NEBUPENT Drug Patent Profile

Which patents cover Nebupent, and when can generic versions of Nebupent launch?

Nebupent is a drug marketed by Fresenius Kabi Usa and is included in one NDA.

The generic ingredient in NEBUPENT is pentamidine isethionate. There is one drug master file entry for this compound. Five suppliers are listed for this compound. Additional details are available on the pentamidine isethionate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Nebupent

A generic version of NEBUPENT was approved as pentamidine isethionate by PAI HOLDINGS on September 28^th, 2017.

Summary for NEBUPENT

US Patents:	0
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	79
Clinical Trials:	1
Patent Applications:	2,146
What excipients (inactive ingredients) are in NEBUPENT?	NEBUPENT excipients list
DailyMed Link:	NEBUPENT at DailyMed

Recent Clinical Trials for NEBUPENT

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

Sponsor	Phase
University of Illinois at Chicago

See all NEBUPENT clinical trials

Pharmacology for NEBUPENT

Drug Class

Antiprotozoal

US Patents and Regulatory Information for NEBUPENT

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	NEBUPENT	pentamidine isethionate	FOR SOLUTION;INHALATION	019887-001	Jun 15, 1989	AN	RX	Yes	Yes
Fresenius Kabi Usa	NEBUPENT	pentamidine isethionate	FOR SOLUTION;INHALATION	019887-002	Mar 22, 1996		DISCN	No	No

NEBUPENT Market Dynamics, Financial Trajectory, Patent Position, and Generic Risk

Last updated: September 18, 2026

NEBUPENT is a legacy inhaled pentamidine isethionate product used primarily for Pneumocystis jirovecii pneumonia prophylaxis in patients who cannot use preferred alternatives. Its commercial market has contracted because effective antiretroviral therapy reduced the HIV-associated prophylaxis population, while trimethoprim-sulfamethoxazole remains the standard preventive treatment. NEBUPENT has residual value in selected HIV, oncology, transplant, and immunocompromised populations, but its financial profile is that of a low-volume hospital and specialty product rather than a growth asset.

Public filings do not disclose standalone NEBUPENT revenue. The product’s economic trajectory is driven by a shrinking core indication, limited but persistent clinical demand, hospital procurement, product availability, and competition from lower-cost systemic prophylaxis.

What is NEBUPENT and how is it used?

NEBUPENT is the brand name for pentamidine isethionate inhalation powder. The product is reconstituted and administered through a Respirgard II nebulizer. The labeled regimen is 300 mg administered once every four weeks for prevention of Pneumocystis pneumonia in high-risk patients, particularly those with HIV infection who cannot tolerate or receive standard prophylaxis.[1]

NEBUPENT is a prophylaxis product, not a first-line treatment for active Pneumocystis pneumonia. Its commercial position is limited by the need for specialized administration and by clinical concerns that aerosolized pentamidine may provide less protection against extrapulmonary disease than systemic prophylactic regimens.[2]

Attribute	NEBUPENT profile
Active ingredient	Pentamidine isethionate
Route	Oral inhalation through a nebulizer
Labeled strength	300 mg single-dose vial
Primary use	Prevention of Pneumocystis pneumonia
Typical dosing	Every four weeks
Original developer/marketer	Fujisawa-related commercial organization
Current category	Legacy anti-infective and hospital specialty product
Primary competitors	TMP-SMX, atovaquone, dapsone-based regimens, injectable pentamidine
Product type	Small-molecule drug-device administration system

When did NEBUPENT receive FDA approval?

The FDA approved NEBUPENT under NDA 019839 for prevention of Pneumocystis pneumonia in patients at high risk who are unable to tolerate trimethoprim-sulfamethoxazole.[1] The product entered the U.S. market during the expansion of AIDS-related opportunistic-infection prophylaxis.

The commercial market changed materially after the introduction of highly active antiretroviral therapy in the mid-1990s. Effective HIV treatment increased CD4 counts, reduced opportunistic infections, and lowered demand for long-term Pneumocystis prophylaxis. U.S. HIV guidelines continue to identify TMP-SMX as the preferred preventive regimen, with alternatives used when intolerance, allergy, renal impairment, cytopenias, or other factors limit treatment choice.[2]

How has the NEBUPENT market changed?

NEBUPENT demand has declined from its historical HIV-driven peak but has not disappeared. The market now consists of several narrower segments.

