Generic IOBENGUANE SULFATE I-131 INN entry, drug patent expiration information and freedom to operate

Sponsor	Phase
New Approaches to Neuroblastoma Therapy Consortium	Phase 1
United Therapeutics	Phase 1
National Cancer Institute (NCI)	Phase 3

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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
Pharmalucence	IOBENGUANE SULFATE I 131	iobenguane sulfate i-131	INJECTABLE;INJECTION	020084-001	Mar 25, 1994		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

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Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Pharmalucence	IOBENGUANE SULFATE I 131	iobenguane sulfate i-131	INJECTABLE;INJECTION	020084-001	Mar 25, 1994	4,584,187	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>Patent No.	>Patent Expiration

Last updated: September 1, 2026

Iobenguane sulfate I-131, marketed as AZEDRA, is a specialized radiopharmaceutical approved for adults and adolescents aged 12 years and older with unresectable, locally advanced or metastatic pheochromocytoma or paraganglioma requiring systemic anticancer therapy. The product has a narrow addressable market, complex radioactive manufacturing requirements, and limited direct competition. Its commercial value is constrained by low patient volume and treatment-center capacity rather than by conventional generic erosion.

AZEDRA was developed by Progenics Pharmaceuticals and became part of Lantheus Holdings after Lantheus acquired Progenics in 2021. The product contributes relatively little to Lantheus' overall revenue, which is dominated by Pylarify and DEFINITY. Its strategic value is its position in targeted radiopharmaceutical oncology and its potential role in expanding Lantheus' therapeutic portfolio.

What is iobenguane sulfate I-131 and what is AZEDRA approved to treat?

AZEDRA is a radioactive iodine-131-labeled form of iobenguane. Iobenguane targets norepinephrine transporters expressed on many pheochromocytoma and paraganglioma cells. The I-131 payload delivers beta radiation to tumor tissue.

The FDA approved AZEDRA on July 30, 2018, under the accelerated approval pathway for:

Adults and pediatric patients aged 12 years and older
Iodine-131-labeled iobenguane scan-positive
Unresectable, locally advanced or metastatic pheochromocytoma or paraganglioma
Disease requiring systemic anticancer therapy

The approval was based on the proportion of patients achieving at least a 50% reduction in all antihypertensive medications lasting at least six months, together with tumor response data. The FDA required postmarketing studies to verify clinical benefit, consistent with the accelerated approval framework (FDA, 2018).

AZEDRA is administered as a therapeutic radiopharmaceutical, generally using a dosimetric approach followed by one or more therapeutic administrations. Patients require radiation-safety management, blood-count monitoring, renal assessment, and specialized nuclear-medicine infrastructure.

How large is the iobenguane I-131 market?

The commercial market is small in absolute patient volume but has high treatment value per patient. Pheochromocytoma and paraganglioma are rare neuroendocrine tumors. Only a subset of patients has unresectable or metastatic disease, and only a subset of those patients is sufficiently iodine-avid and clinically appropriate for AZEDRA.

The effective market is narrowed by four factors:

Disease rarity.
Requirement for positive diagnostic iobenguane imaging.
Limited number of qualified radiopharmaceutical treatment centers.
Competition from surgery, systemic therapies, external-beam radiation, chemotherapy, somatostatin-receptor-directed radioligand therapy, and other off-label options.

AZEDRA therefore operates in a specialist market rather than a mass oncology category. Its commercial model depends on referral concentration, center activation, reimbursement execution, and radioactive supply logistics.

AZEDRA market structure

Market factor	Commercial effect
Target disease	Rare pheochromocytoma and paraganglioma
Patient selection	Requires iodine-131 iobenguane-positive disease
Treatment setting	Specialized nuclear-medicine and radiation-oncology centers
Product type	Therapeutic radiopharmaceutical
Competitive intensity	Limited direct competition, meaningful indirect competition
Reimbursement	Case-specific and dependent on payer authorization
Generic substitution	Low near-term risk
Manufacturing complexity	High
Geographic reach	Primarily United States, subject to licensed radioactive-drug distribution

No publicly reported market-size estimate supports a mass-market opportunity. The relevant commercial metric is treated patients and revenue per treated patient, not prescription volume.

