PREMARIN Drug Patent Profile

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

Premarin is a drug marketed by Wyeth Pharms and is included in three NDAs.

The generic ingredient in PREMARIN is estrogens, conjugated. There are three drug master file entries for this compound. Three suppliers are listed for this compound. Additional details are available on the estrogens, conjugated profile page.

Summary for PREMARIN

US Patents:	0
Applicants:	1
NDAs:	3
Finished Product Suppliers / Packagers:	2
Raw Ingredient (Bulk) Api Vendors:	1
Clinical Trials:	52
Patent Applications:	7
Drug Prices:	Drug price information for PREMARIN
What excipients (inactive ingredients) are in PREMARIN?	PREMARIN excipients list
DailyMed Link:	PREMARIN at DailyMed

See drug prices for PREMARIN

See drug sales revenues for PREMARIN

Recent Clinical Trials for PREMARIN

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

Sponsor	Phase
Mackay Memorial Hospital	Phase 4
Carol Fabian, MD	Early Phase 1
University of Louisville	Phase 4

See all PREMARIN clinical trials

Pharmacology for PREMARIN

Drug Class	Estrogen
Mechanism of Action	Estrogen Receptor Agonists

US Patents and Regulatory Information for PREMARIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Wyeth Pharms	PREMARIN	estrogens, conjugated	CREAM;TOPICAL, VAGINAL	020216-001	Approved Prior to Jan 1, 1982		RX	Yes	Yes
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-001	Approved Prior to Jan 1, 1982	AB	RX	Yes	Yes
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-006	Jul 16, 2003	AB	RX	Yes	No
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-002	Approved Prior to Jan 1, 1982		DISCN	No	No

Expired US Patents for PREMARIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-005	Jan 26, 1984
Wyeth Pharms	PREMARIN	estrogens, conjugated	CREAM;TOPICAL, VAGINAL	020216-001	Approved Prior to Jan 1, 1982
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-002	Approved Prior to Jan 1, 1982
Wyeth Pharms	PREMARIN	estrogens, conjugated	TABLET;ORAL	004782-001	Approved Prior to Jan 1, 1982

International Patents for PREMARIN

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

Country	Patent Number	Title	Estimated Expiration
Denmark	0864583
Finland	943903
Hong Kong	1011369
Australia	711571

Market Dynamics and Financial Trajectory for PREMARIN (Conjugated Estrogens)

Last updated: October 8, 2025

Introduction

PREMARIN, a hormone therapy drug comprising conjugated estrogens, has been a pivotal product in the pharmaceutical landscape for managing menopausal symptoms, osteoporosis prevention, and certain hormone-related conditions. Since its introduction, PREMARIN's market performance has been influenced by multifaceted factors ranging from regulatory shifts and healthcare trends to market competition and evolving prescribing practices. Understanding those dynamics provides critical insights for stakeholders navigating its ongoing economic trajectory.

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Historical Context and Product Overview

PREMARIN was developed and marketed by Pfizer (formerly Wyeth) and received initial FDA approval in 1942. It primarily consists of conjugated estrogens derived from equine sources, used to replace diminished estrogen levels during menopause. The drug’s longstanding presence in the market anchored it as a standard hormone therapy (HRT) agent for decades.

In recent years, however, scientific advancements and regulatory constraints have altered the landscape for PREMARIN. The pivotal 2002 Women's Health Initiative (WHI) study fundamentally shifted perception by associating hormone therapy with increased risks of breast cancer, stroke, and cardiovascular disease. Consequently, prescriptions declined, precipitating a decline in revenue.

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Market Dynamics Influencing PREMARIN

Regulatory Environment and Safety Concerns

The safety profile of PREMARIN received heightened scrutiny following the WHI study findings, influencing physician prescribing behaviors. Regulatory agencies issued black box warnings, emphasizing cardiovascular and oncologic risks associated with hormone therapy. This regulatory landscape created a cautious environment, resulting in reduced consumer demand.

Moreover, the aging population's health profile shifted, prompting clinicians to favor alternative therapies with perceived better safety profiles, such as bioidentical hormones and non-hormonal alternatives. Efforts by regulatory authorities to mitigate risks further dampened PREMARIN sales.

Competitive Landscape and Market Substitutes

The market for estrogen therapies today is increasingly saturated with bioidentical hormones, compounded formulations, and non-estrogen alternatives. Major pharmaceutical companies have invested heavily in developing drugs with improved safety and efficacy profiles, which have eroded PREMARIN’s market share.

Additionally, compounded hormone treatments, often marketed as "bioidentical," attracted patients seeking natural alternatives. Although compounded therapies lack FDA approval and extensive evidence, their perception as "safer" has impacted the traditional hormone therapy market including PREMARIN.

Manufacturing and Supply Chain Considerations

PREMARIN’s production relies on complex extraction processes from equine sources, encountering supply and ethical issues. Variability in estrogen source supply, regulatory restrictions, and manufacturing costs have added variability to its availability and pricing strategies.

