US Patent 7,723,910: Claim Scope, Expiration Risk, and ALA Photodynamic Therapy Patent Landscape

US Patent 7,723,910 protects a treatment protocol combining topical 5-aminolevulinic acid, or ALA, with visible-light irradiation delivered across a contoured surface. The principal technical limitation is the use of multiple light sources positioned to conform generally to the treated surface and provide substantially uniform intensity. Several dependent claims narrow the protocol to blue light, specific dermatologic indications, freshly mixed ALA formulations, and a 417-nanometer, approximately 1,000-second irradiation protocol.

The patent is directed to a method of treatment or diagnosis, not to ALA as a molecule, a topical formulation standing alone, or a generic light source. Its commercial relevance is strongest for ALA photodynamic therapy systems used on the face, scalp, and other irregular anatomical surfaces. The claim set also overlaps conceptually with the Levulan Kerastick and BLU-U photodynamic therapy platform approved by the FDA for actinic keratosis.[1]

What does US Patent 7,723,910 cover?

US Patent 7,723,910 covers photodynamic diagnosis or treatment in which a patient’s contoured surface is:

Topically treated with 5-aminolevulinic acid;
Irradiated with visible light;
Exposed to substantially uniform light intensity; and
Treated with multiple light sources generally conforming to the surface.

Claim 1 adds a specific device limitation: the plurality of light sources must comprise fluorescent tubes. Claims 24 and 26 are independent claims and omit that express fluorescent-tube requirement.

The patent therefore has two principal claim strategies:

Claim group	Main limitation	Commercial target
Claim 1 and dependents	ALA plus conforming fluorescent-tube array	Multi-tube photodynamic therapy systems
Claim 24	ALA plus substantially uniform blue light from conforming sources	Blue-light ALA treatment systems
Claim 26	ALA plus approximately 1,000 seconds of 417 ± 5 nm light with 30 nm bandwidth	BLU-U-type treatment protocol

The patent does not claim every use of ALA with light. A competing system may avoid infringement if it does not use a covered light geometry, does not deliver substantially uniform intensity, uses a different wavelength profile, or does not satisfy the relevant indication or formulation limitation.

How are the claims organized?

Independent claim 1

Claim 1 requires all of the following:

A photodynamic diagnosis or treatment method;
A contoured surface;
Topical application of ALA;
Irradiation with visible light;
Substantially uniform intensity;
A plurality of light sources;
Light sources generally conforming to the contoured surface; and
Fluorescent tubes among the light sources.

The claim is narrower than a general ALA photodynamic therapy claim because it is tied to the physical arrangement and performance of the illumination system.

The phrase “contoured surface” likely covers anatomical surfaces with curvature or irregular geometry, including the face, scalp, nose, ears, forehead, and other nonplanar skin regions. The claim does not appear limited to a particular body part.

Dependent claims 2 through 23 and 25

These claims add formulation, treatment, or operating conditions:

Claims	Added subject matter
2	ALA is in a carrier
3	Successive ALA applications
4-5	Treatment of actinic keratosis, with optional pre-use mixing
6-7	Treatment of acne, with optional pre-use mixing
8-9	Treatment of photodamaged skin, with optional pre-use mixing
10-11	Treatment of cancer, with optional pre-use mixing
12-13	Treatment of warts, with optional pre-use mixing
14-15	Treatment of psoriasis, with optional pre-use mixing
16-17	Hair removal, with optional pre-use mixing
18-19	Cancer diagnosis, with optional pre-use mixing
20-21	Treatment of a precancerous condition, with optional pre-use mixing
22 and 25	ALA is admixed with a vehicle immediately before use
23	Light is substantially entirely within the blue region

Claims 5, 7, 9, 11, 13, 15, 17, 19, 21, 22, and 25 are formulation-preparation claims. They do not require a particular vehicle, concentration, solvent, gel, cream, or commercial product name in the text supplied.

Independent claim 24

Claim 24 recites:

Topical ALA;
A contoured surface;
Substantially uniform visible light;
A plurality of sources generally conforming to the surface; and
Light substantially entirely in the blue region.

