List of Excipients in Branded Drug KORLYM

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	ALUMINUM OXIDE
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	CELLULOSE, MICROCRYSTALLINE
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	D&C YELLOW NO. 10
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	FD&C YELLOW NO. 6
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	HYDROXYPROPYL CELLULOSE
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	HYPROMELLOSE
Corcept Therapeutics Incorporated	KORLYM	mifepristone	76346-073	MAGNESIUM STEARATE

Korlym Excipient Strategy and Commercial Opportunities

Last updated: September 24, 2026

Korlym is a 300 mg mifepristone tablet marketed by Corcept Therapeutics for adults with endogenous Cushing’s syndrome who have type 2 diabetes mellitus or glucose intolerance and have failed surgery or are not candidates for surgery. Its excipient platform is conventional and appears optimized for immediate-release oral delivery, tablet robustness, and scalable commercial manufacturing rather than differentiated drug delivery. The main commercial opportunities are generic development, excipient and contract-manufacturing supply, lifecycle reformulation, and products that improve dose flexibility or reduce administration burden.

What is Korlym and how is it formulated?

Korlym is an immediate-release, film-coated tablet containing 300 mg of mifepristone. The product is administered orally once daily, with or without food, and the dose can be increased in 300 mg increments to a maximum of 1,200 mg daily, subject to tolerability and clinical response (U.S. Food and Drug Administration [FDA], 2024).

Korlym formulation profile

Attribute	Korlym specification
Active ingredient	Mifepristone
Strength	300 mg
Dosage form	Film-coated tablet
Route	Oral
Release profile	Immediate release
Administration	Once daily, with or without food
Approved indication	Hyperglycemia secondary to endogenous Cushing’s syndrome
Marketing authorization holder	Corcept Therapeutics
U.S. approval	February 17, 2012
NDA	202107
Key safety constraints	Adrenal insufficiency, hypokalemia, QT prolongation, endometrial effects, drug-drug interactions
Distribution	Restricted commercial distribution under product-specific prescribing and monitoring requirements

What excipients are used in Korlym?

The FDA prescribing information identifies the following inactive ingredients:

• Lactose monohydrate
• Microcrystalline cellulose
• Croscarmellose sodium
• Povidone
• Magnesium stearate

The film coating contains polyvinyl alcohol, titanium dioxide, talc, and polyethylene glycol (FDA, 2024).

The formulation uses a standard direct-compression or high-shear wet-granulation excipient architecture, although the public label does not disclose the manufacturing process. Microcrystalline cellulose provides bulk and compaction. Croscarmellose sodium supports tablet disintegration. Povidone functions as a binder. Magnesium stearate provides lubrication. The film-coating system improves handling, appearance, swallowability, and protection from mechanical abrasion.

Why is excipient selection important for mifepristone?

Mifepristone presents several formulation considerations that affect excipient selection:

1. It is a high-dose active ingredient in Korlym, with 300 mg of drug substance per tablet.
2. The active ingredient is highly lipophilic and has limited aqueous solubility.
3. The product requires reliable oral absorption across a broad dose range.
4. The label permits administration with or without food, so formulation performance must be commercially reproducible under normal patient-use conditions.
5. Mifepristone is metabolized through CYP3A pathways, making clinical drug-drug interactions more important than small formulation differences in many prescribing situations.
6. The tablets must remain mechanically robust despite a relatively high drug load.

A generic or reformulated product therefore needs to control particle-size distribution, polymorphic form, blend uniformity, disintegration, dissolution, compression force, lubrication time, and coating weight. Excipient substitution that changes dissolution or gastrointestinal exposure could create bioequivalence or clinical-risk issues.

