Selenomethionine se-75 - Generic Drug Details

What are the generic drug sources for selenomethionine se-75 and what is the scope of freedom to operate?

Selenomethionine se-75 is the generic ingredient in two branded drugs marketed by Ge Healthcare, Mallinckrodt, Pharmalucence, and Bracco, and is included in four NDAs. Additional information is available in the individual branded drug profile pages.

Summary for selenomethionine se-75

US Patents:	0
Tradenames:	2
Applicants:	4
NDAs:	4
Raw Ingredient (Bulk) Api Vendors:	12
Clinical Trials:	10
DailyMed Link:	selenomethionine se-75 at DailyMed

Recent Clinical Trials for selenomethionine se-75

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Counties Manukau Health	Phase 1
University of Auckland, New Zealand	Phase 1
Cancer Trials New Zealand	Phase 1

See all selenomethionine se-75 clinical trials

Anatomical Therapeutic Chemical (ATC) Classes for selenomethionine se-75

V03AB	Antidotes
V03A	ALL OTHER THERAPEUTIC PRODUCTS
V03	ALL OTHER THERAPEUTIC PRODUCTS
V	Various

US Patents and Regulatory Information for selenomethionine se-75

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Bracco	SETHOTOPE	selenomethionine se-75	INJECTABLE;INJECTION	017047-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Mallinckrodt	SELENOMETHIONINE SE 75	selenomethionine se-75	INJECTABLE;INJECTION	017098-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Ge Healthcare	SELENOMETHIONINE SE 75	selenomethionine se-75	INJECTABLE;INJECTION	017257-001	Approved Prior to Jan 1, 1982		DISCN	No	No
Pharmalucence	SELENOMETHIONINE SE 75	selenomethionine se-75	INJECTABLE;INJECTION	017322-001	Approved Prior to Jan 1, 1982		DISCN	No	No

Selenomethionine Se-75 Market Dynamics and Financial Trajectory

Last updated: September 5, 2026

Selenomethionine Se-75 is a legacy diagnostic radiopharmaceutical with limited current commercial relevance. Its historical use was pancreatic imaging and, in some markets, specialized metabolic or tumor-localization studies. The product has not developed into a broad modern pharmaceutical franchise because fluorodeoxyglucose F-18, technetium-99m agents, CT, MRI, endoscopic ultrasound, and improved laboratory diagnostics displaced most historical applications.

No current public revenue series, active U.S. Orange Book listing, major branded manufacturer, or meaningful generic-development pipeline is evident for Selenomethionine Se-75. Its present economic profile is best characterized as a low-volume, institutionally supplied radiopharmaceutical rather than a growth product.

What is Selenomethionine Se-75 used for?

Selenomethionine Se-75 is L-selenomethionine labeled with selenium-75. Selenomethionine is incorporated into proteins in a manner related to methionine metabolism. The selenium-75 radionuclide emits gamma radiation that can be detected by nuclear-imaging equipment.

Historically, the product was used for:

• Pancreatic scintigraphy
• Assessment of pancreatic uptake and morphology
• Research on amino-acid metabolism
• Selected tumor-imaging investigations
• Specialized gastrointestinal or metabolic studies

Its clinical role declined as newer imaging methods became more sensitive, faster, easier to deploy, and less dependent on the availability of a long-lived radioactive isotope.

Key technical characteristics

Attribute	Selenomethionine Se-75
Active component	L-selenomethionine labeled with selenium-75
Modality	Nuclear medicine diagnostic imaging
Radiation type	Gamma emission
Physical half-life	Approximately 119.8 days
Primary historical use	Pancreatic imaging
Administration	Typically injectable radiopharmaceutical preparation
Product economics	Low-volume, specialized supply
Current market position	Legacy or niche diagnostic use
Main substitutes	FDG F-18 PET, technetium-99m agents, CT, MRI, endoscopic ultrasound

The long half-life creates a logistical advantage over very short-lived isotopes in some settings because the product can be transported over longer distances. It also creates radiation-management and inventory considerations that reduce its commercial appeal.

What is the FDA regulatory status of Selenomethionine Se-75?

Selenomethionine Se-75 does not have the profile of an actively promoted, broadly distributed FDA-approved specialty drug. Historical U.S. radiopharmaceutical products were supplied through nuclear-medicine channels and may have been discontinued, withdrawn, or limited to investigational and institutional use.

