ZOVIRAX Drug Patent Profile

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

Zovirax is a drug marketed by Pharmobedient, Bausch, and Glaxosmithkline. and is included in six NDAs.

The generic ingredient in ZOVIRAX is acyclovir sodium. There are fifty-six drug master file entries for this compound. Eight suppliers are listed for this compound. Additional details are available on the acyclovir sodium profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Zovirax

A generic version of ZOVIRAX was approved as acyclovir sodium by FRESENIUS KABI USA on May 13^th, 1998.

Summary for ZOVIRAX

US Patents:	0
Applicants:	3
NDAs:	6
Finished Product Suppliers / Packagers:	3
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	13
Patent Applications:	1,753
Drug Prices:	Drug price information for ZOVIRAX
What excipients (inactive ingredients) are in ZOVIRAX?	ZOVIRAX excipients list
DailyMed Link:	ZOVIRAX at DailyMed

See drug prices for ZOVIRAX

Recent Clinical Trials for ZOVIRAX

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

Sponsor	Phase
International Bio service	PHASE1
PT. Kimia Farma (Persero) Tbk	N/A
PT Pharma Metric Labs	N/A

See all ZOVIRAX clinical trials

Pharmacology for ZOVIRAX

Drug Class	Herpes Simplex Virus Nucleoside Analog DNA Polymerase Inhibitor Herpes Zoster Virus Nucleoside Analog DNA Polymerase Inhibitor Herpesvirus Nucleoside Analog DNA Polymerase Inhibitor
Mechanism of Action	DNA Polymerase Inhibitors

US Patents and Regulatory Information for ZOVIRAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pharmobedient	ZOVIRAX	acyclovir	CAPSULE;ORAL	018828-001	Jan 25, 1985		DISCN	Yes	No
Pharmobedient	ZOVIRAX	acyclovir	SUSPENSION;ORAL	019909-001	Dec 22, 1989		DISCN	Yes	No
Glaxosmithkline	ZOVIRAX	acyclovir sodium	INJECTABLE;INJECTION	018603-003	Aug 30, 1983		DISCN	Yes	No
Pharmobedient	ZOVIRAX	acyclovir	TABLET;ORAL	020089-001	Apr 30, 1991		DISCN	Yes	No

Expired US Patents for ZOVIRAX

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Pharmobedient	ZOVIRAX	acyclovir	CAPSULE;ORAL	018828-001	Jan 25, 1985
Pharmobedient	ZOVIRAX	acyclovir	TABLET;ORAL	020089-002	Apr 30, 1991
Bausch	ZOVIRAX	acyclovir	OINTMENT;TOPICAL	018604-001	Mar 29, 1982
Pharmobedient	ZOVIRAX	acyclovir	TABLET;ORAL	020089-001	Apr 30, 1991

International Patents for ZOVIRAX

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

Country	Patent Number	Title	Estimated Expiration
Netherlands	7702175
Switzerland	628897	VERFAHREN ZUR HERSTELLUNG NEUER SUBSTITUIERTER PURINE.
Finland	770655
Kenya	3561	TOPICAL FORMULATIONS OF 9-(2-HYDROXYETHOXYMETHYL)GUANINE

Supplementary Protection Certificates for ZOVIRAX

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0809498	SPC/GB10/012	United Kingdom		PRODUCT NAME: A COMBINATION OF ACYCLOVIR AND HYDROCORTISONE; REGISTERED: UK PL18191/0001-0001 20091112
0809498	10C0038	France		PRODUCT NAME: ACYCLOVIR ET HYDROCORTISONE; NAT. REGISTRATION NO/DATE: NL 36 826 20100420; FIRST REGISTRATION: SK - 2108/08467-R 20091026

Market Dynamics and Financial Trajectory for Zovirax (Acyclovir)

Last updated: July 27, 2025

Introduction

Zovirax, the brand name for Acyclovir, remains a critical antiviral medication primarily used to treat herpes simplex virus (HSV) infections, including oral and genital herpes, as well as varicella-zoster virus (VZV) infections such as shingles and chickenpox. Since its introduction, Zovirax has experienced evolving market dynamics driven by technological advancements, competitive pressure, and changing epidemiology. This article analyzes the current market landscape, demographic factors influencing demand, regulatory influences, and the financial trajectory of Zovirax.

Market Landscape and Key Drivers

Global Market Overview

The global antiviral drugs market, inclusive of herpes treatments, was valued at approximately USD 37 billion in 2022 and is projected to reach over USD 50 billion by 2028, growing at a compound annual growth rate (CAGR) of around 5.3% (source: Fortune Business Insights). Zovirax holds a significant market share owing to its longstanding efficacy, widespread acceptance, and extensive patent protection until recent patent expirations.

Epidemiological Trends

Herpes simplex virus infections are endemic worldwide, with an estimated 67% of the global population aged 0-49 having been infected with HSV-1, and approximately 13% of individuals aged 15-49 globally living with HSV-2 (WHO, 2020). The rising prevalence of genital herpes, coupled with aging populations prone to shingles, fuels demand for antiviral therapies like Zovirax.

Technological and Formulation Advancements

Although Zovirax's original intravenous (IV), oral, and topical formulations remain effective, newer formulations—such as controlled-release and combination therapies—are emerging. Nonetheless, Zovirax's established safety profile sustains its market demand, especially in developing regions with limited access to newer antivirals.

