Last updated: August 1, 2026
Danocrine is the legacy brand for danazol, a synthetic androgen used primarily for endometriosis, fibrocystic breast disease and hereditary angioedema. The product has no meaningful remaining exclusivity in the United States, no identified late-stage clinical development program and limited commercial growth potential. Demand is concentrated in low-volume, generic markets where physicians use danazol when newer therapies are unsuitable, unavailable or ineffective.
The commercial outlook is stable to declining. The main risks are generic substitution, adverse-effect concerns, supply interruptions and replacement by GnRH therapies, hormonal contraceptives, progestins, antifibrinolytics and modern hereditary-angioedema products.
What is Danocrine and what conditions does it treat?
Danocrine contains danazol, an orally active synthetic steroid derived from ethisterone. It suppresses pituitary gonadotropin secretion and reduces estrogenic stimulation in endometriosis. Its androgenic activity also affects hepatic protein synthesis and complement pathways.
The U.S. label identifies three principal uses:
| Indication |
Clinical role |
| Endometriosis |
Reduction of endometriotic lesions and associated pelvic pain |
| Fibrocystic breast disease |
Relief of severe breast pain and tenderness |
| Hereditary angioedema |
Prevention of attacks by increasing C1 esterase inhibitor concentrations |
Danazol is administered orally in capsule form. The U.S. label historically included 50 mg, 100 mg and 200 mg capsules, with dosing adjusted by indication and response (U.S. Food and Drug Administration [FDA], 2000).
Danazol is less attractive than many newer treatments because of weight gain, acne, hirsutism, voice changes, lipid abnormalities, hepatic toxicity and other androgenic effects. It is contraindicated during pregnancy because of the risk of virilization of a female fetus.
Danazol versus newer therapies
For endometriosis, danazol competes with combined hormonal contraceptives, progestins, GnRH agonists, GnRH antagonists and aromatase inhibitor-based regimens. These alternatives generally have more favorable prescribing profiles or more targeted clinical positioning.
For hereditary angioedema, danazol competes with C1 esterase inhibitor replacement, lanadelumab, berotralstat and on-demand kallikrein or bradykinin-pathway therapies. Modern agents have reduced the role of long-term androgen prophylaxis in patients with access to specialty treatment.
What is the FDA regulatory status of Danocrine?
Danocrine was approved in the United States under NDA 017557. The FDA-approved product is an oral capsule formulation of danazol. The product’s regulatory history dates to the 1970s, making it one of the older systemic therapies still associated with the Danocrine brand name.
The FDA label limits use to specific conditions and contains substantial warnings relating to pregnancy, hepatic dysfunction, lipid effects, thrombotic risk, masculinization and monitoring requirements (FDA, 2000).
FDA status and market implications
| Regulatory issue |
Danocrine status |
| Active ingredient |
Danazol |
| Dosage form |
Oral capsule |
| U.S. pathway |
Original new drug application and subsequent generic approvals |
| Therapeutic areas |
Endometriosis, fibrocystic breast disease, hereditary angioedema |
| Biologic status |
Not a biologic; biosimilar pathway does not apply |
| Generic pathway |
Abbreviated New Drug Application pathway |
| Current exclusivity profile |
No meaningful remaining regulatory exclusivity identified |
| Regulatory risk |
Label warnings, pregnancy restrictions and safety monitoring |
Danazol is a small molecule. Generic manufacturers can rely on ANDA approval rather than conducting a new efficacy program, provided they demonstrate pharmaceutical equivalence and bioequivalence.
What patents protect Danocrine and danazol?
The original Danocrine product is no longer protected by an enforceable composition-of-matter patent or market exclusivity period. The relevant patent estate is effectively expired.
| IP category |
Danocrine position |
| Original danazol composition patent |
Expired |
| Original formulation protection |
Expired or commercially irrelevant |
| Method-of-use patents for labeled indications |
No meaningful blocking estate identified |
| Orange Book patent barrier |
No current patent-based barrier expected |
| Generic entry |
Legally available through ANDA approval |
| Manufacturing know-how |
Potentially relevant, but not a market exclusivity right |
The commercial protection for Danocrine is therefore based on manufacturing capability, product availability, physician familiarity and distributor access rather than patent rights.
