List of Excipients in Branded Drug NOURIANZ

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Kyowa Kirin Inc	NOURIANZ	istradefylline	42747-602	CARNAUBA WAX	2027-09-05
Kyowa Kirin Inc	NOURIANZ	istradefylline	42747-602	CELLULOSE, MICROCRYSTALLINE	2027-09-05
Kyowa Kirin Inc	NOURIANZ	istradefylline	42747-602	CROSPOVIDONE	2027-09-05

NOURIANZ Excipient Strategy and Commercial Opportunities for Istradefylline

Last updated: September 4, 2026

NOURIANZ is a 20 mg and 40 mg immediate-release istradefylline tablet marketed by Kyowa Kirin for adjunctive treatment of “off” episodes in adults with Parkinson’s disease receiving levodopa/carbidopa. Its excipient system is conventional, low-cost, and potentially reproducible through a standard ANDA strategy. The main commercial opportunities are generic supply, excipient sourcing, alternative oral dosage forms, and regional licensing rather than biosimilar development.

The strongest near-term opportunity is a cost-competitive immediate-release tablet using pharmacopeial lactose, corn starch, croscarmellose sodium, magnesium stearate, hypromellose, talc, titanium dioxide, and iron oxide colorants. Differentiated products such as orally disintegrating tablets, sprinkle formulations, and lower-dose tablets may create commercial value but would require clinical, bioequivalence, stability, and regulatory work.

What is NOURIANZ and how is it positioned commercially?

NOURIANZ contains istradefylline, a selective adenosine A2A receptor antagonist. FDA approved the product in August 2019 as an adjunct to levodopa/carbidopa for Parkinson’s disease patients experiencing “off” episodes.[1]

Attribute	NOURIANZ profile
Active ingredient	Istradefylline
Strengths	20 mg and 40 mg
Dosage form	Film-coated immediate-release tablet
Route	Oral
Sponsor/marketer	Kyowa Kirin Co., Ltd.
FDA approval	August 20, 2019
Therapeutic area	Parkinson’s disease, adjunctive treatment
Indication	Reduction of “off” episodes with levodopa/carbidopa
Biologic status	Small molecule; biosimilar pathway does not apply
Primary regulatory route for a generic	ANDA under section 505(j) of the FD&C Act

NOURIANZ is administered once daily. The recommended starting dose is 20 mg once daily, with an increase to 40 mg once daily where clinically appropriate. The label includes important interaction considerations involving CYP3A4 inducers and inhibitors.[1]

The product competes indirectly with other treatments for motor fluctuations, including dopamine agonists, monoamine oxidase-B inhibitors, catechol-O-methyltransferase inhibitors, amantadine products, and device-based therapies. Its commercial value depends on use as an add-on treatment rather than replacement of levodopa.

What excipients are used in NOURIANZ tablets?

The FDA prescribing information identifies the following inactive ingredients for NOURIANZ tablets:[1]

Formulation component	Function	Commercial relevance
Lactose monohydrate	Diluent and tablet filler	Widely available; low-cost; may require lactose-labeling controls
Corn starch	Filler and disintegrant	Supports tablet breakup and compressibility
Croscarmellose sodium	Superdisintegrant	Supports rapid disintegration in an immediate-release tablet
Magnesium stearate	Lubricant	Requires control of blending time and concentration
Hypromellose	Film former	Used in the tablet coating
Talc	Anti-tacking and coating aid	Common film-coating component
Titanium dioxide	Opacifier and pigment	Used in film-coating systems
Ferric oxide colorant	Tablet-color component	Supports strength identification and product differentiation

The formulation is not dependent on a novel excipient, lipid system, controlled-release polymer, or complex manufacturing process. That lowers technical barriers for a generic manufacturer. The key development variables are blend uniformity, tablet hardness, disintegration, dissolution, coating uniformity, and impurity control.

What formulation attributes matter for generic development?

A generic developer would typically target the same immediate-release profile and comparable tablet dimensions, appearance, and strength differentiation. The most sensitive excipient variables are likely:

1. Croscarmellose sodium level and grade, which affect disintegration and dissolution.
2. Magnesium stearate concentration and lubrication time, which can slow dissolution if overprocessed.
3. Lactose and starch particle-size distribution, which affect flow and compression.
4. Film-coat weight gain, which affects appearance and moisture protection.
5. Colorant concentration, which affects visual identification and product sameness.

An ANDA sponsor does not generally need to copy every excipient source or manufacturing parameter. It must demonstrate pharmaceutical equivalence and bioequivalence and satisfy quality requirements. The sponsor must also address inactive-ingredient safety and product-performance differences through the ANDA review process.[2]

What excipient strategy is most attractive for a NOURIANZ generic?

The most defensible strategy is a direct-compression or wet-granulated immediate-release tablet with the listed excipient classes and a supplier-qualified coating system.

Strategy 1: Direct generic substitution

This approach uses:

• Lactose monohydrate as the principal diluent.
• Corn starch and croscarmellose sodium for disintegration.
• Magnesium stearate for lubrication.
• A conventional hypromellose-based film coating.
• Iron oxide to distinguish 20 mg and 40 mg strengths.

