United States Drug Patent 7,348,361: Claim Scope, Expiration, Orange Book Status, and Competitive Patent Landscape

U.S. Patent No. 7,348,361 protects low-concentration pharmaceutical preparations containing ALA hexylester, also called hexaminolevulinate or h-ALA, for photodynamic diagnosis and treatment. The core limitation is an h-ALA concentration below 1% by weight, with dependent claims covering 0.01% to 0.5%, physiologically compatible solvents, pH 4.8 to 8.1, EDTA or deferoxamine, and fluorescence-based diagnosis.

The patent was granted on March 25, 2008. Based on its pre-2000 priority framework and the 20-year patent term measured from the earliest effective nonprovisional filing date, the enforceable term has expired. U.S. Patent No. 7,348,361 therefore does not present a current U.S. blocking patent for a properly authorized generic or competing h-ALA product. Its historical relevance is strongest for Cysview and related hexaminolevulinate photodynamic products.

What does U.S. Patent 7,348,361 protect?

The patent protects two related categories:

Pharmaceutical compositions containing h-ALA in a physiologically acceptable solvent.
Diagnostic and treatment methods using the composition followed by localized light irradiation.

The independent claims are claims 1, 12, 14, and 22.

Claim	Claim type	Principal subject matter
1	Composition	h-ALA below 1% by weight in a physiologically acceptable solvent
12	Composition	h-ALA below 1%, pH 4.8 to 8.1, and EDTA or deferoxamine
14	Method	Administration, irradiation, and detection of PpIX fluorescence
22	Method	Administration and irradiation for treatment

The patent does not broadly claim every photodynamic preparation containing aminolevulinic acid. Its central chemical limitation is the use of the hexyl ester of ALA rather than unmodified ALA or a different ALA ester.

The composition claims also require a preparation intended for administration before localized irradiation. That intended-use language may matter in infringement analysis where a product is sold for a non-photodynamic use.

How broad is the h-ALA concentration limitation?

The principal concentration limitation is "less than 1% by weight." This is a broad upper-bound limitation, subject to the requirement that the preparation contain h-ALA and be used in a photodynamic diagnosis or treatment context.

Claims 15, 23, 30, and 31 narrow the concentration to 0.01% to 0.5% by weight.

Concentration	Claims implicated	Scope
Less than 1% by weight	1 and 12, and their method descendants	Broad independent-claim range
0.01% to 0.5% by weight	15, 23, 30, 31	Narrower dependent-claim range
At least 1% by weight	Outside the literal concentration limitation	Potential noninfringement position, subject to claim construction

A formulation containing 0.17% h-ALA by weight or weight-equivalent concentration would fall within the numerical range of the independent claims and the dependent 0.01% to 0.5% range. Cysview contains hexaminolevulinate hydrochloride reconstituted for intravesical administration at a concentration commonly described as approximately 1.7 mg/mL, or approximately 0.17% w/v, according to the FDA prescribing information. Weight percent and weight/volume percent are not always interchangeable in litigation, but the numerical relationship is commercially relevant. (U.S. Food and Drug Administration, 2021)

What formulations are protected by U.S. Patent 7,348,361?

The solvent limitations are broad. Claims 3, 9, 16, and 24 identify:

Sterilized water
Physiological sodium chloride solution
Phosphate buffer solution

Claims 4, 10, 17, and 25 cover a pH-adjusting component producing a pH of approximately 4.8 to 8.1.

The formulation coverage can be summarized as follows:

Formulation element	Claims	Practical significance
Physiologically acceptable solvent	1, 2, 12	Captures human pharmaceutical preparations
Animal-compatible solvent	8	Extends the formulation concept to veterinary use
Sterilized water	3, 9, 16, 24	Covers aqueous sterile formulations
Physiological NaCl	3, 9, 16, 24	Covers saline formulations
Phosphate buffer	3, 9, 16, 24	Covers buffered formulations
pH approximately 4.8 to 8.1	4, 10, 12, 17, 25	Covers broad near-physiological pH conditions
EDTA	6, 19, 27	Iron-complexing adjunct
Deferoxamine mesylate	7, 20, 28	Alternative iron-complexing adjunct
PpIX fluorescence detection	11, 13, 14	Diagnostic use
Localized irradiation for treatment	22	Therapeutic use

The claims do not require a particular light wavelength, laser manufacturer, light intensity, irradiation duration, tissue type, lesion type, route of administration, or diagnostic instrument. The absence of those limitations increases the potential literal scope of the method claims.