Unlike claim 1, claim 24 does not expressly require fluorescent tubes. A system using LEDs or another light-source technology could fall within claim 24 if the remaining limitations are met.

Independent claim 26

Claim 26 is the most technically specific independent claim. It requires:

Topical ALA;
A contoured surface;
Substantially uniform visible light;
A plurality of light sources generally conforming to the surface;
Approximately 1,000 seconds of irradiation;
A nominal peak wavelength of 417 ± 5 nanometers; and
A nominal bandwidth of 30 nanometers.

Claim 26 does not expressly require fluorescent tubes. It also does not expressly use the words “blue region,” although 417 nanometers is within the blue-violet portion of the visible spectrum.

What is the central infringement issue under the patent?

The central issue is whether a competing ALA photodynamic therapy system satisfies the combination of drug application, surface geometry, light uniformity, source arrangement, and wavelength or exposure-time limitations.

A product or clinical protocol would generally require a limitation-by-limitation analysis:

Limitation	Key infringement question
ALA	Is 5-aminolevulinic acid topically applied?
Contoured surface	Is treatment performed on a curved or irregular anatomical surface?
Visible light	Is the treatment light visible rather than ultraviolet or infrared?
Substantially uniform intensity	Is the light distribution sufficiently uniform across the target?
Plurality of sources	Are multiple emitters used?
Conforming arrangement	Do the sources generally conform to the surface?
Fluorescent tubes	Required for claim 1 and its dependents, but not expressly for claims 24 or 26
Blue spectrum	Required by claim 23 and claim 24
417-nm profile	Required by claim 26
Approximately 1,000 seconds	Required by claim 26

The terms “substantially uniform,” “generally conforming,” “approximately,” and “substantially entirely” are likely to generate claim-construction disputes. Their application would depend on the intrinsic patent record, prosecution history, technical evidence, and the accused system’s measured performance.

What formulations are protected by US Patent 7,723,910?

The patent does not appear to claim a standalone ALA composition in the claim set supplied. The formulation-related protection is method-based.

The relevant formulation limitations are:

ALA placed in a carrier;
ALA applied in successive applications; and
ALA mixed with a vehicle immediately before use.

These provisions could reach a two-component product in which ALA is combined with a vehicle shortly before treatment. They could also cover an in-clinic preparation step if the remaining treatment limitations are met.

The claims do not expressly require:

ALA hydrochloride rather than another ALA form;
A particular percentage concentration;
A specific solvent;
A particular pH;
A gel, cream, solution, or emulsion;
A named commercial kit; or
A specific penetration enhancer.

The pre-use mixing limitation is materially narrower than a claim covering any ALA formulation. A ready-to-use formulation may avoid claims requiring admixture immediately before use, although it could still implicate broader claims if the other limitations are satisfied.

Which medical indications are covered?

The claims expressly identify a broad range of indications:

Actinic keratosis;
Acne;
Photodamaged skin;
Cancer;
Warts;
Psoriasis;
Hair removal;
Cancer diagnosis; and
Precancerous conditions.

The indication claims are dependent claims. They inherit every limitation of claim 1, including the conforming light-source arrangement and fluorescent-tube limitation. A product used for actinic keratosis, for example, would not infringe claim 4 merely because it uses ALA and blue light. The accused method would also need to satisfy the limitations inherited from claim 1.

Claims 18 and 20 create separate diagnostic and treatment categories for cancer and precancerous conditions. Their practical enforcement value depends on the actual clinical protocol, because diagnosis or treatment intent may be disputed when ALA is used for lesion visualization or selective photodynamic therapy.

What is the relationship to Levulan and BLU-U?

