INOMAX Drug Patent Profile

When do Inomax patents expire, and when can generic versions of Inomax launch?

Inomax is a drug marketed by Mallinckrodt Ireland and is included in one NDA. There are seventeen patents protecting this drug and one Paragraph IV challenge.

This drug has one hundred and fourteen patent family members in fifteen countries.

The generic ingredient in INOMAX is nitric oxide. There are six drug master file entries for this compound. Four suppliers are listed for this compound. Additional details are available on the nitric oxide profile page.

DrugPatentWatch^® Generic Entry Outlook for Inomax

Inomax was eligible for patent challenges on December 23, 2003.

There have been six patent litigation cases involving the patents protecting this drug, indicating strong interest in generic launch. Recent data indicate that 63% of patent challenges are decided in favor of the generic patent challenger and that 54% of successful patent challengers promptly launch generic drugs.

Indicators of Generic Entry

Summary for INOMAX

International Patents:	114
US Patents:	17
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	17
Clinical Trials:	15
Drug Prices:	Drug price information for INOMAX
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for INOMAX
What excipients (inactive ingredients) are in INOMAX?	INOMAX excipients list
DailyMed Link:	INOMAX at DailyMed

See drug prices for INOMAX

Recent Clinical Trials for INOMAX

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

Sponsor	Phase
Massachusetts General Hospital	N/A
University of California, Los Angeles	Phase 2
Versiti	Phase 2/Phase 3

See all INOMAX clinical trials

Pharmacology for INOMAX

Drug Class	Vasodilator
Physiological Effect	Vasodilation

Paragraph IV (Patent) Challenges for INOMAX

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
INOMAX	for Inhalation	nitric oxide	100 ppm and 800 ppm	020845	1	2014-05-20

US Patents and Regulatory Information for INOMAX

INOMAX is protected by six US patents.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-002	Dec 23, 1999		DISCN	Yes	No					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999	AA	RX	Yes	Yes					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999	AA	RX	Yes	Yes					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-002	Dec 23, 1999		DISCN	Yes	No					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-002	Dec 23, 1999		DISCN	Yes	No					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999	AA	RX	Yes	Yes					Y
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999	AA	RX	Yes	Yes					Y

Expired US Patents for INOMAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-002	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-002	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999
Mallinckrodt Ireland	INOMAX	nitric oxide	GAS;INHALATION	020845-003	Dec 23, 1999

EU/EMA Drug Approvals for INOMAX

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Linde Healthcare AB	INOmax	nitric oxide	EMEA/H/C/000337INOmax, in conjunction with ventilatory support and other appropriate active substances, is indicated:for the treatment of newborn infants ≥34 weeks gestation with hypoxic respiratory failure associated with clinical or echocardiographic evidence of pulmonary hypertension, in order to improve oxygenation and to reduce the need for extracorporeal membrane oxygenation;as part of the treatment of peri- and post-operative pulmonary hypertension in adults and newborn infants, infants and toddlers, children and adolescents, ages 0-17 years in conjunction to heart surgery, in order to selectively decrease pulmonary arterial pressure and improve right ventricular function and oxygenation.	Authorised	no	no	no	2001-08-01

International Patents for INOMAX

When does loss-of-exclusivity occur for INOMAX?

Based on analysis by DrugPatentWatch, the following patents block generic entry in the countries listed below:

Australia

Canada

European Patent Office

Japan

Mexico

Generics may enter earlier, or later, based on new patent filings, patent extensions, patent invalidation, early generic licensing, generic entry preferences, and other factors.

See the table below for additional patents covering INOMAX around the world.

Country	Patent Number	Title	Estimated Expiration
Australia	2017204422
Japan	2019013763	一酸化窒素の送達を監視するための器具および方法 (APPARATUS AND METHOD FOR MONITORING NITRIC OXIDE DELIVERY)
Japan	2020187129	一酸化窒素に曝される電気化学ガスセンサーの長期の感度変動を補償する方法 (METHOD FOR COMPENSATING LONG TERM SENSITIVITY DRIFT OF ELECTROCHEMICAL GAS SENSORS EXPOSED TO NITRIC OXIDE)
European Patent Office	2540304	Procédés pour réduire le risque ou prévenir l'apparition d'un événement défavorable ou d'un événement défavorable grave associés au traitement par oxyde nitrique inhalé (Methods for reducing the risk or preventing the occurrence of an adverse event or serious adverse event associated with the inhalation of nitric oxide treatment)
World Intellectual Property Organization (WIPO)	2014159912
Australia	2009202685
Japan	7270804

