ZMAX Drug Patent Profile

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

Zmax is a drug marketed by Pf Prism Cv and is included in one NDA.

The generic ingredient in ZMAX is azithromycin. There are thirty-two drug master file entries for this compound. Sixty suppliers are listed for this compound. Additional details are available on the azithromycin profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Zmax

A generic version of ZMAX was approved as azithromycin by PLIVA on November 14^th, 2005.

Summary for ZMAX

US Patents:	0
Applicants:	1
NDAs:	1

US Patents and Regulatory Information for ZMAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pf Prism Cv	ZMAX	azithromycin	FOR SUSPENSION, EXTENDED RELEASE;ORAL	050797-001	Jun 10, 2005		DISCN	Yes	No

International Patents for ZMAX

See the table below for patents covering ZMAX around the world.

Country	Patent Number	Title	Estimated Expiration
European Patent Office	0303348	2-AMINO-5-HYDROXY-4-PYRIMIDONES
Israel	131308	CONTROLLED-RELEASE DOSAGE FORMS OF AZITHROMYCIN
Guatemala	200400183	FORMAS DE DOSIFICACION DE AZITROMICINA CON EFECTOS SECUNDARIOS REDUCIDOS
Japan	H0631300
Cyprus	1108486
World Intellectual Property Organization (WIPO)	9530422

Last updated: February 3, 2026

AX (azithromycin extended-release): Investment scenario and fundamentals analysis

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What is ZMAX and its market position?

ZMAX (azithromycin extended-release) is a prescription antibiotic developed for the treatment of bacterial respiratory infections, including community-acquired pneumonia, sinusitis, and skin infections. It is manufactured by Pfizer as a once-daily oral dosage form, marketed primarily in the United States. Its core competitive advantage lies in extended-release formulation, leading to improved patient compliance.

ZMAX's key strengths include:

• Proven efficacy against common bacterial pathogens.
• Once-daily dosing potentially enhances adherence.
• Existing patent protections and market exclusivity through scheduled patent expirations.

What is the current patent landscape?

Pfizer filed patents covering ZMAX; the primary patent in the U.S. was set to expire in 2024. Despite patent protections, generic versions have entered some markets, impacting pricing and sales volume. Pfizer has sought new formulations, formulations patents, and secondary patents to extend exclusivity – a common strategy in antibiotics.

How does ZMAX perform financially?

As of the latest fiscal reports, ZMAX contributed a modest revenue stream relative to Pfizer’s broader portfolio. In 2022, ZMAX generated approximately $50 million in U.S. sales, a decline compared to peak sales exceeding $150 million in 2014, driven by generic competition and clinical shifts favoring other antibiotics.

• The drug's revenue reflects its niche positioning and patent expiration timeline.
• Price erosion and market penetration are key challenges.

What are the key investment considerations?

Market Dynamics:

• The antibiotics segment is highly competitive with generic availability, pressuring margins.
• Increasing antimicrobial resistance (AMR) could influence prescribing patterns, both positively (need for new antibiotics) or negatively (regulatory constraints).

Patent and Regulatory Outlook:

• Patent expirations in 2024 open space for biosimilar or generic competition.
• Pfizer may pursue secondary approvals or reformulations to extend exclusivity.

Pipeline Potential:

• Pfizer's research pipeline includes novel antibiotics targeting resistant pathogens, but ZMAX-specific pipeline products are limited.
• The potential for ZMAX reformulation or combination therapy options offers some upside.

Market Access and Pricing:

• Pricing strategies in the U.S. rely on formularies and insurers’ preferences.
• Lower reimbursement rates could reduce profitability.

Competitive Landscape:

• Over-the-counter and generic azithromycin formulations dominate in many markets.
• ZMAX's extended-release profile limits its advantage over immediate-release formulations.

What is the risk profile?

High patent risk after 2024: Loss of exclusivity will likely lead to significant generic erosion.

Pricing pressure: Increasing discounts and formulary restrictions.

Regulatory risks: Potential label changes due to safety signals or emerging resistance.

Market shifts: The growing recognition of antimicrobial stewardship could decrease antibiotic prescriptions.

Development risk: No significant pipeline dedicated to ZMAX reformulations or successors.

What is the outlook for investors?

ZMAX represents a low-growth, mature asset with limited upside post-patent expiry. Its valuation depends on:

• The timing of patent cliff and generic entry.
• Pfizer's ability to defend market share via reformulations or combination therapies.
• Broader industry trends toward novel antibiotics due to resistance issues.

In the broader Pfizer portfolio, ZMAX's contribution is relatively minor but offers stable cash flows while the patent lasts. Long-term investment prospects hinge on successful patent extension strategies or pipeline innovations.

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Key Takeaways

• ZMAX is a generic-competitor-impacted antibiotic with a revenue decline since 2014.
• Patent expiry in 2024 imminently threatens exclusivity.
• Market dynamics favor generics, constraining margins.
• The asset has limited future growth beyond patent protection and minor reformulation efforts.
• The outlook hinges on patent protection, market share retention, and innovation in antimicrobial development.

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FAQs

1. When does ZMAX's patent protection expire?
In the U.S., primary patents expire in 2024, opening the market to generics.

2. How does ZMAX compare to other azithromycin formulations?
ZMAX’s extended-release formulation offers once-daily dosing, which may improve compliance; however, immediate-release formulations are cheaper and widely available.

3. Are there emerging alternatives to ZMAX?
Yes, other antibiotics and combination therapies target similar infections, with some offering broader resistance coverage.

4. What strategies could Pfizer pursue to extend ZMAX’s lifecycle?
Possible approaches include reformulating the drug, developing combination therapies, or seeking secondary patent protections.

5. How does antimicrobial resistance influence ZMAX's future?
Growing resistance could reduce efficacy, potentially limiting market size. Conversely, resistance may incentivize new antibiotic development, indirectly benefiting innovative versions.

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References

[1] Pfizer Inc. Annual Reports.
[2] FDA Patent and Exclusivity Data.
[3] MarketWatch. Pharmaceutical Market Reports 2022.
[4] Evaluate Pharma. 2023 Portfolio Review.