How do the EDTA and deferoxamine limitations affect infringement?

Claims 5 through 7 and 18 through 20 cover an optional complementary substance that prevents conversion of PpIX into heme through iron complexing in cells.

The two named alternatives are:

Ethylenediaminetetraacetic acid, or EDTA
Deferoxamine mesylate

A product without either EDTA or deferoxamine may still fall within claim 1 or the basic method claims. It would not satisfy the added limitation in claims 5 through 7, 12, or 18 through 20.

Claim 12 contains a drafting anomaly. It identifies the chelator as "BDTA" in the supplied claim text, while the dependent claims identify EDTA. The likely intended term is EDTA. The legal effect would depend on the issued patent record, prosecution history, and whether the discrepancy is treated as a typographical error, an indefinite limitation, or a claim-construction issue. A commercial freedom-to-operate opinion should rely on the certified issued claims rather than an unofficial transcription.

What do the diagnostic method claims cover?

Claim 14 requires three steps:

Administering the claim 1 preparation to an organism.
Irradiating the lesion with a source of light energy.
Detecting fluorescence emitted by PpIX generated from h-ALA.

The claim covers photodynamic diagnosis, not merely administration of h-ALA. A competing product would need to be assessed against the full sequence, including the irradiation and fluorescence-detection steps.

Claim 11 is a composition claim containing a functional diagnostic use limitation. Claim 13 similarly depends from claim 12. Claims 14 through 21 are method claims and extend to both human and animal organisms.

The diagnostic scope includes procedures in which PpIX fluorescence assists in identifying or delineating a lesion. It does not expressly require a particular cancer, organ, imaging device, or fluorescence wavelength.

What do the treatment method claims cover?

Claim 22 covers a method of treating a tissue or cell lesion by:

Administering the claim 1 pharmaceutical preparation; and
Irradiating the lesion with a light-energy source.

Unlike claim 14, claim 22 does not expressly require detection of fluorescence. A treatment protocol may therefore fall within claim 22 even when fluorescence is used only as an operational guide and is not separately measured.

Claims 23 through 29 add the same concentration, solvent, pH, chelator, and organism limitations found elsewhere in the patent.

The treatment claims are broad in the identity of the lesion and the light source. They may encompass dermatologic, urologic, oncologic, veterinary, and other lesion-directed photodynamic procedures, provided that the preparation and h-ALA limitations are met.

When did U.S. Patent 7,348,361 lose exclusivity?

U.S. Patent No. 7,348,361 was issued on March 25, 2008. Its patent term was governed by the 20-year term applicable to the relevant application filing and priority structure, not by the grant date. The patent’s effective term therefore ran from the late 1990s or early 2000s and ended no later than the early 2020s, subject to any patent-term adjustment shown in the USPTO record. (United States Patent and Trademark Office, n.d.; 35 U.S.C. § 154)

Event	Date or period
Earliest priority framework	Late 1990s
U.S. patent grant	March 25, 2008
Standard 20-year term endpoint	Approximately 2019 to 2021, depending on the effective filing date
Current status	Expired or no longer enforceable by ordinary term expiration

The patent should not be treated as a live U.S. exclusion right. A final legal conclusion on the precise day of expiration requires the USPTO patent-term calculation, including any patent-term adjustment and terminal disclaimer information. The commercial conclusion is unchanged: the patent is not a current barrier to U.S. entry.

What is the FDA and Orange Book status of the patent?

Cysview, containing hexaminolevulinate hydrochloride, is FDA-approved for photodynamic detection of non-muscle-invasive bladder cancer during cystoscopy. The FDA approved Cysview under NDA 022555. (U.S. Food and Drug Administration, 2010, 2021)

The Orange Book is relevant because listed patents can trigger a Paragraph IV certification and a statutory 30-month stay if the NDA holder or patent owner brings a timely infringement action. However, Orange Book listing does not extend patent term. An expired listed patent cannot provide a current period of enforceability after expiration.

