Drugs in MeSH Category Radiation-Sensitizing Agents

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Fresenius Kabi Usa	CISPLATIN	cisplatin	INJECTABLE;INJECTION	074735-001	Jul 16, 1999	AP	RX	No	Yes
Biogen	TECFIDERA	dimethyl fumarate	CAPSULE, DELAYED RELEASE;ORAL	204063-001	Mar 27, 2013	AB	RX	Yes	No
Lupin	DIMETHYL FUMARATE	dimethyl fumarate	CAPSULE, DELAYED RELEASE;ORAL	210226-002	Oct 5, 2020	AB	RX	No	No
Alembic	METRONIDAZOLE	metronidazole	GEL;TOPICAL	212646-001	Sep 3, 2021	AB	RX	No	No

Last updated: July 26, 2026

Market dynamics and patent landscape for Radiation-Sensitizing Agents (NLM MeSH)

Radiation-sensitizing agents (radiation modifiers) sit at the intersection of oncology radiation therapy and combination drug development. Patent estates cluster around (1) radiosensitizing small molecules and adjuvants, (2) radiosensitizing biologics and immune-radiation combinations, and (3) delivery and formulation patents that extend exclusivity by tightening pharmacokinetic and tumor exposure control. Market dynamics are dominated by combination strategy uptake (standard-of-care radiation regimens), payor pressure for overall survival and toxicity endpoints, and regulatory review pathways that reward clinically validated radiosensitization.

Core commercial pattern: most proprietary revenue is protected not only by the original active-ingredient patent but also by method-of-use (MOA) patents tied to specific radiotherapy regimens, plus formulation and manufacturing-process patents that preserve IP barriers against “composition-of-matter only” generics.

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What are radiation-sensitizing agents in MeSH and how big is the market exposure?

Featured snippet answer: Radiation-sensitizing agents are drugs used with radiotherapy to improve tumor kill by modulating cellular response to radiation, often by targeting hypoxia, DNA repair, cell-cycle checkpoints, or immune activation. Revenue exposure is concentrated in oncology lines where radiotherapy is standard and where combination trials demonstrate clinically meaningful benefit.

How MeSH maps to real-world product classes

MeSH “Radiation-Sensitizing Agents” typically captures drugs that increase radiosensitivity, including:

• Hypoxia-targeting radiosensitizers (oxygen mimetics, hypoxia modifiers)
• DNA repair / replication stress modifiers (checkpoint inhibitors paired with radiation)
• Cell cycle and mitotic regulators used as radiosensitizers
• Broad oncology adjuncts used in defined radiation regimens
• Radiation-immunotherapy combinations (biologics that modulate immune response in the setting of radiation)

Where commercialization concentrates

Radiation-sensitizing agents generate revenue primarily through:

• Definitive chemoradiation (pan-tumor use where radiotherapy plus systemic therapy is standard)
• Locoregional therapy intensification (dose fractionation modifications with targeted drugs)
• Postoperative adjuvant radiation with systemic radiosensitization
• Reirradiation strategies in select disease settings (highest IP leverage due to MOA specificity)

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Which companies dominate radiation-sensitizing agents IP, and what are the main patent holders by modality?

Featured snippet answer: IP leadership is split between large pharma oncology portfolios and specialty biopharma in checkpoint and DNA repair combinations. Patent holders often include the sponsor of the pivotal trials and the entity that owns drug substance and formulation know-how.

Likely patent-holder clusters by mechanism (commercially relevant)

Because MeSH is a broad umbrella category, patent landscapes usually split across:

• Large oncology sponsors (checkpoint inhibition platforms plus radiotherapy combinations)
• DNA repair platform companies (PARP and replication stress modifiers)
• Hypoxia and redox biology specialists (oxygen delivery or hypoxia pathways)
• Drug-device and formulation specialists (localized delivery and pharmacokinetic control)

Jurisdiction patterns

• US: Orange Book practice dominates for small molecules with listed patents; complex combinations often rely on method-of-use patents.
• EP/WO: composition-of-matter plus formulation and process family breadth.
• CN/JP: local validation and manufacturing-process claims influence entry risk.

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What patents protect radiation-sensitizing agents the most: composition-of-matter, formulation, or method-of-use?

Featured snippet answer: Method-of-use (MOA) patents tied to specific radiation regimens frequently provide the most enforceable exclusivity “residual” after composition-of-matter expiration, especially for combination therapy indications.

Typical patent estate structure in radiosensitizers

A representative radiation-sensitizing asset often has:

1. Composition-of-matter (active ingredient and sometimes salts/polymorphs)
2. Formulation (solubility, stability, release profile, or dose-form specific)
3. Method-of-use (treatment of specific cancers with radiation and the drug, sometimes with dose and schedule)
4. Manufacturing/process patents (purity, intermediates, crystallization control)
5. Combination regimens (fractionation, sequencing, or toxicity management)

How MOA claims shape exclusivity value

In radiotherapy combinations, MOA claims are frequently written to:

• require concurrent or sequential administration
• specify fractionation or total dose
• target a patient subpopulation by staging, biomarkers, or prior therapy
• define an endpoint linked to radiosensitization (tumor response, progression metrics, radiation-associated outcomes)

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When do radiation-sensitizing agents lose exclusivity in the US, and how do “patent + exclusivity” timelines interact?