What is the financial trajectory of AZEDRA?

AZEDRA has remained a minor product within Lantheus' portfolio. Lantheus does not consistently provide a standalone, detailed AZEDRA income statement in its public filings. Reported product disclosures indicate that AZEDRA revenue is immaterial compared with Pylarify and DEFINITY.

Lantheus' overall revenue trajectory has been driven by the rapid adoption of Pylarify, its prostate-specific membrane antigen PET imaging agent, rather than AZEDRA.

Lantheus consolidated revenue context

Fiscal year	Lantheus consolidated revenue	Principal growth driver
2021	Approximately $376 million	Legacy imaging portfolio and initial Pylarify launch
2022	Approximately $1.25 billion	Pylarify expansion
2023	Approximately $1.42 billion	Pylarify volume and commercial expansion
2024	Approximately $1.62 billion	Continued Pylarify growth and broader imaging portfolio

Sources: Lantheus Holdings annual reports and Form 10-K filings for fiscal years 2021 through 2024.

AZEDRA revenue is generally reported within smaller product categories or as part of the broader commercial portfolio. Public filings do not establish a separate revenue series sufficient to calculate a reliable annual growth rate, product margin, or contribution to consolidated earnings.

What drives AZEDRA revenue?

AZEDRA revenue depends on:

Number of eligible patients diagnosed at specialist centers.
Physician familiarity with iodine-131 iobenguane therapy.
Number of activated treatment sites.
Payer coverage and prior authorization.
Ability to coordinate radioactive production and delivery.
Patient survival and treatment sequencing.
Availability of competing radioligand or systemic treatments.

A single treatment course can generate substantial revenue relative to a conventional specialty drug prescription. The product nevertheless remains commercially limited because the eligible population is small and treatment is episodic.

When does AZEDRA lose FDA exclusivity?

AZEDRA received orphan-drug designation. The standard orphan-drug exclusivity period is seven years from FDA approval, subject to statutory exceptions. Based on the July 30, 2018 approval date, the core orphan exclusivity period ran through July 30, 2025.

AZEDRA exclusivity timeline

Event	Date
FDA approval	July 30, 2018
Orphan-drug exclusivity	Generally through July 30, 2025
Accelerated approval status	Approval subject to postmarketing obligations
Expected conventional generic risk	Low because of product complexity and small market
Post-exclusivity commercial exposure	Dependent on patents, regulatory pathway, manufacturing access, and payer economics

Orphan exclusivity blocks FDA approval of the same drug for the same indication during the exclusivity period. It does not prevent approval of a different drug, a different indication, or potentially a product that qualifies under statutory exceptions.

The end of orphan exclusivity does not automatically create immediate generic competition. A competitor would still need to address the radioactive isotope, drug substance, formulation, labeling, manufacturing controls, distribution, radiation handling, and clinical or bridging requirements.

What patents protect iobenguane sulfate I-131 and AZEDRA?

AZEDRA's protection consists of a combination of regulatory exclusivity, formulation and drug-product rights, manufacturing know-how, radioactive-material logistics, and potential patent protection. The commercial barrier is broader than a single composition-of-matter patent.

Public company filings identify intellectual-property protection around Progenics' radiopharmaceutical technologies and related products, but Lantheus' financial disclosures do not provide a complete, product-specific patent schedule for AZEDRA comparable to the detailed patent tables commonly available for major small-molecule drugs.

The relevant patent categories include:

Iobenguane radiolabeling and preparation methods.
Therapeutic dosing and administration methods.
Pharmaceutical formulations.
Stabilization and storage of iodine-131 products.
Manufacturing and quality-control processes.
Use of the product in pheochromocytoma and paraganglioma.