Likely formulation challenges

Formulation issue	Commercial consequence
High mifepristone drug load	Limited room for large quantities of functional excipients
Low aqueous solubility	Dissolution optimization is critical
Lipophilicity	Surfactants, wetting agents, or particle engineering may be relevant
Once-daily dosing	Exposure consistency is commercially important
Broad dose range	Tablet strength and dose-flexibility strategy affect prescribing
Film-coated tablet	Coating materials must preserve immediate release
Lactose-containing formulation	Creates an opportunity for lactose-free alternatives
Chronic use	Excipient tolerability and supply continuity matter

What commercial opportunities exist in Korlym excipients?

The most practical opportunities are incremental rather than disruptive. A supplier does not need to replace the entire formulation to create value. It can target one performance attribute, such as dissolution, tablet hardness, flow, stability, or lactose elimination.

1. Generic Korlym excipient platform

A generic developer can use the current excipient profile as a starting point because it is composed of widely used compendial materials. The commercial challenge is less the availability of excipients than reproducing the reference product's critical quality attributes.

Potential generic strategies include:

• Using an equivalent lactose-cellulose filler system.
• Replacing lactose with mannitol, dibasic calcium phosphate, or a co-processed filler.
• Using crospovidone or sodium starch glycolate instead of croscarmellose sodium.
• Replacing povidone with copovidone or hydroxypropyl cellulose.
• Using a lower-level or alternative lubricant to reduce hydrophobic dissolution effects.
• Optimizing the coating for faster disintegration and better tablet appearance.

Excipients used in an abbreviated new drug application must comply with applicable FDA requirements, and significant changes can require additional comparative dissolution work or regulatory justification.

2. Lactose-free Korlym formulation

The current label identifies lactose monohydrate. A lactose-free product could target patients with lactose intolerance, excipient sensitivity, dietary preferences, or pharmacy procurement policies.

Potential replacement systems include:

Current function	Potential alternative
Lactose filler	Mannitol
Lactose filler	Microcrystalline cellulose
Lactose filler	Dibasic calcium phosphate
Lactose filler	Spray-dried or co-processed excipient
Binder	Copovidone or hydroxypropyl cellulose
Disintegrant	Crospovidone or sodium starch glycolate

A lactose-free formulation would not automatically gain regulatory or patent exclusivity. Its value would depend on improved tolerability, reliable supply, a clinically meaningful differentiation claim, or an enforceable formulation patent.

3. Dissolution-enhanced mifepristone tablets

Mifepristone's lipophilicity creates a potential market for excipient systems designed to improve wetting and dissolution. Candidates include:

• Surfactant-assisted tablets
• Self-emulsifying or self-microemulsifying systems
• Amorphous solid dispersions
• Co-processed polymers
• Nanocrystal or micronized drug systems
• Lipid-based granules
• Wetting-agent-containing immediate-release tablets

The commercial case depends on whether improved dissolution produces a meaningful benefit. Because Korlym is already approved for administration with or without food, a new formulation would need to demonstrate a clear advantage rather than simply a different in vitro dissolution profile.

Potential advantages include reduced food sensitivity, lower interpatient exposure variability, smaller tablets, or more consistent absorption at lower doses. The burden is substantial because changes to solubilization technology can alter systemic exposure and safety.

4. Dose-flexible tablet design

Korlym dosing can rise from 300 mg to 1,200 mg daily. The current product strategy uses a 300 mg tablet, allowing titration through multiple tablets. A reformulation opportunity exists for:

• Scored 300 mg tablets
• Lower-strength tablets for titration
• A 600 mg tablet for maintenance dosing
• Fixed-dose multi-tablet starter packs
• Calendar or titration packaging
• Tablets designed to reduce pill burden

A 600 mg product could improve convenience for patients receiving higher doses, but it would require a separate regulatory submission and commercial justification. A lower-strength product could support patients who cannot tolerate the initial dose or who require slower titration.

5. Modified-release or targeted delivery

Modified-release Korlym is a technically possible but commercially difficult opportunity. Mifepristone has a long terminal half-life, reported at approximately 85 hours in the prescribing information, so extended release may offer limited clinical benefit compared with immediate release (FDA, 2024).

