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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pliva	PENTOXIFYLLINE	pentoxifylline	TABLET, EXTENDED RELEASE;ORAL	074874-001	May 25, 1999		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Validus Pharms	TRENTAL	pentoxifylline	TABLET, EXTENDED RELEASE;ORAL	018631-001	Aug 30, 1984		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Heritage	PENTOXIFYLLINE	pentoxifylline	TABLET, EXTENDED RELEASE;ORAL	074877-001	Jul 8, 1997		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Exclusivity Expiration

Last updated: July 13, 2026

Market dynamics and patent landscape for radiation-protective agents (NLM MeSH Class: Radiation-Protective Agents)

Radiation-protective agents sit at the intersection of radiotherapy-supportive care and occupational/radiation-emergency countermeasures. Patent value clusters around (1) specific active ingredients and dosing regimens, (2) protected formulations and routes (notably oral small molecules vs. parenteral/alternative delivery), and (3) method-of-use in defined indications such as acute radiation syndrome (ARS), radiation-induced mucositis/dermatitis, and bone marrow protection. The economic profile is typically “small but durable”: low routine-market volumes compared with oncology drugs, but concentrated demand from hospital formularies, government stockpiles, and niche payer coverage.

This dynamic drives two consistent IP patterns: (a) follow-on patents that extend coverage by tying claims to an optimized regimen or formulation rather than the core chemical entity, and (b) litigation and regulatory leverage in the form of exclusivity and label-specific exclusivity around FDA-approved indications.

What patents protect radiation-protective agents in the MeSH class?

Featured snippet answer: Patent protection for radiation-protective agents usually spans active ingredient compositions, pharmaceutical formulations, and method-of-use claims tied to radiation-related injuries (ARS, mucositis, dermatitis, marrow suppression). The strongest estates are those that combine entity-level coverage with regimen- and formulation-level follow-ons.

How the patent estate breaks down across typical radiation-protective categories

Radiation-protective agents in MeSH are a heterogeneous class. Patent landscapes commonly group by mechanism:

Thiol-based radioprotectors and antioxidants
- Entity-level IP on small molecules (often historic generics in some jurisdictions, limiting new filings).
- Follow-on protection on dosing schedules, prodrugs, and delivery systems.
Cytokine pathway and hematopoietic modulators
- Method-of-use claims often dominate: claims for bone marrow recovery, neutrophil recovery, or ARS subsets.
- Formulation and manufacturing method patents can matter if a specific product is the reference.
Receptor/chemopreventive and signaling modulators
- IP often clusters around cancer-adjunct regimens, radiation fraction timing, and combination protocols.
Medical countermeasures for ARS
- Patents tied to defined ARS phases and supportive-care protocols.
- US-facing value is shaped by FDA approval pathway choice, indication scope, and product labeling.

Common claim types that hold up in litigation

Radiation-protective drug patents frequently assert:

Composition of matter (drug substance, salts, solvates)
Pharmaceutical compositions (excipients, stabilized blends, dosage forms)
Method-of-use (administration timing relative to radiation; dose range; patient selection)
Manufacturing processes (sterility, encapsulation, lyophilization)
Combination claims (with radiation plans, chemotherapy, or supportive care)

When does radiation-protective agent exclusivity end in the US (Orange Book and exclusivity timelines)?

Featured snippet answer: Exclusivity timelines are driven by the “first approval” date and the number of regulatory touchpoints, while patent expiration is typically staggered by patent family priority and follow-on filings. For niche radiation-protective products, the practical end of exclusivity often arrives when the last non-expired patent covering an asserted claim scope aligns with discontinuation of exclusivity or the end of use-relevant label exclusivity.

US structural drivers

Hatch-Waxman patent term and extensions: If a qualifying extension exists, entity-level patents can be extended, but method-of-use coverage typically requires separate expiration modeling.
Orphan drug exclusivity (if applicable): For ARS-focused or rare-indication agents, orphan status can add several years of marketing exclusivity, independent of patent expiration.
Three-year new clinical investigation exclusivity and five-year exclusivity: These can delay generic competition even when patents are weak or already near expiration.

Practical “market lock” logic

In radiation-protective agents, market lock is often label- and hospital-protocol dependent. Even when patents expire, uptake may lag due to:

formulary inertia
protocol standardization
supply chain and stability requirements
reimbursement coding aligned to labeled indications and product identity

How many patents cover top-selling radiation-protective agents, and where do they cluster?

Featured snippet answer: Patent counts tend to cluster around formulation and method-of-use families rather than a single, long entity-level patent. The number of enforceable claims depends on whether the product has multiple clinical studies and regulatory updates that triggered follow-on patenting.

Patent clustering pattern used in freedom-to-operate

For radiation-protective agents, risk models usually treat families as three layers:

Layer 1: Composition of matter and dosage form
Layer 2: Method-of-use (timing and dose regimen)
Layer 3: Manufacturing and stability

For generics and biosimilar-like entrants (where relevant), Layer 2 method-of-use claims are often the last meaningful barrier because labeling changes are slower than generic launch timelines.

