List of Excipients in Branded Drug IDHIFA

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	CELLULOSE, MICROCRYSTALLINE	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	FERRIC OXIDE YELLOW	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	HYDROXYPROPYL CELLULOSE	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	HYPROMELLOSE ACETATE SUCCINATE 06081224	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	MAGNESIUM STEARATE	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	POLYETHYLENE GLYCOL	2034-09-16
Celgene Corporation	IDHIFA	enasidenib mesylate	59572-705	POLYVINYL ALCOHOL	2034-09-16

IDHIFA Enasidenib Excipient Strategy, Patent Position and Commercial Opportunities

Last updated: August 25, 2026

IDHIFA (enasidenib) is an oral, small-molecule isocitrate dehydrogenase-2 (IDH2) inhibitor for adults with relapsed or refractory acute myeloid leukemia (AML) carrying susceptible IDH2 mutations. Its commercial opportunity is concentrated in targeted AML treatment, formulation differentiation, generic substitution management, and adjacent development in combination regimens. The product’s excipient architecture is conventional and provides limited standalone protection, but it can support robust manufacturing, dose flexibility, stability, and bioequivalence strategies.

What is IDHIFA and how is it used?

IDHIFA contains enasidenib mesylate and is marketed as film-coated tablets in 50 mg and 100 mg strengths. The FDA approved IDHIFA on August 1, 2017, under the accelerated approval pathway for adults with relapsed or refractory AML with an IDH2 mutation identified by an FDA-approved test.[1]

The labeled adult dose is 100 mg orally once daily, with or without food, until disease progression or unacceptable toxicity. The principal target population is molecularly selected AML patients who have relapsed after, or are refractory to, prior treatment.

Attribute	IDHIFA
Active ingredient	Enasidenib mesylate
Pharmacologic class	Mutant IDH2 inhibitor
Dosage form	Immediate-release film-coated tablet
Strengths	50 mg and 100 mg
FDA approval	August 1, 2017
Initial indication	Relapsed or refractory AML with susceptible IDH2 mutation
Regulatory pathway	Accelerated approval
Primary commercial owner	Bristol Myers Squibb through Celgene
Key commercial risk	Small addressable population, treatment sequencing, generic entry and limited-label expansion

IDHIFA differs from IDH1 inhibitor Tibsovo (ivosidenib), which targets IDH1-mutated disease. The two products compete for molecularly defined AML patients, although their biomarker populations are distinct.

What excipients are used in IDHIFA tablets?

IDHIFA uses a conventional immediate-release tablet platform. Public labeling identifies the core excipients as lactose monohydrate, microcrystalline cellulose, hydroxypropyl cellulose, croscarmellose sodium, and magnesium stearate. The film coating contains standard coating materials, including polyvinyl alcohol-based coating components, polyethylene glycol, talc, titanium dioxide, and colorants.[2]

The formulation performs four primary functions:

1. It disperses a potent active pharmaceutical ingredient at a commercially manageable tablet mass.
2. It provides rapid disintegration and dissolution.
3. It supports dose-strength manufacturing at 50 mg and 100 mg.
4. It improves tablet appearance, handling, and product identification.

Formulation element	Likely function	Commercial relevance
Lactose monohydrate	Diluent	Controls tablet mass and manufacturability
Microcrystalline cellulose	Diluent and compression aid	Supports tablet hardness and production yield
Hydroxypropyl cellulose	Binder	Improves granule and tablet integrity
Croscarmellose sodium	Superdisintegrant	Promotes immediate-release dissolution
Magnesium stearate	Lubricant	Supports tablet ejection and tooling performance
Film-coating polymers	Protective and aesthetic coating	Improves handling, identification and swallowability
Titanium dioxide and iron oxides	Opacifying and coloring agents	Supports strength differentiation and brand recognition
Polyethylene glycol and talc	Coating modifiers	Controls coating flexibility and processability

The disclosed excipient system does not create a high barrier to generic development. A generic manufacturer can generally pursue a qualitatively and quantitatively different formulation if it demonstrates pharmaceutical equivalence, bioequivalence, stability, and compliance with FDA requirements.

How strong is the IDHIFA excipient strategy?

The excipient strategy is operationally strong but appears limited as a standalone intellectual-property barrier. The formulation uses widely available pharmaceutical excipients with established compendial or regulatory histories. That reduces supply risk and simplifies scale-up, but it also makes design-around relatively straightforward.

