CLINICAL TRIALS PROFILE FOR PREMARIN

505(b)(2) Clinical Trials for PREMARIN

This table shows clinical trials for potential 505(b)(2) applications. See the next table for all clinical trials

Trial Type	Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
New Formulation	NCT00380887 ↗	Study Comparing Four New Formulations for Premarin in Healthy Postmenopausal Women	Completed	Wyeth is now a wholly owned subsidiary of Pfizer		2005-06-01	The purpose of this study is to determine bioequivalence and bioavailability of four different Premarin/MPA test formulations versus the current formulation for Prempro.
New Formulation	NCT00381251 ↗	Study Comparing Bioequivalence of Two New Formulations of Premarin/MPA With Premarin/MPA Reference Formulation.	Completed	Wyeth is now a wholly owned subsidiary of Pfizer	Phase 1	2006-09-01	This study will compare the bioequivalence of two new investigational combination formulations of Premarin and medroxyprogesterone acetate (MPA) with a currently marketed formulation of Premarin and medroxyprogesterone, Prempro™. Prempro is indicated for use after menopause in women with a uterus to reduce moderate to severe hot flashes; to treat moderate to severe dryness, itching, and burning, in and around the vagina; and to help reduce your chances of getting osteoporosis (thin weak bones). The purpose of this study is to determine if these new formulations of Premarin and MPA provide the same levels of estrogen and MPA in the blood as Prempro in healthy postmenopausal women.
New Formulation	NCT00401219 ↗	Study Comparing Bioavailability of 3 New Formulations of Premarin/MPA With Premarin/MPA (PREMPRO) Reference Formulation	Completed	Wyeth is now a wholly owned subsidiary of Pfizer	Phase 1	2006-11-01	This study will compare the bioavailabity of three new investigational combination formulations of Premarin and medroxyprogesterone acetate (MPA) with a currently marketed formulation of Premarin and MPA, Prempro™. Prempro™ is indicated for use after menopause in women with a uterus to reduce moderate to severe hot flashes; to treat moderate to severe dryness, itching, and burning, in and around the vagina; and to help reduce your chances of getting osteoporosis (thin weak bones). The purpose of this study is to determine if these new formulations of Premarin/MPA provide the same levels of estrogen and MPA in the blood as Prempro in healthy postmenopausal women.
New Formulation	NCT00472927 ↗	Bioequivalence Study of 3 New Formulations of Premarin/MPA Compared With Premarin/MPA (Prempro)	Completed	Wyeth is now a wholly owned subsidiary of Pfizer	Phase 1	2007-05-01	To evaluate three new investigational tablet formulations of the Food and Drug Administration (FDA) approved medication Prempro™, Premarin combined with medroxyprogesterone acetate (MPA).
New Formulation	NCT00630435 ↗	Study Comparing 3 New Formulations of Premarin® 0.625 mg/MPA 2.5 mg With a Reference Formulation	Completed	Wyeth is now a wholly owned subsidiary of Pfizer	Phase 1	2008-02-01	The purpose of this trial is to determine the equivalence of 3 new formulations of a Premarin®/medroxyprogesterone acetate (MPA) combination tablet to the currently marketed dosage form (Prempro® [TM]). This study will be performed in healthy postmenopausal women. Each subject will participate in the study for approximately 14 weeks, including a screening evaluation within 3 weeks before the study, and four, 6-day, 5-night inpatient periods with at least a 21-day washout interval between each dose administration.
New Formulation	NCT01436513 ↗	A Study To Compare The Amount Of Premarin Components That Is Absorbed Into The Blood Of Japanese Healthy Postmenopausal Women Following Oral Administration Of Two Different Tablets Of Premarin Under Fast and Fed Conditions.	Completed	Pfizer	Phase 1	2011-10-01	The purpose of this study is to assess the bioequivalence and food effect for a new Premarin formulation compared with a Premarin reference tablet in Japanese healthy postmenopausal women.

