US Patent 6,264,923: Ciclesonide HFA Aerosol Claims, Patent Scope, and Generic Risk

US Patent 6,264,923 protects a solvent-based hydrofluoroalkane aerosol formulation containing certain steroid compounds, including ciclesonide, ethanol, and HFA propellant. Its strongest commercial claim is directed to ciclesonide at 1 to 5 mg/mL in an 8:92 by-weight blend of ethanol and HFA-134a. The patent does not claim ciclesonide as a molecule, a therapeutic indication, or a manufacturing process.

The patent was issued on July 24, 2001. Based on the US filing chronology, its nominal patent term ran approximately to November 2018 before any patent-term adjustment or extension. The claims are therefore primarily relevant to historical launch barriers, validity analysis, and the design of later formulation patents rather than to a currently enforceable standalone exclusionary right.

What does US Patent 6,264,923 protect?

The patent covers pharmaceutical aerosol formulations in which a defined corticosteroid is solubilized in ethanol and delivered from a pressurized HFA system. The formulation architecture has four principal elements:

A steroid compound within a defined chemical genus.
HFA-134a, HFA-227, or a mixture of the two.
Ethanol in an amount effective to solubilize the steroid.
An optional surfactant in the primary composition claims.

The compound genus is defined through two substituent variables:

Variable	Claimed alternatives
R1	1-butyl, 2-butyl, cyclohexyl, or phenyl
R2	Acetyl or isobutanoyl

The claim set contains both broad genus claims and progressively narrower formulation claims. Claim 2 identifies ciclesonide specifically. Claims 3 through 10 narrow the composition by surfactant status, ethanol concentration, steroid concentration, and propellant identity. Claims 11 and 12 use different drafting structures and create separate infringement targets.

How broad is claim 1?

Claim 1 is a composition claim covering:

Any therapeutically effective amount of a qualifying compound;
HFA-134a, HFA-227, or a mixture;
Ethanol sufficient to solubilize the compound; and
An optional surfactant.

The claim is broad in formulation composition but narrow in chemical and propellant selection. A product must meet every limitation for literal infringement. A product using a different propellant, such as HFA-152a, a non-HFA propellant, or a materially different solvent system would fall outside the literal language of claim 1.

The phrase "amount effective to solubilize" is functional. It does not impose a fixed ethanol percentage in claim 1. Claims 4 through 7 provide narrower quantitative ranges:

Claim	Ethanol limitation
1	Amount effective to solubilize
4	3% to 25% by weight
5	5% to 20% by weight
6	7% to 12% by weight
7	8% by weight

A formulation containing 8% ethanol would fall within claims 1, 4, 5, 6, and 7 if the other limitations were satisfied. The dependent claims do not replace the broader claim; they add narrower fallback positions.

Which claims specifically cover ciclesonide?

Claim 2 expressly covers ciclesonide within the formulation of claim 1. Ciclesonide is therefore protected only when formulated with the required HFA propellant and ethanol system. Claim 2 does not cover:

Ciclesonide alone;
Oral, injectable, ophthalmic, or nasal ciclesonide products;
A dry-powder inhaler;
A nebulized aqueous suspension;
A ciclesonide formulation using a non-HFA propellant;
A ciclesonide formulation without ethanol where ethanol is required for the claimed composition.

Claim 8 narrows the ciclesonide composition to 1 to 8 mg/mL. Claim 12 narrows it further to:

Ciclesonide;
1 to 5 mg/mL;
Ethanol and HFA-134a;
An 8:92 ethanol-to-HFA-134a ratio by weight; and
A "consisting of" formulation structure.

Claim 12 is the most commercially specific claim in the set. It maps closely to a solution aerosol product containing ciclesonide, ethanol, and HFA-134a.

What formulations are protected by claims 3 through 12?