Competitive Environment

The patent expiration of Zovirax's core formulation has led to the proliferation of generic acyclovir products, intensifying price competition. Generic manufacturers have captured a substantial portion of the market, often leading to a significant drop in prices. New entrants, notably branded alternatives like Valacyclovir (Valtrex), have also garnered market share due to their improved bioavailability and dosing convenience.

Regulatory and Patent Dynamics

Acyclovir's original patent expired in 2003 globally, exposing Zovirax to generic competition (source: U.S. Patent and Trademark Office). Despite loss of patent exclusivity, GSK (GlaxoSmithKline), the original manufacturer, retains rights through partial patents and formulations, enabling market differentiation. Regulatory pathways for biosimilars and formulations influence market access and pricing strategies.

Financial Trajectory and Revenue Trends

Historical Revenue Performance

Zovirax's revenue has experienced notable declines post-patent expiration. GSK reported that acyclovir sales in the U.S. peaked at approximately USD 1 billion annually before 2004. Post-generic entry, annual sales dwindled, with estimates around USD 300-400 million globally, predominantly driven by brand loyalty in certain regions and hospital demand [2].

Pricing and Market Penetration

Generic competition has exerted downward pressure on unit prices. In some markets, prices for generic acyclovir have fallen by upwards of 70%. However, formulations with improved bioavailability or branded combinations maintain premium pricing in select markets, sustaining profitability.

Emerging Revenue Opportunities

While Zovirax faces declining sales in mature markets, growth prospects lie in developing nations with expanding healthcare infrastructure and high herpes prevalence. Aligning with regional pricing and distribution policies could stabilize or even expand the revenue base.

Impact of New Therapies and Biosimilars

Newer drugs such as Valacyclovir and Famciclovir, which offer more convenient dosing schedules, have pressure on Zovirax's market share. The advent of biosimilars may further challenge branded acyclovir’s revenue streams, reminiscent of the impact seen in other antiviral sectors.

Forecasting Future Trends

Considering patent expiry effects and market competition, Zovirax's revenues are projected to decline by CAGR of approximately 3-5% over the next five years. However, strategic diversification, such as expanding into combination therapies and expanding into emerging markets, could mitigate downside risks.

Market Segments and Geographic Insights

Regional Disparities

• North America: Mature market with established generics, experiencing gradual decline in Zovirax revenues.
• Europe: Similar patterns to North America, with variations due to healthcare policies and local generics.
• Asia-Pacific: High HSV and VZV prevalence, combined with increasing healthcare spending, offers growth potential.
• Emerging Markets: Rapid adoption driven by affordability and expanding healthcare infrastructure.

Consumer Digitalization and Prescription Trends

The digital health revolution influences prescription behaviors. Telemedicine adoption has increased antiviral prescriptions, including Zovirax, especially in remote areas where herpes outbreaks are common. Market access strategies leveraging digital platforms may influence future sales.

Regulatory and Patent Considerations

Patent Status and Legal Landscape

With core patents expired in many jurisdictions, the entrance of generics is inevitable. However, secondary patents and formulations continue to extend exclusivity slightly, providing short-term revenue buffers.

Regulatory Barriers and Opportunities

Stringent regulatory pathways in certain markets may delay generic entry, preserving revenues temporarily. Conversely, accelerated approval processes and biosimilar pathways could threaten future profitability.

Conclusion: Strategic Outlook

Zovirax remains a cornerstone antiviral despite declining revenues due to patent expiration. Its future financial trajectory depends on strategic positioning in emerging markets, continued innovation in formulations, and navigating competitive pressures from generics and new therapies. Companies leveraging its legacy brand will need adaptive strategies including pricing, digital engagement, and pipeline diversification to sustain profitability.

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Key Takeaways

• Market decline due to patent expiry: Generic competition has significantly reduced Zovirax’s global revenues, with a projected CAGR decline of 3-5% over the next five years.
• Growth potential in emerging markets: High prevalence rates and expanding healthcare infrastructure in Asia-Pacific and developing regions present growth opportunities.
• Competition from newer antivirals: Branded drugs like Valacyclovir encroach on Zovirax’s share, emphasizing the importance of formulation improvements and differentiations.
• Regulatory landscape: Patent expirations and biosimilar pathways are critical factors influencing future market dynamics.
• Strategic positioning: Diversification into combination therapies, digital health initiatives, and regional expansion are vital for maintaining market relevance.

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FAQs

1. How has patent expiration affected Zovirax's market share?
The expiration of core patents in 2003 led to widespread generic entry, reducing Zovirax's market share and significantly decreasing revenues in mature markets.

2. Are there any new formulations of Zovirax that could regain market share?
Currently, Zovirax's formulations remain largely unchanged. However, innovation through controlled-release or topical combinations could provide competitive edges, though no recent major reformulations have emerged.

3. What are the primary competitors to Zovirax in the herpes treatment market?
Valacyclovir (Valtrex), Famciclovir (Famvir), and newer antiviral agents with improved dosing and pharmacokinetics are primary competitors.

4. Can emerging markets sustain Zovirax’s profitability?
Yes, high disease prevalence combined with lower generic penetration makes emerging markets promising for sustained or increased revenues.

5. How does the emergence of biosimilars impact Zovirax?
While acyclovir itself isn’t a biologic, biosimilar pathways for related drugs can influence perceptions, pricing, and competition strategies in the antiviral segment.

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References:

[1] Fortune Business Insights. (2022). "Antiviral Drugs Market Size, Share & Industry Analysis."
[2] GSK Annual Reports, 2000–2022.
[3] WHO, Global Epidemiology of HSV and VZV, 2020.
[4] U.S. Patent and Trademark Office. Patent Expiry Records, 2003.