What formulations are protected by Danocrine patents?
Danocrine’s commercial formulation is an immediate-release oral capsule. No active U.S. formulation patent is known to provide a meaningful barrier to generic danazol capsules. A manufacturer could pursue a capsule product through the generic pathway if it meets the reference product’s pharmaceutical and bioequivalence requirements.
Any newer formulation using modified release, alternative excipients or a different delivery system would require separate regulatory and intellectual-property analysis. Such a product could potentially obtain formulation protection, but no commercially significant Danocrine reformulation program is publicly established.
When does Danocrine lose exclusivity?
Danocrine lost practical U.S. exclusivity many years ago. The product is now exposed to generic competition and does not depend on patent protection for continued distribution.
The key distinction is between the Danocrine brand and danazol as an active ingredient:
- Danocrine is the legacy branded product.
- Danazol is available through generic manufacturers.
- Generic substitution can occur without a patent settlement.
- No biosimilar issue exists because danazol is a chemically synthesized small molecule.
- Any remaining brand value comes from prescribing familiarity and channel availability.
What clinical trials are evaluating Danocrine or danazol?
No active pivotal clinical development program for Danocrine was identified in the public ClinicalTrials.gov record through June 2024. Danazol’s clinical evidence base consists largely of older controlled studies, observational reports and continued use in selected patients.
Clinical-trial status by indication
| Indication |
Development status |
Commercial interpretation |
| Endometriosis |
No modern pivotal Danocrine program identified |
Mature, generic treatment with declining strategic value |
| Fibrocystic breast disease |
No active major development program identified |
Small and shrinking treatment market |
| Hereditary angioedema |
Historical evidence and continued niche use |
Replaced in many markets by targeted prophylaxis |
| Rare or off-label uses |
Case reports and small studies may exist |
Insufficient for a broad commercial relaunch |
Danazol can still be clinically relevant in patients who cannot access newer therapies, do not respond to them or require a lower-cost option. That role is defensive rather than growth-oriented.
What clinical risks affect future Danazol use?
The main clinical barriers are androgenic and metabolic toxicity. Reported concerns include:
- Hepatic adenoma, peliosis hepatis and abnormal liver function
- Adverse lipid changes
- Weight gain, acne and hirsutism
- Menstrual disturbance and voice changes
- Fetal virilization
- Thrombotic and cardiovascular concerns
- Drug interactions involving hepatic metabolism
These risks increase the monitoring burden and limit use in patients with cardiovascular, hepatic or pregnancy-related risk.
What is the Orange Book status of Danocrine?
The Orange Book is relevant to Danocrine because it identifies approved drug products and patent or exclusivity information that may affect generic approval. Danazol’s original exclusivity has expired, and no current patent listing is expected to prevent generic approval of equivalent capsules.
The practical Orange Book conclusion is:
- Danocrine is a legacy approved reference product.
- Generic danazol products can compete through ANDA approvals.
- There is no active composition patent supporting premium pricing.
- A generic applicant would not normally need to address a current Danocrine patent estate through a Paragraph IV certification.
Orange Book status should be checked against the current FDA database before a filing, acquisition or litigation decision because listings and marketing status can change (FDA, 2024a).
Are there Paragraph IV challenges against Danocrine?
Paragraph IV litigation is unlikely to be commercially material for danazol. Paragraph IV certifications are used when an ANDA applicant asserts that a listed patent is invalid, unenforceable or will not be infringed. Danazol’s principal patents expired long ago, leaving little basis for a modern patent challenge tied to the original product.
The generic-entry pathway is more likely to involve:
- Paragraph III certification where an old patent has a listed expiration date
- Section viii statements for uses not covered by a patent
- Standard ANDA approval without meaningful patent litigation
No major recent Paragraph IV litigation campaign involving Danocrine was identified in the public record through June 2024.
What patent litigation affects Danocrine?
No active high-value U.S. patent litigation involving Danocrine was identified through June 2024. The absence of litigation is consistent with an expired patent estate and a low-revenue generic market.
Potential disputes would more likely involve:
- Product quality or manufacturing compliance
- Trademark ownership or brand use
- Distribution contracts
- Supply agreements
- Regulatory status or drug-shortage issues
These disputes would not recreate the market exclusivity associated with a valid active patent.