Which companies are challenging patents for radiation-protective agents (Paragraph IV and litigation risks)?

Featured snippet answer: Patent challenges in this class are less frequent than in mainstream oncology, but when they occur they are concentrated around product-specific method-of-use and formulation claims. Entry risk is shaped more by litigation posture than by the existence of a large number of generic candidates.

What to look for in dockets

When screening challenges for radiation-protective agents, focus on:

asserted patents relating to “timing relative to radiation” (method-of-use)
asserted patents relating to “dosage form” and “stability/sterility” (formulation/manufacturing)
settlements that include “design-around” label limitations or switching dates

What generic entry risks exist for radiation-protective agents after patent expiration?

Featured snippet answer: Generic entry risk after expiration is lower when method-of-use claims remain active and when the label includes specific ARS subsets or radiation-injury protocols that a generic cannot legally replicate without infringement.

Key risk vectors

Label-anchored method-of-use
- A generic may be a “pharmaceutical equivalent” but still infringe via method-of-use if the generic is marketed for the infringing indication or protocol.
Orange Book listing scope
- If the Orange Book lists method-of-use patents for the reference product, generic applicants face tighter constraints.
Design-around that affects commercial viability
- Even if infringement can be avoided by changing regimen language, hospitals may require the labeled regimen for procurement and outcomes monitoring.

What formulations are protected for radiation-protective agents (delivery systems, stability, and manufacturing)?

Featured snippet answer: Formulation protection most often targets dosage form identity, excipient selection, stability under storage/infusion conditions, and manufacturing steps that ensure consistent radioprotective pharmacokinetics.

Typical protected formulation areas

Oral tablets/capsules with defined particle size, disintegration profile, and excipient ratios
Injectable solutions and sterile manufacturing
Lyophilized products with defined reconstitution parameters
Encapsulation systems that protect active ingredients from degradation

Why formulation patents matter commercially

Hospitals and government stockpiles care about:

shelf-life and storage conditions
transport stability for emergency use
reconstitution time and usability in austere settings

These constraints turn formulation IP into operational barriers, not just legal risk.

What method-of-use patents matter most for radiation-protective agents (timing relative to radiation, ARS phases)?

Featured snippet answer: Method-of-use patents are central. The strongest claims typically tie administration timing and dose ranges to specific radiation outcomes such as hematopoietic suppression, mucosal injury, or cutaneous injury.

Common claim hooks

“Administer before radiation” vs. “after radiation” protocols
Specific dose schedules across fractions or time windows
Patient stratification defined by radiation exposure severity
Defined endpoints in clinical protocols (e.g., neutrophil recovery timelines)

How does the patent landscape for radiation-protective agents compare with oncology supportive care drugs?

Featured snippet answer: Radiation-protective agents show a similar supportive-care pattern to oncology supportive drugs: method-of-use and formulation follow-ons are common, and hospital protocol adoption can preserve market share even when entity patents weaken. The key difference is that radiation countermeasures can add government procurement and stockpile dynamics, making exclusivity and label scope more commercially decisive.

Comparative drivers

Oncology supportive care (e.g., antiemetics, growth factors): larger market volumes and more entrants
Radiation-protective agents: smaller commercial base, but higher “protocol lock-in” from emergency preparedness and radiation therapy regimens
Regulatory behavior: label scope is often narrower; exclusivity and litigation become more “all-or-nothing” for a given product

What is the FDA regulatory status of radiation-protective agents (approval pathway, label scope, exclusivity hooks)?

Featured snippet answer: FDA regulatory posture in this class is typically characterized by narrow indications and specific administration protocols, which intensify the impact of regulatory exclusivity and label interpretation in enforcement.

Regulatory mechanics that shape IP value

Narrow indication labeling can make method-of-use patents more enforceable via marketing and physician prescribing patterns.
Orphan designation and rare disease incentives, when applicable, add layers of non-patent exclusivity.
Emergency countermeasure relevance can create additional programmatic purchasing even in the absence of broad civilian market penetration.

What patent litigation affects radiation-protective agents most (settlement terms, last-launch dates, design-arounds)?

Featured snippet answer: Where litigation occurs, settlement terms commonly set a launch delay keyed to the expiration of specific method-of-use or formulation patents and may require label carve-outs.

Settlement term patterns

“Entry on/after” a specific date tied to the last-to-expire asserted patent
License scope limiting distribution outside a defined indication
Restrictions on promotional language to avoid inducement around method-of-use claims

Revenue exposure: how much is at stake when radiation-protective agent patents expire?

Featured snippet answer: Revenue exposure is concentrated in products that are embedded in radiation therapy pathways or government ARS preparedness programs. Exposure is usually less about broad consumer substitution and more about hospital procurement continuity and label-driven prescribing norms.

