Drugs in MeSH Category Abortifacient Agents, Steroidal

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Corcept Therap	KORLYM	mifepristone	TABLET;ORAL	202107-001	Feb 17, 2012	AB	RX	Yes	Yes	10,195,214
Corcept Therap	KORLYM	mifepristone	TABLET;ORAL	202107-001	Feb 17, 2012	AB	RX	Yes	Yes	10,780,097
Corcept Therap	KORLYM	mifepristone	TABLET;ORAL	202107-001	Feb 17, 2012	AB	RX	Yes	Yes	10,166,242
Corcept Therap	KORLYM	mifepristone	TABLET;ORAL	202107-001	Feb 17, 2012	AB	RX	Yes	Yes	10,495,650
Corcept Therap	KORLYM	mifepristone	TABLET;ORAL	202107-001	Feb 17, 2012	AB	RX	Yes	Yes	10,166,243

Last updated: July 3, 2026

Abortifacient Agents, Steroidal (MeSH): Market Dynamics and Patent Landscape

Executive summary

Steroidal abortifacient agents marketed in the U.S. and key ex-US jurisdictions are dominated by mifepristone-based products (often in fixed-dose or co-pack regimens) and other steroidal pathways that intersect with progesterone receptor activity. Patent coverage is typically split across: (1) active ingredient and early composition of matter, (2) method-of-use and dosing regimen patents tied to pregnancy indication and termination schedules, (3) formulation and pack-device patents (including blister and co-pack designs), and (4) manufacturing and process patents that extend exclusivity through generic “design-around” barriers. Revenue exposure concentrates in the earliest-to-expire mifepristone-related estates, while generic entry risk is highest when Orange Book-listed method-of-use claims are narrow, when FDA labeling is changed by post-approval supplements, and when Paragraph IV certifications target non-core formulation or process claims.

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Which steroidal abortifacient agents are used clinically and how is the market structured?

Steroidal abortifacient agents in the NLM MeSH Class Abortifacient Agents, Steroidal are largely defined by progesterone receptor modulation and downstream uterotonic physiology. The commercial footprint is primarily driven by mifepristone-containing regimens and derivative commercial formats, with market segmentation by:

• Regimen type (mifepristone alone vs mifepristone-and-misoprostol co-regimens)
• Care setting (office-based, telehealth-enabled in jurisdictions that permit it, and clinic/hospital protocols)
• Regulatory status (approval pathway alignment affects switching and generic uptake)
• Access and distribution (touchpoints include REMS-like controls where applicable, distribution restrictions, and payer formulary coverage)

Key commercial patterns impacting patent value

• Labeling is the gating factor for “regimen” exclusivity. Method-of-use patents that map tightly to labeled timing and dosage can slow generic substitutions even when composition-of-matter expires.
• Formulation and packaging patents can become de facto barriers when the generic product must match the labeling’s co-administration timing while using a different dose form or pack architecture.
• Country-by-country dynamics matter because pregnancy termination frameworks differ widely, affecting both launch timing and litigation incentives.

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What patents protect steroidal abortifacient agents (mifepristone and related progesterone antagonists) in the U.S.?

Patent estates for steroidal abortifacient agents commonly include four layers:

1. Composition of matter
   • Active ingredient synthesis and polymorph claims
   • Salt forms (if applicable), crystal form, and hydrates
2. Formulation
   • Tablet composition, excipient selection, dissolution profile targets
   • Film coating and stability packages designed to maintain bioavailability under controlled storage
3. Method of use
   • Specific dosing schedules for pregnancy indication and termination time windows
   • Gestational-age boundaries and clinical administration steps
4. Manufacturing/process
   • High-yield routes, crystallization control, impurity limits
   • Scale-up controls and validated process parameters

Patent landscape mechanics that drive licensing and Paragraph IV challenges

• Generics often seek approval that references the brand NDA, but certification strategy targets claims they believe are invalid, unenforceable, or not infringed.
• In progesterone antagonist regimens, the most litigated claims tend to be method-of-use rather than pure composition-of-matter, because a generic can often sell the same active ingredient after expiration but still need a compliant label.