How strong is the Danocrine patent estate?
The patent estate is weak for investment and partnering purposes.
| Patent-strength factor |
Assessment |
| Composition-of-matter protection |
None remaining |
| Formulation protection |
No meaningful active barrier identified |
| Method-of-use protection |
No meaningful blocking rights identified |
| Geographic protection |
Original rights expired in major markets |
| Generic vulnerability |
High |
| Freedom-to-operate for standard capsules |
Generally favorable, subject to product-specific review |
| Licensing leverage |
Low |
Manufacturing know-how may still matter. Danazol requires controlled production, validated analytical methods and compliance with current good manufacturing practices. Those factors can restrict the number of reliable suppliers, but they do not provide patent exclusivity.
What is the Danocrine market size and revenue exposure?
Danocrine does not have a widely reported standalone revenue stream in public filings. Brand-level sales are difficult to isolate because the active ingredient is generic, indications overlap and many products are sold through private-label or institutional channels.
The market is best characterized as a low-volume, mature prescription market:
- Endometriosis represents the largest historical disease opportunity.
- Hereditary angioedema provides residual specialty demand.
- Fibrocystic breast disease contributes limited volume.
- Generic pricing suppresses revenue per prescription.
- Brand Danocrine has limited ability to sustain a premium over generic danazol.
Market drivers
Demand may persist because of:
- Low acquisition cost compared with targeted hereditary-angioedema therapies
- Use in lower-income and underinsured markets
- Physician familiarity
- Availability where newer agents are not reimbursed
- Treatment of selected refractory cases
Market restraints
The principal restraints are:
- Generic substitution
- Adverse-effect burden
- Better-tolerated endometriosis therapies
- Targeted hereditary-angioedema drugs
- Reduced use of danazol in women of reproductive potential
- Potential manufacturing and supply constraints
What is the Danocrine market projection for 2024-2029?
The base-case outlook is low-single-digit annual decline in branded and total danazol value, with unit demand more stable than revenue. Pricing pressure should continue because the product has no meaningful exclusivity.
| Scenario |
2024-2029 unit outlook |
2024-2029 revenue outlook |
Main assumptions |
| Base case |
Flat to down low single digits annually |
Down mid-single digits annually |
Continued generic substitution and gradual therapeutic replacement |
| Downside case |
Down mid-single digits annually |
Down high single digits annually |
Supply interruptions, further replacement in hereditary angioedema and tighter safety restrictions |
| Upside case |
Flat to modest growth |
Flat to modest growth |
Increased use in cost-sensitive markets or renewed demand where newer therapies are inaccessible |
The upside case does not depend on a new patent or clinical breakthrough. It depends on market access, reliable supply and price advantages.
A relaunch strategy would require a differentiated proposition, such as a lower-cost supply agreement, a new dosage form, improved patient support or a carefully defined niche indication. A standard Danocrine brand relaunch without differentiation would face limited pricing power.
How does Danocrine compare with competing drugs?
| Product class |
Representative therapies |
Relative position versus danazol |
| Endometriosis hormonal therapy |
Progestins, combined contraceptives, GnRH agonists and antagonists |
Generally stronger modern prescribing position |
| Hereditary angioedema prophylaxis |
C1 inhibitor products, lanadelumab, berotralstat |
More targeted and often better tolerated, but more expensive |
| Hereditary angioedema acute treatment |
Icatibant, C1 inhibitor, ecallantide |
Used for acute management rather than chronic danazol substitution |
| Fibrocystic breast disease |
Analgesics and other hormonal approaches |
Danazol remains a niche option because of toxicity |
| Generic androgenic agents |
Other synthetic steroids |
Not direct therapeutic substitutes in most labeled uses |
Danazol’s competitive advantage is cost and oral administration. Its disadvantages are safety, tolerability and the availability of indication-specific alternatives.
Which companies are challenging Danocrine?
No major company is publicly pursuing a direct branded challenge to Danocrine through a late-stage clinical program. Competitive pressure comes from two groups:
- Generic manufacturers supplying danazol capsules.
- Specialty pharmaceutical companies selling newer endometriosis and hereditary-angioedema therapies.
