in thalassemia or sickle cell disease, and the tablet must have the claimed enteric core + enteric coating architecture and (for certain claims) meet fed-state PK windows.
-
What makes this patent different from a standard deferiprone formulation patent?
The claims combine tablet composition (enteric polymer in core and coating plus specific excipient categories) with method constraints tied to BID suitability, splitting/scoring, and fed-state PK metrics.
-
Which excipients are most likely to be important in infringement analysis?
Enteric polymers (HPMCAS, HPMC phthalate, PVAP, methacrylic acid copolymers and derivatives, plus expanded coating polymers in dependent claims), plus pH adjusting agents, glidant (colloidal silicon dioxide example), and plasticizer/anti-tacking in the coating.
-
Can a competitor design around by changing the enteric polymer?
Changing enteric polymer may reduce overlap, but multiple claims specify enteric polymer classes. Even with a substitution, the product must avoid both the claimed enteric-polymer lists and the claimed fed-state PK windows where applicable.
-
Are half-tablet dosing and scoring central to the claims?
They appear in dependent claims, which supports enforcement against tablets that are scored and administered as whole or half tablets. The core infringement risk remains highest when the tablet also matches the enteric architecture and PK elements.
References
[1] US Patent 11,357,731 (claim text provided by user).
