List of Excipients in Branded Drug MYFEMBREE

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Sumitomo Pharma America Inc	MYFEMBREE	relugolix, estradiol hemihydrate, and norethindrone acetate	72974-415	FERRIC OXIDE YELLOW	2042-11-05
Sumitomo Pharma America Inc	MYFEMBREE	relugolix, estradiol hemihydrate, and norethindrone acetate	72974-415	HYDROXYPROPYL CELLULOSE	2042-11-05
Sumitomo Pharma America Inc	MYFEMBREE	relugolix, estradiol hemihydrate, and norethindrone acetate	72974-415	HYPROMELLOSE 2910	2042-11-05
Sumitomo Pharma America Inc	MYFEMBREE	relugolix, estradiol hemihydrate, and norethindrone acetate	72974-415	LACTOSE MONOHYDRATE	2042-11-05
Sumitomo Pharma America Inc	MYFEMBREE	relugolix, estradiol hemihydrate, and norethindrone acetate	72974-415	MAGNESIUM STEARATE	2042-11-05

MYFEMBREE Excipient Strategy and Commercial Opportunities

Last updated: August 11, 2026

MYFEMBREE is a once-daily, fixed-dose oral tablet combining relugolix 40 mg, estradiol 1 mg, and norethindrone acetate 0.5 mg. Its commercial value depends on maintaining low-dose hormonal stability, protecting relugolix exposure, limiting tablet size, and supporting long-term adherence in uterine fibroids and endometriosis. The strongest excipient opportunities are in bioequivalent generic development, formulation-risk reduction, supply-chain redundancy, and differentiated oral delivery systems.

What is MYFEMBREE and why does its excipient system matter?

MYFEMBREE is a fixed-dose combination product developed by Myovant Sciences and marketed in the United States within the Sumitomo Pharma group. The FDA approved it for:

• Management of heavy menstrual bleeding associated with uterine leiomyomas in premenopausal women.
• Management of moderate to severe pain associated with endometriosis in premenopausal women.

The formulation contains three pharmacologically active ingredients:

Component	Strength per tablet	Formulation role
Relugolix	40 mg	GnRH receptor antagonist
Estradiol	1 mg	Estrogen add-back therapy
Norethindrone acetate	0.5 mg	Progestin add-back therapy

The formulation challenge is not the active-load quantity. The total active ingredient content is relatively small, but the product combines compounds with different physicochemical and dose-control requirements. Relugolix requires consistent dissolution and systemic exposure, while estradiol and norethindrone acetate are low-dose hormones that require tight content uniformity and protection against segregation during blending and compression.

The FDA prescribing information identifies inactive ingredients including mannitol, sodium starch glycolate, magnesium stearate, hydroxypropyl cellulose, hypromellose, talc, titanium dioxide, and iron oxide colorant. The precise quantitative composition and manufacturing process are not disclosed in the public prescribing information.[1]

What excipients are used in MYFEMBREE?

The public label identifies the following excipient categories:

Excipient	Likely technical function
Mannitol	Diluent, mouthfeel modifier, tablet-mass builder
Sodium starch glycolate	Superdisintegrant
Hydroxypropyl cellulose	Binder and granulation aid
Magnesium stearate	Lubricant
Hypromellose	Film-coating polymer
Talc	Coating aid and anti-tacking agent
Titanium dioxide	Opacifier and coating pigment
Iron oxide	Colorant

The label does not establish the exact grade, particle-size distribution, concentration, granulation sequence, or supplier for each excipient. Those parameters can materially affect dissolution, compression, tablet robustness, and scale-up performance.

Why mannitol is commercially relevant

Mannitol can support direct-compression or dry-granulation strategies, depending on grade and process design. It offers low hygroscopicity relative to several alternative polyols and can improve tablet mouthfeel. For a chronic oral product, mannitol may also help control moisture exposure to low-dose hormones.