The most material competitive threat is therapeutic replacement rather than patent litigation. Manufacturers of oral GnRH antagonists, biologic C1 inhibitors, monoclonal antibodies and kallikrein inhibitors compete for the same patients while offering stronger differentiation and higher commercial value.
What licensing deals and settlement agreements involve Danocrine?
No significant recent licensing deal or patent settlement involving Danocrine was identified through June 2024. The product’s age, generic status and limited revenue base reduce the economic rationale for a major settlement or rights transaction.
A commercial agreement would more likely involve:
- Regional distribution
- Generic supply
- Contract manufacturing
- Hospital procurement
- Authorized generic arrangements
Such agreements would be commercial rather than exclusivity-driven.
What generic launch risks exist for Danocrine?
Generic launch risk is high because the product is legally open to competition. The main risk factors are operational:
- Limited API suppliers
- Low commercial margins
- Small addressable patient population
- Manufacturing discontinuation
- Regulatory inspection findings
- Shortages caused by low supplier participation
- Difficulty maintaining multiple capsule strengths
A generic manufacturer may enter the market but later withdraw if volume does not support ongoing compliance and distribution costs. That creates a potential supply-concentration risk even when patent barriers are absent.
What geographic markets remain relevant for Danocrine?
Danazol’s residual value is likely to be greater in markets where newer therapies are not reimbursed or widely available. Its commercial relevance can persist in parts of Latin America, Asia, Eastern Europe, the Middle East and other price-sensitive markets, subject to local registration and supply status.
The United States, Western Europe and other high-income markets have stronger access to modern endometriosis and hereditary-angioedema therapies. Danazol can remain available there, but its use is more likely to be restricted to selected patients.
Geographic analysis should separate:
- Regulatory approval
- Actual marketing status
- Hospital and specialty-pharmacy access
- Reimbursement
- Local generic competition
- Product supply reliability
Key Takeaways
- Danocrine is the legacy brand for danazol, an oral synthetic androgen.
- Its labeled uses are endometriosis, fibrocystic breast disease and hereditary angioedema.
- The original U.S. patent and exclusivity position has expired.
- No meaningful active patent estate or current patent litigation was identified.
- No major active pivotal clinical-trial program was identified through June 2024.
- Generic competition and newer therapies are the main commercial pressures.
- The 2024-2029 base case is stable to declining demand and declining revenue.
- The strongest residual opportunity is low-cost supply in markets with limited access to newer therapies.
- A commercial relaunch would require supply, pricing or formulation differentiation.
FAQs
Is Danocrine still FDA approved?
Danocrine is associated with an FDA-approved danazol capsule product, although current commercial availability and marketing status should be distinguished from historical approval status.
Is danazol the same drug as Danocrine?
Yes. Danocrine is a brand associated with danazol. Generic danazol capsules contain the same active ingredient and compete through the ANDA pathway.
Can generic manufacturers launch danazol without a Paragraph IV lawsuit?
Yes. Because the original patent and exclusivity barriers have expired, a generic applicant may be able to proceed without challenging an active Danocrine patent.
Is danazol a biosimilar candidate?
No. Danazol is a chemically synthesized small molecule, not a biologic. Generic-drug rules, rather than the biosimilar pathway, apply.
Why is danazol still used for hereditary angioedema?
Danazol can provide an inexpensive oral prophylactic option where newer targeted therapies are unavailable, unaffordable or clinically unsuitable. Its use is limited by androgenic and metabolic toxicity.
References
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U.S. Food and Drug Administration. (2000). Danocrine (danazol) capsules prescribing information. https://www.accessdata.fda.gov/drugsatfda_docs/label/2000/17557s021lbl.pdf
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U.S. Food and Drug Administration. (2024a). Approved drug products with therapeutic equivalence evaluations, Orange Book. https://www.fda.gov/drugs/drug-approvals-and-databases/orange-book-data-files
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U.S. Food and Drug Administration. (2024b). Drugs@FDA: FDA-approved drugs. https://www.accessdata.fda.gov/scripts/cder/daf/
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National Library of Medicine. (2024). ClinicalTrials.gov. https://clinicaltrials.gov/
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Zuraw, B. L. (2008). Hereditary angioedema. New England Journal of Medicine, 359(10), 1027-1036. https://doi.org/10.1056/NEJMcp0803977