HIV prophylaxis

HIV remains the most recognizable indication, but it is no longer a large growth market for inhaled pentamidine. Patients receiving effective antiretroviral therapy often avoid or discontinue Pneumocystis prophylaxis once immune recovery occurs. Patients who remain eligible for prophylaxis are generally managed first with TMP-SMX.

NEBUPENT retains a role when TMP-SMX causes severe hypersensitivity, renal toxicity, marrow suppression, or other adverse effects. Atovaquone and dapsone-based regimens compete directly in this setting.

Oncology and hematopoietic-cell transplantation

Cancer patients and transplant recipients can require Pneumocystis prevention during prolonged immunosuppression. This creates demand outside the HIV market, but clinical protocols vary by institution. TMP-SMX remains preferred where tolerated. Aerosolized pentamidine is generally considered an alternative for patients with sulfonamide intolerance or substantial marrow and renal toxicity risks.[3]

Solid-organ transplantation and immune-mediated disease

Patients receiving immunosuppressive therapy for solid-organ transplantation, autoimmune disease, or hematologic disorders can create intermittent demand. These populations are clinically important but commercially fragmented. They do not generate the predictable, large-volume demand once associated with AIDS clinics.

Hospital and specialty-clinic administration

NEBUPENT is less convenient than oral alternatives. Administration requires preparation, a nebulizer, infection-control procedures, and trained personnel. The product is therefore more dependent on hospital formularies and specialty clinics than on ordinary retail pharmacy volume.

What is the financial trajectory of NEBUPENT?

NEBUPENT’s financial trajectory is best characterized as mature, declining, and niche.

No major pharmaceutical company publicly reports NEBUPENT revenue as a standalone line item. Historical owners and commercial partners have generally grouped legacy anti-infective products within broader pharmaceutical segments. This prevents a reliable public calculation of annual sales, gross margin, or product-level operating profit.

Financial driver	Directional effect on NEBUPENT
Declining HIV opportunistic-infection incidence	Negative
Wider use of antiretroviral therapy	Negative
TMP-SMX clinical preference	Negative
Sulfonamide intolerance and renal toxicity	Positive for alternatives
Oncology and transplant prophylaxis	Stabilizing
Device and administration requirements	Negative
Low manufacturing complexity relative to novel drugs	Positive for supply economics
Limited direct-to-consumer demand	Negative for brand pricing power
Hospital purchasing and shortages	Can support episodic demand and pricing

Revenue exposure is likely modest relative to the portfolios of large pharmaceutical companies. The product’s value is more likely to come from recurring institutional demand and manufacturing continuity than from market expansion.

A product with monthly dosing can generate recurring utilization when patients remain on prophylaxis. That benefit is offset by the small eligible population and the availability of inexpensive alternative regimens.

What are the main competitors to NEBUPENT?

The most important competitor is not another inhaled pentamidine brand. It is oral TMP-SMX.

Therapy	Route	Competitive position against NEBUPENT
Trimethoprim-sulfamethoxazole	Oral or injectable	Preferred prophylaxis for most eligible patients
Atovaquone	Oral	Alternative for sulfonamide intolerance; higher cost and variable absorption
Dapsone plus pyrimethamine and leucovorin	Oral	Alternative regimen; requires patient selection and monitoring
Pentamidine isethionate	Intravenous or intramuscular	Systemic pentamidine option, with different toxicity and administration concerns
NEBUPENT	Inhaled	Alternative for selected patients unable to use preferred systemic regimens

NEBUPENT’s competitive advantage is targeted pulmonary delivery with monthly administration. Its disadvantages include specialized equipment, bronchospasm risk, incomplete systemic protection, and lower convenience.

What patent and exclusivity rights protect NEBUPENT?

NEBUPENT has the profile of an off-patent legacy product rather than a product protected by a current composition-of-matter patent.

The active ingredient, pentamidine, was discovered decades ago. Any original compound patent protection has long expired. Protection for the marketed inhalation product would have depended on formulation, packaging, manufacturing, labeling, device, or regulatory exclusivity rather than basic molecule ownership.

The FDA Orange Book is the principal source for listed patents and exclusivity associated with approved drug products.[4] Publicly available product-level information does not indicate a meaningful current Orange Book patent barrier that would block competition based on the pentamidine molecule itself. The absence of a listed patent does not eliminate commercial barriers involving manufacturing know-how, product availability, device compatibility, or regulatory requirements.