Data requirement constraint: A complete, accurate, jurisdiction-specific patent list (numbers, assignees, filing dates, expiration dates, and Orange Book status) cannot be generated from the prompt alone without a mapped reference drug and its FDA application identifiers.

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When does mifepristone lose exclusivity, and what specific exclusivity periods matter for generics?

Generic entry timing is driven by multiple clocks:

• Statutory patent expiration (composition and method-of-use patents)
• Regulatory exclusivity (new chemical entity and new clinical investigations, if applicable)
• Patent term adjustments and extensions (PTA/PTE)
• FDA labeling exclusivity via method-of-use coverage when Orange Book-listed claims align tightly with the approved regimen

Practical “loss of exclusivity” triggers

• A generic can launch only when it has an approval pathway that permits it to include labeling consistent with its certification and any litigation stay provisions.
• Even if composition claims expire, remaining method-of-use claims can block full label parity.

Data requirement constraint: No specific drug product name, NDA/BLA number, strength, dosage form, or Orange Book listing can be mapped from the prompt alone, so an accurate expiration timetable cannot be produced.

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What is the Orange Book status of steroidal abortifacient agents, and how does it affect Paragraph IV filings?

Orange Book status is the primary operational dataset for:

• Determining which patents are Orange Book-listed and claim-relevant for infringement analysis
• Identifying claim numbers that generics certify under 21 USC 355(b)(2)(A)/(B)/(C)/(D)

How Orange Book structure impacts litigation outcomes

• If an estate includes many Orange Book-listed claims, Paragraph IV challengers typically attack the smallest infringement set first.
• Brands often have leverage when they can secure early injunctions based on broad method claims that read on labeled regimen steps.

Data requirement constraint: The prompt does not identify the specific FDA reference listed drug (RLD). Without RLD mapping, Orange Book status cannot be stated accurately.

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How many patents cover steroidal abortifacient drugs, and what claim categories dominate?

In steroidal abortifacient estates, it is common that:

• Early composition coverage provides baseline exclusivity.
• Later patenting concentrates on method-of-use and formulation/process improvements that keep litigation viable after early compound claims are aged.

Claim-category dominance and litigation strategy

• Method-of-use claims: high litigation frequency due to regimen step infringement.
• Formulation: can matter when generics must match release characteristics affecting dosing timing.
• Process: less frequently determinative for infringement unless the generic route uses a materially identical process or product-by-process claim theory is strong.

Data requirement constraint: Patent counts require an identified reference product and a dataset-backed enumeration.

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Which companies are challenging steroidal abortifacient patents, and what are typical settlement patterns?

Paragraph IV challenges are usually filed by mid-tier and large generic manufacturers plus authorized labelers. Settlement patterns typically include:

• License to market after a design-around period
• Staggered entry across strengths or package formats
• Label carve-outs that mirror patent scope
• Cross-licensing linked to formulation or distribution arrangements

Data requirement constraint: The prompt does not provide named challengers, listed drugs, or litigation dockets, so company and settlement detail cannot be stated without risking inaccuracy.

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What generic entry risks exist for steroidal abortifacient regimens if key method-of-use claims narrow?

Generic risk increases when:

• Method-of-use claims are narrowly tied to specific gestational windows that are not required for all labeled uses.
• Brand labeling changes after approval reduce the factual basis for infringement.
• Generic uses a different dosing schedule that still falls within permitted labeling, supported by updated clinical evidence.

Attack vectors that reduce brand leverage

• Non-infringement via different regimen steps
• Invalidity arguments targeting claim novelty and obviousness using prior art
• Inequitable conduct allegations where prosecution history supports it (rare but consequential)

Data requirement constraint: Actual claim text and label history must be identified to assess infringement and generic risk.

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How do formulation and packaging patents affect biosimilar-like substitution risk in steroidal abortifacient drugs?

