SYNTHETIC CONJUGATED ESTROGENS A Drug Patent Profile

When do Synthetic Conjugated Estrogens A patents expire, and when can generic versions of Synthetic Conjugated Estrogens A launch?

Synthetic Conjugated Estrogens A is a drug marketed by Teva Womens and is included in one NDA.

The generic ingredient in SYNTHETIC CONJUGATED ESTROGENS A is estrogens, conjugated synthetic a. There is one drug master file entry for this compound. Additional details are available on the estrogens, conjugated synthetic a profile page.

Summary for SYNTHETIC CONJUGATED ESTROGENS A

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	33
Clinical Trials:	6
Patent Applications:	1,826
DailyMed Link:	SYNTHETIC CONJUGATED ESTROGENS A at DailyMed

Recent Clinical Trials for SYNTHETIC CONJUGATED ESTROGENS A

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

Sponsor	Phase
Duramed Research	Phase 4
Stanley Medical Research Institute	Phase 2
The Alfred	Phase 2

See all SYNTHETIC CONJUGATED ESTROGENS A clinical trials

US Patents and Regulatory Information for SYNTHETIC CONJUGATED ESTROGENS A

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Teva Womens	SYNTHETIC CONJUGATED ESTROGENS A	estrogens, conjugated synthetic a	CREAM;VAGINAL	021788-001	Nov 28, 2008		DISCN	No	No

Synthetic Conjugated Estrogens A Market Dynamics, Patent Position, and Financial Trajectory

Last updated: August 23, 2026

Synthetic conjugated estrogens A is a small-molecule oral estrogen product used primarily for menopausal vasomotor symptoms, vulvar and vaginal atrophy, and postmenopausal osteoporosis prevention. Its commercial history is tied mainly to the Enjuvia brand and generic competition. The product has limited standalone financial visibility because manufacturers have generally reported it within broader women’s-health portfolios rather than as a separately disclosed revenue line.

The commercial profile is structurally mature: FDA approval dates back to 2003, regulatory exclusivity has expired, generic estrogen alternatives are widely available, and the principal competitive pressure comes from estradiol products, generic conjugated estrogens, vaginal estrogen products, and nonhormonal menopause therapies.

What is synthetic conjugated estrogens A?

Synthetic conjugated estrogens A is a mixture of synthetic estrogen sulfate compounds, principally sodium estrone sulfate and sodium equilin sulfate. It is distinct from natural-source conjugated estrogens, including Pfizer’s Premarin product, although both products are used in overlapping menopausal hormone-therapy indications.

The principal U.S. branded product was Enjuvia, an oral tablet available in multiple strengths. The product label identifies the following approved uses:

• Treatment of moderate-to-severe vasomotor symptoms associated with menopause.
• Treatment of moderate-to-severe symptoms of vulvar and vaginal atrophy.
• Prevention of postmenopausal osteoporosis.

FDA labeling requires the lowest effective dose for the shortest duration consistent with treatment objectives. Estrogen therapy carries boxed-warning risks involving endometrial cancer, cardiovascular events, breast cancer and probable dementia in certain postmenopausal populations. These safety considerations constrain prescribing and limit long-term market expansion. [1]

How does synthetic conjugated estrogens A differ from Premarin?

Attribute	Synthetic conjugated estrogens A	Premarin
Active ingredient	Synthetic conjugated estrogens A	Conjugated estrogens
Principal brand	Enjuvia	Premarin
Sponsor history	Duramed, Warner Chilcott, Actavis/Allergan-associated portfolios	Pfizer
Dosage form	Oral tablets	Oral tablets, vaginal cream and other formulations
FDA approval	2003 for Enjuvia	Earlier approval; multiple formulations
Product type	Small-molecule estrogen	Small-molecule estrogen mixture
Biosimilar exposure	None	None
Main competitive risk	Generic and alternative estrogen products	Generic and alternative estrogen products

Premarin has historically had greater brand recognition, a broader product franchise and more durable commercial scale. Synthetic conjugated estrogens A has competed primarily through product differentiation and substitution within the systemic oral estrogen segment.

What is the FDA regulatory status of synthetic conjugated estrogens A?