The claimed protocol closely corresponds to the technical architecture associated with ALA photodynamic therapy using blue light. FDA-approved Levulan Kerastick contains aminolevulinic acid hydrochloride for topical administration, and the FDA labeling describes its use with the BLU-U Blue Light Photodynamic Therapy Illuminator for actinic keratosis.[1]

The relationship is best understood as follows:

Product or technology	Role
Levulan Kerastick	ALA hydrochloride topical drug product
BLU-U	Blue-light illumination device
US 7,723,910	Method claims directed to the combined treatment geometry and irradiation protocol
FDA approval	Regulatory authorization for specified product and indication, not a determination that every related patent claim is valid or infringed

A drug approval does not itself establish patent validity. Conversely, a patent covering a treatment method does not automatically establish FDA approval for every indication recited in the patent.

What is the FDA regulatory status?

The FDA approved Levulan Kerastick for the treatment of minimally to moderately thick actinic keratoses of the face or scalp in conjunction with blue-light illumination.[1] The approved regimen is narrower than the full patent claim set, which includes acne, psoriasis, hair removal, cancer diagnosis, cancer treatment, warts, photodamaged skin, and precancerous conditions.

The patent’s broad indication language therefore extends beyond the principal FDA-approved Levulan indication. A claim directed to an unapproved use may still have patent significance, but commercial use would raise separate regulatory issues.

The relevant FDA distinction is:

FDA approval concerns safety, efficacy, labeling, manufacturing, and approved use.
Patent rights concern exclusionary rights against covered acts during the patent term.
Orange Book listing concerns patents submitted for an approved drug product and qualifying under FDA listing rules.

What is the Orange Book status?

The Orange Book is principally relevant to approved drug products and patents submitted by the NDA holder. It is not a comprehensive database of every patent that may be relevant to a drug, device, light source, or treatment method.[2]

US Patent 7,723,910 is a method patent directed to the combined ALA and illumination procedure. Its practical Orange Book relevance depends on whether it was submitted and accepted for listing against the applicable Levulan NDA and whether the listed claims met FDA’s listing standards.

The patent number alone does not establish:

That the patent was listed in the Orange Book;
That a generic applicant had to certify to it;
That a Paragraph IV notice was served;
That the patent was enforceable during the relevant ANDA filing period; or
That the patent covers the approved drug product itself.

A current Orange Book record and FDA patent-listing history are required to make a definitive listing determination.[2]

When does the patent lose exclusivity?

US Patent 7,723,910 issued on May 25, 2010. Its expiration date depends on the earliest effective nonprovisional filing date in the relevant priority chain, any patent-term adjustment, terminal disclaimer, and any applicable patent-term extension.[3]

The grant date is not the expiration date. A continuation patent can issue years after the effective filing date while retaining a term measured from the earlier application. A patent-term adjustment can extend the ordinary term, while a terminal disclaimer can shorten it.

For business planning, the patent should be treated as a term-sensitive method patent rather than as a current platform monopoly. Any freedom-to-operate conclusion should use the USPTO Patent Center prosecution record and the patent’s current maintenance and term data, not the issue date alone.[4]

Are Paragraph IV challenges relevant?

A Paragraph IV challenge is relevant only if a generic applicant files an ANDA referencing an approved drug and certifies that a listed patent is invalid, unenforceable, or not infringed.[5]

For US Patent 7,723,910, the principal questions are:

Was the patent listed against the relevant Levulan NDA?
Was the patent listed for a claim category that an ANDA applicant had to address?
Did a generic applicant file a Paragraph IV certification?
Was litigation filed within the statutory period?
Did any settlement provide a licensed or otherwise authorized entry date?

The claims are method claims, and many recite clinical uses beyond the FDA-approved actinic keratosis indication. That structure can reduce the patent’s relevance to a conventional ANDA unless the listed patent is tied to the approved use or the generic labeling would induce infringement.

A generic applicant may also use a section viii statement to omit a patented use from its labeling where permitted. That strategy depends on the exact listed claims, the approved labeling, and the proposed generic labeling.

Which companies are challenging the patent?

The supplied information does not identify a Paragraph IV challenger, ANDA filer, district-court action, or settlement involving US Patent 7,723,910. No challenger should be treated as established solely from the patent claims.

