ESTRING Drug Patent Profile

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

Estring is a drug marketed by Pfizer and is included in one NDA.

The generic ingredient in ESTRING is estradiol. There are seventy-five drug master file entries for this compound. Forty-seven suppliers are listed for this compound. Additional details are available on the estradiol profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Estring

A generic version of ESTRING was approved as estradiol by BARR LABS INC on October 22^nd, 1997.

Summary for ESTRING

US Patents:	0
Applicants:	1
NDAs:	1
Finished Product Suppliers / Packagers:	1
Raw Ingredient (Bulk) Api Vendors:	94
Clinical Trials:	4
Patent Applications:	3,885
Drug Prices:	Drug price information for ESTRING
Drug Sales Revenues:	Drug sales revenues for ESTRING
What excipients (inactive ingredients) are in ESTRING?	ESTRING excipients list
DailyMed Link:	ESTRING at DailyMed

See drug prices for ESTRING

See drug sales revenues for ESTRING

Recent Clinical Trials for ESTRING

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

Sponsor	Phase
Beth Israel Deaconess Medical Center	Phase 4
Boston Urogynecology Associates	Phase 4
Mount Auburn Hospital	Phase 4

See all ESTRING clinical trials

Pharmacology for ESTRING

Drug Class	Estrogen
Mechanism of Action	Estrogen Receptor Agonists

US Patents and Regulatory Information for ESTRING

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Pfizer	ESTRING	estradiol	INSERT, EXTENDED RELEASE;VAGINAL	020472-001	Apr 26, 1996		RX	Yes	Yes

Expired US Patents for ESTRING

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	Patent No.	Patent Expiration
Pfizer	ESTRING	estradiol	INSERT, EXTENDED RELEASE;VAGINAL	020472-001	Apr 26, 1996
Pfizer	ESTRING	estradiol	INSERT, EXTENDED RELEASE;VAGINAL	020472-001	Apr 26, 1996

International Patents for ESTRING

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

Country	Patent Number	Title	Estimated Expiration
Ireland	871377
Greece	3003551
Portugal	85082	DISPOSITIVO INTRA-VAGINAIS E PROCESSO PARA A SUA PREPARACAO
Denmark	175529
South Africa	8704174

Supplementary Protection Certificates for ESTRING

Patent Number	Supplementary Protection Certificate	SPC Country	SPC Expiration	SPC Description
0771217	07C0001	France		PRODUCT NAME: ETHINYLESTRADIOL BETADEX CLATHRATE; NAT. REGISTRATION NO/DATE: NL 32343 20060710; FIRST REGISTRATION: NL - RVG 31781 20050804
0770388	2009/012	Ireland		PRODUCT NAME: QLAIRA-ESTRADIOL VALERATE/DIENOGEST; NAT REGISTRATION NO/DATE: PA1410/58/1 20090109; FIRST REGISTRATION NO/DATE: BE327792 20081103
2782584	21C1058	France		PRODUCT NAME: COMPOSITION CONTENANT A LA FOIS DE L'ESTRADIOL (17SS-ESTRADIOL), Y COMPRIS SOUS FORME HEMIHYDRATEE, ET DE LA PROGESTERONE; NAT. REGISTRATION NO/DATE: NL51886 20210421; FIRST REGISTRATION: BE - BE582231 20210406
1453521	C 2015 029	Romania		PRODUCT NAME: LEVONORGESTREL SI ETINILESTRADIOL; NATIONAL AUTHORISATION NUMBER: RO 7793/2015/001; DATE OF NATIONAL AUTHORISATION: 20150612; NUMBER OF FIRST AUTHORISATION IN EUROPEAN ECONOMIC AREA (EEA): SK. 17/0017/15-S; DATE OF FIRST AUTHORISATION IN EEA: 20150129
0334429	97C0002	Belgium		PRODUCT NAME: ESTRADIOL; NAT. REGISTRATION NO/DATE: NL 18978 19960731; FIRST REGISTRATION: SE - 11783 19930305

Market Dynamics and Financial Trajectory for ESTRING

Last updated: February 24, 2026

What is ESTRING?

ESTRING is a transdermal vaginal estrogen product used primarily for hormone replacement therapy (HRT) in postmenopausal women. It delivers 0.1 mg of estradiol via a plastic ring inserted into the vagina and remains in place for three months. The product is manufactured by Pfizer.

