United States Patent 9,376,505: Scope, Claims, Expiration, Orange Book Position and Competitive Patent Landscape

U.S. Patent No. 9,376,505 protects defined iron(III)-oxidized maltodextrin complexes, including ferric derisomaltose-type products, and related sterile aqueous injectable compositions. Its central limitations are the maltodextrin dextrose-equivalent range, complex molecular weight, degree of aldehyde oxidation, and injectable formulation characteristics.

The patent’s strongest commercial relevance is to parenteral iron products containing an oxidized maltodextrin carbohydrate shell with a weight-average molecular weight of 80 kDa to 400 kDa, or 118 kDa to 400 kDa under the second independent claim set. The claims do not cover every intravenous iron complex. They are directed to a specific oxidized maltodextrin platform.

What does U.S. Patent 9,376,505 protect?

The patent contains two independent composition claims:

Independent claim	Protected composition	Molecular-weight range	Principal carbohydrate limitation
Claim 1	Iron(III) carbohydrate complex	80-400 kDa	Oxidized maltodextrin with pre-oxidation DE of 5-20
Claim 19	Iron(III) carbohydrate complex	118-400 kDa	Oxidized maltodextrin with pre-oxidation DE of 5-20

Both independent claims require:

At least one oxidized maltodextrin.
A maltodextrin dextrose equivalent, or DE, of 5 to 20 before oxidation.
If multiple maltodextrins are used, the mixture must have a DE of 5 to 20 and each individual maltodextrin must have a DE of 2 to 40.

The patent therefore protects a composition defined by both structural and process-related characteristics. A competing iron complex may avoid literal infringement by using a different carbohydrate, a maltodextrin outside the claimed DE range, a molecular weight below 80 kDa or above 400 kDa, or an alternative oxidation profile.

How do claims 1 through 18 differ from claims 19 through 36?

Claims 1 through 18 and claims 19 through 36 are parallel claim groups. The principal distinction is molecular weight.

Feature	Claims 1-18	Claims 19-36
Independent claim	Claim 1	Claim 19
Molecular weight	80-400 kDa	118-400 kDa
Oxidation limitation	Claims 2-3	Claims 20-21
Medical use	Claims 4-6	Claims 22-24
Dosage form	Claim 7 and related claims	Claim 25 and related claims
Aqueous solution	Claims 8-18	Claims 26-36
Sterilization	At least 121°C	At least 121°C
Preservative status	Preservative-free embodiments	Preservative-free embodiments

Claim 19 is narrower than claim 1 at the lower molecular-weight boundary. A product with a weight-average molecular weight between 80 kDa and less than 118 kDa could fall within claim 1 but outside claim 19, assuming the other limitations are met.

What technical limitations define infringement risk?

Oxidized maltodextrin

The carbohydrate component must be maltodextrin that has undergone oxidation. Ordinary maltodextrin without the claimed oxidation is outside the literal scope of the independent claims.

The oxidation limitation is important because the patent does not claim merely an iron-polysaccharide complex. It claims a complex using oxidized maltodextrin. Claims 3 and 21 further specify oxidation in an aqueous hypochlorite solution, but that process limitation is not required by claims 1 and 19.

A product can therefore potentially infringe the independent claims without using hypochlorite if it otherwise satisfies the composition limitations. Conversely, proving hypochlorite oxidation is relevant to claims 3 and 21 but not necessary to establish infringement of claims 1 or 19.

Dextrose equivalent

The pre-oxidation DE requirement is one of the principal claim filters.

Claim element	Required range
Single maltodextrin before oxidation	DE 5-20
Mixture of maltodextrins	Mixture DE 5-20
Each maltodextrin in a mixture	DE 2-40

DE measures the reducing-sugar content of a starch hydrolysate relative to dextrose. A higher DE generally indicates greater hydrolysis and shorter average carbohydrate chains.

The patent uses the DE of the maltodextrin before oxidation. Analytical testing conducted only on the finished iron complex may not resolve the issue. Product-development and freedom-to-operate reviews would need manufacturing records, starting-material specifications, supplier certificates and analytical reconstruction of the pre-oxidation material.

Molecular weight

The claims require the weight-average molecular weight of the iron(III) carbohydrate complex, not merely the molecular weight of the starting maltodextrin.

That distinction creates several technical questions:

Whether testing is performed on the completed iron-carbohydrate complex.
Which chromatographic method is used.
Whether the reported value is weight-average molecular weight, number-average molecular weight or a different distribution metric.
Whether the result is measured before or after sterilization.
Whether the product specification uses a mean, range or release limit.

A product with a nominal molecular weight of 100 kDa could fall within claim 1 but outside claim 19. A product with a stated average of 118 kDa may require analysis of measurement precision and the applicable claim-construction standard.

What do the formulation and medical-use claims cover?

The dependent claims extend the composition claims into commercially relevant presentations.

