METHOXSALEN Drug Patent Profile

Which patents cover Methoxsalen, and what generic alternatives are available?

Methoxsalen is a drug marketed by Actavis Inc, Ani Pharms, and Onesource Specialty. and is included in three NDAs.

The generic ingredient in METHOXSALEN is methoxsalen. There are seven drug master file entries for this compound. One supplier is listed for this compound. Additional details are available on the methoxsalen profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Methoxsalen

A generic version of METHOXSALEN was approved as methoxsalen by ONESOURCE SPECIALTY on June 5^th, 2014.

Summary for METHOXSALEN

US Patents:	0
Applicants:	3
NDAs:	3

US Patents and Regulatory Information for METHOXSALEN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Actavis Inc	METHOXSALEN	methoxsalen	CAPSULE;ORAL	202603-001	Jun 9, 2015		DISCN	No	No
Ani Pharms	METHOXSALEN	methoxsalen	CAPSULE;ORAL	087781-001	Jun 8, 1982		DISCN	No	No
Onesource Specialty	METHOXSALEN	methoxsalen	CAPSULE;ORAL	202687-001	Jun 5, 2014	AB	RX	No	No

Last updated: July 26, 2026

Methoxsalen (8-MOP) investment scenario and patent/equity fundamentals analysis: exclusivity, generic risk, and monetization levers

Methoxsalen (8-methoxypsoralen; “8-MOP”) is a small-molecule psoralen used with UV-A (photochemotherapy, often via PUVA protocols) for dermatologic indications including cutaneous T-cell lymphoma (CTCL). In investment terms, the drug looks like a “commodity-adjacent legacy” asset: modest total-addressable demand, low differentiation versus competing photochemotherapy workflows, and a risk profile dominated by (1) aging patent estate coverage for specific formulations and dosing regimens, (2) FDA/Orange Book-driven generic substitution, and (3) manufacturing continuity and regulatory quality. The upside case typically hinges on capture of niche workflows (specialty compounding scarcity, device-protocol bundling, or protected formulation upgrades). The downside case is a fast path to generic substitution plus weak ability to sustain premium pricing.

This analysis maps the investment drivers that matter most for a legacy topical/oral psoralen therapy: market structure, regulatory status, patent estate durability (where protectable subject matter exists), and generic/biosimilar substitution risk.

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What is methoxsalen and how does it generate revenue in photochemotherapy?

Mechanism and usage model

Methoxsalen is a psoralen that intercalates into DNA and, upon UV-A exposure, forms covalent crosslinks. Revenue depends on how providers structure PUVA/photochemotherapy and whether methoxsalen is a separately reimbursed drug input versus bundled care.

Common commercial and operational realities for methoxsalen products:

• Provider workflow: drug administration plus UV-A exposure scheduling.
• Supply sensitivity: UV phototherapy programs require consistent availability of drug and compatible protocols.
• Demand concentration: use is concentrated in specialized dermatology and oncology centers.

Therapeutic scope that drives market size

High-intent spend for methoxsalen is tied to dermatology/oncology photochemotherapy protocols, especially:

• CTCL (including mycosis fungoides and related PUVA-responsive disease patterns)
• Psoriasis and other phototherapy-responsive dermatoses in jurisdictions where PUVA is used

Investment implication: methoxsalen revenue is correlated with the number of active phototherapy centers and patient throughput, not with broad chronic utilization like large-market drugs.

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What is the Orange Book status of methoxsalen products and what does that imply for exclusivity?

How to interpret Orange Book listings for a legacy drug

For a legacy compound like methoxsalen, the key question for exclusivity is not “is the molecule patented,” but whether current FDA-approved product(s) still list unexpired patents for:

• drug substance
• drug product/formulation (composition of matter or formulation patents)
• method-of-use (approved indications or dosing regimens)
• manufacturing process

Orange Book status drives the Paragraph IV framework and generic launch feasibility. If the Orange Book for an approved methoxsalen NDA shows no unexpired patents, generic substitution risk rises sharply.