A modified-release product could be justified only if it materially improves:

• Peak-related adverse effects
• Exposure variability
• Drug-drug interaction management
• Dosing convenience
• Tolerability during dose escalation

Without a clear pharmacokinetic or clinical benefit, modified release would add development cost and regulatory risk without a strong market advantage.

What patents protect Korlym and its formulation?

Korlym's protection is likely to rely more heavily on composition, method-of-use, and formulation claims than on basic mifepristone compound protection. Mifepristone was disclosed and developed decades before Korlym's approval, so the active ingredient itself is not the principal source of current product exclusivity.

Patent categories relevant to Korlym

Patent category	Relevance to Korlym
Compound patents	Generally weak or expired for mifepristone
Salt or crystal-form patents	Potentially relevant if a specific form is used
Tablet composition patents	May cover excipient combinations or performance characteristics
Method-of-use patents	May cover treatment of Cushing's syndrome or related metabolic conditions
Dosing patents	May cover titration, dose range, or patient selection
Manufacturing patents	May cover granulation, particle engineering, or process controls
Packaging patents	Usually limited commercial value unless linked to stability or distribution controls

The FDA Orange Book must be reviewed for the current patent list, expiration dates, pediatric exclusivity, and any listed exclusivity associated with NDA 202107. Orange Book entries can change through patent-list corrections, litigation outcomes, pediatric extensions, and administrative updates (FDA, 2025).

Public product information alone does not establish that a specific excipient combination is protected by an enforceable patent. A label's inactive-ingredient list identifies what is present in the marketed product, not the full scope of the sponsor's patent estate.

When does Korlym lose exclusivity?

Korlym's five-year new chemical entity exclusivity expired in 2017 because FDA approved the product in 2012. Any remaining market protection depends on listed patents, pediatric extensions, regulatory exclusivity, settlements, and the timing of approved generic applications.

The relevant commercial question is not simply the nominal expiration date of one patent. It is whether a generic applicant can obtain approval before the last enforceable patent expires and whether the applicant has made a Paragraph IV certification.

Exclusivity timeline

Event	Date or status
Mifepristone first approved in the United States for another indication	2000
Korlym approved	February 17, 2012
Five-year NCE exclusivity	Expired in 2017
Current protection	Depends on Orange Book patents and litigation
Generic entry mechanism	ANDA approval with Paragraph IV, expiration, or settlement pathway
Biosimilar pathway	Not applicable

A definitive generic-entry date requires a current Orange Book review and the status of any ANDA litigation. The commercial window can also differ by strength, indication, and product design.

Has Korlym faced Paragraph IV challenges or patent litigation?

Paragraph IV litigation is the primary legal risk for an oral small-molecule product such as Korlym. A generic applicant may certify that an Orange Book-listed patent is invalid, unenforceable, or not infringed. The filing can trigger a 45-day period for the innovator to sue, followed by a potential 30-month stay of FDA approval under the Hatch-Waxman framework.

Relevant litigation questions include:

• Which Korlym patents were listed in the Orange Book?
• Which patents were challenged by an ANDA applicant?
• Did Corcept sue within 45 days?
• Was a 30-month stay imposed?
• Did the parties settle?
• Did the settlement permit an authorized generic or licensed launch?
• Was any patent invalidated or narrowed?

Patent litigation records should be checked through PACER, FDA Orange Book updates, and Federal Circuit decisions. A conclusion about current litigation status should not rely on a historical press release alone.

What is the FDA regulatory status of Korlym?

Korlym is an FDA-approved prescription drug under NDA 202107. It is not a biologic and therefore has no biosimilar pathway. A follow-on product would generally use an ANDA if it can demonstrate pharmaceutical equivalence and bioequivalence to the reference listed drug.