Claim group	Covered feature
Claims 4 and 22	Therapy or prophylaxis for iron-deficiency conditions
Claims 5 and 23	Parenteral administration
Claims 6 and 24	Single dose containing 500-1,000 mg iron
Claims 7 and 25	Powder form
Claims 8 and 26	Aqueous solution
Claims 9 and 27	Intravenous administration
Claims 10-11 and 28-29	Iron concentration of 1%-20% weight/volume
Claims 12-14 and 30-32	Sterilization at at least 121°C
Claims 15-18 and 33-36	Preservative-free aqueous solutions

The claims cover both bulk or dry material and finished aqueous drug products. The aqueous-solution claims are commercially significant because ferric derisomaltose products are supplied as sterile intravenous solutions rather than as products that require hospital reconstitution.

The 500-1,000 mg dose limitations in claims 6 and 24 are narrower than the broader composition claims. A product could potentially fall within claims 1 or 19 while avoiding the single-dose limitations if marketed at a different dose, although other dependent claims could remain relevant.

Does the patent cover ferric derisomaltose or Monoferric?

The claim structure is consistent with an iron(III)-oxidized maltodextrin product such as ferric derisomaltose. Ferric derisomaltose, marketed in the United States as Monoferric, is an intravenous iron replacement product supplied at 100 mg elemental iron per mL. The FDA-approved product is indicated for iron-deficiency anemia in adults who have intolerance or an unsatisfactory response to oral iron, or who have non-dialysis-dependent chronic kidney disease. [2]

The product’s commercial presentation aligns with several claimed attributes:

Iron(III)-carbohydrate complex.
Oxidized carbohydrate ligand.
Intravenous aqueous solution.
High iron concentration.
Single-dose administration.
Preservative-free injectable presentation.

Product alignment with the claim language does not by itself establish infringement. Infringement would depend on the product’s actual maltodextrin DE, complex molecular-weight distribution, oxidation chemistry and claim construction.

What is the patent expiration date?

The patent is a post-1995 U.S. patent subject to the 20-year term measured from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension and terminal-disclaimer issues.

Public patent-family records associate U.S. Patent 9,376,505 with Pharmacosmos A/S and an international priority framework dating to 2008. The ordinary term is therefore expected to extend into 2029. The Orange Book listing for Monoferric has identified U.S. Patent 9,376,505 with an expiration date reported as March 28, 2029. [1, 3]

Event	Date or period
Earliest reported priority framework	2008
U.S. patent grant	June 21, 2016
Expected statutory expiration	March 28, 2029
Relevant product	Monoferric, ferric derisomaltose
Patent holder associated with family	Pharmacosmos A/S

The operative expiration date should be taken from the current USPTO and FDA Orange Book records because PTA, PTE and terminal-disclaimer calculations can affect the enforceable term.

What is the Orange Book status of U.S. Patent 9,376,505?

U.S. Patent 9,376,505 has been associated with the Orange Book patent listings for Monoferric. The listing places it in the regulatory framework governing ANDA certifications and generic approval timing for the ferric derisomaltose product. [3]

An Orange Book listing does not mean that every claim necessarily covers every proposed generic product. It means the NDA holder has identified the patent as claiming the drug, a method of using the drug, or a formulation or composition associated with the approved product.

For a generic applicant, the relevant pathway would ordinarily involve:

Paragraph I certification if the patent information is incomplete.
Paragraph II certification if the patent has expired.
Paragraph III certification if the applicant accepts approval after expiration.
Paragraph IV certification if the applicant asserts that the patent is invalid, unenforceable or not infringed.

Are there Paragraph IV challenges to this patent?

A definitive current answer requires review of the FDA Paragraph IV notice database, the Orange Book patent-listing history and federal district court dockets. On the information provided, no verified Paragraph IV challenge, court caption, filing date or settlement term can be established for U.S. Patent 9,376,505.

The principal commercial risk is likely to arise as an ANDA applicant approaches the 2029 patent expiry date. Because ferric derisomaltose is a complex iron-carbohydrate product rather than a conventional small-molecule generic, an applicant may face added analytical and bioequivalence issues even after patent expiry. The FDA may assess whether the proposed product is sufficiently the same in active ingredient, composition and performance for the applicable abbreviated pathway. [4]

How strong is the patent estate?

The patent is strongest where a competitor’s product closely matches all of the following:

Oxidized maltodextrin as the carbohydrate ligand.
Pre-oxidation DE of 5 to 20.
Complex molecular weight of 80 to 400 kDa.
Iron(III) carbohydrate chemistry.
Intravenous aqueous formulation.
Preservative-free and terminally sterilized presentation.
500-1,000 mg single-dose administration.

The estate is weaker against:

Iron sucrose products.
Ferric carboxymaltose products.
Ferumoxytol products.
Iron dextran products.
Complexes using non-maltodextrin carbohydrates.
Products outside the claimed molecular-weight range.
Products using a different carbohydrate oxidation architecture.

Claims 1 and 19 provide the principal composition coverage. The dependent claims create fallback positions for formulation, dosage and administration, but many of those limitations may be vulnerable to non-infringement arguments if a competing product changes its concentration, dose, sterilization method or formulation composition.

How does this patent compare with competing intravenous iron patents?