Synthetic conjugated estrogens A is an FDA-approved small-molecule drug. The Enjuvia product received U.S. approval in 2003 under NDA 021438, according to FDA product records and labeling materials. [1,2]

The product does not have biologic status. Biosimilar pathways therefore do not apply. Competitive entry is governed through abbreviated new drug applications, subject to the availability of reference-product data, applicable patent certifications and FDA requirements for pharmaceutical equivalence.

When did synthetic conjugated estrogens A lose exclusivity?

The product’s original regulatory exclusivity has expired. A 2003 approval date means any standard new chemical entity exclusivity associated with approval would have ended no later than the traditional five-year period, while any three-year clinical-investigation exclusivity would also have expired long ago. Current commercial protection depends primarily on patents, formulation differentiation, manufacturing know-how, trademarks and distribution economics rather than FDA exclusivity.

The relevant commercial conclusion is that synthetic conjugated estrogens A is a mature product with no meaningful remaining regulatory barrier to generic substitution.

What patents protect synthetic conjugated estrogens A?

The key patent issue is not whether synthetic conjugated estrogens A once had patent protection. It did. The issue is whether any enforceable, unexpired U.S. patent currently blocks generic approval or launch.

For a mature product approved in 2003, composition and formulation patents filed near the approval period would generally have statutory terms extending approximately 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment or patent-term extension. That places the likely end of the principal patent window in the early 2020s, absent later-filed formulation or method-of-use patents.

The relevant protection categories are:

1. Composition patents covering the synthetic estrogen mixture.
2. Formulation patents covering tablet composition, dissolution, stability or dose uniformity.
3. Method-of-use patents covering menopausal symptoms, vaginal atrophy or osteoporosis.
4. Manufacturing patents covering synthesis, purification or blend specifications.
5. Regulatory exclusivity and labeling protection, which are distinct from patent rights.

Public FDA materials should be distinguished from patent-office records. The Orange Book identifies patents submitted by an NDA holder for approved drug products, but it does not establish that every listed patent is currently enforceable or commercially blocking. Patent status must be assessed against USPTO records, terminal disclaimers, maintenance-fee status, court decisions and any settlement agreements. [2,3]

What formulation patents are relevant?

Formulation patents are potentially more relevant than broad composition claims because synthetic conjugated estrogens A is an established active ingredient. A generic entrant may avoid an expired formulation claim by using different excipients, manufacturing processes or dissolution characteristics, provided the product satisfies FDA pharmaceutical-equivalence requirements.

The remaining value of formulation intellectual property is therefore likely to be narrow. It may protect a specific tablet architecture or manufacturing process, but it is unlikely to preserve broad market exclusivity for the active ingredient.

What manufacturing barriers affect generic entry?

Manufacturing barriers are more significant than biosimilar barriers because the active ingredient is a defined mixture of estrogen sulfate compounds. A producer must control:

• Identity and ratio of estrogen components.
• Batch-to-batch consistency.
• Impurity profile.
• Content uniformity.
• Dissolution performance.
• Stability under the proposed shelf life.
• Analytical methods capable of distinguishing component concentrations.

These requirements can raise development costs and delay entry, but they do not create the biologic comparability burden associated with monoclonal antibodies or other complex biologics. Once an applicant establishes adequate chemistry, manufacturing and controls data, the barrier is primarily operational rather than legal.

How many patents cover synthetic conjugated estrogens A?

The number of relevant patents depends on the jurisdiction, reference product, Orange Book update date and whether expired patents are counted. A simple patent count is therefore a weak measure of exclusivity.

The commercially important distinction is:

Patent category	Likely commercial relevance
Core composition patents	Low if expired
Early formulation patents	Low to moderate, depending on claim scope and validity
Method-of-use patents	Potentially relevant only if listed, unexpired and enforceable
Manufacturing patents	Moderate for supply protection; usually avoidable by process design
Trademark rights	Brand protection without blocking generic approval
Trade secrets	Possible protection for manufacturing know-how, but not a substitute for market exclusivity

The patent estate should be classified as mature and limited unless a current Orange Book review identifies an unexpired, litigation-tested patent with broad claims.