The principal commercial issue is grade selection. Generic developers may need to evaluate spray-dried, crystalline, and directly compressible mannitol grades for:

• Flowability.
• Compactability.
• Blend uniformity.
• Dissolution consistency.
• Compatibility with low-dose estradiol and norethindrone acetate.

A grade change can create a formulation or process difference even when the excipient’s compendial identity remains unchanged.

Why sodium starch glycolate matters

Sodium starch glycolate provides rapid tablet breakup. Its performance is sensitive to:

• Substitution level.
• Particle size.
• Intragranular versus extragranular addition.
• Compression force.
• Magnesium stearate exposure.
• Storage humidity.

Over-lubrication can reduce wetting and delay disintegration. Under-disintegration can affect relugolix dissolution and produce a meaningful bioequivalence risk.

Why magnesium stearate is a formulation-control issue

Magnesium stearate is common in immediate-release tablets, but its concentration and blending time require control. Excessive lubrication can create hydrophobic surfaces, reduce tablet tensile strength, and slow dissolution. A generic formulation that uses a different lubricant, such as sodium stearyl fumarate, may gain process advantages but must demonstrate equivalent performance.

Why the film coat creates differentiation opportunities

The hypromellose-based film coat protects the tablet and provides visual identification. Coating differences can be commercially useful if they improve:

• Moisture protection.
• Light protection.
• Color stability.
• Swallowability.
• Printing or serialization.
• Compatibility with high-speed packaging.

A transparent or low-pigment coating may reduce material cost, but it can increase light or identification risks. A moisture-barrier coating may increase stability and extend manufacturing options, but it may also change dissolution or tablet weight.

How does MYFEMBREE’s formulation compare with other GnRH antagonist products?

MYFEMBREE competes most directly with ORIAHNN, which contains elagolix, estradiol, and norethindrone acetate, and with relugolix monotherapy products such as ORGOVYX.

Product	Active ingredients	Dosage form	Add-back strategy	Commercial formulation issue
MYFEMBREE	Relugolix, estradiol, norethindrone acetate	Once-daily tablet	Estradiol plus norethindrone acetate	Fixed-dose exposure and chronic adherence
ORIAHNN	Elagolix, estradiol, norethindrone acetate	Two capsules twice daily	Estrogen/progestin in separate capsule combination	Higher daily pill burden
ORGOVYX	Relugolix	Once-daily tablet	No fixed add-back combination	Separate management of hormone-related effects
Lupron Depot	Leuprolide	Injectable depot	No oral excipient system	Injection administration and depot manufacturing

MYFEMBREE’s once-daily tablet is a commercial advantage over products requiring multiple daily units. It also creates a higher formulation burden because the three actives must remain uniformly distributed in one immediate-release unit.

What commercial opportunities exist for MYFEMBREE excipients?

Which excipient suppliers can benefit?

The largest opportunities are in high-quality, pharmaceutical-grade excipients with reliable global supply and strong documentation. Potential supplier categories include:

• Direct-compression mannitol.
• High-functionality sodium starch glycolate.
• Low-peroxide cellulose binders.
• Low-moisture hypromellose.
• Functional magnesium stearate.
• Film-coating systems.
• Pharmaceutical pigments and colorants.

Suppliers can compete through:

1. Multiple manufacturing sites.
2. Narrow particle-size specifications.
3. Low elemental impurity profiles.
4. Reduced peroxide and aldehyde content.
5. Better flow and compactability.
6. Technical support for bioequivalence and scale-up.
7. Regulatory packages for FDA, EMA, and other agencies.

Excipients with formal quality-by-design data have greater value than commodity materials when the product contains low-dose hormones and a narrow dissolution target.

What opportunities exist for generic MYFEMBREE manufacturers?

A generic applicant can pursue the reference formulation closely or develop a functionally equivalent formulation using alternative excipient grades. The core commercial opportunity is a lower-cost, once-daily generic combination tablet after applicable patent and regulatory barriers expire or are successfully challenged.