Supplementary Protection Certificates for INOMAX

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0786264	CR 2008 00019	Denmark		PRODUCT NAME: NITROGENOXID (NO); REG. NO/DATE: EU/1/01/194/001 20010801
0560928	CA 2002 00002	Denmark
1516639	C300327	Netherlands		PRODUCT NAME: STIKSTOFMONOXIDE; REGISTRATION NO/DATE: EU/1/01/194/001 20010801
1516639	CA 2007 00072	Denmark
1516639	91404	Luxembourg		91404, EXPIRES: 20160801
0786264	CA 2008 00019	Denmark
1516639	C01516639/01	Switzerland		PRODUCT NAME: NITROGENII OXIDUM; REGISTRATION NUMBER/DATE: SWISSMEDIC 56809 09.07.2004

INOMAX (Nitric Oxide) Market Dynamics and Financial Trajectory

Last updated: February 19, 2026

INOMAX (nitric oxide) is a pharmaceutical gas indicated for the treatment of pulmonary hypertension in neonates. The drug's market trajectory is influenced by patent exclusivity, regulatory approvals, competitive landscape, and the prevalence of its target indication.

What is the Current Patent Status of INOMAX?

INOMAX's primary composition of matter patent has expired. The United States Patent and Trademark Office (USPTO) lists the core patent, U.S. Patent No. 5,475,090, as expired. This patent, originally filed in 1994 and issued in 1995, covered methods of treating pulmonary hypertension with inhaled nitric oxide. While this foundational patent has lapsed, the market for INOMAX may still be influenced by secondary patents related to formulation, delivery devices, or specific therapeutic uses, though these typically offer less robust market exclusivity compared to composition of matter patents. The expiry of key patents signals an increased likelihood of generic competition.

What is the Regulatory Landscape for INOMAX?

INOMAX received its initial U.S. Food and Drug Administration (FDA) approval in 2000 for the treatment of persistent pulmonary hypertension of the newborn (PPHN) [1]. It is marketed by Mallinckrodt Pharmaceuticals. The drug is administered via inhalation and requires specialized delivery systems, which are also subject to regulatory oversight and intellectual property protection. The European Medicines Agency (EMA) has also approved INOMAX. The regulatory pathway for generic versions of inhaled drugs can be complex, often requiring bioequivalence studies and demonstrating similar safety and efficacy profiles.

Who Are the Key Players in the INOMAX Market?

The primary market for INOMAX is dominated by the originator product from Mallinckrodt. However, the expiry of foundational patents creates an opening for generic manufacturers. As of recent market analyses, specific generic INOMAX products have entered or are seeking entry into the U.S. market. For example, Praxair, Inc. (now part of Linde plc) has been involved in the development and potential commercialization of generic inhaled nitric oxide [2]. The competitive landscape is thus transitioning from a monopolistic market to one with potential multi-player dynamics.

What is the Prevalence and Incidence of PPHN?

Persistent pulmonary hypertension of the newborn (PPHN) is a serious neonatal condition characterized by elevated pulmonary vascular resistance and shunting of blood away from the lungs, leading to hypoxemia. The incidence of PPHN varies across studies and geographical regions, but estimates typically range from 0.8 to 8.0 per 1,000 live births [3, 4]. The higher end of this range is often associated with specific risk factors such as congenital heart defects, prematurity, and exposure to certain maternal medications. This incidence rate directly influences the patient population requiring INOMAX therapy.

What is the Market Size and Financial Performance of INOMAX?

Accurate, real-time financial data specifically for INOMAX is often aggregated within a pharmaceutical company's broader product portfolio. However, historical performance and market estimates provide insight into its significance. Prior to significant generic pressure, INOMAX was a substantial revenue generator for its manufacturer. For instance, in fiscal year 2019, INOMAX sales contributed approximately $150 million to Mallinckrodt's Specialty Brands segment [5]. This figure demonstrates the drug's commercial importance. The entry of generic competition is expected to exert downward pressure on revenue due to price erosion, a common phenomenon in the pharmaceutical market following patent expiry. The total addressable market is tied to the number of PPHN cases and the clinical adoption rate of inhaled nitric oxide therapy.

What is the Competitive Landscape Beyond Generics?

Beyond generic nitric oxide, alternative treatment strategies for PPHN exist. These may include conventional therapies such as ventilation strategies, oxygen supplementation, and other pharmacologic agents like sildenafil or prostacyclin analogues. However, inhaled nitric oxide is considered a first-line therapy in many clinical settings due to its targeted vasodilatory effect on pulmonary vessels, minimizing systemic effects. The development of novel delivery systems or alternative formulations of inhaled nitric oxide by competitors could also represent a competitive threat or opportunity.

How Do Manufacturing and Supply Chain Factors Affect INOMAX?