Which companies are challenging synthetic conjugated estrogens A?

Generic competition is the principal challenge. The likely competitive set includes manufacturers of:

• Generic synthetic conjugated estrogens A tablets.
• Generic conjugated estrogens tablets.
• Oral estradiol.
• Estradiol transdermal patches and gels.
• Vaginal estradiol tablets, creams and rings.
• Estradiol-progestin combination products.

Specific Paragraph IV challengers and their launch dates require a current review of FDA Orange Book certifications, ANDA litigation dockets and commercial launch notices. FDA approval alone does not prove that a product has launched, and an ANDA approval may be delayed by patent litigation or a settlement agreement.

No biosimilar company is relevant because synthetic conjugated estrogens A is not a biologic.

What generic entry risks exist?

Generic entry risk is high. The main factors are:

• Long-expired approval exclusivity.
• Mature active-ingredient technology.
• Availability of alternative estrogen products.
• Limited brand differentiation.
• Physician familiarity with generic hormone therapy.
• Payer incentives favoring low-cost products.
• Limited protection from complex-device or biologic comparability requirements.

Generic entry may not produce a single abrupt launch event. It can occur through multiple approved strengths, limited initial distribution, authorized-generic supply and payer-driven substitution.

What is the Orange Book status of synthetic conjugated estrogens A?

The Orange Book is the controlling FDA reference for listed patents, therapeutic equivalence codes and reference-product status. For a product such as Enjuvia, an Orange Book review should focus on:

• NDA 021438.
• Approved dosage strengths.
• Listed patents and their expiration dates.
• Paragraph IV certifications associated with approved ANDAs.
• Therapeutic-equivalence ratings for generic products.
• Whether the reference product remains commercially marketed.

The Orange Book does not provide revenue, market-share or current supply information. It also does not resolve patent validity. Those questions require SEC filings, company announcements, court records and commercial-distribution data. [2]

What patent litigation affects synthetic conjugated estrogens A?

The primary litigation risk would arise from a Paragraph IV certification alleging that an Orange Book-listed patent is invalid, unenforceable or not infringed. Potential litigation issues include:

• Whether a generic formulation falls within a tablet-composition claim.
• Whether the listed patent is properly submitted to the Orange Book.
• Whether method-of-use claims are carved out through a section viii statement.
• Whether the brand holder seeks a 30-month stay.
• Whether a settlement permits an agreed generic launch date.
• Whether the generic applicant launches at risk.

For this mature product, the economic value of litigation is likely lower than for a high-revenue drug. A brand holder may still litigate to protect residual revenue, but the expected return depends on remaining branded volume and the number of substitute estrogen products.

What is the commercial market for synthetic conjugated estrogens A?

The product competes in the broader menopausal hormone-therapy market. Market demand is shaped by five forces:

1. Declining use of systemic hormone therapy after publication of major safety findings and subsequent changes in prescribing behavior.
2. Aging populations creating a continuing need for menopause treatment.
3. Growth of lower-cost generic estradiol.
4. Increased use of transdermal and local vaginal estrogen products.
5. Patient and physician preference for individualized risk-benefit decisions.

Oral synthetic conjugated estrogens A has a narrower commercial position than a diversified women’s-health franchise. It lacks the scale of a leading estrogen brand and faces substitution from products with different administration routes.

How strong is the commercial position?

Driver	Assessment
Regulatory exclusivity	Exhausted
Patent protection	Likely mature and limited
Brand recognition	Lower than Premarin
Prescriber demand	Stable but constrained
Generic substitution	High
Product differentiation	Limited
Manufacturing complexity	Moderate
Biosimilar risk	Not applicable
Pricing power	Low
Long-term growth potential	Limited

What is the financial trajectory for synthetic conjugated estrogens A?

A reliable standalone revenue series is not generally available from public company filings. Sponsors have historically grouped the product with broader women’s-health or legacy pharmaceutical portfolios. As a result, product-level revenue, gross margin and market share cannot be reconstructed with the same confidence available for major publicly reported brands.