All Clinical Trials for PREMARIN

Trial ID	Title	Status	Sponsor	Phase	Start Date	Summary
NCT00000175 ↗	The Effects of Sex Hormones on Cognition and Mood in Older Adults	Terminated	National Institute on Aging (NIA)	N/A	1969-12-31	This study is investigating the effects of hormone replacement therapy on memory, mental abilities and mood in older adults aged 65-90. During the nine month long study, men will take testosterone for three months and women will take estrogen for three months. At four points during the study (once every three months), participants will complete a test battery and have blood drawn.
NCT00000555 ↗	Women's Angiographic Vitamin and Estrogen Trial (WAVE)	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 3	1996-08-01	To assess whether hormonal replacement therapy and/or antioxidant treatment would stabilize or inhibit progression, and induce regression of coronary plaques. The mechanisms by which these treatments modified atherosclerosis in women were also explored.
NCT00002976 ↗	Estrogen Replacement Therapy in Treating Women With Early-Stage Endometrial Cancer	Terminated	Eastern Cooperative Oncology Group	Phase 3	1997-06-01	RATIONALE: Estrogen replacement therapy may improve quality-of-life in postmenopausal women with endometrial cancer. It is not yet known whether estrogen replacement therapy will affect cancer recurrence. PURPOSE: Randomized double-blinded phase III trial to determine the effectiveness of estrogen replacement therapy in treating women who have stage I or stage II endometrial cancer.
NCT00002976 ↗	Estrogen Replacement Therapy in Treating Women With Early-Stage Endometrial Cancer	Terminated	National Cancer Institute (NCI)	Phase 3	1997-06-01	RATIONALE: Estrogen replacement therapy may improve quality-of-life in postmenopausal women with endometrial cancer. It is not yet known whether estrogen replacement therapy will affect cancer recurrence. PURPOSE: Randomized double-blinded phase III trial to determine the effectiveness of estrogen replacement therapy in treating women who have stage I or stage II endometrial cancer.
NCT00002976 ↗	Estrogen Replacement Therapy in Treating Women With Early-Stage Endometrial Cancer	Terminated	Southwest Oncology Group	Phase 3	1997-06-01	RATIONALE: Estrogen replacement therapy may improve quality-of-life in postmenopausal women with endometrial cancer. It is not yet known whether estrogen replacement therapy will affect cancer recurrence. PURPOSE: Randomized double-blinded phase III trial to determine the effectiveness of estrogen replacement therapy in treating women who have stage I or stage II endometrial cancer.
NCT00002976 ↗	Estrogen Replacement Therapy in Treating Women With Early-Stage Endometrial Cancer	Terminated	Gynecologic Oncology Group	Phase 3	1997-06-01	RATIONALE: Estrogen replacement therapy may improve quality-of-life in postmenopausal women with endometrial cancer. It is not yet known whether estrogen replacement therapy will affect cancer recurrence. PURPOSE: Randomized double-blinded phase III trial to determine the effectiveness of estrogen replacement therapy in treating women who have stage I or stage II endometrial cancer.
NCT00083824 ↗	Estrogen, HDL, and Coronary Heart Disease in Women	Completed	National Heart, Lung, and Blood Institute (NHLBI)	Phase 2/Phase 3	2004-03-01	To clarify the effects of estrogen, with or without progestin, on high density lipoprotein (HDL) in postmenopausal women.

Clinical Trial Conditions for PREMARIN

Condition Name

Condition Name for PREMARIN
Intervention	Trials
Postmenopause	10
Menopause	8
Pelvic Organ Prolapse	3
Healthy	2

Condition MeSH

Condition MeSH for PREMARIN
Intervention	Trials
Prolapse	4
Pelvic Organ Prolapse	4
Vaginitis	4
Atrophic Vaginitis	3

Clinical Trial Locations for PREMARIN

Trials by Country

Trials by Country for PREMARIN
Location	Trials
United States	150
Germany	7
Canada	6
United Kingdom	5
Australia	3

Trials by US State

Trials by US State for PREMARIN
Location	Trials
Florida	9
Texas	8
California	7
Massachusetts	7
Arizona	6

Clinical Trial Progress for PREMARIN

Clinical Trial Phase

Clinical Trial Phase for PREMARIN
Clinical Trial Phase	Trials
Phase 4	10
Phase 3	6
Phase 2/Phase 3	2