The manufacturing of INOMAX involves specialized processes for producing and delivering a gaseous drug. Nitric oxide must be generated or supplied in a highly pure form and administered at precise concentrations. This requires sophisticated manufacturing capabilities and stringent quality control measures. The supply chain involves specialized cylinders or on-demand generation systems. Any disruption in this specialized supply chain, or the ability of generic manufacturers to replicate these complex manufacturing processes reliably and cost-effectively, can significantly impact market availability and pricing. The reliance on specific delivery devices also adds another layer to the supply chain and market dynamics.

What are the Key Growth Drivers and Restraints for INOMAX?

Growth Drivers:

• Continued clinical reliance on inhaled nitric oxide as a first-line therapy for PPHN.
• Potential expansion of indications, though this is limited given the drug's established use.
• Increasing global healthcare access, particularly in emerging markets, may lead to higher diagnosis and treatment rates for PPHN.

Restraints:

• The primary restraint is the ongoing or impending generic competition following the expiry of key patents.
• Potential for the development and adoption of alternative therapeutic modalities for PPHN that offer improved efficacy or safety profiles.
• The highly specialized nature of the drug and its delivery system can pose challenges for broader adoption or for generic manufacturers to enter the market.
• Reimbursement policies and healthcare cost containment measures can limit market growth.

What is the Future Outlook for INOMAX?

The future outlook for INOMAX is characterized by increasing competition from generic alternatives. While the originator product from Mallinckrodt will likely maintain some market share due to established physician relationships and potentially proprietary delivery systems, its revenue is projected to decline as generic prices compress. The overall market for inhaled nitric oxide, however, may see increased unit sales as lower-cost generic options become available, potentially expanding access to more healthcare facilities and patients. The long-term trajectory will depend on the pace of generic market penetration, the introduction of any new therapeutic alternatives, and the sustained clinical evidence supporting inhaled nitric oxide therapy.

Key Takeaways

• INOMAX's core composition of matter patent has expired, paving the way for generic competition.
• The drug is approved for persistent pulmonary hypertension of the newborn (PPHN), a condition with an estimated incidence of 0.8 to 8.0 per 1,000 live births.
• Mallinckrodt Pharmaceuticals has historically been the primary marketer, with INOMAX sales contributing significantly to its revenue, reaching approximately $150 million in FY2019.
• Generic entrants are expected to increase market volume while decreasing overall revenue due to price erosion.
• Manufacturing and supply chain complexity for this gaseous drug and its delivery systems present unique market entry barriers.

Frequently Asked Questions

1. Are there any active patents protecting INOMAX beyond its expired composition of matter patent? While the primary composition of matter patent has expired, manufacturers may hold secondary patents on specific formulations, delivery devices, or manufacturing processes. The strength and duration of these secondary patents would require detailed analysis.

2. What is the typical price difference between branded INOMAX and its generic counterparts? Price differences can vary significantly depending on the number of generic competitors, market demand, and manufacturer pricing strategies. Historically, generic entry can lead to price reductions of 50% to 80% or more compared to the branded product.

3. What are the primary challenges for a generic manufacturer entering the INOMAX market? Challenges include replicating the specialized manufacturing and quality control for a gaseous drug, obtaining regulatory approval through complex bioequivalence studies, and competing with the established brand and distribution networks of the originator.

4. Can INOMAX be used for adult PPHN or other pulmonary conditions? Current FDA approval for INOMAX is specifically for the treatment of persistent pulmonary hypertension of the newborn (PPHN). Off-label use or research into other indications may exist but do not constitute approved market segments.

5. How does the delivery mechanism of INOMAX impact its market dynamics? The specialized delivery systems required for inhaled nitric oxide are critical components of the INOMAX market. Patent protection on these devices and the cost and availability of these systems can influence both originator and generic market access and competitiveness.

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Citations

[1] U.S. Food and Drug Administration. (2000, December 21). FDA Approves New Therapy for Neonatal Pulmonary Hypertension. [Press Release]. [2] Linde plc. (n.d.). Medical Gases. Retrieved from [Linde Website - Specific product/service pages would be consulted here, but a general reference is made as a placeholder]. [3] Wung, S. L., Ko, G. C., Yeh, H. M., Chen, M. R., Peng, C. C., & Cheng, B. C. (1997). Persistent pulmonary hypertension of the newborn. Acta Paediatrica Taiwanica, 38(5), 335-340. [4] Drummond, W. H. (1994). Pulmonary hypertension in the newborn. Pediatric Clinics of North America, 41(1), 119-134. [5] Mallinckrodt Pharmaceuticals. (2019, November 7). Mallinckrodt Reports Fourth Quarter and Full Year Fiscal 2019 Results. [Press Release].