Advantages of the current formulation

The formulation has several commercial benefits:

• Immediate-release performance aligns with once-daily dosing.
• Standard excipients reduce development and validation complexity.
• Lactose and microcrystalline cellulose support cost-efficient tablet production.
• A conventional film coat allows visual differentiation of the 50 mg and 100 mg strengths.
• The formulation avoids a complex modified-release delivery system.
• The platform is suitable for conventional oral solid-dose manufacturing.

Limitations of the current formulation

The principal limitations are:

• No apparent formulation-based barrier comparable to an extended-release, depot, lipid, or device-enabled product.
• Potential lactose-related restrictions for patients with severe lactose intolerance, although the tablet quantity is generally small.
• Limited commercial differentiation from a future generic immediate-release tablet.
• A narrow opportunity to improve convenience because the approved dose is already once daily.
• Limited ability to extend market exclusivity through routine excipient substitutions alone.

A follow-on formulation could target reduced tablet size, improved swallowability, lower excipient burden, enhanced moisture protection, or improved dissolution under gastrointestinal conditions. Those modifications would have commercial value only if they produced measurable clinical, adherence, stability, or manufacturing benefits.

What formulation opportunities exist for enasidenib?

The most credible formulation opportunities are incremental rather than transformational.

Smaller or higher-load tablets

A high drug-load tablet could reduce tablet size and improve swallowing. This is relevant for older AML patients who may take multiple medicines and experience nausea, mucositis, or dysphagia. A smaller tablet could support lifecycle management, but it would need to show adequate content uniformity, mechanical strength, dissolution, and stability.

Orally disintegrating or dispersible tablets

An orally disintegrating tablet could address patients with swallowing difficulty. The commercial opportunity is narrower because AML treatment is usually administered in a supervised or closely monitored clinical setting, and patients who cannot swallow may receive broader supportive care or alternative administration strategies.

Pediatric or low-dose presentations

Although the principal IDHIFA market is adult AML, lower-strength tablets, granules, or oral suspensions could support pediatric investigation or dose titration. The commercial case depends on regulatory expansion and the number of eligible patients.

Fixed-dose combinations

A fixed-dose combination with an AML backbone such as azacitidine would have clinical and regulatory complexity. Enasidenib has been studied with other agents, but combination packaging or co-formulation would require compatibility, dose flexibility, and interaction data. Separate co-packaging is more commercially practical than a single-tablet combination.

Stability and supply-chain formulations

A moisture-protective blister or high-barrier bottle could improve distribution in hot and humid markets. This opportunity is more likely to produce manufacturing and logistics benefits than meaningful new exclusivity.

Excipient substitution

Replacing lactose, changing the binder system, or adopting a directly compressible formulation could broaden tolerability or reduce manufacturing costs. These changes are commercially relevant for generic developers and contract manufacturers, but they are unlikely to create durable exclusivity unless linked to a patentable process or clinically meaningful performance advantage.

What patents protect IDHIFA?

Enasidenib protection is expected to rely primarily on active-ingredient, chemical-compound, use, and manufacturing patent claims rather than on the public excipient list. The relevant estate may include:

• Composition-of-matter claims covering enasidenib or related IDH2 inhibitors.
• Salt, crystalline-form, and polymorph claims.
• Pharmaceutical-composition claims.
• Methods of treating IDH2-mutated AML.
• Biomarker-selection and mutation-specific treatment claims.
• Processes for producing enasidenib or its intermediates.
• Formulation or dosage-regimen claims, where listed or granted.

The FDA Orange Book should be used to identify current patents listed against IDHIFA and their stated expiration dates. FDA’s public labeling identifies the product and approved use, but patent status must be checked against the current Orange Book entry and relevant USPTO records because listed patents, terminal disclaimers, pediatric extensions, and litigation outcomes can alter the practical exclusivity date.[3]

A reliable commercial assessment should distinguish three dates:

Date type	Relevance
Regulatory exclusivity expiry	Determines when certain ANDA approvals may issue
Patent expiry	Determines potential lawful generic launch timing
Litigation or settlement date	Determines whether an earlier agreed launch date applies

When does IDHIFA lose exclusivity?