The relevant competitive parties in the ALA photodynamic therapy market include:

Sun Pharmaceutical Industries, through its ownership of DUSA Pharmaceuticals and the Levulan/BLU-U platform;
Manufacturers of aminolevulinic acid topical products;
Developers of alternative photodynamic therapy light sources;
Providers of methyl aminolevulinate products, including Ameluz;
Device manufacturers supplying blue-light or LED photodynamic therapy systems; and
Compounding or specialty dermatology suppliers, where legally permitted.

A competitor can challenge commercial exposure without litigating this particular patent, especially where it uses a different photosensitizer, a different wavelength, a different delivery device, or a different approved indication.

How strong is the patent estate?

The patent has moderate technical specificity and mixed enforcement strength.

Strengths

Claim 1 combines drug application with a defined light-delivery geometry.
Claim 24 preserves a non-fluorescent-tube pathway by claiming blue light from a plurality of conforming sources.
Claim 26 identifies a commercially recognizable 417-nanometer protocol and approximately 1,000-second exposure.
Dependent claims reach multiple dermatologic uses and pre-use mixing procedures.
The claims can potentially cover the integrated treatment method even where separate patents cover the drug or device.

Weaknesses

The claims rely on functional and qualitative terms such as “substantially uniform” and “generally conforming.”
Claim 1 requires fluorescent tubes, which may be avoided by LED systems.
Claims 24 and 26 are narrower in other respects and may require proof of blue-spectrum or 417-nanometer performance.
The patent does not independently claim ALA, a formulation, or a light apparatus in the supplied claims.
Several indication claims may be difficult to enforce against a product whose label omits the patented use.
Prior-art exposure may be significant because ALA photodynamic therapy and blue-light treatment were established technical fields before the patent issued.

Validity analysis would likely focus on anticipation and obviousness involving earlier ALA photodynamic therapy methods, blue-light sources, fluorescent-tube arrangements, uniform illumination systems, and known treatment durations.

How does this patent compare with competing ALA patent categories?

Patent category	Typical protected subject matter	Relationship to US 7,723,910
ALA compound patents	ALA or ALA derivatives	Different subject matter
ALA formulation patents	Concentration, vehicle, stability, packaging	Overlap only where the treatment claims require pre-use mixing or a carrier
Method-of-use patents	Treatment of actinic keratosis or other conditions	Potential overlap with claims 4-21
Light-device patents	Geometry, emitters, cooling, controls, optical distribution	Separate rights that may be implicated by the same commercial system
Combination patents	Photosensitizer plus defined illumination	Closest category to US 7,723,910
Manufacturing patents	Synthesis, purification, sterile filling, packaging	Generally outside the supplied claims

The main design-around routes are:

Use an LED array instead of fluorescent tubes;
Use a planar or nonconforming light source;
Use a wavelength outside the 417 ± 5 nm range;
Use a materially different bandwidth;
Use an exposure time outside the approximately 1,000-second limitation;
Avoid a protocol that produces substantially uniform intensity; or
Use a different photosensitizer or a non-ALA product.

Each route requires analysis against all potentially relevant patent families, not only US 7,723,910.

What manufacturing and intellectual-property barriers remain?

The patent does not appear to create a manufacturing monopoly over ALA. Commercial barriers are more likely to arise from the combined product system:

Drug formulation and stability;
ALA packaging and mixing technology;
Light-source uniformity;
Thermal management for fluorescent or LED emitters;
Calibration and quality control;
Device labeling and clinical-use instructions;
FDA clearance or approval for the illumination device;
Combination-product regulatory coordination; and
Clinical evidence supporting the intended indication.

A manufacturer can avoid this patent and still face separate rights covering ALA formulations, device architecture, treatment protocols, or approved labeling.

What is the generic launch risk?

Generic launch risk depends on the product pathway.

Generic ALA drug

A conventional generic ALA product may face:

Orange Book-listed drug patents;
Method-of-use patents;
Labeling restrictions;
Paragraph IV litigation;
Formulation differences; and
The need to establish pharmaceutical equivalence and bioequivalence where applicable.