Steroidal abortifacient agents are typically small molecules, not biologics. “Biosimilar-like” substitution is not the correct mechanism. However, formulation and packaging patents can create analogous substitution barriers:

• Generic must match not only API identity but also dissolution, stability, and administration timing that the label assumes.
• Co-pack or device-linked patents can limit a generic’s ability to sell an equivalent regimen without infringing pack-device or kit claims.

Key patent types that act as substitutes-for-bioequivalence barriers

• Kit compositions and co-pack designs
• Specific excipient combinations to support rapid dissolution
• Stability claims tied to storage and handling windows required for the regimen

Data requirement constraint: Without product identification and patent dataset linkage, formulation and packaging coverage cannot be enumerated.

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What method-of-use patents are most likely to be litigated for steroidal abortifacient regimens?

Method-of-use claims most likely to be asserted cover:

• Pregnancy termination administration timing
• Gestational age boundaries
• Specific clinical step sequences (administration order, follow-up evaluation timing)
• Use in particular patient subpopulations when supported by trial data

Litigation economics

• Claims tightly tied to labeled steps are easier to prove infringement.
• Claims that read broadly on therapeutic intent can be attacked as obvious or not novel, depending on prior art.

Data requirement constraint: Claim scope can only be assessed with the identified patents and the labeled regimen.

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Which regulatory milestones shape market entry for steroidal abortifacient generics in the U.S. and EU?

Key milestones include:

• FDA submission and approval timeline under ANDA referencing the RLD
• FDA labeling negotiation tied to certification and litigation outcomes
• For EU markets, EMA national authorization pathways and local labeling practices
• Post-approval changes that trigger supplements and can alter label requirements that drive infringement

How regulatory outcomes drive patent leverage

• If a brand’s label expands or contracts, the infringement footprint changes.
• Regimen timing label changes can shift whether method-of-use claims are enforceable against the generic.

Data requirement constraint: Regulatory milestone timelines require the specific ANDA filings and agency communications.

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How does mifepristone compare with other steroidal abortifacient agents in patent estate strength?

Patent estate strength can be compared along:

• Number and recency of Orange Book-listed patents
• Breadth of method-of-use claims
• Remaining life of formulation and process patents
• Litigation history and outcomes

Data requirement constraint: No competitor agents or specific products are identified; without product mapping the comparative assessment cannot be made accurately.

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Key timelines: where market exclusivity usually breaks first for steroidal abortifacient drugs

A typical break sequence in steroidal small-molecule estates:

1. Composition of matter ages first (early patents)
2. Method-of-use remains longer due to later clinical data and regimen claims
3. Formulation/process patents can extend practical barriers even after core patents expire

Data requirement constraint: A real timeline requires the exact patent set and expiration dates.

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Key Takeaways

• Steroidal abortifacient markets are driven by progesterone receptor pathway products where exclusivity is sustained through stacked patents across composition, formulation, and labeled regimen method-of-use.
• Orange Book alignment and labeling specificity determine whether generics face meaningful litigation friction at launch.
• Generic entry risk is highest where method-of-use claims are narrow, label steps can be changed, or infringement can be designed around via alternate dosing administration routes.
• Patent estate strength for a specific drug cannot be quantified from the prompt alone without identifying the exact FDA RLD and enumerating its Orange Book-listed patents.

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FAQs

1. How do Orange Book method-of-use patents delay ANDA launches for progesterone antagonist abortifacient regimens?
2. What patent claim types most often survive challenges in steroidal small-molecule abortifacient estates?
3. Which factors most influence whether a generic can launch with a fully label-matching regimen?
4. How do post-approval label supplements change infringement analysis for method-of-use claims?
5. What commercial levers (co-pack, dosing kit, distribution controls) can brands use alongside patents to slow generic substitution?

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References

1. U.S. FDA, Orange Book: Approved Drug Products with Therapeutic Equivalence Evaluations (Orange Book).
2. 21 U.S.C. § 355.
3. FDA Guidance for Industry: Patent Certifications and Section viii Statements (ANDA).