The principal regulatory issues are:

1. Product approval status. A historical approval or marketed presentation does not establish current commercial availability.
2. Drug listing status. An NDC or older labeling record may remain in historical databases after commercial discontinuation.
3. Radiopharmaceutical controls. Production, packaging, transportation, handling, and administration require compliance with FDA requirements and state or federal radioactive-material controls.
4. Institutional use. Hospitals and nuclear pharmacies may obtain radioactive diagnostic products through specialized procurement arrangements rather than conventional retail pharmaceutical channels.

The FDA’s Drugs@FDA database and current commercial labeling records are the relevant sources for determining whether a specific sponsor maintains an active application or marketed presentation. Historical references to Selenomethionine Se-75 should not be treated as evidence of a current commercial product without confirmation from current FDA labeling and manufacturer records. (U.S. Food and Drug Administration, n.d.-a)

What is the Orange Book status of Selenomethionine Se-75?

Selenomethionine Se-75 has no commercially meaningful Orange Book patent-exclusivity position.

The expected status is:

Orange Book issue	Assessment
Active branded reference product	No significant current commercial presence identified
Listed patents	No material active patent estate identified
Paragraph IV activity	No notable current Paragraph IV challenge identified
Pediatric exclusivity	None of commercial significance identified
New chemical entity exclusivity	Expired or not commercially relevant
Generic substitution market	Limited or absent
Patent cliff	Not a current commercial event

Orange Book economics generally apply to active approved drug products with an identifiable reference listed drug and current generic competition. Selenomethionine Se-75 is primarily a legacy radiopharmaceutical issue rather than an active branded-drug patent case. (U.S. Food and Drug Administration, n.d.-b)

How many patents protect Selenomethionine Se-75?

No material active composition-of-matter patent protection is expected for Selenomethionine Se-75.

The underlying molecule, methionine-related chemistry, and selenium-75 isotope are long-established. Any historical protection would more likely have involved:

• Radiolabeling methods
• Formulation stability
• Sterile injectable preparation
• Kit or generator processes
• Manufacturing and purification methods
• Specific imaging protocols
• Packaging or radiation-shielding systems

Those categories generally do not create a durable monopoly comparable to a modern small-molecule drug patent estate. Any historical formulation or process patents would likely have expired by the time the product’s clinical market declined.

Patent-strength assessment

Patent category	Current commercial strength
Active ingredient	Very low
Selenium-75 isotope use	Very low
Injectable formulation	Low
Radiolabeling process	Low to moderate in a narrow jurisdiction, if any live claims exist
Method of pancreatic imaging	Very low
Manufacturing know-how	Potentially relevant but not publicly quantifiable
Trade secrets	Possible for validated radiochemistry processes
Regulatory exclusivity	No meaningful current protection identified

A new supplier would face regulatory validation, radioactive-material licensing, sterile manufacturing, quality assurance, and distribution requirements rather than a significant blocking patent portfolio.

When did Selenomethionine Se-75 lose exclusivity?

Selenomethionine Se-75 lost practical exclusivity decades ago. The key commercial change was not a single modern patent expiration date. It was the progressive replacement of the product’s clinical indications by superior diagnostic technologies.

The market decline followed several developments:

• Expansion of cross-sectional imaging
• Increased availability of CT and MRI
• Improved pancreatic ultrasound and endoscopic ultrasound
• Adoption of technetium-99m and fluorine-18 radiopharmaceuticals
• Greater use of FDG PET for oncology
• Reduced clinical demand for direct pancreatic scintigraphy

The product therefore experienced a technology-substitution decline rather than a conventional post-patent generic surge.

What is the competitive landscape?

Selenomethionine Se-75 competes primarily against diagnostic modalities, not against branded pharmaceutical products.

Direct and indirect alternatives

Alternative	Competitive advantage
CT	Fast anatomical imaging and broad hospital availability
MRI	Strong soft-tissue contrast without ionizing radiation
Endoscopic ultrasound	High-resolution pancreatic and biliary assessment
Technetium-99m agents	Established nuclear-medicine supply infrastructure
FDG F-18 PET	Strong oncology adoption and clinical familiarity
Gallium-68 agents	Targeted PET imaging in selected diseases
Laboratory biomarkers	Lower procedural burden for some diagnostic questions
Biopsy and endoscopic methods	Direct tissue or structural assessment

The product’s competitive weakness is its narrow clinical utility. The long half-life of selenium-75 can support distribution, but it does not compensate for limited demand and the availability of better-established diagnostic pathways.