Are AZEDRA patents listed in the Orange Book?

AZEDRA is a drug product approved under an NDA, so Orange Book listing is legally relevant. The FDA Orange Book may contain product and exclusivity information, but an Orange Book patent listing does not by itself determine the full commercial protection of a radiopharmaceutical.

For AZEDRA, the more important barriers may be:

Specialized manufacturing facilities.
Licensed radioactive-material handling.
Access to iodine-131 supply.
Validated radiolabeling processes.
Distribution within the isotope's physical half-life.
Treatment-center qualification.
Physician and payer adoption.

The FDA Orange Book should be checked for the current patent-listing status before relying on a specific Paragraph IV strategy or launch date. Public Lantheus filings do not provide a definitive, consolidated AZEDRA patent-expiration table.

What generic entry risks exist for AZEDRA?

Near-term generic substitution risk is low, but the product is not immune from competition.

A conventional ANDA pathway would be difficult because AZEDRA is a therapeutic radiopharmaceutical with a radioactive active ingredient and specialized manufacturing requirements. A competitor may pursue a 505(b)(2) pathway or another application route if it can rely partly on existing FDA findings while addressing product-specific safety, dosimetry, chemistry, manufacturing, and clinical questions.

Potential entry routes

Entry route	Relevance to AZEDRA
ANDA under section 505(j)	Technically possible in principle, but difficult for a complex radiopharmaceutical
505(b)(2) NDA	More plausible for a modified formulation, dosing approach, or related product
New NDA	Required for a materially distinct radioligand or new clinical profile
Competing radioligand	More likely than direct generic substitution
Off-label therapy	Existing source of indirect competition

The largest competitive threat is not necessarily a chemically identical generic. It is the emergence of alternative radioligand therapies, especially agents targeting somatostatin receptors or other tumor-specific markers.

Which companies challenge AZEDRA's market position?

AZEDRA has limited direct branded competition, but its clinical alternatives include:

Lutetium-177 dotatate, marketed as Lutathera by Novartis, for appropriate somatostatin-receptor-positive neuroendocrine tumors.
Lutetium-177-based investigational therapies directed at other tumor targets.
High-specific-activity iodine-131 MIBG products or regional alternatives.
CVD chemotherapy, consisting of cyclophosphamide, vincristine, and dacarbazine.
Temozolomide-based treatment in selected patients.
Somatostatin analogues and other systemic therapies.
External-beam radiation and surgery where clinically appropriate.

Lutathera is not a direct substitute for every AZEDRA patient. Eligibility depends on tumor biology, receptor expression, prior therapy, disease distribution, and treatment objectives. It is nevertheless a meaningful competitive reference because both products are systemic radioligand therapies for rare neuroendocrine malignancies.

AZEDRA versus Lutathera

Attribute	AZEDRA	Lutathera
Active radioligand	Iobenguane labeled with iodine-131	DOTATATE labeled with lutetium-177
Primary target	Norepinephrine transporter	Somatostatin receptor 2
Main disease relevance	Pheochromocytoma and paraganglioma	Somatostatin-receptor-positive gastroenteropancreatic neuroendocrine tumors
Patient selection	Iobenguane scan positivity	Somatostatin-receptor imaging positivity
Direct substitution	Limited	Limited
Commercial scale	Small orphan market	Larger neuroendocrine-tumor market
Manufacturing complexity	High	High
Strategic threat to AZEDRA	Indirect	Material in overlapping neuroendocrine referral networks

What manufacturing and supply-chain barriers protect AZEDRA?

Manufacturing is a major barrier to entry. Iodine-131 has a relatively short half-life, requiring coordinated production, quality release, shipment, and administration. Delays can reduce usable activity and increase waste.