Development priorities include:

• Matching dissolution across multiple pH conditions.
• Demonstrating content uniformity for estradiol and norethindrone acetate.
• Controlling relugolix exposure.
• Establishing stability under accelerated and long-term conditions.
• Avoiding a tablet-size increase.
• Demonstrating batch-to-batch uniformity.
• Validating extractables and leachables from packaging.
• Establishing supplier redundancy for all critical excipients.

A generic developer may also pursue a formulation that retains the same active ingredients but improves manufacturability. Such a product may reduce compression defects, increase yield, or permit lower-cost continuous manufacturing.

What formulation patents protect MYFEMBREE?

MYFEMBREE’s protection is likely based on a combination of:

• Composition-of-matter patents for relugolix.
• Fixed-dose combination patents.
• Pharmaceutical-composition patents.
• Method-of-use patents for uterine fibroids and endometriosis.
• Manufacturing and formulation disclosures.
• Regulatory exclusivity associated with the approved indication.

The FDA Orange Book is the controlling public source for patents listed against an approved NDA. Patent listings can change through updates, corrections, delistings, and new listing submissions. The relevant product record is NDA 214846.[2]

The commercial analysis should distinguish between:

Protection type	Relevance to MYFEMBREE
Relugolix composition patent	May cover the active ingredient broadly
Combination patent	May cover relugolix with estradiol and norethindrone acetate
Formulation patent	May cover dosage form, ratios, excipients, or release characteristics
Method-of-use patent	May cover treatment of fibroid-related bleeding or endometriosis pain
Manufacturing patent	May increase process-development and supply-chain risk
Regulatory exclusivity	Can delay approval even where patent exposure is limited

The presence of a listed patent does not establish that every claim is valid or infringed. Generic applicants can submit Paragraph IV certifications, triggering potential litigation and a statutory 30-month stay under the Hatch-Waxman framework if the patent holder files suit within the applicable period.[3]

When does MYFEMBREE lose exclusivity?

MYFEMBREE received FDA approval in May 2021 for uterine fibroids and August 2022 for endometriosis. The relevant exclusivity timeline depends on whether the FDA granted new chemical entity exclusivity for the fixed-dose product, three-year exclusivity for new clinical investigations, pediatric exclusivity, and the patent expiration dates listed in the Orange Book.

Milestone	Date or status
FDA approval for uterine fibroids	May 2021
FDA approval for endometriosis	August 2022
NDA	214846
Dosage form	Immediate-release oral tablet
Regulatory pathway for generics	ANDA, subject to patent and exclusivity status
Patent status	Must be assessed from current Orange Book listings
Earliest generic timing	Controlled by the latest applicable exclusivity, patent, settlement, or court outcome

A fixed-dose combination containing an already approved active ingredient does not automatically receive five-year new chemical entity exclusivity. The regulatory status must be assessed against the active ingredients, prior approvals, and FDA exclusivity determinations. A three-year period may apply to a new clinical investigation supporting the approval of a new indication or formulation, but it does not block all generic applications in the same manner as five-year NCE exclusivity.

What Paragraph IV and generic-entry risks exist?

The principal generic-entry risks are formulation similarity and patent claim scope.

Formulation risk

A generic applicant must reproduce the clinical performance of the reference product without necessarily using identical excipients. Differences in mannitol grade, disintegrant level, lubricant concentration, or coating composition can affect:

• Dissolution.
• Tablet disintegration.
• Hormone content uniformity.
• Relugolix pharmacokinetics.
• Stability.
• Manufacturing yield.

The low dose of estradiol makes analytical sensitivity and blend uniformity important. Hormonal actives can also create occupational-handling requirements during manufacturing.

Patent risk

A Paragraph IV filing may challenge:

• Relugolix composition claims.
• Fixed-dose combination claims.
• Use of the combination for fibroids.
• Use of the combination for endometriosis.
• Formulation or process claims.