What manufacturing and IP barriers affect the market?

Manufacturing barriers are more important than patent barriers.

A supplier must manage:

• Production of selenium-75 or access to an isotope source
• Radiochemical incorporation into L-selenomethionine
• Sterile injectable manufacturing
• Radiochemical purity
• Chemical purity
• Stability over the product’s distribution period
• Dose calibration and decay correction
• Radiation shielding
• Transport under radioactive-material regulations
• Nuclear pharmacy and hospital handling requirements
• Batch release and quality-control procedures

The long physical half-life reduces the need for same-day production but increases the duration over which the product remains radioactive. It can also increase disposal, storage, and inventory-management costs.

The commercial barrier is demand aggregation. A manufacturer may be able to produce the product technically, but a small and geographically dispersed customer base can make validation, inventory, regulatory maintenance, and distribution uneconomic.

Are there biosimilar or generic risks?

Traditional biosimilar risk is not relevant because Selenomethionine Se-75 is not a biologic product.

Generic risk is also limited in practical terms. The underlying molecule is old and technically reproducible, but a new entrant would not necessarily find a large substitution market. The relevant risk is competition from another supplier serving the same institutional radiopharmaceutical demand, not a large-scale Abbreviated New Drug Application wave.

A competing product could still encounter:

• Limited clinical demand
• Difficult reference-product issues
• Specialized manufacturing requirements
• Radioactive-material licensing obligations
• Hospital formulary inertia
• Lack of reimbursement incentives
• Competition from non-radioactive imaging

Which companies are challenging or commercializing Selenomethionine Se-75?

No major current branded challenger landscape is evident. Historical supply may have involved radiopharmaceutical manufacturers, nuclear pharmacies, hospital radiopharmacies, or regional distributors. The product is not associated with a current multinational launch program comparable to diagnostic agents such as FDG F-18, fluciclovine F-18, gallium-68 products, or amyloid PET agents.

The market structure is likely to be fragmented:

1. A radioisotope producer or specialized radiochemistry manufacturer supplies the isotope or labeled compound.
2. A radiopharmaceutical distributor or nuclear pharmacy manages regional supply.
3. Hospitals and imaging centers administer the product under institutional protocols.
4. Demand is determined by specialist use rather than consumer or retail prescribing.

Because the product is not a major commercial franchise, public licensing announcements and company-level revenue disclosures are unlikely.

What is the financial trajectory of Selenomethionine Se-75?

The financial trajectory is mature-to-declining, with limited visibility into absolute revenue.

Period	Commercial profile
Early development and clinical adoption	Specialized diagnostic product with use in pancreatic imaging
Expansion period	Institutional nuclear-medicine demand and research utilization
Technology-substitution period	Decline as CT, MRI, ultrasound, and other radiopharmaceuticals expanded
Current period	Niche, legacy, or institution-specific use
Forward outlook	Flat at best in isolated applications, with continued structural decline overall

No reliable public revenue figure should be assigned without a current manufacturer, product code, geographic scope, and sales disclosure. The product is unlikely to generate material revenue for a large pharmaceutical company. Any remaining revenue would more likely be recognized within a nuclear pharmacy or specialty radiopharmaceutical portfolio.

Commercial indicators

The most important commercial indicators are:

• Number of active hospital protocols
• Current manufacturer or compounder availability
• Annual administered doses
• Reimbursement by indication
• Cost of isotope acquisition
• Radiopharmacy distribution radius
• Product wastage and decay losses
• Competing imaging utilization
• Regulatory maintenance cost per batch

A modest price per administered dose would not necessarily produce attractive margins if annual demand is low and quality-control and licensing costs remain fixed.

What generic launch scenarios exist?

A conventional generic launch is unlikely to materially change the market.

Scenario 1: No active commercial market

The product remains absent from routine procurement. Historical references continue to appear in scientific literature and regulatory databases, but no significant sales channel develops.

Scenario 2: Regional specialty supply

A nuclear pharmacy or radiopharmaceutical manufacturer restores supply for a small number of academic or specialist centers. Revenue remains limited and dependent on institutional protocols.

Scenario 3: Research-driven reactivation

A new pancreatic or metabolic imaging application creates renewed interest. This would require clinical evidence, regulatory support, reimbursement, and a sponsor willing to invest in manufacturing infrastructure.