IDHIFA’s five-year new chemical entity exclusivity would have run from the 2017 approval date, subject to the FDA’s applicable regulatory calculations. Its orphan-drug designation created a separate seven-year exclusivity period for the approved orphan indication, generally extending into 2024.[1]

Neither regulatory period necessarily determines the earliest generic launch. Patent protection may extend beyond regulatory exclusivity, while a patent challenge, settlement, invalidity ruling, or non-infringement determination could alter launch timing.

Generic entry scenarios

The main entry scenarios are:

1. A generic applicant files an ANDA after relevant regulatory exclusivity expires and certifies against listed patents.
2. A Paragraph IV certification alleges that one or more listed patents are invalid, unenforceable, or not infringed.
3. The patent owner files litigation within the statutory period, triggering a potential 30-month stay of approval.
4. The parties settle, creating a negotiated launch date or other market-access terms.
5. The generic waits for patent expiry or avoids the listed claims through a Paragraph III certification or product design-around.

Publicly available information should not be interpreted as proof that an active Paragraph IV challenge, settlement, or final court decision exists unless confirmed through FDA, district-court, or company records.

What is the FDA regulatory status of IDHIFA?

IDHIFA received accelerated approval based on response rate and duration of response in patients with relapsed or refractory AML harboring an IDH2 mutation. The FDA label includes a boxed warning concerning differentiation syndrome, a potentially serious complication associated with differentiation therapies.[2]

Regulatory risks include:

• Continued confirmatory-trial obligations.
• Label restrictions linked to the IDH2 mutation requirement.
• Safety monitoring for differentiation syndrome, leukocytosis, and tumor lysis syndrome.
• Competition from other targeted and non-targeted AML therapies.
• Potential changes in treatment sequencing as first-line molecularly targeted therapies mature.

Because IDHIFA is a small molecule, biosimilar competition is not applicable. Competition would come from generic enasidenib products, alternative IDH2 inhibitors, IDH1 inhibitors in different biomarker populations, venetoclax-based regimens, intensive chemotherapy, transplant strategies, and clinical trials.

Which companies compete with IDHIFA?

The closest branded comparator is Tibsovo, marketed by Servier for IDH1-mutated AML and related indications. Tibsovo and IDHIFA are biomarker-segmented rather than directly interchangeable.

Product	Active ingredient	Target	Principal AML positioning
IDHIFA	Enasidenib	Mutant IDH2	Relapsed or refractory IDH2-mutated AML
Tibsovo	Ivosidenib	Mutant IDH1	IDH1-mutated AML and other IDH1-driven diseases
Venclexta combinations	Venetoclax	BCL-2	Broad AML use with hypomethylating agents or low-dose cytarabine
Azacitidine	Azacitidine	Hypomethylating agent	Backbone therapy in less-intensive AML treatment
Intensive chemotherapy	Multiple agents	Non-targeted	Fit patients and selected treatment settings

Commercial substitution depends on mutation status, prior therapy, patient fitness, transplant plans, toxicity, payer policy, and physician preference.

What commercial opportunities exist for IDHIFA excipients?

The largest excipient-related opportunity is generic and contract-manufacturing support rather than a premium branded reformulation.

Generic development

Manufacturers can compete through:

• Lower-cost immediate-release tablets.
• Lactose-free or low-lactose formulations.
• Smaller tablets.
• Improved film-coating efficiency.
• High-throughput direct compression.
• Blister packaging for stability and adherence.
• Regional manufacture using locally qualified excipient suppliers.

Bioequivalence development should focus on dissolution method sensitivity, food-effect comparability, impurity control, polymorph management, and dose-strength proportionality.

Specialty excipient supply

Excipient suppliers may target:

• Direct-compression microcrystalline cellulose.
• Low-moisture lactose grades.
• High-functionality croscarmellose sodium.
• Low-lubrication excipient systems.
• Film-coating premixes.
• High-barrier packaging components.

The opportunity is strongest where a supplier can demonstrate improved tablet robustness, shorter processing time, or improved stability without materially increasing cost.

Lifecycle management

A branded lifecycle program could evaluate:

• A smaller 100 mg tablet.
• A lactose-reduced product.
• A dispersible or orally disintegrating dosage form.
• A co-packaged AML regimen.
• Geographic presentations adapted to climate-zone stability requirements.
• A formulation with improved handling for specialty-pharmacy distribution.

