CENESTIN Drug Patent Profile

Which patents cover Cenestin, and what generic alternatives are available?

Cenestin is a drug marketed by Aspen and is included in one NDA.

The generic ingredient in CENESTIN is estrogens, conjugated synthetic a. There are three drug master file entries for this compound. Additional details are available on the estrogens, conjugated synthetic a profile page.

Summary for CENESTIN

US Patents:	0
Applicants:	1
NDAs:	1

Paragraph IV (Patent) Challenges for CENESTIN

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
CENESTIN	Tablets	estrogens, conjugated synthetic a	0.3 mg, 0.45 mg and 0.9 mg	020992	1	2009-03-19
CENESTIN	Tablets	estrogens, conjugated synthetic a	0.625 mg	020992	1	2009-03-02
CENESTIN	Tablets	estrogens, conjugated synthetic a	1.25 mg	020992	1	2008-11-03

US Patents and Regulatory Information for CENESTIN

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Aspen	CENESTIN	estrogens, conjugated synthetic a	TABLET;ORAL	020992-001	Jun 21, 2002		DISCN	Yes	No
Aspen	CENESTIN	estrogens, conjugated synthetic a	TABLET;ORAL	020992-003	Mar 24, 1999		DISCN	Yes	No
Aspen	CENESTIN	estrogens, conjugated synthetic a	TABLET;ORAL	020992-005	Feb 5, 2004		DISCN	Yes	No
Aspen	CENESTIN	estrogens, conjugated synthetic a	TABLET;ORAL	020992-002	Mar 24, 1999		DISCN	Yes	No
Aspen	CENESTIN	estrogens, conjugated synthetic a	TABLET;ORAL	020992-004	Mar 13, 2000		DISCN	Yes	No

International Patents for CENESTIN

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

Country	Patent Number	Title	Estimated Expiration
Austria	401062
Canada	2227887	COMPOSITIONS PHARMACEUTIQUES D'OESTROGENES CONJUGUES ET LEURS PROCEDES D'UTILISATION (PHARMACEUTICAL COMPOSITIONS OF CONJUGATED ESTROGENS AND METHODS FOR THEIR USE)
China	100421652
China	1197387
Germany	69637601
European Patent Office	0840599	COMPOSITIONS PHARMACEUTIQUES D'OESTROGENES CONJUGUES ET LEURS PROCEDES D'UTILISATION (PHARMACEUTICAL COMPOSITIONS OF CONJUGATED ESTROGENS AND METHODS FOR THEIR USE)

Cenestin (Estrogens, Esterified) Investment Scenario and Patent/Exclusivity Fundamentals Analysis

Last updated: July 13, 2026

Cenestin (esterified estrogens) is a long-established hormone therapy marketed in the US under multiple dosage strengths. Patent and exclusivity positions are likely to be limited in the near term given age of origin, with value driven more by formulation/labeling remaining on the US market, buyer-specific contracts, and generic competitive intensity than by near-term IP-led upside. Core investment diligence should focus on (1) whether any active Orange Book listings remain tied to the currently marketed strengths, (2) launch and settlement history for likely generics/authorized equivalents, and (3) litigation and FDA status that can delay generic competition.

What patents protect Cenestin (esterified estrogens) in the US?

A complete US patent estate analysis requires the drug’s exact Orange Book listing entries by strength and dosage form (listed active ingredients, dosage form, applicant/holder, and each listed US patent number with expiry). The request requires a complete and accurate response, including enumerated patent numbers and expiration dates, but those Orange Book listings are not provided in the prompt.

How many Orange Book listings does Cenestin have and what are their patent expiry dates?

Orange Book status is the control point for US market exclusivity and patent expiration sequencing. The prompt does not include the current Orange Book entries for Cenestin (active ingredients, strengths, dosage forms, patent numbers, and expiry dates). Without that data, an expiry timeline and count of listings cannot be produced accurately.

When does Cenestin lose exclusivity in the US?

“Loss of exclusivity” must be tied to either (a) patent expiration(s) listed for the relevant marketed strength/dosage form or (b) FDA exclusivity types (including 5-year, 3-year, orphan, pediatric, and any granted exclusivity extensions). The prompt does not include any FDA exclusivity identifiers or Orange Book expiry dates for Cenestin. A correct exclusivity date cannot be computed from the information given.

What generic entry risks exist for Cenestin (and which Paragraph IV filings matter)?

Paragraph IV litigation risk depends on specific ANDA filings challenging Orange Book patents for the relevant Cenestin listing(s). That requires the ANDA docket history and which patents were challenged. No ANDA or Paragraph IV litigation docket details are provided.

Is Cenestin facing generic competition and how has market share shifted?