Regulatory issue	Assessment
FDA-approved h-ALA product	Cysview
Active ingredient	Hexaminolevulinate hydrochloride
FDA route	NDA approval
Primary indication	Photodynamic cystoscopic detection of bladder cancer
Patent relevance	Historical formulation and use coverage
Current patent blocking effect	None after expiration
Paragraph IV exposure to this patent	Historically possible; no current stay value from an expired patent
Biosimilar pathway	Not applicable; Cysview is a small-molecule drug

A generic applicant for an h-ALA product could still face active patents covering a specific formulation, device, manufacturing process, route of administration, or approved use. Those issues must be separated from the expired claims of U.S. Patent 7,348,361.

Were Paragraph IV challenges or patent litigation associated with this patent?

The patent was commercially relevant to hexaminolevulinate products, particularly Cysview and the broader Hexvix product family. The supplied record does not establish a specific Paragraph IV notice, district-court case, settlement agreement, or litigation judgment directed to U.S. Patent 7,348,361.

A Paragraph IV challenge would have required a generic applicant to certify that the patent was invalid, unenforceable, or not infringed. The possible defenses would have included:

Lack of novelty or obviousness based on earlier ALA-ester photodynamic therapy disclosures
Indefiniteness of functional and intended-use language
Written-description or enablement challenges to the broad formulation and concentration ranges
Noninfringement based on concentration, solvent, chelator, or use
Invalidity based on an inadequate priority claim or prosecution defect

Because the patent has expired, a new Paragraph IV challenge to this patent would have little practical value unless pursued for declaratory, launch-planning, or historical reasons.

How does this patent compare with competing photodynamic drug patents?

U.S. Patent 7,348,361 is narrower chemically than patents covering the entire photodynamic therapy field, but broader in certain formulation and use dimensions.

Product or technology	Active agent	Relationship to 7,348,361
Cysview	Hexaminolevulinate hydrochloride	Closest commercial product; same h-ALA concept
Gleolan	Aminolevulinic acid hydrochloride	Different active compound; not automatically within h-ALA claims
Photofrin	Porfimer sodium	Different photosensitizer
Metvix or Metvixia	Methyl aminolevulinate	Different ALA ester
Talaporfin products	Talaporfin sodium	Different photosensitizer

The patent does not cover all uses of ALA, all PpIX-generating agents, or all photodynamic diagnosis products. A formulation containing unmodified ALA or methyl aminolevulinate would not literally satisfy the h-ALA limitation.

How strong was the patent estate?

The patent had useful commercial breadth during its term because the independent claims combined a specific active compound with a wide concentration ceiling and broad photodynamic use language.

Its principal strengths were:

Coverage of both composition and method claims
Inclusion of human and animal use
Broad solvent alternatives
Broad pH range
No limitation to a particular lesion or light source
Dependent claims directed to clinically plausible concentration ranges
Direct relevance to hexaminolevulinate photodynamic diagnosis

Its principal weaknesses were:

Dependence on the specific identity of h-ALA
Functional and intended-use limitations
Potential ambiguity surrounding weight percent versus weight/volume concentration
Possible vulnerability of broad claims to prior-art ALA-ester disclosures
Lack of current term after expiration
Limited ability to block products using a different ALA derivative

The estate was therefore commercially relevant but not field-wide. Its current patent strength is zero as an enforceable U.S. exclusion right because the term has ended.

What generic entry risks remain after expiration?

The expired patent removes one central barrier, but an entrant could still face other barriers:

Regulatory barriers

Cysview is an approved drug product with product-specific labeling, sterility, reconstitution, manufacturing, and clinical requirements. A generic applicant would need to satisfy the applicable abbreviated new drug application requirements or pursue another FDA pathway.

Formulation barriers

Hexaminolevulinate can present stability, solubility, light sensitivity, pH, packaging, and reconstitution issues. These may be protected by later patents or confidential know-how even when the 7,348,361 patent is expired.

Manufacturing barriers

Potential barriers include:

Synthesis and purification of h-ALA
Control of ester hydrolysis
Impurity limits
Sterile manufacture
Stability during storage
Light-protective packaging
Consistent reconstitution performance

Commercial barriers

The U.S. market is procedure-driven. Market access depends on urology adoption, cystoscopy equipment compatibility, reimbursement, supply reliability, and physician familiarity.

Use-patent barriers

Later patents may cover particular bladder-cancer protocols, dosing schedules, imaging procedures, light parameters, or combination methods. Those patents are separate from the claims of U.S. Patent 7,348,361.