A competing manufacturer would need capabilities in:

Radioiodination.
Sterile fill-finish.
Radiation shielding.
Dosimetry and activity calibration.
Radioactive-material licensing.
Short-cycle logistics.
Pharmacovigilance for radiation exposure and marrow toxicity.
Consistent supply of pharmaceutical-grade precursor and iodine-131.

These requirements limit the number of credible entrants. They also make inventory management and treatment scheduling central to product economics.

The same supply-chain structure creates commercial risk. Production interruptions, isotope shortages, failed quality release, shipping delays, or treatment-center cancellations can directly reduce revenue.

What is the regulatory status of AZEDRA?

AZEDRA has FDA approval under the accelerated approval pathway. Its label includes safety risks associated with myelosuppression, radiation exposure, renal toxicity, hormonal effects, and long-term malignancy risk. Patients may require thyroid blockade and intensive monitoring.

The accelerated approval structure gives the FDA authority to modify labeling or take regulatory action if required postmarketing work does not verify clinical benefit. Continued commercial availability therefore depends on compliance with postapproval obligations and maintenance of an acceptable benefit-risk profile.

AZEDRA is not a biosimilar product and does not face biosimilar competition. Biosimilar law applies to biologics, while AZEDRA is a radiolabeled small-molecule drug product.

Has AZEDRA faced Paragraph IV litigation or settlement agreements?

No major publicly established Paragraph IV litigation or settlement involving AZEDRA is central to the product's commercial outlook through the available Lantheus and FDA disclosures.

That outcome is consistent with the product's small market, complex manufacturing profile, and limited incentive for a conventional generic challenge. A future applicant could still pursue patent litigation through an ANDA Paragraph IV certification or challenge patents in other proceedings. The absence of a prominent challenge does not eliminate that possibility after orphan exclusivity ends.

There is no publicly disclosed settlement agreement that materially sets a generic launch date for AZEDRA.

How strong is the AZEDRA patent estate?

AZEDRA's effective protection is moderate to strong against immediate direct substitution but weaker as a long-term franchise protection strategy.

Strengths

Seven years of orphan-drug exclusivity from FDA approval.
Specialized radioactive manufacturing.
Limited qualified treatment centers.
Complex logistics and short product shelf life.
Disease-specific clinical positioning.
High regulatory burden for a competing therapeutic radiopharmaceutical.

Constraints

Small patient population limits the value of prolonged litigation.
Orphan exclusivity does not block different drugs or indications.
Alternative radioligand therapies can bypass AZEDRA patents.
Public disclosures do not establish a broad, late-expiring patent wall.
Episodic treatment limits recurring revenue.
Product use depends on diagnostic imaging and referral infrastructure.

The estate is stronger as an operational and regulatory moat than as a conventional high-volume small-molecule patent franchise.

What generic launch scenarios are most plausible?

Scenario 1: No direct generic entry

This is the most commercially plausible near-term scenario. The market remains too small and technically demanding to support rapid direct substitution.

Scenario 2: 505(b)(2) competitor

A modified iodine-131 iobenguane product could seek approval using some reliance on existing findings while introducing differences in formulation, dosing, manufacturing, or administration. Patent litigation and regulatory exclusivity would determine timing.

Scenario 3: Competing radioligand therapy

A different targeted radiopharmaceutical gains adoption in overlapping referral networks. This is the principal strategic risk because it can compete without infringing AZEDRA's product claims.

Scenario 4: Institutional or regional compounding

A nuclear pharmacy or specialty manufacturer develops a lower-cost alternative under a permissible regulatory framework. This could pressure pricing, but radioactive-drug manufacturing and FDA compliance requirements limit the likelihood of broad substitution.

What is the commercial outlook for AZEDRA?

AZEDRA is likely to remain a niche revenue product within Lantheus. Its growth ceiling is set by the incidence of eligible tumors, diagnostic identification, treatment-center availability, and competing radioligand options.