A successful challenge can accelerate entry. A settlement may produce a licensed launch date earlier than the nominal patent expiration date. Without a confirmed Orange Book and court docket review, a specific generic-entry date cannot be assigned accurately.

Does MYFEMBREE have biosimilar risk?

No. MYFEMBREE is a chemically synthesized small-molecule product, not a biologic. Biosimilar pathways under the Public Health Service Act do not apply. Competitive entry would occur through an ANDA or, depending on the product and claims, a 505(b)(2) application.

The practical substitute risk comes from:

• Generic fixed-dose tablets.
• Alternative GnRH antagonists.
• Injectable GnRH agonists.
• Hormonal contraceptive or progestin-based therapies.
• Surgical treatment for fibroids.
• Endometriosis treatments with different mechanisms.

What manufacturing and IP barriers affect MYFEMBREE?

Manufacturing barriers are moderate rather than biologic-level. The product does not require aseptic processing, cold-chain distribution, or complex protein characterization. Its barriers are analytical and process-based.

Key controls include:

• Low-dose blend uniformity.
• Segregation prevention.
• Relugolix dissolution.
• Hormone assay sensitivity.
• Cross-contamination controls.
• Granulation endpoint.
• Lubrication time.
• Film-coating uniformity.
• Packaging moisture protection.
• Stability-indicating analytical methods.

The most valuable process IP may concern blend design, granulation sequence, compression parameters, coating conditions, and impurity control rather than novel excipient identity.

What licensing and partnership opportunities exist?

The commercial structure creates several licensing opportunities:

Excipient and formulation licensing

A specialty excipient supplier could license a high-functionality mannitol, disintegrant, or coating system with validated performance in low-dose combination tablets. The strongest value proposition would be reduced development time and lower bioequivalence risk.

Generic development partnerships

A finished-dose manufacturer could partner with:

• An ANDA sponsor.
• A hormone-product specialist.
• A contract development and manufacturing organization.
• A regional distributor seeking rights outside the United States.

The main negotiation points would include geographic rights, patent-risk allocation, technology transfer, minimum purchase commitments, and responsibility for post-approval changes.

Regional commercialization

MYFEMBREE’s regulatory and commercial profile is most attractive in markets with:

• High prevalence of uterine fibroids.
• High unmet need in endometriosis.
• Limited access to injectable therapy.
• Established reimbursement for chronic oral medicines.
• Demand for once-daily alternatives.

Geographic expansion requires assessment of local patent term, data exclusivity, labeling restrictions on hormonal add-back therapy, and national requirements for excipient acceptability.

How strong is the MYFEMBREE patent estate?

The estate is potentially stronger than a simple active-ingredient patent because it can combine relugolix rights with fixed-dose composition and method-of-use claims. Its practical strength depends on:

1. Whether combination claims cover the marketed strength or only broader ratios.
2. Whether claims require a specific excipient or manufacturing process.
3. Whether method claims are listed and enforceable against an ANDA applicant.
4. The remaining patent term.
5. The outcome of any Paragraph IV litigation.
6. Whether a generic can design around the formulation claims.
7. The availability of non-infringing alternative excipient systems.

A formulation claim limited to a specific excipient ratio may be easier to design around than a broad claim covering relugolix with estrogen and progestin. A process claim may be difficult to enforce if the manufacturing process is not observable in the commercial product.

What is the FDA regulatory status of MYFEMBREE?

MYFEMBREE is FDA-approved as an oral tablet under NDA 214846. The label includes boxed-warning and limitation-of-use information relating to thromboembolic, cardiovascular, bone-loss, and hormonal risks associated with the product’s mechanism and estrogen/progestin components.[1]

Commercial development must account for:

• Contraindications and warnings associated with estrogen-containing therapy.
• Bone mineral density monitoring and treatment duration limits.
• Pregnancy-related restrictions.
• Drug-interaction management.
• Labeling requirements for both fibroids and endometriosis.
• Post-approval manufacturing-change obligations.