Regulatory routes

Product strategy	Likely FDA pathway
Same 300 mg immediate-release tablet	ANDA
New strength	ANDA supplement or separate regulatory strategy
New excipient system with same product profile	Usually ANDA if equivalence is demonstrated
New dosage form	505(b)(2) or other applicable pathway
Modified-release product	Likely 505(b)(2), depending on product design
New indication	Supplemental NDA or 505(b)(2) strategy
Mifepristone biologic	Not applicable

A generic developer must also consider mifepristone-specific prescribing controls, dispensing requirements, pregnancy-related contraindications, drug-interaction restrictions, and postmarketing safety obligations.

How strong is the Korlym patent estate?

The estate should be viewed as moderate rather than compound-driven. Its strength depends on the breadth and validity of product-specific claims.

Factors supporting patent strength

• A branded formulation with a defined excipient profile
• Method-of-use claims linked to a narrow disease population
• Dosing and titration claims that may be difficult to design around
• Potential manufacturing claims
• A specialty indication with clinically specific prescribing criteria

Factors limiting patent strength

• Old active-ingredient disclosures
• Standard excipients that are easy to substitute
• Multiple possible tablet formulations
• Potential design-around routes using different binders or disintegrants
• The ability of ANDA applicants to challenge formulation and method claims
• Limited value of patents that cover only routine excipient combinations

A formulation patent is strongest when it claims a measurable technical result, such as a defined dissolution profile, stability range, impurity limit, particle-size distribution, or bioavailability parameter, rather than a routine mixture of known excipients.

Which companies could challenge Korlym commercially?

The most credible challengers are established generic manufacturers with oral solid-dose capabilities, specialty generic companies, and contract development and manufacturing organizations with high-potency or poorly soluble compound experience.

Competitive groups

Challenger type	Competitive advantage
Large generic manufacturers	ANDA infrastructure, litigation budgets, national distribution
Specialty generic companies	Willingness to pursue narrow markets
Regional manufacturers	Lower overhead and targeted access
CDMOs	Formulation development and manufacturing partnerships
Specialty-pharma licensees	Commercial infrastructure in endocrinology
Compounding pharmacies	Limited substitution potential; not equivalent to FDA-approved generic supply

The main competitive barrier is not production scale. It is the combination of patent risk, bioequivalence, controlled distribution requirements, high-potency handling, and the relatively specialized Cushing's syndrome market.

What manufacturing and IP barriers affect Korlym opportunities?

Commercial developers face several technical barriers:

1. Drug-substance control. Mifepristone particle size, polymorphic form, and impurity profile can affect dissolution and content uniformity.
2. High drug load. The 300 mg dose reduces formulation space and can create compression or capping problems.
3. Dissolution reproducibility. A generic product must match the reference product across relevant media and manufacturing lots.
4. High-potency containment. Facilities may need dedicated controls, validated cleaning, and occupational-exposure procedures.
5. Packaging stability. Moisture and oxygen protection must be established through stability studies.
6. Supply-chain qualification. Each excipient supplier needs appropriate quality documentation, change control, and supply continuity.
7. Regulatory controls. Mifepristone products have pregnancy-related safety requirements and restricted dispensing considerations.

For excipient suppliers, the best entry point is a qualified, low-change-risk product with strong regulatory documentation. For CDMOs, the opportunity is integrated development that combines particle engineering, tablet manufacture, analytical method development, and ANDA support.

How does Korlym compare with other endocrine drugs?

Korlym has a narrower indication than many diabetes and Cushing's syndrome products. Its commercial profile is therefore driven by specialty pricing, limited patient volume, and high clinical need rather than broad primary-care demand.