Clinical Trial Status

Clinical Trial Status for PREMARIN
Clinical Trial Phase	Trials
Completed	38
Terminated	5
Recruiting	3

Clinical Trial Sponsors for PREMARIN

Sponsor Name

Sponsor Name for PREMARIN
Sponsor	Trials
Wyeth is now a wholly owned subsidiary of Pfizer	13
University of Washington	4
Pfizer	4

Sponsor Type

Sponsor Type for PREMARIN
Sponsor	Trials
Other	69
Industry	23
NIH	8

Last updated: April 26, 2026

Premarin (conjugated estrogens) | Clinical Trials Update, Market Analysis, and Projection

Premarin is a long-established estrogen therapy (conjugated estrogens) used primarily for menopausal vasomotor symptoms and related estrogen-deficiency conditions. The product’s current market and pipeline profile is shaped by (i) limited meaningful late-stage development activity for the reference brand, (ii) steady demand from legacy users and prescribers, and (iii) ongoing competitive pressure from branded and authorized generics and alternative estrogen formulations.

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What is Premarin’s clinical-trials activity profile right now?

Late-stage and “registration-enabling” trials

No contemporaneous, publicly tracked, registration-enabling Phase 3 program for Premarin (reference product) is evident in major public trial registries in the last several years based on the available registry record set reviewed (clinical trial record visibility varies by sponsor intent, but no clear Phase 3 registration path is apparent for the reference brand).

What dominates “new” clinical evidence

The observable clinical evidence surrounding Premarin is typically driven by:

• Label maintenance and post-authorization studies (safety, utilization, comparative tolerability, adherence)
• Comparative pharmacokinetics and formulation work tied to generic and biosimilar-adjacent market participants (where applicable)
• Broader estrogen-class observational research that supports guideline adherence rather than a new Premarin-specific mechanism or formulation

Evidence that is still clinically relevant to market access

Premarin’s prescribing position is anchored in FDA labeling history and ongoing safety communications for estrogen therapies. The labeling and safety framework is the main channel through which new clinical data affects uptake, not a visible wave of brand-new Phase 3 trials.

Key labeling-safety governance that continues to influence use and prescriber comfort

• Contraindications and boxed warning framework for estrogen-containing products includes uterine malignancy risk considerations and serious adverse risks that drive patient selection and monitoring. (FDA prescribing information for Premarin.) [1]
• Risk-benefit framing tied to route, dose, duration, and patient profile remains the operational determinant of prescribing volume. [1]

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How does Premarin perform in the market today?

Market structure

Premarin competes in the systemic estrogen therapy segment that is characterized by:

• High switching pressure between branded reference and authorized generics
• Formulation breadth across tablets, creams, and other estrogen delivery systems
• Patient-specific selection (uterus status, indication, tolerability, contraindications)

Demand drivers

• Chronic, repeat prescribing for symptom management and other approved indications
• Long patient histories with conjugated estrogens in the community
• Clinician inertia in favor of established therapies when patients stabilize on treatment

Demand headwinds

• Generic competition compresses unit pricing and reduces branded share
• Shift to alternative estrogen formulations (routes and drug classes) based on tolerability, convenience, and updated risk perceptions across patient populations
• Long-cycle safety scrutiny for systemic estrogen class continues to constrain conversion for new initiations in some settings

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Where does Premarin face the most direct commercial pressure?

Primary competitive buckets

1. Authorized generics of conjugated estrogens (direct substitution)
2. Other systemic estrogen options (different molecules and delivery routes)
3. Therapy substitution driven by changing risk-benefit decision patterns

Why substitution matters operationally

In a mature market, the unit growth is often limited, while share movement captures most of the value. Brand differentiation is typically insufficient to prevent downward pricing pressure and utilization drift once generic coverage expands.

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What does the current patent and exclusivity landscape imply for brand share?

Premarin’s reference product is long past initial approval-era exclusivities, and the market is dominated by authorized generics and therapeutic alternatives. The practical implication is that near-term brand revenue dynamics depend more on:

• managed-care formulary positioning,
• prescriber preference patterns,
• and persistence rates, than on exclusivity-driven price floors.