An excipient substitution that changes dissolution, impurity levels, stability, or tolerability may require regulatory reporting or prior approval, depending on the scale and effect of the change.

What is the revenue opportunity for MYFEMBREE?

The commercial opportunity is linked to the size of the premenopausal uterine fibroid and endometriosis populations, the shift from surgery or injectable treatment to oral therapy, and persistence with once-daily dosing.

Revenue drivers include:

• New patient starts.
• Duration of treatment.
• Insurance coverage.
• Prior-authorization requirements.
• Physician adoption.
• Generic timing.
• Expansion outside the United States.
• Patient affordability programs.
• Competition from ORIAHNN and nonhormonal or procedural therapies.

Excipient suppliers capture a smaller share of product revenue but can create recurring value through approved, difficult-to-substitute materials. The highest-margin opportunity is usually a performance excipient supported by formulation data, not a commodity diluent.

Key Takeaways

• MYFEMBREE is a once-daily fixed-dose tablet containing relugolix, estradiol, and norethindrone acetate.
• Its public label identifies mannitol, sodium starch glycolate, hydroxypropyl cellulose, magnesium stearate, hypromellose, talc, titanium dioxide, and iron oxide among the inactive ingredients.
• The principal formulation risks are low-dose hormone uniformity, relugolix dissolution, lubrication control, moisture management, and scale-up reproducibility.
• Generic developers can pursue alternative excipient grades, but formulation changes may create bioequivalence and stability risks.
• The product is not exposed to biosimilar competition. Generic entry would proceed through Hatch-Waxman pathways.
• Patent analysis must cover relugolix, fixed-dose combination, formulation, method-of-use, and manufacturing claims.
• Commercial opportunities exist for high-functionality excipients, formulation platforms, CDMO partnerships, regional licensing, and generic development.
• The current Orange Book record and litigation history determine the practical generic-entry timeline.

FAQs

Can MYFEMBREE be reformulated as a capsule?

Yes, a capsule could be technically feasible, but a capsule formulation would require a new development program and would not automatically qualify as an ANDA-equivalent product. The dosage form, dissolution profile, stability, content uniformity, and bioequivalence would require regulatory evaluation.

Which excipient is most important for MYFEMBREE bioequivalence?

No single excipient controls the entire product. Mannitol affects tablet structure and manufacturability, sodium starch glycolate affects disintegration, and magnesium stearate can affect wetting and dissolution. The interaction among these materials is more important than any individual excipient.

Can a generic manufacturer use different excipients from MYFEMBREE?

Yes. An ANDA applicant generally does not need to use identical inactive ingredients, subject to FDA requirements for safety, performance, and pharmaceutical equivalence. The alternative formulation must demonstrate comparable quality and bioequivalence.

Is MYFEMBREE suitable for continuous manufacturing?

Potentially. Its relatively low active load and immediate-release tablet format are compatible with continuous blending and compression platforms. The primary technical challenge is maintaining uniform distribution of estradiol and norethindrone acetate during continuous feeding and preventing segregation.

Could a long-acting MYFEMBREE formulation create a new commercial category?

Yes, but it would be a new product-development program rather than a simple reformulation. A depot, implant, transdermal, or extended-release product would require new pharmacokinetic, safety, and efficacy evidence and could receive separate formulation or method-of-use protection.

References

1. U.S. Food and Drug Administration. (2024). MYFEMBREE (relugolix, estradiol, and norethindrone acetate) prescribing information.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
3. U.S. Food and Drug Administration. (2024). Hatch-Waxman amendments and abbreviated new drug applications.
4. U.S. Pharmacopeia. (2024). United States Pharmacopeia and National Formulary.
5. U.S. Food and Drug Administration. (2024). Inactive Ingredient Database.