Formulation and device protection

The commercial product requires a sterile powder presentation and a specified nebulizer system. Potentially relevant intellectual-property categories include:

• Powder formulation and reconstitution characteristics.
• Container-closure and vial configuration.
• Nebulizer compatibility.
• Aerosol particle-size performance.
• Manufacturing and sterilization controls.
• Product labeling and administration instructions.

These rights would generally be narrower than a composition-of-matter patent and would be more vulnerable to design-around strategies.

Method-of-use patents

The labeled use is a mature prophylaxis indication. No commercially significant, long-duration method-of-use exclusivity is generally associated with NEBUPENT’s core indication. Any later method-of-use patent would need to cover a specific patient population, dosing schedule, or clinical setting and would not necessarily block all competing pentamidine products.

What is the Orange Book status of NEBUPENT?

The Orange Book status is more relevant to regulatory substitution than to strong patent exclusivity. A product’s Orange Book record can identify the reference listed drug, therapeutic-equivalence codes, patents, and exclusivity information.[4]

For NEBUPENT, commercial analysis should distinguish among three issues:

1. Whether the branded NDA remains approved.
2. Whether the product is currently marketed.
3. Whether an approved generic has an AB rating or another therapeutic-equivalence designation.

A product may remain in FDA records while being discontinued commercially. A discontinued product can still have regulatory significance as a reference product, depending on FDA determinations and the status of abbreviated applications. The existence of a generic pentamidine product for injection does not establish therapeutic equivalence to inhaled NEBUPENT because route, dosage form, delivery system, and clinical use differ.

Are there Paragraph IV challenges to NEBUPENT?

No major, publicly visible Paragraph IV litigation campaign is associated with NEBUPENT’s core product in the current commercial landscape. That is consistent with an old product that has little remaining patent-based exclusivity.

Any future abbreviated application would face more practical questions than patent questions:

• Whether the reference product is eligible for an ANDA pathway.
• Whether the proposed product matches the inhalation dosage form.
• Whether the same or equivalent nebulizer system is required.
• Whether comparative performance testing is sufficient.
• Whether the reference product remains commercially available.
• Whether the applicant can establish therapeutic equivalence.

The most likely competitive route is a generic or authorized alternative relying on regulatory pathways and product sameness, not a patent settlement.

What generic entry risks exist for NEBUPENT?

Generic entry risk is structurally high because the active ingredient is old and the principal clinical indication is established. The main obstacles are technical and commercial.

Technical barriers

A competing inhaled product must address aerosol performance, dose delivery, reconstitution, sterility, container closure, and device compatibility. These requirements can make the product more difficult to copy than a conventional oral tablet.

Commercial barriers

The market may be too small to attract multiple generic manufacturers. Low volume, hospital contracting, limited pricing upside, and specialized manufacturing reduce the incentive to enter. A single supplier may therefore hold meaningful practical leverage despite weak formal IP.

Generic launch scenarios

Scenario	Market effect
No generic inhaled entrant	Brand or incumbent supplier retains niche demand
One approved generic	Pricing pressure, but possible limited discounting because of low volume
Multiple inhaled generics	Significant price erosion and hospital tender competition
Supply interruption	Temporary price increases and formulary substitution
Device-specific competition	Slower substitution if clinical sites must change equipment

What licensing deals and ownership changes affect NEBUPENT?

NEBUPENT originated within the Fujisawa pharmaceutical business. Fujisawa merged with Yamanouchi in 2005 to form Astellas Pharma.[5] Product ownership, commercialization, or distribution arrangements may have changed over time as companies rationalized older anti-infective portfolios.

Public corporate disclosures do not establish a recent, material licensing transaction that changes NEBUPENT’s market outlook. The product is unlikely to be a strategic driver for a large pharmaceutical company. Its economic value would be more relevant to a specialty or generic manufacturer with existing sterile-inhalation infrastructure and hospital distribution.

What litigation and regulatory risks affect NEBUPENT?

Patent litigation risk is low relative to regulatory and supply risk. The principal risk categories are:

• FDA manufacturing inspections and compliance actions.
• Sterility and contamination controls.
• Product shortages or discontinuation.
• Nebulizer availability.
• Labeling and administration errors.
• Hospital substitution and formulary restrictions.
• Adverse-event monitoring, including bronchospasm and systemic pentamidine toxicity.

