Generic SODIUM PHOSPHATE P-32 INN equivalents, drug patent expiration information and freedom to operate

Sponsor	Phase
Nextrast, Inc.	PHASE1
Union Hospital, Tongji Medical College, Huazhong University of Science and Technology	NA
University of Chicago	EARLY_PHASE1

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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
Mallinckrodt	SODIUM PHOSPHATE P 32	sodium phosphate p-32	SOLUTION;INJECTION, ORAL	011777-002	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Mallinckrodt	SODIUM PHOSPHATE P 32	sodium phosphate p-32	SOLUTION;INJECTION, ORAL	011777-001	Approved Prior to Jan 1, 1982		DISCN	No	No	⤷ Start Trial	⤷ Start Trial				⤷ Start Trial
Bracco	PHOSPHOTOPE	sodium phosphate p-32	SOLUTION;INJECTION, ORAL	010927-001	Approved Prior to Jan 1, 1982		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: September 7, 2026

Sodium phosphate P-32 is a legacy therapeutic radiopharmaceutical with a shrinking but persistent niche in hematology and oncology. Its commercial value is limited by declining clinical use, radioactive logistics, short shelf life, and competition from hydroxyurea, interferons, ruxolitinib, and other modern treatments. The product has little remaining patent-based exclusivity. Its financial profile is driven more by manufacturing authorization, isotope supply, nuclear-pharmacy distribution, and institutional demand than by intellectual property.

What is sodium phosphate P-32 used for?

Sodium phosphate P-32 is an injectable radiopharmaceutical containing phosphorus-32, a beta-emitting radioactive isotope with a physical half-life of approximately 14.3 days. The radiopharmaceutical is administered systemically and concentrates in tissues with active cellular proliferation, particularly the bone marrow.

Historically, sodium phosphate P-32 was used for:

Polycythemia vera
Essential thrombocythemia
Chronic myelogenous leukemia
Selected hematologic malignancies
Palliative treatment of certain disorders involving excessive blood-cell production

The product is associated with delayed marrow suppression and carries a risk of prolonged cytopenias and treatment-related leukemia. Modern practice has reduced its role, particularly in younger patients and patients with long expected survival.

How does sodium phosphate P-32 work?

Phosphorus-32 emits high-energy beta particles. After administration, the isotope is incorporated into biologic phosphate pools and delivers localized radiation to proliferating hematopoietic cells.

The drug is not a targeted molecular therapy. Its therapeutic effect depends on systemic radiation exposure and marrow uptake. That mechanism limits dosing flexibility and contributes to its declining use relative to molecularly targeted or cytoreductive therapies.

What is the FDA regulatory status of sodium phosphate P-32?

Sodium phosphate P-32 is an FDA-approved prescription radiopharmaceutical, but it is a legacy product rather than a newly developed commercial medicine. FDA labeling identifies sodium phosphate P-32 injection as a therapeutic radiopharmaceutical for selected hematologic indications [1].

The product is supplied through the radiopharmaceutical distribution system, which differs from ordinary pharmaceutical wholesaling. Facilities generally require:

An authorized nuclear pharmacy or radiopharmacy supplier
Appropriate radioactive-material licensing
Radiation-safety infrastructure
Personnel trained in handling therapeutic radionuclides
Validated dose calibration and administration procedures
Disposal procedures for radioactive materials

The drug’s clinical availability can vary by region because production, shipment, and administration must occur within the isotope’s usable shelf life.

What is the Orange Book status of sodium phosphate P-32?

The Orange Book is not the principal commercial barrier for sodium phosphate P-32. The product is a legacy radiopharmaceutical, and its commercial position is not protected by a recently issued active composition-of-matter patent.

Publicly available FDA resources do not indicate a meaningful current Orange Book patent barrier comparable to those affecting newer small-molecule products. Any generic or alternative supplier would still need to satisfy FDA approval requirements, radioactive-material controls, manufacturing standards, and reliable isotope distribution.

What patents protect sodium phosphate P-32?

The original composition and therapeutic-use concepts for sodium phosphate P-32 date back many decades. Any early patents covering phosphorus-32 radiopharmaceutical use or related therapeutic applications would have expired long ago.

How strong is the patent estate for sodium phosphate P-32?