Scenario 4: Continued displacement

More sensitive imaging, molecular diagnostics, or targeted PET products further reduce the already limited demand.

The fourth scenario is the most consistent with the product’s historical trajectory.

How does Selenomethionine Se-75 compare with modern radiopharmaceuticals?

Factor	Selenomethionine Se-75	Modern PET or targeted radiopharmaceutical
Clinical adoption	Limited and historical	Expanding in selected indications
Imaging technology	Conventional gamma imaging	PET or targeted molecular imaging
Half-life logistics	Long, approximately 120 days	Often short, requiring rapid distribution
Manufacturing challenge	Radioactive labeling and sterile production	Isotope access plus complex targeting chemistry
Patent opportunity	Limited	Often meaningful composition, linker, ligand, or use patents
Reimbursement potential	Narrow	Higher in validated oncology and neurology indications
Revenue opportunity	Low	Moderate to high in successful products
Competitive threat	Modalities and institutional substitution	Other targeted agents and platform technologies

Selenomethionine Se-75 has a logistical advantage from its long half-life but lacks the clinical and commercial differentiation needed to compete with modern molecular imaging products.

What litigation and settlement activity affects the product?

No significant current patent litigation or Paragraph IV settlement activity is associated with Selenomethionine Se-75.

The absence of litigation is consistent with:

• No major active patent estate
• No large branded reference product
• No material generic-entry event
• Limited commercial sales
• Lack of a high-value market to defend

Any disputes would more likely concern supply contracts, radiopharmaceutical compounding, regulatory compliance, or institutional procurement than patent infringement.

What is the geographic coverage?

Historical and potential supply is constrained by radioactive-material regulation and local radiopharmacy infrastructure.

The product’s practical geographic market would depend on:

• Authorized isotope transport routes
• National nuclear-medicine regulations
• Import and export controls
• Regional sterile manufacturing capacity
• Hospital demand density
• Decay-adjusted product economics
• Local reimbursement

The long half-life permits broader transport than short-lived PET products, but geographic reach alone does not create demand. In the United States, supply would require compliance with FDA requirements and radioactive-material licensing. In Europe and other regions, national radiopharmaceutical rules, hospital procurement systems, and isotope supply chains would control access. (International Atomic Energy Agency, 2018)

Key Takeaways

• Selenomethionine Se-75 is a legacy diagnostic radiopharmaceutical, historically associated with pancreatic imaging.
• Its market declined because CT, MRI, ultrasound, modern PET agents, and other diagnostic methods replaced much of its clinical utility.
• No material active patent estate, Orange Book position, Paragraph IV challenge, biosimilar issue, or current patent litigation is evident.
• Manufacturing and radioactive-material compliance are more important barriers than intellectual property.
• Public revenue data are not established, and the product is unlikely to represent material revenue for a major pharmaceutical company.
• The forward market is niche and structurally declining unless a new clinical application creates demand.
• The most plausible commercial model is regional or institutional supply through a nuclear pharmacy or specialty radiopharmaceutical manufacturer.

FAQs About Selenomethionine Se-75

Is Selenomethionine Se-75 still used clinically?

Use is limited and specialized. It is no longer a mainstream pancreatic-imaging product in most modern diagnostic pathways.

Is Selenomethionine Se-75 FDA approved?

Historical U.S. regulatory references may exist, but current commercial approval and marketing status must be distinguished from legacy labeling or discontinued product records.

Does Selenomethionine Se-75 have generic competition?

There is no significant conventional generic market. Any competition would likely come from specialty radiopharmaceutical suppliers or alternative imaging modalities.

What is the half-life of Selenomethionine Se-75?

Selenium-75 has a physical half-life of approximately 119.8 days. (National Nuclear Data Center, n.d.)

Could Selenomethionine Se-75 become commercially relevant again?

A revival would require a validated clinical indication, regulatory support, reimbursement, reliable manufacturing, and evidence that the product provides diagnostic value unavailable from CT, MRI, ultrasound, or newer PET agents.

References

International Atomic Energy Agency. (2018). Operational guidance on hospital radiopharmacy: A safe practice guide. IAEA.

National Nuclear Data Center. (n.d.). NuDat 3: Selenium-75 nuclear data. Brookhaven National Laboratory.

U.S. Food and Drug Administration. (n.d.-a). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/

U.S. Food and Drug Administration. (n.d.-b). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/