The product has favorable characteristics for a specialty portfolio:

High unmet need in a rare disease.
Limited direct competition.
Strong treatment-center dependence.
Regulatory and manufacturing barriers.
Potentially high revenue per treatment course.

Its weaknesses are equally clear:

Low absolute patient volume.
Limited recurring prescription revenue.
Dependence on radioactive supply.
Reimbursement friction.
Competition from alternative systemic and radioligand treatments.
Lack of meaningful contribution to Lantheus' consolidated financial results.

AZEDRA's value is strategic rather than transformational. It strengthens Lantheus' presence in therapeutic radiopharmaceuticals, but it does not materially alter the company's financial trajectory, which is driven primarily by diagnostic imaging products, especially Pylarify.

Key Takeaways

AZEDRA is the FDA-approved brand for iobenguane sulfate I-131.
It treats iodine-131 iobenguane-positive unresectable or metastatic pheochromocytoma and paraganglioma.
FDA approval occurred on July 30, 2018.
Orphan-drug exclusivity generally ran through July 30, 2025.
Direct generic substitution risk is low because of radioactive manufacturing, logistics, treatment-center, and regulatory barriers.
A 505(b)(2) product or competing radioligand is more plausible than a conventional ANDA generic.
Lantheus' financial growth is driven by Pylarify and DEFINITY, not AZEDRA.
Public filings do not provide a definitive, standalone AZEDRA patent-expiration schedule.
AZEDRA's strongest protection is its combined regulatory, manufacturing, clinical, and distribution infrastructure.
Biosimilar risk is not applicable because AZEDRA is a radiolabeled small-molecule drug, not a biologic.

FAQs

Is AZEDRA the same as MIBG therapy?

Yes. AZEDRA is a therapeutic iodine-131-labeled iobenguane product, commonly described as I-131 MIBG therapy.

Can AZEDRA be used for neuroblastoma?

The FDA indication discussed here covers pheochromocytoma and paraganglioma in patients aged 12 years and older. Use in neuroblastoma depends on the applicable regulatory indication, clinical setting, and physician judgment.

Does Lutathera replace AZEDRA?

No. Lutathera targets somatostatin receptors, while AZEDRA targets norepinephrine transporters. The products serve overlapping but distinct patient populations.

Why is AZEDRA difficult to manufacture?

It requires controlled radioiodination, sterile production, radiation shielding, activity calibration, regulatory licensing, and rapid shipment before radioactive decay reduces usable activity.

Is AZEDRA a major revenue product for Lantheus?

No. AZEDRA is strategically relevant but financially small relative to Lantheus' consolidated business, particularly Pylarify and DEFINITY.

References

U.S. Food and Drug Administration. (2018, July 30). FDA approves iobenguane I 131 for metastatic or unresectable pheochromocytoma or paraganglioma. https://www.fda.gov/
U.S. Food and Drug Administration. (2024). AZEDRA (iobenguane I 131) prescribing information. https://www.accessdata.fda.gov/
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov/drugsatfda
Lantheus Holdings, Inc. (2022). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for fiscal year 2021. U.S. Securities and Exchange Commission.
Lantheus Holdings, Inc. (2023). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for fiscal year 2022. U.S. Securities and Exchange Commission.
Lantheus Holdings, Inc. (2024). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for fiscal year 2023. U.S. Securities and Exchange Commission.
Lantheus Holdings, Inc. (2025). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 for fiscal year 2024. U.S. Securities and Exchange Commission.
U.S. Food and Drug Administration. (2024). Orphan drug designation and exclusivity. https://www.fda.gov/industry/designating-orphan-product-drugs-and-biological-products/orphan-drug-designation-and-exclusivity

US Patents:	0
Tradenames:	1
Applicants:	1
NDAs:	1
Clinical Trials:	4
DailyMed Link:	IOBENGUANE SULFATE I-131 at DailyMed

Summary for IOBENGUANE SULFATE I-131

Recent Clinical Trials for IOBENGUANE SULFATE I-131