The patent estate is weak from a market-exclusivity perspective.

Patent category	Current commercial relevance
Phosphorus-32 composition patents	Minimal; legacy rights would be expired
Sodium phosphate formulation patents	Minimal; basic aqueous formulations are mature
Method-of-use patents	Limited; historical uses are generally old
Manufacturing patents	Possible process know-how, but unlikely to create broad exclusivity
Delivery-device patents	Low relevance for a conventional injectable
Regulatory exclusivity	Not a major current barrier
Trade secrets and operating know-how	More relevant than patents

The remaining competitive advantage is likely operational. A supplier with dependable isotope procurement, validated production, and established nuclear-pharmacy relationships can compete even without meaningful patent protection.

When does sodium phosphate P-32 lose exclusivity?

Sodium phosphate P-32 effectively lost conventional patent exclusivity decades ago. No reliable commercial analysis should assign a future patent cliff to the product unless a new formulation, delivery system, or method of use is separately developed and approved.

The relevant commercial question is not when a patent expires. It is whether a supplier can maintain an economically viable, licensed production and distribution network.

What formulations are protected by sodium phosphate P-32 patents?

The marketed dosage form is an injectable sodium phosphate solution containing phosphorus-32. It is a mature formulation with limited technical complexity compared with liposomal drugs, long-acting injectables, biologics, or drug-device combinations.

Potentially protectable formulation attributes could include:

Isotopic concentration
Buffer composition
Chemical stability
Radiochemical purity
Container closure
Dose-calibration procedures
Shelf-life extension
Combination use with a delivery system

These attributes are more likely to support regulatory differentiation or manufacturing quality claims than durable patent exclusivity. A standard aqueous sodium phosphate injection does not create a substantial modern formulation barrier.

How large is the sodium phosphate P-32 market?

No audited, product-level global revenue figure is publicly disclosed for sodium phosphate P-32. The product occupies a small specialty segment within the broader therapeutic radiopharmaceutical market.

Demand is constrained by four factors:

The addressable patient population is limited.
Many patients are treated with nonradioactive cytoreductive therapy.
The product is used mainly in specialized centers.
The isotope has a short half-life and requires time-sensitive distribution.

The broader radiopharmaceutical market is expanding because of newer targeted agents, including lutetium-177 and actinium-225 programs. That growth does not translate directly into growth for sodium phosphate P-32. Capital is moving toward radioligand therapies with biomarker-defined populations and higher commercial pricing, rather than legacy systemic beta emitters.

What drives sodium phosphate P-32 pricing?

Pricing is influenced by:

Phosphorus-32 production costs
Reactor or accelerator availability
Radiochemical processing
Quality-control testing
Radioactive shipping
Nuclear-pharmacy handling
Dose wastage
Facility licensing
Short product shelf life
Low production scale

The list price of a radiopharmaceutical dose does not necessarily equal manufacturer revenue. Hospitals and nuclear pharmacies may purchase based on individual patient doses, scheduled treatment courses, or institutional contracts. Revenue recognition can also be affected by dose cancellation, decay, and unused inventory.

What is the financial trajectory for sodium phosphate P-32?

The financial trajectory is mature to declining in most developed markets.

Financial driver	Direction	Effect
Clinical demand	Declining or stable at a low base	Reduces volume
Unit economics	Potentially resilient	Specialty handling supports pricing
Manufacturing scale	Limited	Raises fixed cost per dose
Competition from modern therapies	Increasing	Reduces use in hematology
Isotope logistics	Structurally difficult	Increases operating cost
Patent protection	Negligible	Limits pricing power
Radiopharmaceutical sector investment	Increasing elsewhere	Diverts capital from legacy products
Institutional use	Concentrated	Creates regional dependence

A supplier can maintain positive contribution margins if it has low-cost isotope access, established production infrastructure, and predictable hospital demand. A new entrant would face a less attractive business case because it would need to build a licensed radioactive supply chain for a small market without patent protection.

What revenue exposure does sodium phosphate P-32 create for manufacturers?

Revenue exposure is generally low for diversified pharmaceutical companies and potentially material for a small radiopharmaceutical supplier.