Claim	Technical scope	Commercial significance
3	Claim 1 formulation free of surfactant	Protects a surfactant-free solution aerosol
4	3% to 25% ethanol	Broad quantitative solvent range
5	5% to 20% ethanol	Intermediate fallback range
6	7% to 12% ethanol	Narrower operating range
7	8% ethanol	Exact concentration limitation
8	Ciclesonide at 1 to 8 mg/mL	Covers concentration range for active ingredient
9	HFA-134a as propellant	Targets HFA-134a products
10	HFA-227 as propellant	Targets HFA-227 products
11	Canister and dispensing valve, HFC propellant, cosolvent	Separate aerosol-device formulation claim
12	Ciclesonide at 1 to 5 mg/mL in ethanol:HFA-134a 8:92	Narrowest and most product-specific claim

Claim 3 is important because many inhalation solution formulations avoid surfactants to reduce irritation, valve interaction, and formulation complexity. A surfactant-free product can still infringe if it satisfies the remaining limitations.

How does claim 11 differ from claims 1 through 10?

Claim 11 is drafted as a pharmaceutical aerosol formulation contained in a canister equipped with a dispensing valve. It requires:

The defined steroid compound;
A hydrofluorocarbon propellant; and
A cosolvent effective to solubilize the compound.

Unlike claim 1, claim 11 does not expressly limit the propellant to HFA-134a or HFA-227. It also does not expressly require ethanol. A cosolvent other than ethanol could potentially satisfy the claim if it performs the claimed solubilizing function.

Claim 11 therefore has a different infringement profile:

Issue	Claims 1-10	Claim 11
Propellant	HFA-134a, HFA-227, or mixture	Hydrofluorocarbon broadly
Solvent	Ethanol	Cosolvent broadly
Device limitation	Not expressly required in claims 1-10	Canister and dispensing valve required
Concentration	Several dependent limitations	No stated concentration
Product fit	Solution composition	Packaged aerosol system

A product could avoid claims 1 through 10 by changing the solvent or propellant but still require analysis under claim 11. Conversely, a bulk formulation without a canister and dispensing valve would face a stronger argument against literal infringement of claim 11.

What is the scope of claim 12?

Claim 12 is a highly constrained formulation claim. It requires ciclesonide at 1 to 5 mg/mL in a blend containing 8% ethanol and 92% HFA-134a by weight.

The claim's practical coverage can be expressed as follows:

[ \text{Ciclesonide }(1-5\text{ mg/mL}) + 8\%\text{ ethanol} + 92\%\text{ HFA-134a} ]

The "consisting of" language may limit the claim to the recited formulation components, subject to the interpretation of claim construction and whether incidental ingredients are legally considered material. A formulation containing a surfactant, stabilizer, or other additive presents a claim-construction issue because those ingredients may be inconsistent with a closed transitional phrase.

Claim 12 is easier to design around than claim 1 because it requires all of the following:

Ciclesonide rather than another steroid;
1 to 5 mg/mL concentration;
HFA-134a rather than HFA-227;
An 8:92 ethanol-to-propellant ratio; and
The claimed formulation structure.

A product using 7% or 10% ethanol, HFA-227, a different concentration, or a different cosolvent system would not literally satisfy every limitation of claim 12.

Does the patent cover the ciclesonide molecule itself?

No. US 6,264,923 is a formulation patent. It does not claim:

The ciclesonide chemical structure standing alone;
The synthesis of ciclesonide;
A crystalline or polymorphic form of ciclesonide;
A salt or metabolite of ciclesonide;
A method of treating asthma or allergic rhinitis; or
A specific dosing regimen.

Separate composition-of-matter, process, method-of-use, device, and formulation patents may have created additional barriers for ciclesonide products. Those rights must be analyzed independently from US 6,264,923.

What is the patent landscape around ciclesonide inhalers?

The relevant landscape has four patent categories.

Active-ingredient patents

These cover ciclesonide or related corticosteroid structures. They historically provided the earliest and strongest exclusivity because composition-of-matter claims are broader than formulation claims. Their term depends on the specific priority and US filing dates.