The financial trajectory is nevertheless clear:

• Early commercialization benefited from branded pricing and limited direct competition.
• Revenue potential was constrained by competition from Premarin, estradiol and other hormone products.
• Mature-product economics deteriorated as generic alternatives expanded.
• Portfolio ownership changes reduced continuity of brand investment.
• Current value is more likely to come from low-cost supply, licensing or residual cash flow than from brand growth.
• Any future upside would depend on a differentiated formulation, a new indication or a supply disruption affecting competing estrogen products.

The principal financial risk is price erosion rather than sudden clinical obsolescence. Menopausal hormone therapy remains an established treatment area, but the active ingredient is readily substitutable and lacks a strong exclusivity moat.

How does synthetic conjugated estrogens A compare with competing estrogen products?

Product class	Competitive position	Generic risk	Growth profile
Synthetic conjugated estrogens A	Mature oral estrogen	High	Low
Premarin oral tablets	Larger legacy brand	High	Low to stable
Generic estradiol oral	Broad payer access	High, already established	Stable
Transdermal estradiol	Route and safety-perception advantage	High	Stable to moderate
Vaginal estradiol	Local therapy positioning	High	Moderate
Nonhormonal menopause therapies	Alternative mechanism	Product-specific	Potentially higher

Transdermal estradiol has a strategic advantage for some patients because clinicians may prefer lower systemic exposure or different thromboembolic-risk considerations. Vaginal estrogen products compete for genitourinary symptoms but do not fully replace systemic therapy for vasomotor symptoms.

What licensing deals affect synthetic conjugated estrogens A?

The product’s ownership history has involved corporate portfolio transfers associated with women’s-health businesses, including the movement of products from Duramed and Warner Chilcott into larger pharmaceutical portfolios. Public disclosures do not establish a major current licensing transaction that materially changes the product’s competitive outlook.

The more relevant commercial arrangements are likely to involve:

• Contract manufacturing.
• Authorized distribution.
• Generic supply agreements.
• Portfolio divestitures.
• Regional commercialization rights.

Without separately disclosed product economics, the value of any licensing deal cannot be measured from public filings alone.

Key Takeaways

• Synthetic conjugated estrogens A is a mature oral estrogen product associated principally with Enjuvia.
• FDA approval dates to 2003, and regulatory exclusivity has expired.
• Generic entry risk is high because the active ingredient is a small molecule with multiple therapeutic substitutes.
• Biosimilar risk is irrelevant.
• Patent value is likely concentrated in narrow formulation, method-of-use or manufacturing claims rather than broad composition protection.
• The Orange Book is necessary for current listed-patent and therapeutic-equivalence analysis, but it does not establish patent validity or commercial launch.
• Standalone revenue is generally not publicly disclosed, making precise product-level financial modeling unreliable.
• The financial trajectory is consistent with a mature, low-growth product facing price erosion and substitution.
• The strongest remaining commercial defenses are supply reliability, manufacturing capability, distribution access and any differentiated formulation.

FAQs

Is synthetic conjugated estrogens A the same as Premarin?

No. Both are estrogen products used in overlapping menopausal indications, but synthetic conjugated estrogens A and Premarin contain different estrogen mixtures and have different product histories.

Can a generic manufacturer use the Enjuvia label?

A generic applicant may rely on the reference product’s safety and efficacy findings through the ANDA pathway, but it must meet FDA requirements for pharmaceutical equivalence, bioequivalence, labeling and manufacturing quality.

Is synthetic conjugated estrogens A a biologic drug?

No. It is a small-molecule estrogen mixture, so the biosimilar pathway does not apply.

Does an expired patent prevent generic approval?

No. An expired patent cannot independently block approval or launch. A current, enforceable patent or other regulatory barrier would be required.

What is the main investment risk for this product?

The main risk is sustained price and volume erosion caused by generic substitution and competition from estradiol, transdermal estrogen and vaginal estrogen products.

References

1. U.S. Food and Drug Administration. (2003). Enjuvia (synthetic conjugated estrogens, A) tablets: Prescribing information. FDA.

2. U.S. Food and Drug Administration. (n.d.). Drugs@FDA: Enjuvia, NDA 021438. FDA.

3. U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations. FDA.

4. U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA.

5. U.S. Food and Drug Administration. (2023). Menopause and hormone therapy information. FDA.