What licensing and geographic issues matter?

Hexaminolevulinate has been commercialized through regional rights, product licenses, and collaborations involving the originator and marketing partners. The relevant product names include Hexvix outside the United States and Cysview in the United States.

Patent rights are territorial. Expiration of U.S. Patent 7,348,361 does not determine the status of corresponding European, Canadian, Japanese, or other national patents. A company planning international launch must review:

National-stage counterparts
Continuations and divisionals
Patent-term extensions
Supplementary protection certificates
Later formulation patents
Use patents
License restrictions
Regulatory exclusivity in each market

The U.S. expiration conclusion should not be exported automatically to Europe or other jurisdictions.

What is the commercial exposure for Cysview?

Cysview is the product most directly associated with the claimed h-ALA formulation and photodynamic diagnostic use. Its commercial exposure from this patent has ended because the patent term has expired.

The remaining competitive questions concern:

Whether other active U.S. patents cover the marketed product
Whether a generic can demonstrate pharmaceutical equivalence
Whether the FDA requires a full clinical or comparative pathway
Whether the entrant can reproduce the sterile product and imaging workflow
Whether reimbursement and physician adoption support launch

The patent itself should not be included as a current revenue-protection asset in a valuation of the Cysview franchise. Any remaining exclusivity value would need to come from regulatory status, trade secrets, later patents, market access, or commercial execution.

Key Takeaways

U.S. Patent 7,348,361 covers h-ALA pharmaceutical preparations below 1% by weight for photodynamic diagnosis and treatment.
Dependent claims cover 0.01% to 0.5% h-ALA, aqueous or buffered solvents, pH 4.8 to 8.1, EDTA, and deferoxamine mesylate.
Claims 14 and 22 separately cover fluorescence-based diagnosis and lesion treatment.
Cysview is the closest FDA-approved commercial product.
The patent’s term has expired, eliminating it as a current U.S. blocking patent.
The patent does not cover unmodified ALA, methyl aminolevulinate, porfimer sodium, or every PpIX-generating product.
New entrants must still assess later formulation, manufacturing, method-of-use, regulatory, and device-related rights.
U.S. expiration does not establish expiration of foreign counterparts or later related patents.

FAQs

Does U.S. Patent 7,348,361 cover Cysview?

It is closely aligned with Cysview because both involve hexaminolevulinate for photodynamic detection and h-ALA concentrations below 1%. The patent has expired, so it no longer blocks Cysview competitors in the United States.

Can a product containing 5-ALA avoid this patent?

A product containing unmodified 5-aminolevulinic acid may avoid literal infringement because the claims require ALA hexylester. Other patent families and regulatory requirements may still apply.

Does the patent cover intravesical bladder-cancer diagnosis?

The claims are broad enough to encompass intravesical photodynamic diagnosis when the formulation contains h-ALA within the claimed concentration and is followed by irradiation and PpIX fluorescence detection.

Is a biosimilar application required for a competing h-ALA product?

No. Hexaminolevulinate is a small-molecule drug, not a biologic. A competing product would generally be evaluated under an abbreviated new drug application or another small-molecule FDA pathway.

Can expired patent claims support a Paragraph IV lawsuit?

An expired patent generally cannot support a current infringement claim or a meaningful 30-month stay. A Paragraph IV analysis may still be relevant to historical approval strategy, but the expired patent does not provide ongoing market exclusivity.

References

U.S. Food and Drug Administration. (2010). Cysview: NDA 022555 approval history. FDA Drugs@FDA.
U.S. Food and Drug Administration. (2021). Cysview prescribing information. Photocure ASA.
United States Patent and Trademark Office. (n.d.). U.S. Patent No. 7,348,361, patent center record. USPTO Patent Center.
United States Code. (2023). 35 U.S.C. § 154: Contents and terms of patents; provisional rights.
United States Code. (2023). 21 U.S.C. § 355: New drugs.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
France	98 05425	Apr 22, 1998

PCT Information
PCT Filed	April 22, 1999	PCT Application Number:	PCT/CH99/00163
PCT Publication Date:	October 28, 1999	PCT Publication Number:	WO99/53962

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	228018	⤷ Start Trial
Canada	2327393	⤷ Start Trial
Germany	69904033	⤷ Start Trial
European Patent Office	1073472	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,348,361

Summary for Patent: 7,348,361