Formulation patents

US 6,264,923 belongs to this category. Such patents protect the combination of ciclesonide, ethanol, HFA propellant, concentration, and formulation architecture. They can delay or complicate generic entry even after the active ingredient patent expires.

Device and container patents

These may cover metering valves, canister coatings, actuator geometry, dose-counter systems, or compatibility between the formulation and the valve. Claim 11 of US 6,264,923 includes a canister and dispensing valve, but it is still principally a formulation claim.

Method-of-use patents

Ciclesonide inhalation products may be associated with patents covering asthma treatment, allergic rhinitis, dosing schedules, pediatric use, or reduction of systemic corticosteroid exposure. A generic applicant can sometimes carve out patented uses through a section viii statement, but the outcome depends on the listed indications and the approved labeling.

What was the FDA and Orange Book position?

Ciclesonide inhalation aerosol was approved by the FDA as Alvesco, an inhaled corticosteroid product. The product was submitted through an NDA rather than an ANDA because it was an innovator product requiring clinical and chemistry, manufacturing, and controls data.

For an Orange Book analysis, the relevant questions are:

Whether US 6,264,923 was listed against the applicable ciclesonide NDA.
Whether the listed patent covered the reference product's formulation.
Whether the patent was active when an ANDA applicant filed.
Whether the applicant submitted a Paragraph IV certification.
Whether the NDA holder filed an infringement action within 45 days.
Whether a 30-month stay, settlement, or license affected approval timing.

Patent listing does not prove validity or infringement. It identifies patents submitted by the NDA holder or approved product sponsor for FDA publication under the Orange Book framework. The FDA does not adjudicate patent validity.

Were Paragraph IV challenges or generic litigation relevant?

A generic ciclesonide inhaler would normally use the ANDA pathway and address listed patents through one of four certifications:

Certification	Meaning
Paragraph I	No patent information listed
Paragraph II	Listed patent has expired
Paragraph III	Applicant will wait until patent expiration
Paragraph IV	Listed patent is invalid, unenforceable, or not infringed

For US 6,264,923, the most important Paragraph IV issues would have been:

Whether the proposed formulation used ethanol as a solubilizing cosolvent;
Whether the propellant was HFA-134a or HFA-227;
Whether the proposed concentration fell within the dependent claims;
Whether the canister and valve met claim 11;
Whether the patent had expired before ANDA approval;
Whether the claims were anticipated or obvious in view of earlier CFC or HFA aerosol formulations.

No litigation conclusion should be drawn solely from the claim text. A complete litigation position requires the Orange Book listing history, district court docket, Federal Circuit decisions, settlement agreements, and any FDA approval records.

How strong are the patent claims?

Strengths

Claim 2 directly identifies ciclesonide.
Claims 4 through 7 provide multiple quantitative fallback positions.
Claim 12 targets a commercially realistic formulation.
The HFA and ethanol combination addresses the technical problem of solubilizing a corticosteroid in a propellant-based aerosol.
The claims can reach both bulk composition and packaged aerosol configurations.

Vulnerabilities

HFA aerosol systems and ethanol cosolvents were established technologies before the patent's filing date.
Obviousness could focus on combining known HFA propellants with ethanol and a known inhaled corticosteroid.
The functional phrase "effective to solubilize" may raise claim-construction and written-description issues.
The chemical genus is limited but still requires adequate support across the claimed substituent combinations.
Claim 12's narrow ratio and "consisting of" language create design-around opportunities.
The patent is formulation-specific and cannot block all ciclesonide products.

The strongest commercial position would have been against a ciclesonide HFA solution using ethanol and HFA-134a within the claimed concentration and ratio ranges. The weakest position would have been against a dry-powder, nebulized, non-HFA, or materially different solvent formulation.

What generic launch scenarios would avoid the claims?

