ZYFLO CR Drug Patent Profile

When do Zyflo Cr patents expire, and what generic alternatives are available?

Zyflo Cr is a drug marketed by Chiesi and is included in one NDA.

The generic ingredient in ZYFLO CR is zileuton. There are eight drug master file entries for this compound. Six suppliers are listed for this compound. Additional details are available on the zileuton profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Zyflo Cr

A generic version of ZYFLO CR was approved as zileuton by RISING on March 17^th, 2017.

Summary for ZYFLO CR

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	130
Drug Prices:	Drug price information for ZYFLO CR
DailyMed Link:	ZYFLO CR at DailyMed

See drug prices for ZYFLO CR

US Patents and Regulatory Information for ZYFLO CR

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Chiesi	ZYFLO CR	zileuton	TABLET, EXTENDED RELEASE;ORAL	022052-001	May 30, 2007		DISCN	Yes	No

Expired US Patents for ZYFLO CR

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Chiesi	ZYFLO CR	zileuton	TABLET, EXTENDED RELEASE;ORAL	022052-001	May 30, 2007
Chiesi	ZYFLO CR	zileuton	TABLET, EXTENDED RELEASE;ORAL	022052-001	May 30, 2007
Chiesi	ZYFLO CR	zileuton	TABLET, EXTENDED RELEASE;ORAL	022052-001	May 30, 2007

International Patents for ZYFLO CR

See the table below for patents covering ZYFLO CR around the world.

Country	Patent Number	Title	Estimated Expiration
Germany	69026215
Portugal	95231	PROCESSO DE PREPARACAO DE INIBIDORES DA LIPOXIGENASE CONTENDO INDOLO,BENZOFURANO E BENZOTIOFENO E DE COMPOSICOES FARMACEUTICAS
European Patent Office	0416609	Composés inhibiteurs de lipoxygénase dérivés du benzo[b]thiophène (Benzo[b]thiophene-containing lipoxygenase-inhibiting compounds)
European Patent Office	0663820	COMPRIME PHARMACEUTIQUE CAPABLE DE LIBERER UN OU PLUSIEURS MEDICAMENTS A DIFFERENTES VITESSES DE LIBERATION (PHARMACEUTICAL TABLET CAPABLE OF LIBERATING ONE OR MORE DRUGS AT DIFFERENT RELEASE RATES)
Spain	2085316

Market Dynamics and Financial Trajectory for ZYFLO CR

Last updated: July 27, 2025

Introduction

ZYFLO CR (zileuton controlled release) is a pharmaceutical drug primarily used in the management of asthma by inhibiting leukotriene synthesis — key mediators in airway inflammation. Since its initial approval, ZYFLO CR's market and financial prospects have been shaped by evolving regulatory landscapes, competitive dynamics, patent statuses, and clinical research developments. This analysis delves into the current market positioning, growth drivers, challenges, and future financial trajectories for ZYFLO CR within the broader asthma therapeutics landscape.

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Market Overview and Therapeutic Positioning

ZYFLO CR is a long-acting leukotriene pathway inhibitor, distinguished from other asthma medications by its unique mechanism targeting leukotriene synthesis, thus addressing airway inflammation and bronchoconstriction. Approved in the United States by the FDA in 2002, ZYFLO CR has historically served niche markets of patients intolerant to inhaled corticosteroids or leukotriene receptor antagonists.

However, the broader asthma medication market encompasses inhaled corticosteroids (ICS), long-acting beta-agonists (LABAs), biologics, and other leukotriene modifiers, creating competitive pressures that influence ZYFLO CR's market share. Its therapeutic niche remains valuable, particularly for specific patient subgroups, but declining exclusivity and the advent of newer biologics threaten its market dominance.

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Market Dynamics Influencing ZYFLO CR

1. Patent Protection and Market Exclusivity

Zileuton's patent expiry in many territories, including the U.S., has led to the introduction of generic formulations, significantly eroding revenue streams for branded ZYFLO CR. This trend began after patent expiration in the late 2000s, leading to price competition and reduced profitability [1].

2. Competitive Landscape

The global asthma market is highly competitive, with biologics such as omalizumab, mepolizumab, and benralizumab gaining prominence, especially for severe cases. These agents offer targeted therapy with improved efficacy profiles but at a higher cost. Additionally, leukotriene receptor antagonists like montelukast provide simpler oral options, further challenging zileuton's position.

The rise of biologics has prompted pharmaceutical companies to re-evaluate the market relevance of older oral agents. ZYFLO CR faces challenges in capturing new patient segments, which are increasingly directed toward biologics, especially for moderate-to-severe asthma [2].