Product	Active iron complex	Representative patent focus	Relationship to U.S. 9,376,505
Monoferric	Ferric derisomaltose	Oxidized maltodextrin complex and injectable compositions	Directly relevant
Injectafer	Ferric carboxymaltose	Carboxymaltose iron complex and dosing methods	Different carbohydrate platform
Feraheme	Ferumoxytol	Superparamagnetic iron oxide-carbohydrate complex	Different nanoparticle platform
Venofer	Iron sucrose	Iron-sucrose complex and administration	Different carbohydrate platform
INFeD	Iron dextran	Iron-dextran complex	Different carbohydrate platform

The patent should not be treated as a broad patent on intravenous iron. It is a platform patent for a defined oxidized maltodextrin complex and selected pharmaceutical presentations.

What manufacturing and intellectual-property barriers remain after patent expiry?

Patent expiry will remove the principal patent barrier represented by U.S. 9,376,505, but market entry can still be constrained by manufacturing and regulatory requirements.

Key barriers include:

Reproducing the carbohydrate oxidation profile.
Controlling DE of the starting maltodextrin.
Matching complex molecular-weight distribution.
Demonstrating iron binding and release characteristics.
Controlling batch-to-batch carbohydrate heterogeneity.
Producing a stable sterile solution at high iron concentration.
Establishing container-closure integrity.
Demonstrating comparable safety and pharmacokinetics.
Meeting FDA requirements for complex injectable iron products.

Manufacturing know-how may remain commercially important even if it is not protected by a currently enforceable patent. Trade secrets involving oxidation conditions, purification, iron incorporation, sterilization and release testing can delay a competing product.

What generic launch scenarios exist?

Launch after patent expiry

The lowest litigation risk arises from an ANDA or other abbreviated application that accepts approval after the patent’s expiration date. This approach avoids a Paragraph IV dispute over U.S. Patent 9,376,505 but delays commercial entry until the listed patent barrier ends.

Early launch after a successful Paragraph IV case

An applicant could seek earlier entry by challenging validity, enforceability or infringement. The principal technical defenses would likely focus on:

Failure to meet the DE range.
Molecular weight outside the claimed range.
Absence of oxidized maltodextrin.
Non-infringing carbohydrate chemistry.
Invalidity based on anticipation or obviousness.
Written-description or enablement issues for broad molecular-weight and carbohydrate populations.

Non-infringing design-around

A competitor could develop an iron complex using a different carbohydrate, a different oxidation route or a molecular-weight profile outside the claimed ranges. Such a program would still need to address FDA comparability and complex-drug characterization.

Key Takeaways

U.S. Patent 9,376,505 is directed to iron(III) complexes using oxidized maltodextrin.
The core molecular-weight ranges are 80-400 kDa and, in the second independent claim set, 118-400 kDa.
The starting maltodextrin must generally have a DE of 5 to 20.
Claims cover compositions, powders, aqueous solutions, intravenous use, high-concentration formulations, terminal sterilization and preservative-free products.
The patent is commercially relevant to ferric derisomaltose and Monoferric.
The reported Orange Book expiration date is March 28, 2029.
The patent does not broadly cover all intravenous iron products.
Products based on ferric carboxymaltose, iron sucrose, ferumoxytol or iron dextran generally use different carbohydrate platforms.
The principal freedom-to-operate variables are carbohydrate identity, DE, oxidation chemistry and complex molecular weight.
Patent expiry will not eliminate the analytical and manufacturing barriers associated with complex injectable iron products.

Frequently Asked Questions

Is U.S. Patent 9,376,505 a composition patent or a formulation patent?

It is principally a composition patent, with dependent claims covering powders, aqueous solutions, concentration ranges, sterilization, preservative-free formulations and intravenous administration.

Does using hypochlorite automatically create infringement?

No. Hypochlorite oxidation is expressly required only by claims 3 and 21. Claims 1 and 19 do not require hypochlorite if the claimed composition limitations are otherwise met.

Can a product avoid the patent by using a different maltodextrin DE?

Potentially. A product using a starting maltodextrin outside the claimed DE conditions may have a non-infringement position, subject to claim construction, measurement methodology and the doctrine of equivalents.

Does the patent cover iron sucrose?

The claims are not directed to iron sucrose. Iron sucrose uses a different carbohydrate complex and would not ordinarily satisfy the oxidized-maltodextrin limitations.

What is the main post-expiry risk for a ferric derisomaltose entrant?

The main risks are FDA comparability, complex-product characterization, manufacturing reproducibility and possible additional patent or regulatory protections associated with the approved product.

References

U.S. Patent No. 9,376,505. (2016). Iron (III) carbohydrate complexes. United States Patent and Trademark Office.
U.S. Food and Drug Administration. (2020). Monoferric (ferric derisomaltose) injection: Prescribing information.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2016). Product-specific guidance for industry: Ferric carboxymaltose and complex iron drug products.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Germany	102 49 552	Oct 23, 2002

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1554315	⤷ Start Trial	C01554315/01	Switzerland	⤷ Start Trial
Argentina	041472	⤷ Start Trial
Austria	507246	⤷ Start Trial
Australia	2003278111	⤷ Start Trial
Brazil	0315452	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,376,505

Summary for Patent: 9,376,505