Product class	Primary use	Excipient opportunity
Korlym, mifepristone	Hyperglycemia associated with endogenous Cushing's syndrome	Generic tablet, lactose-free formulation, dose-flexible product
Isturisa, osilodrostat	Cushing's syndrome	Different active ingredient and tablet platform
Ketoconazole tablets	Off-label or adjunctive endocrine use	Older generic competition and broader excipient substitution
Pasireotide	Cushing's disease and acromegaly	Injectable and specialty formulation barriers
Metyrapone	Hypercortisolism	Capsule or oral formulation opportunities
Diabetes medicines	Broad glucose control	Much larger markets but substantially greater competition

Korlym does not face biosimilar competition. Its main future risk is an FDA-approved generic or an authorized generic, not a biosimilar.

What are the highest-value commercial opportunities?

The strongest opportunities rank as follows:

1. A compliant 300 mg generic tablet with competitive manufacturing cost.
2. A lactose-free immediate-release formulation supported by a clear excipient-differentiation strategy.
3. A dose-flexible product that reduces pill burden at higher daily doses.
4. A dissolution-optimized tablet that improves manufacturing robustness without materially changing exposure.
5. A formulation-development partnership for ANDA applicants or specialty-pharma licensees.
6. Excipient supply agreements involving co-processed fillers, disintegrants, binders, and coating systems.
7. Contract manufacturing for high-potency oral solid-dose production.

A modified-release or highly novel delivery system has lower near-term attractiveness because the clinical rationale is less clear and the regulatory burden is higher.

Key Takeaways

• Korlym is a 300 mg immediate-release mifepristone film-coated tablet.
• Its excipient system uses lactose monohydrate, microcrystalline cellulose, croscarmellose sodium, povidone, magnesium stearate, and a conventional film coating.
• The formulation is commercially accessible to generic developers because it does not depend on an obviously exotic excipient platform.
• The strongest excipient opportunities are lactose replacement, dissolution optimization, tablet-strength expansion, and reduced pill burden.
• Mifepristone's compound protection is not the principal current barrier; formulation, method-of-use, dosing, and manufacturing patents are more relevant.
• Korlym has no biosimilar risk. The principal competitive threat is an FDA-approved generic or authorized generic.
• A successful challenger must address bioequivalence, dissolution, high drug load, manufacturing containment, regulatory controls, and patent litigation.
• A new formulation has meaningful commercial value only if it improves dose flexibility, tolerability, dissolution consistency, or manufacturing economics.

FAQs

Can a generic Korlym use different excipients?

Yes. An ANDA applicant can use different inactive ingredients if the product meets FDA requirements, remains pharmaceutically equivalent where required, and demonstrates bioequivalence and acceptable safety.

Is lactose-free Korlym commercially viable?

Potentially. A lactose-free formulation could differentiate on tolerability and procurement, but it would need a clear commercial benefit because lactose replacement alone may not create durable market exclusivity.

Does Korlym need a biosimilar competitor?

No. Korlym is a small-molecule tablet. Competitive follow-on products would generally use an ANDA or, for materially different formulations, a 505(b)(2) pathway.

Could a 600 mg Korlym tablet reduce treatment burden?

Yes, if developed and approved. A 600 mg tablet could reduce tablet count for patients receiving higher doses, but it would require formulation development, bioequivalence or bridging evidence, and regulatory approval.

Are Korlym excipients likely to be patentable?

Individual excipients such as lactose, cellulose, povidone, and magnesium stearate are not proprietary in this context. Patentability would depend on a novel combination, manufacturing process, defined performance characteristic, stability result, or clinically relevant formulation advantage.

References

1. Corcept Therapeutics Incorporated. (2025). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. U.S. Securities and Exchange Commission.

2. U.S. Food and Drug Administration. (2024). Korlym (mifepristone) tablets, for oral use: Prescribing information. FDA.

3. U.S. Food and Drug Administration. (2025). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.

4. U.S. Food and Drug Administration. (2025). Inactive ingredient database. FDA.

5. U.S. Food and Drug Administration. (2025). Abbreviated new drug application process. FDA.

6. United States Code. (2024). 21 U.S.C. § 355: New drugs. U.S. Government Publishing Office.