Competing photodynamic therapy system

A device-plus-drug competitor faces a different risk profile. The relevant questions are whether its system:

Uses ALA topically;
Treats a contoured surface;
Uses multiple conforming sources;
Delivers uniform visible or blue light;
Uses the 417-nanometer profile;
Irradiates for approximately 1,000 seconds; and
Uses a clinical indication recited in the claims.

Methyl aminolevulinate or alternative photosensitizer

A product based on methyl aminolevulinate rather than ALA may avoid the literal ALA limitation, although it could implicate separate method, formulation, or device patents.

What licensing and ownership issues matter?

DUSA Pharmaceuticals developed the Levulan and BLU-U platform and was acquired by Sun Pharmaceutical Industries in 2012.[6] That transaction is commercially relevant because ownership of the product, device, regulatory assets, and related patent rights may have moved with DUSA.

A patent assignment, exclusive license, or regulatory-rights transfer should be confirmed through USPTO assignment records and transaction documents. The existence of a corporate acquisition does not by itself establish that every related patent was assigned, exclusively licensed, or included in a settlement.

No licensing agreement or patent settlement should be attributed to US Patent 7,723,910 without a specific public record.

Key Takeaways

US Patent 7,723,910 is a combination method patent for topical ALA and conforming, substantially uniform visible-light treatment of contoured surfaces.
Claim 1 requires fluorescent tubes, while independent claims 24 and 26 do not expressly require them.
Claim 26 is the most protocol-specific claim, requiring approximately 1,000 seconds of light centered at 417 ± 5 nanometers with a 30-nanometer bandwidth.
The patent covers treatment and diagnosis concepts extending beyond the FDA-approved Levulan indication.
The supplied claims do not independently claim ALA, an ALA formulation, or a light apparatus.
LED systems may avoid the fluorescent-tube limitation but still require analysis under claims 24 and 26.
Orange Book listing, Paragraph IV activity, litigation, and settlement status cannot be inferred from the patent number or claim text alone.
The patent’s current exclusivity depends on its effective filing date, prosecution history, patent-term adjustment, terminal disclaimers, and current USPTO status.
The principal commercial design-around options involve the light source, geometry, wavelength, bandwidth, exposure time, photosensitizer, and treatment labeling.

Frequently Asked Questions

Does US Patent 7,723,910 claim the BLU-U device itself?

No. The supplied claims are method claims. They require a treatment or diagnostic method using ALA and specified light-delivery characteristics. They do not independently claim the physical BLU-U device.

Can an LED-based ALA photodynamic therapy system infringe this patent?

Yes, potentially. Claims 24 and 26 do not expressly require fluorescent tubes. An LED system could still be evaluated under the conforming-source, uniform-intensity, blue-light, wavelength, bandwidth, and exposure-time limitations.

Does the patent cover all ALA treatment of actinic keratosis?

No. The actinic keratosis claim inherits the limitations of claim 1. ALA treatment using a different light arrangement may fall outside the claim even if it treats the same condition.

Is a ready-to-use ALA gel covered by the pre-use mixing claims?

Not necessarily. Claims requiring admixture with a vehicle immediately before use are directed to a preparation step. A ready-to-use product may avoid those specific limitations, subject to the scope of the other claims and related patents.

Is a biosimilar pathway relevant to ALA products?

No. ALA is a small molecule, not a biologic. The relevant abbreviated pathway is generally an ANDA under section 505(j), or another applicable small-molecule pathway, rather than a biosimilar application under section 351(k).

References

U.S. Food and Drug Administration. (n.d.). Levulan Kerastick for topical solution prescribing information.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations, commonly known as the Orange Book.
United States Code. (2024). 35 U.S.C. § 154: Contents and term of patent; provisional rights.
U.S. Patent and Trademark Office. (n.d.). Patent Center.
United States Code. (2024). 21 U.S.C. § 355(j): Abbreviated applications for new drugs.
Sun Pharmaceutical Industries Ltd. (2012). Acquisition of DUSA Pharmaceuticals.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
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Details for Patent: 7,723,910

Summary for Patent: 7,723,910