Market-share and revenue exposure analysis requires at least one of the following: FDA approvals of competing ANDAs, IMS sales or syndicated market data for Cenestin, or contract/manufacturer statements with revenue breakdown by strength and channel. The prompt provides none of these.

What patent litigation affects Cenestin (settlements, injunctions, and court outcomes)?

Patent litigation fundamentals must be built from docket records (complaints, counterclaims, Markman orders, injunction status, settlements, and any Federal Circuit outcomes). The prompt contains no litigation history, case numbers, parties, or settlement terms.

What settlements or licensing deals govern Cenestin generics or authorized equivalents?

Settlement and licensing analysis requires named parties, agreement dates, and the list of products covered (NDCs/strengths) plus the effective launch dates and any “carve-outs.” No such deal documentation is supplied.

What formulations are protected for Cenestin (dosage forms, strengths, and manufacturing methods)?

Formulation and manufacturing patent scope is strength- and process-dependent (for example, changes to release characteristics, excipients, or manufacturing parameters). A valid analysis needs the specific listed patents and their claims tied to the marketed dosage forms and strengths. The prompt does not supply Orange Book or patent-number details.

Do method-of-use patents protect Cenestin (indications, dosing regimens, and labeling)?

Method-of-use protection is indication- and claim-scope-specific. For an accurate method-of-use estate, the analysis must identify asserted or listed US patents that claim specific uses (e.g., menopausal symptoms, vasomotor symptoms, hypoestrogenism, prevention/treatment contexts) and identify expiration. The prompt provides no patent list or claim summaries.

How does Cenestin compare with other esterified estrogen brands and generics (competitive landscape)?

A credible competitive landscape comparison requires (1) competitor list with their FDA approval status, (2) strength-level mapping to NDCs and active ingredient (esterified estrogens), and (3) patent/Orange Book comparisons for overlapping strengths. None of that detail is included.

What biosimilar risk exists for Cenestin?

Cenestin is a small-molecule/estrogen drug, not a biologic. Biosimilar risk is generally not applicable, but a correct statement still depends on confirming the regulatory classification and whether any biologic pathway equivalent exists, which is not provided.

What is the FDA regulatory status of Cenestin (NDA/ANDA history and current pathway)?

FDA status analysis requires the NDA number, supplement history, listed reference product details, current manufacturing information, and any FDA enforcement (e.g., product discontinuations or withdrawals). The prompt includes none of these identifiers.

Which companies hold the Cenestin reference product and who are likely generic challengers?

Company-level analysis requires the current reference listed drug (RLD) holder/applicant in the Orange Book and the list of ANDA applicants with potential challenges. The prompt does not include those entities or applicant names.

What is the patent strength of Cenestin for investors (claim defensibility, remaining term, and geographic coverage)?

Patent strength is assessed with remaining claim term, claim breadth, remaining unexpired patents, and the history of successful challenges. Without listed patent numbers, filing/priority dates, and expiry dates for Cenestin’s active listings, this cannot be evaluated accurately.

Revenue exposure: how sensitive is Cenestin to generic erosion and price compression?

Revenue sensitivity needs baseline sales, gross-to-net trends, wholesaler/channel concentration, and timing of generic entries by strength. The prompt provides no sales data or competitive entry timing.

Investment scenario summary: where is the upside or downside likely to come from?

Downside drivers for an older, likely commoditized estrogen product typically include (1) generic entry at additional strengths, (2) price compression, (3) supply disruptions, and (4) label/market access changes due to regulatory or payer constraints. Upside drivers, if any remain, usually come from (1) strength-specific non-interchangeable coverage via remaining patent or exclusivity, (2) updated labeling or clinical differentiation that blocks substitutes, and (3) manufacturing reliability that supports premium contracts. None of these scenario levers can be tied to Cenestin-specific facts in the absence of Orange Book status, NDA identifiers, litigation history, or sales/market data.

Key Takeaways

• Cenestin fundamentals for investors depend on strength-level US patent and Orange Book status, including exact listing counts and unexpired patent expiry dates.
• The prompt does not include the Orange Book listings, patent numbers, or FDA identifiers required to build a factual exclusivity and litigation timeline.
• Without that control-point data, a complete and accurate investment scenario grounded in patent expiry sequencing, Paragraph IV risk, and generic entry timing cannot be produced.

FAQs

1. What is the Orange Book RLD status for Cenestin by strength?
2. Are there any unexpired formulation patents for Cenestin strengths (NDC-level)?
3. Have any ANDAs filed Paragraph IV certifications against Cenestin listed patents?
4. What NDA and supplement identifiers govern Cenestin labeling and manufacturing changes?
5. What are the most active generic competitors for esterified estrogens in the US market by strength?

References

No sources were cited because the prompt did not include the Orange Book/FDA listing details, litigation records, or company-level identifiers required to produce a complete and accurate, fact-cited analysis.