Potential design-around strategies include:

Using a dry-powder inhaler rather than a pressurized metered-dose inhaler.
Using a nebulized suspension or solution.
Replacing ethanol with another cosolvent.
Using a propellant outside HFA-134a and HFA-227.
Changing the ciclesonide concentration outside the narrower dependent ranges.
Using a materially different ethanol-to-propellant ratio.
Formulating the product as a suspension rather than a true solution.
Changing the container or valve configuration to avoid claim 11, while separately addressing claims 1 through 10.

These strategies do not automatically avoid infringement because the doctrine of equivalents, claim construction, and other patent families may apply. They identify the principal literal claim boundaries.

Does the patent create biosimilar risk?

No. Ciclesonide is a chemically synthesized small molecule, not a biologic. A follow-on product would generally be a generic or therapeutic equivalent submitted through the ANDA pathway, not a biosimilar submitted under the abbreviated biologics license application pathway.

The main regulatory and IP risks are formulation sameness, device sameness or substitutability, pharmaceutical equivalence, bioequivalence, and patent certifications. Biosimilar interchangeability standards do not apply.

Key Takeaways

US 6,264,923 is a formulation patent, not a ciclesonide composition-of-matter patent.
Its central technology is a ciclesonide or related steroid dissolved in ethanol and delivered with an HFA propellant.
Claim 2 specifically covers ciclesonide within the claim 1 formulation.
Claim 12 is the most commercially targeted claim: 1 to 5 mg/mL ciclesonide in 8% ethanol and 92% HFA-134a.
Claim 11 separately covers a canister-based HFC aerosol formulation using a cosolvent.
The patent does not cover dry-powder, nebulized, oral, injectable, or non-HFA ciclesonide products as such.
Generic applicants would address listed claims through Paragraph II, III, or IV certifications depending on the patent's listing and expiration status.
The patent's nominal term was approximately through November 2018 based on the US filing chronology.
No biosimilar pathway applies because ciclesonide is a small-molecule drug.
The principal commercial risk came from formulation similarity, not from the ciclesonide molecule alone.

FAQs About US Patent 6,264,923 and Ciclesonide

What is the most important claim in US 6,264,923?

Claim 12 is the most product-specific claim because it identifies ciclesonide, a 1 to 5 mg/mL concentration, HFA-134a, and an 8:92 ethanol-to-propellant ratio.

Does using HFA-227 instead of HFA-134a avoid the patent?

It may avoid claims limited to HFA-134a, including claim 9 and claim 12, but claim 1 and claim 10 require separate analysis because they expressly cover HFA-227.

Is an ethanol-free ciclesonide inhaler outside the claims?

An ethanol-free formulation would generally avoid claims requiring ethanol. Claim 11 requires a cosolvent rather than expressly requiring ethanol, so an ethanol-free formulation using another solubilizing cosolvent may still require analysis under that claim.

Can a generic applicant use a Paragraph III certification after patent expiration?

Yes. A Paragraph III certification states that the applicant will not market until the relevant listed patent expires. If the patent has expired, a Paragraph II certification may also be relevant, depending on the applicant's legal and regulatory strategy.

Does the patent cover Alvesco's therapeutic use in asthma?

No. The supplied claims are directed to pharmaceutical compositions and an aerosol formulation. They do not claim treating asthma, allergic rhinitis, or another disease indication.

References

United States Patent and Trademark Office. (2001). US Patent No. 6,264,923, Pharmaceutical compositions. U.S. Department of Commerce.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. U.S. Department of Health and Human Services.
U.S. Food and Drug Administration. (n.d.). Alvesco (ciclesonide) inhalation aerosol prescribing information. U.S. Department of Health and Human Services.
U.S. Food and Drug Administration. (2017). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
United States Code, 35 U.S.C. §§ 154, 271, 355.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Chile	2004001325	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 6,264,923

Summary for Patent: 6,264,923