CORCEPT THERAPEUTICS

Mifepristone 300 MG, marketed as Korlym in the United States and Corluxin in Europe, is an oral small-molecule glucocorticoid receptor antagonist developed by Corcept Therapeutics for the treatment of hypercortisolism. The drug has achieved regulatory approval in both the US and EU, with the US approval covering multiple generic and branded formulations across several manufacturers including Teva Pharmaceuticals, Danco Labs, and others. Mifepristone works by blocking glucocorticoid receptor signaling, thereby reducing the effects of excess cortisol in patients with Cushing's syndrome and related hypercortisolemic conditions.

The program represents a mature, approved therapeutic with established clinical utility. Corcept's development strategy has centered on establishing mifepristone as a standard-of-care option for hypercortisolism management, with regulatory approvals secured in major markets. The most recent milestone was recorded on 20 January 2025, though specific details of this milestone are not yet disclosed. The drug is currently in completed development status with an active clinical trial (NCT05772169) ongoing, suggesting potential label expansion or post-approval research activities.

Regulatory status reflects successful market penetration: the US FDA approved the original NDA (NDA020687) with subsequent abbreviated NDAs filed by multiple manufacturers, indicating robust generic competition. The European Medicines Agency initially approved Corluxin on 24 April 2015 under MAH FGK Representative Service GmbH, though the application was subsequently withdrawn. This regulatory history underscores the evolving commercial landscape for this established therapeutic class.

Hypercortisolism, including Cushing's syndrome and ectopic ACTH syndrome, represents a serious endocrine disorder with significant morbidity and mortality if untreated. Excess cortisol causes metabolic complications, cardiovascular disease, immunosuppression, and psychiatric manifestations. While surgical intervention targeting the cortisol source remains first-line, many patients are not surgical candidates or experience recurrence, creating substantial unmet medical need for pharmacological management.

Mifepristone addresses this need as one of the few FDA-approved medical therapies specifically indicated for hypercortisolism. The drug's market relevance is underscored by its approval across multiple manufacturers and regulatory jurisdictions, indicating sustained clinical demand and commercial viability. The competitive landscape includes emerging therapies such as relacorilant (also from Corcept, in Phase 3), suggesting the sponsor recognizes ongoing opportunity for improved agents with potentially better tolerability or efficacy profiles.

The patient population, while relatively small compared to other endocrine disorders, represents a high-acuity, high-need cohort where effective medical management significantly improves quality of life and reduces serious complications. Commercial significance is reflected in the establishment of multiple generic pathways and continued regulatory activity, indicating that despite being an older approved drug, mifepristone maintains clinical and commercial importance. The ongoing trial activity (NCT05772169) suggests potential for label expansion or new indication development, which could broaden the addressable patient population and commercial opportunity.

Drug Class: Glucocorticoid receptor antagonist (selective antagonist of the glucocorticoid receptor)

Modality: Small-molecule oral therapeutic

Route of Administration: Oral

Mechanism of Action: Not yet disclosed in available documentation; however, mifepristone is known to function as a competitive antagonist of the glucocorticoid receptor, blocking cortisol signaling and thereby reducing the biological effects of excess cortisol in hypercortisolemic states.

Molecular Target: Not yet disclosed in available documentation

Therapeutic Class: Nervous system agent (per regulatory classification)

Related Therapies: Mifepristone represents a first-generation glucocorticoid receptor antagonist. Related approved agents in the hypercortisolism space include mitotane (adrenolytic) and metyrapone (11β-hydroxylase inhibitor). Corcept's pipeline includes relacorilant, a next-generation glucocorticoid receptor antagonist in Phase 3 development, suggesting iterative improvement in this drug class.

First Approval: Original US FDA approval date not yet disclosed; however, the regulatory record indicates NDA020687 represents the original new drug application. European approval occurred 24 April 2015 under Corluxin brand name.

Patent Status: Not yet disclosed

United States (FDA): Mifepristone 300 mg (Korlym) is approved for hypercortisolism under original NDA020687 sponsored by Corcept Therapeutics. Multiple abbreviated NDAs (ANDAs) have been approved for generic formulations, including ANDA091178, ANDA211436, and ANDA216616, with sponsors including Teva Pharmaceuticals USA Inc, Danco Labs LLC, and Evita Solutions. This multi-source approval pathway indicates robust generic competition and sustained market availability.

European Union (EMA): Mifepristone 300 mg was approved as Corluxin under EMEA/H/C/002830 on 24 April 2015, with Marketing Authorization Holder (MAH) FGK Representative Service GmbH. However, the application was subsequently withdrawn from the European regulatory pathway, indicating that the product is no longer actively marketed or supported in the EU under this approval.

Japan (PMDA): Regulatory status not yet disclosed.

China (NMPA): Regulatory status not yet disclosed.

Regulatory Summary: Mifepristone demonstrates established regulatory approval in the US with a mature generic market, while European approval has been withdrawn. Regulatory status in other major markets remains not yet disclosed.

Strategic Implications: Mifepristone's transition to a mature, multi-source approved product reflects successful market establishment but also signals declining exclusivity and pricing pressure from generic competition. Corcept's continued investment in the program (evidenced by the January 2025 milestone and ongoing NCT05772169) suggests either label expansion opportunities, post-approval safety monitoring, or potential new indication development. The parallel development of relacorilant indicates Corcept's strategy to maintain market leadership through next-generation product advancement rather than relying solely on mifepristone's established position.

Competitive Implications: The emergence of Phase 3 competitors (FET, relacorilant) and Phase 2 programs (SPI-62) indicates that the hypercortisolism market remains attractive to pharmaceutical developers despite the small patient population. Mifepristone's established approval and clinical track record provide defensive advantages, but newer agents with potentially improved safety or efficacy profiles may capture market share. The withdrawal of Corluxin from the EU market suggests regional commercial challenges that may not be present in the US market.

Future Catalysts: Key catalysts include: (1) results and regulatory decisions for relacorilant (Phase 3), which could represent a next-generation replacement; (2) outcomes of NCT05772169, which may support label expansion or new indication; (3) regulatory approvals or clinical data for competing Phase 3 agents; (4) any post-approval safety signals or efficacy data that could influence clinical adoption patterns.

Expected Milestones: Specific expected milestones are not yet disclosed. However, typical catalysts in the hypercortisolism space include clinical trial readouts, regulatory submissions for label expansions, and competitive agent approvals.