Featured snippet answer: Loss of exclusivity usually occurs in layers: patent expiration of the earliest composition-of-matter, then protection via later-filed formulation and MOA patents, plus regulatory exclusivities like orphan (if applicable) and pediatric extensions (if they apply). For combination assets, MOA patents often extend market protection past composition-of-matter end.

US timeline mechanics that matter for entry planning

• Patent expiry drives statutory injunctive relief risk.
• Regulatory exclusivities can block approval even if patents expire, but for most non-orphan oncology radiosensitizers, the practical barrier is the listed patent set.
• Orange Book patent listing controls which patents are relevant for Paragraph IV analysis.

Practical sequencing for generic entry risk

For a generic or biosimilar competitor:

1. Identify listed patents on the relevant NDA/BLA
2. Map claim type: composition-of-matter vs use vs formulation
3. Assess whether the competitor’s label would infringe MOA claims
4. Determine whether a Section 505(b)(2) or ANDA strategy can avoid the listed claims by changing formulation or regimen

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What Orange Book status exists for leading radiation-sensitizing agents, and how many listed patents typically block generics?

Featured snippet answer: In radiation-sensitizer oncology products, Orange Book listings commonly include multiple patent numbers across composition-of-matter, formulation, and MOA. The practical block is the subset of patents with enforceable claims that the generic must carve out or challenge.

Patent listing density and why it matters

Key business implication:

• High listing counts correlate with higher settlement likelihood or longer “carve-out” negotiations.
• A small set of method-of-use patents can still control the entire entry timetable if claims are broad across radiation regimen and cancer subtype.

How to interpret Orange Book listing strategy

Look for:

• listed patents with early expiries (often composition-of-matter)
• later-expiring MOA patents with regimen specificity
• patents with claims that are difficult to design around without changing the label

(Note: This response does not enumerate specific Orange Book patent numbers because the MeSH umbrella does not map to a single product set. A product-by-product Orange Book audit requires drug-specific inputs.)

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Which Paragraph IV challenges target radiosensitizers, and what settlement patterns appear in radiotherapy combinations?

Featured snippet answer: Paragraph IV challenges in radiosensitizers tend to target method-of-use and formulation patents, aiming to force either design-around or an early settlement that compensates the brand for loss of exclusivity.

Typical litigation objectives

For generic applicants:

• Force dismissal or non-infringement on MOA claims
• Offer an agreed carve-out label that avoids infringement
• Seek a judgment that supports a near-term launch

For originators:

• Secure a delayed launch via injunction risk tied to the strongest listed patents
• Set settlements that define a launch date, labeling, and sometimes supply terms

Settlement terms that commonly control timing

• Launch date agreement
• Label restrictions (no specific regimen, dosing schedule, or cancer subtype)
• Stipulated design-around boundaries
• Reductions in claim scope post-settlement

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How strong is the patent estate for radiosensitizers: what drives enforceability and invalidity risk?

Featured snippet answer: Patent strength depends less on headline claim count and more on the survivability of the key MOA and formulation patents under validity challenges and on how directly the generic’s proposed regimen would infringe.

Enforceability drivers

• clarity of claim construction around dosing schedule and sequencing
• specificity of radiation regimen terms that are difficult to design around
• prosecution history support for broad interpretation (or narrow but enforceable boundaries)

Validity risk drivers

• obviousness over combination-regimen prior art
• written description and enablement gaps in later-filed regimen claims
• obviousness in light of known radiosensitizer/RT pairings and standard-of-care fractionation

Business consequence

A “high count” estate can still be fragile if:

• the strongest claims are easy to distinguish on regimen language
• the key MOA patents have broad claim scope vulnerable to obviousness
• formulation patents depend on narrow process steps that competitors can alter

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What biosimilar risk exists in radiation-sensitizing agents, and how does it differ from small molecules?

Featured snippet answer: Biosimilar risk appears only for radiosensitizing biologics. Unlike small molecules, biosimilars are evaluated under BLA pathways with a different evidentiary burden and typically fewer direct design-around opportunities. Patent barriers often center on biologic substance claims, manufacturing process, and method-of-use.

Distinct risk profile for biologics in radiotherapy combinations

• Reference product exclusivity can extend entry.
• IP estates can include extensive biologic-related claims that are harder to circumvent.
• Method-of-use claims may require label-specific radiation combination language.

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Which formulation and manufacturing patents most often delay generic entry for radiosensitizers?

Featured snippet answer: Formulation patents that improve solubility, stability, or release profile (including controlled dosing) and manufacturing-process patents that secure purity and impurity profiles are the most common technical IP barriers.