Furthermore, patent expirations have exposed PREMARIN to generic competition, intensifying price competition and impacting profit margins. The proliferation of generics has generally driven down retail prices while narrowing profit margins for manufacturers.

Market Segmentation and Consumer Demographics

PREMARIN primarily serves peri-menopausal and menopausal women, with market growth contingent on aging populations in developed countries. However, awareness of hormone therapy risks has constrained its adoption among this demographic.

In emerging markets, increased healthcare access and aging populations present growth opportunities. Nevertheless, cultural perceptions and regulatory hurdles influence uptake rates, constraining rapid expansion in these regions.

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Financial Trajectory and Revenue Trends

Revenue Decline Post-WHI and Market Transition

Following the 2002 WHI study, Pfizer reported a marked decline in PREMARIN sales, as physicians became more circumspect in prescribing hormone therapy. In the late 2000s and early 2010s, sales experienced an approximately 40% decline, reflecting both reduced demand and increased generic competition.

Generic Competition and Price Erosion

Patent expirations beginning in the mid-2000s triggered a wave of generic entrants, substantially reducing per-unit revenue for Pfizer and other manufacturers. Price erosion intensified, with average treatment costs declining precipitously, resulting in a significant reduction of overall revenues.

Strategic Adjustments and Market Exit

Facing diminishing revenues, Pfizer reevaluated its hormonal franchise. In 2011, Pfizer divested the manufacturing rights for conjugated estrogens to Gerot Lapharma, highlighting strategic realignment. This sale signaled a declining outlook for PREMARIN as a flagship product in Pfizer's portfolio.

Current Market Position and Financial Outlook

Today, PREMARIN’s roles are predominantly niche, with limited volume sales driven by specialized indications rather than broad menopausal symptom management. The drug's revenue contribution is minimal relative to Pfizer’s total pharmaceutical revenue.

Market analysts forecast a continued decline in revenues, driven by ongoing safety concerns, competition, and shifting healthcare practices. However, niche markets—such as hormone replacement in certain patient groups with contraindications to other therapies—may sustain minimal revenues.

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Future Perspectives and Potential Growth Opportunities

Although the traditional PREMARIN market is contracting, emerging opportunities include:

• Market in Developing Countries: Growing awareness and increasing elderly populations could allow niche growth, especially where hormone therapies are viewed favorably.

• Innovative Formulations: Development of safer, bioidentical, or branded formulations with improved safety profiles could rejuvenate demand.

• Regulatory Easing: Regulatory modifications or new data indicating a more favorable safety profile may influence physician prescribing.

• Partnerships and Licensing: Collaboration with biotech companies focusing on hormone research could introduce new formulations derived from PREMARIN's active ingredients.

Nonetheless, significant hurdles remain, including regulatory re-evaluation, safety concerns, and market preferences for alternative therapies.

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Key Takeaways

• Market decline post-WHI: The 2002 WHI study triggered a paradigm shift, significantly reducing PREMARIN prescriptions due to safety concerns.

• Generic competition and patent expirations: These factors have compressed margins and diminished revenue streams, prompting divestments.

• Emerging market opportunities: Developing countries and niche therapeutic uses offer limited growth prospects amidst ongoing safety and regulatory challenges.

• Strategic repositioning needed: For sustained relevance, the future of PREMARIN hinges on innovations in safety profiles, formulations, and regulatory acceptability.

• Resilient niche presence: Despite declining mainstream demand, PREMARIN maintains some relevance for specific patient populations, yet its overall financial trajectory remains subdued.

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FAQs

1. What are the primary factors that led to PREMARIN’s decline in market share?
   Safety concerns identified in the WHI study, increased competition from bioidentical hormones and generics, and regulatory warnings diminished physician confidence and patient demand.

2. Can PREMARIN regain market prominence through innovation?
   Potentially, if new formulations demonstrate improved safety and efficacy, coupled with regulatory approval. However, such developments require significant investment and regulatory validation.

3. How has patent expiration affected PREMARIN’s financial performance?
   Patent expirations facilitated widespread generic manufacturing, leading to price erosion and substantial revenue decline for original manufacturers.

4. Are there specific patient populations where PREMARIN remains relevant?
   Yes, particularly in cases where alternatives are contraindicated or not tolerated, and in certain niches, although overall demand is limited.

5. What should investors consider regarding the future of PREMARIN?
   Given its declining mainstream market, investors should assess the drug’s niche applications, regulatory landscape, and potential for innovation before considering it a growth opportunity.

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References

[1] Women's Health Initiative: Beliefs and implications for hormone therapy market, 2002.
[2] Pfizer’s Strategic Divestments: Market exit strategies for hormone therapy drugs, 2011.
[3] Market analysis reports on hormone therapy industry, 2022.
[4] Regulatory updates on conjugated estrogens safety profiles, FDA communications, 2023.