Commercial risk map

High exposure: products with dominant label scope in a radiation-injury endpoint and limited alternatives
Moderate exposure: products with close therapeutic substitutes but fewer protocol-standard references
Lower exposure: products with multiple labeled alternatives or broad overlap where substitution is fast once legal barriers fall

Strength of patent estates: how durable is protection for radiation-protective agents?

Featured snippet answer: Estate durability depends on whether method-of-use and formulation patents remain in force after core composition patents expire. In this class, durability is often sustained by follow-on families that track regimen specificity and dosage form performance.

Estate strength scoring framework used for FTO and licensing

Number of active method-of-use families covering labeled indications
Remaining term in formulation/manufacturing patents
Breadth of claims relative to the approved label
History of settlements or outcomes in comparable cases

Key competitor and licensing dynamics in radiation-protective agents

Featured snippet answer: Licensing and collaboration are more likely when patent scope is concentrated in method-of-use or formulation claims that are difficult to design around while maintaining the approved label and dosing schedule.

What licensing typically covers

Rights to specific formulations or manufacturing process improvements
Rights to commercialize within a defined indication or patient population
Cross-licenses that resolve Paragraph IV disputes

What tends to be negotiated

timing of generic entry or “authorized launch” dates
label carve-outs to avoid method-of-use claim infringement
supply agreements aligned with stability and storage constraints

Geographic coverage: where is patent coverage strongest for radiation-protective agents?

Featured snippet answer: The highest economic leverage is typically in the US, followed by major markets where regulatory exclusivity and hospital procurement systems reinforce label scope. Patent filing strategy often mirrors where reimbursement and procurement mechanisms favor labeled regimens.

Typical geography patterns

US: high enforcement impact due to Orange Book listings and Hatch-Waxman dynamics
EU: strong role for national patent offices and validation in enforcement jurisdictions
UK and select high-liability markets: enforcement and injunction effectiveness
Japan and Canada: important for timeline modeling and where hospitals adopt radiation protocol equivalents

How do biosimilar risks apply to radiation-protective agents?

Featured snippet answer: Biosimilar risk applies only if the protected radiation-protective product is biologic. For non-biologic small molecules, biosimilar frameworks do not apply, but method-of-use and formulation patents remain relevant.

If biologics are involved

Remaining biologic exclusivity periods and patent family coverage determine biosimilar entry risk
Indication-specific data and label scope can slow substitution

Regulatory and litigation interplay: what happens when exclusivity expires but patents remain?

Featured snippet answer: When exclusivity ends but key patents remain, generics can still be constrained by Orange Book-listed patent enforcement. In practice, the market waits for patent expiry dates tied to method-of-use or formulation claims.

Market behavior

Hospitals may continue purchasing reference products if the alternative cannot market for the same labeled indications
Suppliers may delay supply switching while litigation or licensing terms resolve

Key Takeaways

Patent value in radiation-protective agents is concentrated in method-of-use (timing and regimen) and formulation/manufacturing, not just composition of matter.
Exclusivity timelines in the US can delay generic entry even when core composition coverage weakens, especially when label scope is narrow and enforceable.
Generic launch risk after patent expiration is often limited by Orange Book-listed method-of-use patents and label-driven prescribing constraints.
Estate durability typically comes from follow-on patent families that track dose schedules, radiation-injury endpoints, and dosage form stability requirements.
Litigation and settlements, when they occur, tend to set entry dates tied to the last-to-expire asserted patents and may require label or promotional carve-outs.

FAQs

1) What is the Orange Book status of radiation-protective agent patents?

Orange Book status is decisive because it controls whether generics must address listed patents for method-of-use and formulation claims tied to the approved label.

2) Which patent types most often block generic substitutes for radiation-protective agents?

Method-of-use patents tied to administration timing and dosing schedules, plus formulation and manufacturing claims linked to dosage form identity and performance.

3) How long do radiation-protective agent exclusivity and patent terms typically overlap?

Overlaps are common when follow-on patents extend beyond initial entity protection and when regulatory exclusivity is triggered by post-approval investigations or special designations.

4) Do radiation-protective agents face Paragraph IV challenges often?

They face fewer challenges than high-volume drug classes, but when challenges occur they focus on the product-specific method-of-use and formulation claims that map to label usage.

5) How do hospital formularies affect post-expiration substitution for radiation-protective agents?

Hospital procurement and protocol adherence can delay substitution until the legal ability to market for the same labeled regimen is clear, even after some patents expire.

References (APA)

U.S. Food and Drug Administration. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations. FDA.
U.S. Food and Drug Administration. Drug Approval and Databases: Drug Trials Snapshots, Drug Label Information, and Related Regulatory Documents. FDA.
National Library of Medicine. MeSH (Medical Subject Headings): Radiation-Protective Agents. NLM.