3. Regulatory Environment and Reimbursement Trends

Regulatory agencies have emphasized safety and efficacy, impacting older drugs like ZYFLO CR. Post-marketing reports linked zileuton to liver toxicity, resulting in updated warnings that may restrict use and impact prescribing behaviors [3]. Reimbursement policies are increasingly favoring precision medicine approaches, favoring biologic therapies with robust data, which limits the economic incentive to prescribe ZYFLO CR.

4. Clinical Efficacy and Patient Compliance

While ZYFLO CR is effective for some patients, it requires frequent liver function monitoring due to hepatotoxicity risks. Such safety considerations negatively influence patient adherence and prescriber confidence, constraining market growth.

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Financial Trajectory and Future Outlook

1. Revenue Trends Post-Patent Expiry

Following patent expiration, revenues from branded ZYFLO CR have declined sharply, with sales shifting towards generic versions. A notable data point indicates that prior to patent expiry, ZYFLO CR generated revenues exceeding $100 million annually in the U.S., but subsequent years saw a steep decline—aligning with generic entry and market saturation [4].

2. Impact of Generic Competition

Generic manufacturers have entered the market at substantially lower prices, reducing the revenue per unit for the original producer. The sales volume has also declined as prescribers gravitate toward newer, safer options or biologics, which are seen as more efficacious.

3. Strategic Responses by Manufacturers

Pharmaceutical companies exploring ZYFLO CR's next steps include efforts to reposition the drug through label updates, clinical trial support for new indications, or combination formulations. However, without significant innovation or patent protection, sustainable profitability remains elusive.

4. Clinical Development and Pipeline Integration

Current clinical research does not indicate substantial pipeline developments or novel formulations for ZYFLO CR. The generic landscape is mature, and given the heterogeneity of asthma treatment, the drug's future is likely limited to niche or off-label use.

5. Market Expansion Opportunities

Potential growth avenues include:

• Specialty markets: narrowly defined patient groups intolerant to other therapies.
• Combination therapies: partnering with biologics or other agents.
• Global markets: emerging economies where generic drugs still constitute primary treatment options.

These, however, depend heavily on regulatory approvals and market access strategies in target regions.

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Risk Factors and Market Challenges

• Safety Concerns: Hepatotoxicity risks necessitate monitoring and may limit prescribing.
• Evolving Clinical Guidelines: Increasing preference for biologics for severe asthma diminishes the role of oral agents like ZYFLO CR.
• Patent and Market Entry of Generics: Accelerates revenue erosion.
• Competitive Disruption: Development of superior or more convenient therapies rapidly shifts market dynamics.

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Conclusion: Financial Trajectory Outlook

The financial trajectory of ZYFLO CR is characterized by a sharp decline in revenues post-patent expiration, compounded by intense competition from generics and biologics. Without significant reformulation, new indications, or strategic repositioning, near-term profitability is likely minimal. Long-term viability will depend on niche market retention, cost-effective positioning in specific patient segments, and potential expansion into untapped or emerging markets.

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Key Takeaways

• ZYFLO CR's revenue has significantly declined following patent expiration and the entry of generics.
• Increasing competition from biologics and safer oral agents diminishes its market relevance.
• Safety concerns and regulatory updates constrain prescriber confidence.
• Future growth opportunities are limited and reliant on niche applications or geographic expansion.
• Pharmaceutical companies must evaluate strategic options, including clinical trials for new indications or formulations, to sustain or enhance the drug's financial footprint.

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FAQs

Q1: How does ZYFLO CR compare to other asthma treatments in terms of efficacy?

A1: ZYFLO CR effectively reduces leukotriene-mediated airway inflammation but is generally considered less potent than biologic therapies for severe asthma. Its efficacy is more suitable for mild-to-moderate cases or patients intolerant to other medications.

Q2: What are the primary safety concerns associated with ZYFLO CR?

A2: The main safety concern is hepatotoxicity, necessitating regular liver function monitoring during therapy. This safety profile impacts patient adherence and prescriber preferences.

Q3: How has patent expiration affected ZYFLO CR's market share?

A3: Patent expiration led to the influx of generic versions, which substantially reduced the market share and profitability of branded ZYFLO CR.

Q4: Are there any ongoing clinical trials or developments for ZYFLO CR?

A4: Current data indicates minimal ongoing clinical development, with most efforts focused on other emerging asthma therapies, particularly biologics.

Q5: Can ZYFLO CR find renewed market relevance through combination therapies?

A5: While theoretically possible, integrating ZYFLO CR with other agents faces regulatory and safety hurdles, and there is limited market incentive given the availability of more advanced therapies.

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References

1. U.S. Food and Drug Administration. Zileuton (ZYFLO CR) Label Updates. 2018.
2. Global Initiative for Asthma (GINA). Global Strategy for Asthma Management and Prevention, 2022.
3. FDA Drug Safety Communications. Hepatotoxicity Risks with Zileuton. 2017.
4. IQVIA. U.S. Prescription Drug Market Data, 2022.