(For purposes of this update, no forward-looking, brand-relevant exclusivity event is required to explain the core market behavior: generics and substitution constrain branded growth.)

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How should you project Premarin’s revenue trajectory?

Projection basis

Given the mature status of conjugated estrogens and the absence of a visible brand-led Phase 3 registration program, the most defensible projection approach is utilization and price-dynamics modeling:

• Volume: stable to slightly declining due to substitution and initiation constraints
• Net revenue: declines or flat-to-slow growth driven by pricing erosion, offset by persistence

Base-case projection (directional)

• Short term (1-2 years): net revenue likely flat to low single-digit decline driven by continued pricing pressure and generic share capture
• Medium term (3-5 years): net revenue likely low single-digit annual decline unless market-specific access improves (formulary changes, payer steering, or churn back to branded reference)

What could change the trajectory?

• Strong formulary placement or payer-specific utilization programs that improve retention of reference Premarin among patients stable on conjugated estrogens
• Class-wide shifts in prescribing behavior (for example, reduced use of systemic estrogen in certain subpopulations)
• New evidence affecting clinical comfort for systemic estrogen use, which could affect initiation rates more than persistence

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Clinical and regulatory guardrails that shape utilization

Label obligations that affect prescribing

Premarin labeling includes standardized estrogen therapy safety warnings and usage constraints that influence who starts and who continues. This includes:

• Risk-benefit limitations based on age, duration since menopause, and patient risk profile
• Uterine risk considerations for patients with a uterus, which drives requirement for progestin management in many cases
• Thromboembolic and malignancy risk discussion that affects clinician decision-making and patient willingness [1]

Operational impact

Even if symptoms improve in treated patients, these guardrails limit the addressable patient pool for new initiations and can reduce persistence in some risk categories.

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Investment and R&D implications

If you are underwriting a lifecycle strategy

Premarin is not a “renewal pipeline” story. It is a legacy utilization story where upside comes from:

• minimizing revenue leakage to competitors,
• protecting access in key formularies,
• and exploiting patient persistence.

If you are evaluating “next-gen” estrogen delivery

The commercial environment for systemic estrogen therapies rewards formulation and patient-experience differentiation, not necessarily new mechanisms. Premarin’s stable demand can coexist with replacement by:

• more convenient regimens,
• different estrogenic molecules with perceived tolerability advantages,
• and route-specific preferences.

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Key Takeaways

• Premarin’s near-term outlook is defined by mature-market dynamics and substitution pressure, not by visible brand-led late-stage clinical advancement.
• Clinical evidence relevant to market access is largely label-anchored safety governance and post-authorization utilization considerations. [1]
• Projection: expect flat to low single-digit decline in net revenue over the next 1-2 years, with low single-digit annual decline through 3-5 years in the base case.
• Commercial outcomes hinge on formulary access and persistence more than on exclusivity or a new registration pathway.

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FAQs

1) Is Premarin currently advancing through Phase 3 for a new indication?

No clear registration-enabling Phase 3 program for the reference Premarin brand is evident in the available public trial record set reviewed; the observable activity is consistent with post-authorization evidence and class-level research rather than a new Phase 3 brand program.

2) What is the main reason Premarin brand growth is constrained?

Authorized generics and therapeutic substitution constrain branded share and pricing, making unit growth difficult and forcing reliance on retention and formulary positioning rather than new clinical differentiators.

3) What labeling elements most affect prescribing volume?

The boxed warning framework and contraindications around serious risks, plus uterine management considerations, drive patient selection and can limit initiation and persistence in higher-risk groups. [1]

4) How does generic competition translate into revenue impact?

It typically lowers net pricing and shifts volume to cheaper alternatives, causing branded net revenue to decline even if overall estrogen use remains steady.

5) What would be a positive catalyst for Premarin revenue?

Improved formulary access and payer steering that increases reference-product utilization among stable patients, or class-wide guideline shifts that expand eligible initiations without increasing discontinuation rates.

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References

[1] Pfizer. Premarin (conjugated estrogens) Prescribing Information. U.S. Food and Drug Administration. https://www.accessdata.fda.gov/ (accessed via the Premarin label entry in FDA’s drug labeling repository).