Featured snippet answer

Orange Book exclusivity in methoxsalen is typically limited and asset value concentrates in product-specific formulation or process protections rather than broad molecule exclusivity.

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When does methoxsalen lose exclusivity and what patent expirations govern generic timing?

Exclusivity vs patent expiration

Two separate clocks typically govern generic entry:

1. Patent expiration of Orange Book-listed patents tied to the approved product
2. Any regulatory exclusivity (e.g., exclusivity periods attached to approval history)

For legacy drug substances, patent expiration usually becomes the dominant driver.

Practical investor view

• If Orange Book lists only early-expiring formulation or process patents, generic timing can compress into a narrow window.
• If method-of-use patents remain, entry can be delayed by label strategy and “carve-out” or litigation risk.

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Which patents protect methoxsalen formulations, dosage forms, and PUVA regimens?

Typical protectable subject matter for methoxsalen

Even when the active ingredient is old, enforceable IP often clusters in:

• Film-coated or tablet formulation improvements (stability, bioavailability control, photodegradation protection)
• Manufacturing process controls (purity, impurities, particle size, granulation or encapsulation steps)
• Method-of-use claims tied to specific PUVA schedules or administration timing
• Proprietary packaging that reduces light exposure during handling and storage

Investment conclusion

Methoxsalen’s defendable value, when present, is usually product-formulation and patient-protocol-adjacent rather than “new chemical entity” type exclusivity.

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How many patents cover methoxsalen and how strong is the patent estate?

Patent estate strength criteria

For an investment-grade view, patent strength is evaluated by:

• Number of enforceable patents per product (NDA-level coverage)
• Remaining term on each listed patent
• Claim scope breadth (formulation/process limitations often narrow)
• Foreground patent quality for litigation (validity susceptibility and claim clarity)
• Jurisdictional coverage (US only vs global enforcement)

Investor scoring framework (asset-grade)

• High-strength estate: multiple Orange Book-listed patents with long remaining term and broad claim scope
• Medium-strength: fewer patents but at least one formulation/process patent with clear infringement position
• Low-strength: no remaining listed patents or only narrow method-of-use claims that can be designed around

For methoxsalen, the default investment posture is low-to-medium estate strength unless a specific current product shows remaining Orange Book coverage.

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What patent litigation affects methoxsalen and how does it change generic entry risk?

Paragraph IV and generic challenge mechanics

Generic entry risk depends on whether ANDA filers can file with Paragraph IV certifications or whether litigation risk is triggered by unexpired Orange Book patents.

Investor relevance:

• Pending litigation can delay FDA approvals.
• Settlements can create authorized generic windows or “delayed launch” arrangements.
• Consent decrees can shift risk to design-around or label carve-outs.

Competitive risk read-through

If methoxsalen has had multiple generic approvals historically without major litigation, the litigation leverage of any remaining patents is usually lower. If a product has a history of patent challenges, it can signal ongoing enforceability and higher generic entry friction.

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What generic entry risks exist for methoxsalen tablets or oral solutions?

Generic entry vectors

For methoxsalen, the highest-risk vectors are:

• ANDA approvals for tablets/capsules/solutions with equivalence to the reference product
• Design around of formulation-specific patents via manufacturing process and excipient selection
• Label carve-outs that avoid method-of-use infringement while keeping a commercially meaningful label

Barriers that slow generic entry

• Infringement vulnerability: if formulation patents cover a narrow but essential composition feature
• Data exclusivity or use-based regulatory restrictions
• Light-sensitive handling requirements that complicate generic product development or stability proof

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How do methoxsalen products compare with competing photochemotherapy approaches?

Therapy substitution pressure

Methoxsalen sits in a broader care ecosystem that includes:

• Alternative phototherapy modalities (e.g., NB-UVB, excimer, other regimens)
• Systemic therapies in CTCL and psoriasis lines of care
• Biologics and targeted agents that can reduce phototherapy volume in some populations

Investor implication:

• Even without generic competition, pricing power can be constrained by therapy substitution.
• Generic entry tends to accelerate price convergence, and payer pressure increases once multiple options exist.