The commercial return would depend on whether the product gains a new indication, improves adherence, obtains a new patent term, or secures payer-preferred status.

What revenue exposure does IDHIFA create?

IDHIFA revenue exposure is concentrated in a small, high-severity oncology population. Sales depend on:

• The incidence of IDH2-mutated AML.
• The proportion of patients who relapse or remain refractory.
• Duration of treatment.
• Use before transplantation or subsequent salvage therapy.
• Competition from clinical trials and other targeted agents.
• Reimbursement and specialty-pharmacy access.
• Generic entry timing.

Because Bristol Myers Squibb does not consistently report IDHIFA as a separately material revenue category in public financial disclosures, product-level revenue should not be inferred from aggregate hematology revenue. A commercial diligence model should use epidemiology, mutation prevalence, treatment duration, net price, discontinuation rate, and channel discounts rather than relying on company segment figures.[4]

How should investors assess IDHIFA patent strength?

IDHIFA’s strongest potential protection is likely the active-ingredient and chemical patent layer. The excipient layer is weaker unless it includes a genuinely novel composition, solid form, process, or clinically meaningful release profile.

A practical strength assessment should score:

Factor	Assessment focus
Composition of matter	Claim scope, validity, expiration, prosecution history
Solid-state protection	Polymorph, salt, hydrate and crystal-form coverage
Method of use	Mutation-specific AML claims and written-description support
Formulation	Novelty, non-obviousness and design-around risk
Manufacturing	Process complexity, impurity profile and know-how
Orange Book status	Listed patents, certifications and exclusivity
Litigation	Paragraph IV complaints, stays, judgments and settlements
Commercial differentiation	Clinical benefit, convenience and payer preference

The manufacturing barrier may be more important than the excipient barrier if enasidenib requires tight control of impurities, solid-state form, particle size, or process-related degradation products. Such barriers can delay or increase the cost of generic development even where the published formulation is conventional.

Key Takeaways

• IDHIFA is an immediate-release enasidenib tablet for IDH2-mutated AML.
• Its public excipient system is conventional and supports efficient manufacturing but offers limited standalone exclusivity.
• The strongest intellectual-property value is likely in the active ingredient, chemical series, solid form, use, and manufacturing layers.
• The five-year NCE period and seven-year orphan exclusivity period do not by themselves establish the generic launch date.
• IDHIFA has no biosimilar risk because enasidenib is a small molecule.
• Generic opportunities include lactose-reduced tablets, smaller tablets, alternative compression systems, and lower-cost regional manufacture.
• Branded reformulation opportunities exist but require a measurable clinical, adherence, stability, or commercial advantage.
• Tibsovo is the closest targeted competitor, while venetoclax-based regimens create broader treatment competition.
• Product-level revenue should be modeled from patient flow and treatment duration because IDHIFA is not generally disclosed as a separate material revenue line.

FAQs

Can a generic manufacturer use the same IDHIFA excipients?

Yes. A generic manufacturer can generally use the same excipients if the formulation meets applicable quality, safety, pharmaceutical-equivalence, and bioequivalence requirements. It may also use alternative excipients.

Is IDHIFA protected by a formulation patent?

A formulation patent may exist within the broader patent estate, but the public excipient list alone does not establish patent protection. The current Orange Book and USPTO records control the patent assessment.

Does IDHIFA have biosimilar competition?

No. Enasidenib is a chemically synthesized small molecule. Competition would involve generic ANDA products, not biosimilars.

What is the most valuable excipient opportunity for enasidenib?

The strongest opportunity is a generic-oriented formulation that improves tablet manufacturability, reduces tablet size, or provides lactose-reduced composition while preserving bioequivalence and stability.

Could IDHIFA be reformulated as a fixed-dose combination?

Technically possible, but a co-packaged regimen is more practical than a single-tablet combination because AML treatment requires dose adjustments, treatment interruptions, and individualized combinations.

References

1. U.S. Food and Drug Administration. (2017). FDA approves new targeted treatment for relapsed or refractory acute myeloid leukemia. https://www.fda.gov
2. U.S. Food and Drug Administration. (2023). IDHIFA (enasidenib) prescribing information. Bristol Myers Squibb. https://www.accessdata.fda.gov
3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.fda.gov
4. Bristol Myers Squibb. (2024). Annual report and Form 10-K. https://www.bms.com