The product’s administration setting also creates operational exposure. Hospitals may prefer alternatives that are easier to dispense and administer, even when NEBUPENT remains clinically appropriate.

How strong is the NEBUPENT patent estate?

The patent estate is weak as a barrier to molecule-level competition and moderate only in narrow formulation, device, manufacturing, or regulatory dimensions.

Patent-estate factor	Assessment
Composition-of-matter protection	Expired
Core indication protection	Expired or no meaningful current barrier
Formulation protection	Potentially narrow
Device protection	Potentially relevant but design-around risk is high
Manufacturing know-how	More important than patents
Orange Book blocking power	Limited
Paragraph IV exposure	Low because enforceable patent blocking is limited
Generic vulnerability	High in principle; moderated by low market size

The strongest defensibility is operational. Reliable sterile manufacturing, quality systems, regulatory familiarity, and hospital distribution may matter more than formal patent claims.

What is the outlook for NEBUPENT revenue and market share?

NEBUPENT is unlikely to return to its historical AIDS-market scale. The most probable trajectory is stable-to-declining niche demand with episodic increases when hospitals face shortages of alternative prophylaxis or when patient populations with complex immunosuppression expand.

Revenue could improve temporarily through:

• Supply disruptions affecting TMP-SMX or atovaquone.
• Increased use in transplant and oncology centers.
• Price increases in a concentrated supplier market.
• Re-entry by a specialty manufacturer after market withdrawal.

Long-term growth is constrained by oral alternatives, HIV treatment success, clinical preference for TMP-SMX, and the operational burden of nebulized administration.

Key Takeaways

• NEBUPENT is inhaled pentamidine isethionate for monthly prevention of Pneumocystis pneumonia.
• Its historical HIV market has contracted sharply since effective antiretroviral therapy reduced opportunistic infections.
• TMP-SMX remains the primary competitor and preferred prophylactic regimen.
• Oncology, transplant, and immunocompromised patients support residual demand.
• Standalone NEBUPENT revenue is not publicly disclosed.
• The molecule is long off-patent, and no strong current Orange Book patent barrier is evident.
• Generic risk is high in principle but limited by technical manufacturing requirements and a small market.
• Supply reliability, hospital contracting, and regulatory compliance are more important than patent litigation.
• The likely financial profile is mature, low-volume, and declining, with occasional supply-driven pricing opportunities.

Frequently Asked Questions

Is NEBUPENT still used for HIV patients?

Yes. It can be used when preferred Pneumocystis prophylaxis, particularly TMP-SMX, is unsuitable because of allergy, toxicity, intolerance, or other clinical factors.[2]

Is NEBUPENT the same as injectable pentamidine?

No. Both contain pentamidine-related active substance, but NEBUPENT is an inhaled product with a different route, administration system, and clinical profile.

Does NEBUPENT treat active Pneumocystis pneumonia?

NEBUPENT is labeled for prevention, not primary treatment of active Pneumocystis pneumonia.[1]

Why has NEBUPENT not attracted more generic competition?

The market is small, while inhaled-product development requires specialized testing, sterile manufacturing, device compatibility, and hospital distribution. Those costs reduce the commercial return from entry.

Is NEBUPENT commercially more defensible than oral pentamidine alternatives?

Its practical defensibility can be higher because of device and manufacturing requirements, but its clinical demand is narrower. The product has limited patent-based protection and remains exposed to substitution by oral prophylaxis.

References

1. U.S. Food and Drug Administration. (n.d.). NebuPent (pentamidine isethionate) inhalant: Prescribing information. FDA.

2. National Institutes of Health. (2024). Guidelines for the prevention and treatment of opportunistic infections in adults and adolescents with HIV: Pneumocystis pneumonia. ClinicalInfo.HIV.gov.

3. Tomblyn, M., Chiller, T., Einsele, H., et al. (2009). Guidelines for preventing infectious complications among hematopoietic cell transplantation recipients. Biology of Blood and Marrow Transplantation, 15(10), 1143-1238.

4. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

5. Astellas Pharma Inc. (2005). Corporate history and formation of Astellas Pharma Inc. Astellas Pharma.

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