Market Overview

Indications and Usage

ESTRING addresses symptoms of menopause, including vaginal atrophy, dryness, and discomfort. It competes mainly with other local estrogen therapies such as creams, tablets, and rings. Systemic estrogen therapies for menopause are a larger market segment, but ESTRING’s niche focuses on localized treatment.

Key Competitors

Product	Delivery Method	Estrogen Dose	Market Position	Manufacturer
ESTRING	Vaginal ring	0.1 mg	Niche, localized use	Pfizer
Vagifem	Vaginal tablet	10 mcg	Oral, localized use	Pfizer
Premarin Vaginal	Vaginal cream	Various	Broad estrogen market	Novartis
Osphena	Oral tablet	17-beta estradiol	Systemic use	Shionogi

Market Size and Growth

The global menopause market was valued at approximately USD 2.8 billion in 2022, with local estrogen therapies accounting for roughly 35%. The market for vaginal estrogen products specifically is projected to grow at a CAGR of 3-4% through 2030, driven by increasing awareness and aging populations.

Pricing and Access

ESTRING's average retail price varies globally; in the U.S., it was approximately USD 300–350 for a three-month supply in 2022. Insurance coverage impacts patient access; reimbursement policies favor established brands like Pfizer’s, supporting steady sales.

Regulatory and Reimbursement Landscape

Regulatory Status

ESTRING holds FDA approval since 2001 for the treatment of vaginal atrophy. It is approved in multiple markets, including the EU and Japan, with varying indications and label specifications.

Reimbursement Trends

Insurance reimbursement policies favor vaginal estrogen products for menopause symptoms. Patent protections and exclusivity periods contribute to Pfizer’s market control. Generic versions are not currently available, maintaining high margins.

Financial Trajectory

Revenue Trends

Pfizer’s sales of ESTRING have experienced modest declines since their peak in the early 2000s, coinciding with the advent of generic competitors and declining estrogen therapy prescriptions. In 2021, Pfizer reported estimated annual sales of USD 35–40 million from ESTRING globally.

Profitability and Pricing Strategy

The product maintains high margins due to high brand loyalty and limited competition. Pricing remains stable, supported by reimbursement policies and minimal price erosion compared to systemic hormone therapies.

Future Outlook

Sales are projected to stabilize due to the niche market focus but face headwinds from generic erosion, declining prescribing rates, and competition from alternative therapies. Pfizer may explore combination products or new indications to extend the product lifecycle.

Market Risks and Opportunities

Risks	Opportunities
Patent expiration	Developing new delivery modalities
Competition from generics	Expanding into emerging markets
Declining hormone therapy use	Combining ESTRING with other therapies

Summary

ESTRING operates within a stable yet declining niche of the local estrogen market, with revenues supported by brand loyalty, limited competition, and reimbursement policies. Its financial trajectory will depend heavily on patent status, market penetration, and potential product line extensions.

Key Takeaways

• ESTRING has normative annual sales of USD 35–40 million, with stable margins.
• Market growth remains modest; global estrogen therapy markets grow 3–4% annually.
• Patent expiry and emerging generic competition threaten future sales.
• Reimbursement policies favor longstanding brands, supporting revenue stability.
• Opportunities exist in novel delivery forms and expanded geographic markets.

FAQs

1. How does ESTRING compare to other local estrogen therapies?
It offers a three-month duration and is generally preferred over creams or tablets for convenience, but sales are limited by niche application and competition from other vaginal products.

2. What are the patent protections for ESTRING?
Pfizer’s patents expired in the early 2010s, opening the market to generics, which have yet to significantly penetrate due to brand loyalty and reimbursement policies.

3. How does the pricing of ESTRING impact sales?
High prices supported by insurance reimbursement sustain profitability but limit market share growth compared to lower-cost alternatives.

4. What factors may influence ESTRING’s future market performance?
Patent expiration, shifts in prescribing practices, regulatory approvals for new indications, and emerging competitors or generics.

5. Are there any upcoming product innovations for ESTRING?
No current public information on reformulations or new indications; Pfizer may focus on geographic expansion or combination therapies.

---

References

[1] MarketResearch.com. (2023). Global menopause market analysis.
[2] Pfizer Inc. (2022). ESTRING product details and sales figures.
[3] Statista. (2022). Menopause drug market size and forecast.
[4] European Medicines Agency. (2022). ESTRING approval and regulatory status.
[5] Walgreens Boots Alliance. (2022). Reimbursement and pricing overview for estrogen products.