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What FDA regulatory milestones and labeling issues matter for methoxsalen?

Label, dosing, and administration

From a market access standpoint, important label elements include:

• Approved indication scope
• Administration guidance (oral timing relative to UV-A exposure)
• Monitoring and contraindication language tied to phototoxicity risk

Regulatory risk to watch

• Label changes due to safety communications
• Updates to REMS-like handling guidance (if any) or stability packaging requirements
• Postmarketing compliance actions affecting manufacturing continuity

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What commercial drivers determine methoxsalen revenue stability?

Key revenue drivers

• Phototherapy center count and patient throughput
• Average drug dose delivered per course and per patient
• Reimbursement trends for dermatology oncology drug inputs
• Competitive intensity and the speed of generic switching

Key downside drivers

• Generic substitution and authorized generic price compression
• Reduced PUVA volume due to shifts toward competing therapies
• Manufacturing disruptions (light-sensitive and stability-critical products can be fragile operationally)

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Investment scenario map: base case vs bull case vs bear case

Base case (most likely for legacy small molecules)

• Continued generic presence and moderate price erosion
• Revenue holds mostly through volume stability in specialized centers
• Any remaining IP is narrow and does not materially extend pricing power

Bull case

• A specific formulation or method-of-use improvement keeps meaningful remaining IP on a currently marketed product
• Higher utilization via center protocols that favor the protected product
• Reimbursement stability prevents deeper discounting

Bear case

• Loss of any remaining Orange Book patent or settlement-driven delayed launch ends
• Generic entry accelerates and drives rapid margin compression
• PUVA volume continues to decline due to therapy substitution

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Key IP and exclusivity checklist for methoxsalen investors (what to validate in diligence)

1. Orange Book listings for the specific reference methoxsalen NDA/product
   • Drug substance patent presence
   • Drug product/formulation patent presence
   • Method-of-use patent presence
   • Patent expiration dates and any listed “remaining term”
2. ANDA landscape
   • Pending Paragraph IV certifications
   • Generic launch readiness and number of challengers
3. Litigation history
   • Court docket activity tied to Orange Book patents
   • Settlement terms affecting launch timing
4. Manufacturing continuity
   • Stability and light-protection specifications
   • Any recent FDA compliance issues by manufacturer/CMO

This checklist is the practical basis for underwriting whether methoxsalen behaves like a stable niche asset or a price-collapsed legacy product.

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Key Takeaways

• Methoxsalen’s investment profile is dominated by legacy-drug dynamics: narrow differentiation, market concentration in photochemotherapy workflows, and high generic substitution sensitivity.
• Value persistence depends less on the molecule and more on product-specific Orange Book patent listings (formulation/process/method-of-use) and any active patent litigation or settlement constraints.
• The most decision-relevant diligence items are the Orange Book patent expirations for the currently marketed methoxsalen reference product, ANDA/Paragraph IV activity, and manufacturing stability constraints tied to light/UV-sensitive handling.
• Commercial upside requires either protected product economics (remaining unexpired IP) or protocol-driven volume stickiness; downside is driven by patent loss, rapid generic switching, and PUVA utilization substitution.

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FAQs

1. Is methoxsalen still used widely for CTCL, or has PUVA volume declined structurally?
2. How does Orange Book “method-of-use” patent presence affect generic labeling for methoxsalen?
3. What formulation or process features usually remain protectable for legacy psoralens like methoxsalen?
4. Do settlements in Paragraph IV challenges typically result in delayed generic launches or authorized generics for methoxsalen-type products?
5. What manufacturing or stability risks are most relevant for methoxsalen supply continuity?

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References (APA)

1. FDA. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. U.S. Food and Drug Administration.
2. U.S. Patent and Trademark Office. Patent assignment and publication records for methoxsalen-related inventions.