For a diversified manufacturer, sodium phosphate P-32 is unlikely to influence consolidated revenue or valuation. For a specialty nuclear-pharmacy operator, however, the product can provide recurring institutional sales and portfolio diversification. The commercial risk is concentration: a manufacturing interruption, reactor outage, shipping disruption, or regulatory action can remove most or all product revenue for a period.

Public-company filings generally do not report sodium phosphate P-32 as a separate revenue line. Sales are more likely to be aggregated within radiopharmaceuticals, hospital products, or specialty injectables.

Which companies compete with sodium phosphate P-32?

Competition comes primarily from alternative therapies rather than direct generic versions.

Hematology competitors

For polycythemia vera and essential thrombocythemia, alternatives include:

Hydroxyurea
Pegylated interferon alfa
Ropeginterferon alfa-2b
Ruxolitinib
Phlebotomy and low-dose aspirin, depending on disease and risk profile
Other cytoreductive therapies used in selected patients

The National Comprehensive Cancer Network and European clinical guidelines generally place modern cytoreductive options ahead of phosphorus-32 for many patients, especially younger patients and those requiring long-term disease control [2,3].

Direct radiopharmaceutical competitors

There is no perfect direct substitute for sodium phosphate P-32. Other therapeutic radionuclides, including strontium-89, samarium-153, yttrium-90, and lutetium-177, address different diseases or delivery targets.

The competitive threat is therefore clinical substitution rather than direct molecular substitution. A patient who might historically have received P-32 may instead receive hydroxyurea, interferon, ruxolitinib, or another disease-specific therapy.

What generic entry risks exist for sodium phosphate P-32?

Generic entry risk is technically feasible but commercially limited.

A potential competitor would need to establish:

Pharmaceutical equivalence
Radiochemical identity and purity
Sterility and endotoxin control
Stability through the labeled shelf life
Dose assay accuracy
Container compatibility
FDA manufacturing compliance
Reliable phosphorus-32 supply
Licensed radioactive-material distribution
Hospital and nuclear-pharmacy purchasing access

The primary barrier is not patent litigation. It is market economics. A small, declining market may not justify the regulatory and operational investment required to enter.

Could a generic manufacturer launch without patent litigation?

Yes. Because conventional patent exclusivity is not the central barrier, a new entrant could potentially pursue an abbreviated or conventional FDA pathway without facing a major Paragraph IV campaign. The practical risks would be supply continuity, product demand, reimbursement, and production economics.

Are there Paragraph IV challenges involving sodium phosphate P-32?

No material, current Paragraph IV litigation campaign is publicly associated with sodium phosphate P-32. Paragraph IV disputes are more common for newer high-revenue small molecules with active Orange Book patents.

For sodium phosphate P-32, the commercial risk is more likely to involve:

Product discontinuation
Manufacturing interruption
Regulatory compliance
Isotope availability
Contracting and hospital formulary decisions

The absence of significant Paragraph IV activity reflects the product’s age and limited market value.

What patent litigation affects sodium phosphate P-32?

No major current patent litigation materially affecting sodium phosphate P-32 has been identified in the public record. Historical disputes involving radiopharmaceutical manufacturing or radioactive-material licensing would not necessarily create current product-level exclusivity.

Litigation exposure could arise from:

Manufacturing process patents
Supply contracts
Nuclear-material licensing
Product liability
Radiation injury claims
Labeling and informed-consent disputes
Facility or transportation violations

These risks are separate from the patent position of the active ingredient.

Are there licensing deals for sodium phosphate P-32?

No major recent licensing transaction centered on sodium phosphate P-32 is publicly evident. The product is more likely to move through supply, distribution, or contract-manufacturing arrangements than through a conventional branded-drug licensing transaction.

Commercial agreements may cover:

Isotope supply
Radiopharmacy distribution
Contract filling
Dose preparation
Hospital purchasing
Regional commercialization rights

The lack of visible licensing activity is consistent with a mature product with limited growth potential and little remaining patent value.

What manufacturing and geographic barriers affect the product?

Geographic coverage is constrained by the isotope’s half-life and regulatory requirements. Phosphorus-32’s 14.3-day half-life is longer than some modern radiopharmaceutical isotopes, but the product still requires controlled production, testing, packaging, and shipment.

North America

The United States and Canada have established radiopharmacy infrastructure, but availability depends on licensed suppliers and regional demand. Hospitals without nuclear-medicine capabilities generally cannot administer the product.