Typical formulation patent themes

• salt selection, polymorph control, or amorphous forms
• improved solubility leading to a different excipient system
• stability under storage and handling that supports dosing consistency
• controlled-release or altered pharmacokinetic profiles that align with radiation timing

Manufacturing-process themes

• specific crystallization endpoints and impurity acceptance
• intermediate preparation with controlled reaction parameters
• purification steps that reduce a named impurity above a threshold

Business implication: Generic sponsors can attempt to file the same active form but still face infringement via formulation or process claims.

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How does radiosensitizer mechanism-of-action affect patent strategy and competitor likelihood?

Featured snippet answer: The more “standardized” the mechanism pairing with radiation is, the more likely MOA patents are to focus on regimen parameters. The more “platform-like” the asset is (checkpoint/DNA repair), the more likely the patent estate is broad across multiple tumor types but contested on obviousness.

Mechanism-by-patent pattern

• Hypoxia and redox modifiers: strong emphasis on specific radiosensitization schedules and tumor microenvironment targeting.
• DNA repair/replication stress modifiers: frequent expansion via continuation patents across biomarker-defined subgroups and radiation sequencing.
• Checkpoint inhibitors in radiotherapy: heavy reliance on combination trial evidence for method-of-use claims and on dosing schedule specificity.

Competitor likelihood

Competitors enter fastest when:

• there is a single drug substance patent with no strong later MOA/formulation layer
• the generic can omit the regimen-specific label without losing commercial attractiveness Competitors face delay when:
• multiple later-expiring MOA patents cover common-of-care regimens
• formulation is integral to dosing timing and the brand has tightly written claim scope

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What commercial metrics matter most for radiation-sensitizing agents, and how do patents impact revenue exposure?

Featured snippet answer: Revenue exposure is most sensitive to (1) the time to generic entry for the specific labeled regimen, (2) label breadth, and (3) substitution behavior by radiation-oncology practice.

Revenue exposure drivers

• On-label regimen breadth: broader indications increase infringement coverage and raise entry costs for generics.
• Toxicity profile: practice adoption depends on manageable toxicity in combination with radiotherapy.
• Patient selection and biomarkers: biomarker-defined subpopulations can maintain premium pricing even as part-label competition begins.

Patent impact on forecasts

• If key MOA patents remain enforceable, the forecast shifts from “generic launch” to “label carve-out” scenarios.
• If formulation patents survive, competitors may face delayed launches due to process and product equivalence issues.

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How do radiation-sensitizing agents compare across patent estates: what differs between single-agent radiosensitizers and combination-therapy platforms?

Featured snippet answer: Single-agent radiosensitizers often have clearer composition-of-matter dominance, while combination-therapy platforms typically have deeper MOA and regimen-layered estates across tumor types.

Single-agent radiosensitizer profile

• composition-of-matter and formulation are central
• MOA claims focus on cancer types and timing with RT
• competitor entry risk is often tied to whether they can align with label restrictions

Combination platform profile (checkpoint/DNA repair)

• layered continuation families across multiple indications
• regimen sequencing patents that attempt to lock clinical protocols
• broader commercial entrenchment because the therapy is used in standard-of-care bundles

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Key Takeaways

• Radiation-sensitizing agents protect value through layered estates: composition-of-matter plus regimen-specific method-of-use and formulation/process patents.
• For entry risk, Orange Book relevance is driven by which patents are listed and whether competitors can avoid MOA and formulation claims without losing the commercially needed label.
• Market uptake depends on combination RT compatibility and endpoint durability; these same factors drive how strong MOA claims are written and defended.
• Generic or biosimilar entry is less about beating a single patent and more about surviving the enforceability of the small subset of MOA/formulation patents that match standard radiotherapy protocols.

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FAQs

1) What patent claim types are most likely to be listed in Orange Book for radiation-sensitizing oncology drugs?
Method-of-use (combination regimen) and formulation patents are commonly listed alongside composition-of-matter.

2) How do regimen and sequencing details affect infringement risk for generic radiosensitizers?
If claims require concurrent or sequential administration with specific fractionation or dose parameters, generic labeling or clinical use may become a determinative infringement question.

3) Do settlement agreements for radiosensitizers typically restrict label wording?
Yes. Settlements frequently define carve-out language tied to cancer types, dosing schedules, or radiation regimens.

4) What technical barriers slow generic development for radiosensitizers beyond the active ingredient?
Formulation equivalence and manufacturing process controls that map to purity, impurity profiles, and controlled release characteristics.

5) Do biologic radiosensitizers face different exclusivity and IP entry pathways than small molecules?
Yes. The biosimilar route and biologic IP estates create a different enforcement and design-around landscape, often increasing time-to-entry.

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References

1. National Library of Medicine (NLM). Medical Subject Headings (MeSH): Radiation-Sensitizing Agents.
2. FDA. Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations.
3. FDA. Drug Approval Pathways: ANDA, 505(b)(2), and BLA/Biosimilar pathways.
4. USPTO and FDA guidance materials on patent listing and Hatch-Waxman framework (Orange Book and Paragraph IV processes).