Europe

European access is fragmented by national reimbursement, radioactive-material licensing, and centralized procurement. A supplier may need separate commercial and regulatory arrangements across jurisdictions.

Asia-Pacific

Availability varies significantly. Markets with advanced nuclear medicine infrastructure can support supply, while smaller markets may lack isotope production, radiopharmacy capacity, or sufficient clinical demand.

Manufacturing barriers include isotope procurement, validated sterile processing, radioactive waste management, and the need to maintain quality despite radioactive decay.

How does sodium phosphate P-32 compare with modern radiopharmaceuticals?

Attribute	Sodium phosphate P-32	Modern targeted radiopharmaceuticals
Targeting	Systemic, nonspecific	Molecular or receptor-directed
Main use	Legacy hematologic therapy	Oncology and selected endocrine tumors
Half-life	About 14.3 days	Varies by isotope
Patent position	Largely expired	Often active and extensive
Clinical development	Mature	Active and expanding
Pricing power	Limited	Often substantially higher
Manufacturing complexity	Moderate	High, particularly for radioligands
Patient selection	Primarily clinical	Often biomarker or receptor-based
Commercial growth	Low or declining	Stronger in selected categories

Modern radiopharmaceuticals benefit from target specificity, active clinical development, and patent-protected delivery platforms. Sodium phosphate P-32 remains useful where its established therapeutic effect and operational availability justify its use, but it does not participate fully in the growth economics of targeted radioligand therapy.

Key Takeaways

Sodium phosphate P-32 is a legacy beta-emitting radiopharmaceutical with a half-life of about 14.3 days.
Its historical role was concentrated in polycythemia vera, essential thrombocythemia, and selected hematologic diseases.
Conventional patent protection is effectively exhausted, and no major current Orange Book barrier is apparent.
No material current Paragraph IV or patent-litigation threat is associated with the product.
Clinical substitution by hydroxyurea, interferons, ruxolitinib, and other therapies is the main demand risk.
Product economics depend on isotope supply, radioactive logistics, nuclear-pharmacy access, and institutional demand.
No audited public product-level revenue figure is available.
The financial trajectory is mature to declining, with limited upside outside specialized regional supply arrangements.
Manufacturing know-how and regulatory infrastructure are more important than patent rights.
New entrants face a small market, high fixed costs, and limited pricing power.

FAQs

Is sodium phosphate P-32 still commercially available?

Availability depends on the jurisdiction, licensed supplier, and nuclear-pharmacy infrastructure. It is not distributed like a conventional oral generic and may be unavailable in regions without therapeutic radiopharmaceutical capacity.

Is sodium phosphate P-32 a chemotherapy drug?

It is a therapeutic radiopharmaceutical rather than conventional cytotoxic chemotherapy. Its beta radiation suppresses proliferating hematopoietic cells.

Does sodium phosphate P-32 have biosimilar competition?

No. Biosimilar rules apply to biological products, while sodium phosphate P-32 is a radioactive small-molecule chemical drug.

Why did use of sodium phosphate P-32 decline?

Use declined because of treatment-related marrow toxicity, long-term leukemia concerns, and the availability of hydroxyurea, interferons, ruxolitinib, and other less legacy-dependent treatment strategies.

Could sodium phosphate P-32 become commercially attractive again?

A broad resurgence is unlikely without a new indication, improved delivery system, combination strategy, or manufacturing innovation. Its existing market is too mature to support substantial growth based only on the current formulation.

References

U.S. Food and Drug Administration. (n.d.). Sodium phosphate P 32 injection prescribing information. FDA and DailyMed labeling resources.
National Comprehensive Cancer Network. (2024). NCCN clinical practice guidelines in oncology: Myeloproliferative neoplasms. NCCN.
European LeukemiaNet. (2021). European recommendations for the management of polycythemia vera and essential thrombocythemia. Leukemia.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
International Atomic Energy Agency. (2023). Nuclear medicine resources and therapeutic radiopharmaceutical production. IAEA.

US Patents:	0
Tradenames:	2
Applicants:	2
NDAs:	2
Raw Ingredient (Bulk) Api Vendors:	8
Clinical Trials:	205
DailyMed Link:	sodium phosphate p-32 at DailyMed

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