Its advantages are low cost, broad supplier availability, and a straightforward quality-by-design package. The principal risk is dissolution drift caused by differences in excipient grade, particle size, moisture, or lubrication.

Strategy 2: Lactose-free formulation

A lactose-free product could substitute mannitol, microcrystalline cellulose, dibasic calcium phosphate, or a combination of these materials. This may appeal to patients with lactose intolerance and simplify positioning for selected markets.

The commercial benefit is limited in the U.S. unless the product produces a meaningful tolerability or labeling advantage. A formulation change would require comparative dissolution and bioequivalence work. A lactose-free product would also lose the simplicity of following the reference product’s established composition.

Strategy 3: Orally disintegrating tablet

An orally disintegrating tablet could target Parkinson’s patients with dysphagia, delayed gastric emptying, or difficulty swallowing during “off” episodes. Mannitol, crospovidone, low-substituted hydroxypropyl cellulose, and taste-masking systems are plausible excipient platforms.

The opportunity is commercially stronger than a conventional tablet but regulatory risk is higher. An ODT may require new in vitro performance specifications, palatability data, mechanical-strength controls, packaging studies, and potentially a distinct bioequivalence strategy.

Strategy 4: Sprinkle or dispersible formulation

A sprinkle capsule or dispersible tablet could target patients who cannot swallow conventional tablets. This would be a new dosage form rather than a simple generic equivalent. The key technical issues would include dose recovery, uniformity after dispersion, food compatibility, stability after preparation, and administration through feeding tubes.

This opportunity is more likely to support a 505(b)(2) product or a jurisdiction-specific product than a conventional ANDA.

What patents protect NOURIANZ and its excipient formulation?

The original chemical and pharmacology patent estate for istradefylline is unlikely to provide a current barrier to U.S. generic development by itself. The relevant commercial risk is the remaining Orange Book patent listing, including any method-of-use or formulation patents still enforceable in the target market.

FDA’s Orange Book is the controlling source for listed patents and regulatory exclusivity associated with an approved drug product.[3] The NOURIANZ label does not identify a novel excipient as the source of product differentiation, and ordinary excipients such as lactose, starch, croscarmellose sodium, magnesium stearate, and hypromellose are not independently proprietary to Kyowa Kirin.

IP category	Relevance to NOURIANZ generic entry
Istradefylline composition patents	Potentially expired or late-life, depending on jurisdiction and patent family
A2A antagonist pharmacology patents	Mostly relevant to historical development and broad chemical protection
Tablet formulation patents	Must be checked against current Orange Book listings
Method-of-use patents	Could affect use with levodopa/carbidopa or particular dosing regimens
Excipient patents	No clear barrier from the conventional excipient system disclosed in the label
Manufacturing patents	May affect API production, impurity control, or specific process routes
Trade secrets	May cover process parameters, suppliers, analytical methods, and scale-up controls

A generic applicant should conduct a current Orange Book review and a patent-family analysis covering U.S. continuation patents, terminal disclaimers, reissue activity, and litigation history. An excipient substitution alone does not eliminate infringement risk if a patent claims the active ingredient, dosage regimen, tablet composition, or manufacturing process.

When does NOURIANZ lose exclusivity?

NOURIANZ received five-year new chemical entity exclusivity from FDA approval in 2019. That exclusivity period ended in 2024, subject to statutory calculation and any pediatric extension.[2]

Exclusivity or protection	Timing and commercial implication
FDA approval	August 20, 2019
NCE exclusivity	Generally ran for five years from approval
NCE barrier to ANDA approval	Generally ended in 2024
Patent protection	Depends on the current Orange Book and underlying patent families
Pediatric exclusivity	No extension should be assumed without an FDA-recognized award
Generic launch	Depends on patent certifications, litigation, settlement terms, and approval timing

Loss of NCE exclusivity does not guarantee immediate generic launch. A generic applicant may face listed patents, a Paragraph IV challenge, a 30-month stay from patent litigation, or a settlement that delays launch.

What Paragraph IV challenges and patent litigation affect NOURIANZ?

A Paragraph IV certification is the standard route for challenging an Orange Book-listed patent before its expiration. The ANDA applicant asserts that the listed patent is invalid, unenforceable, or will not be infringed by the proposed generic.[2]

The commercial sequence is:

1. An ANDA applicant files with a Paragraph IV certification.
2. The patent holder receives notice.
3. The patent holder may file suit within 45 days.
4. Litigation can trigger a statutory 30-month stay of FDA approval.
5. The first substantially complete Paragraph IV applicant may obtain 180-day generic exclusivity if statutory conditions are met.

Publicly available FDA materials do not establish a broad, commercially material biosimilar or biologic challenge because istradefylline is a small molecule. Any current NOURIANZ litigation position must be assessed through PACER, FDA’s Orange Book, and USPTO records rather than inferred from the product label.

What FDA regulatory status applies to alternative NOURIANZ products?

Product concept	Likely U.S. pathway	Main requirements
Same 20 mg or 40 mg tablet	505(j) ANDA	Pharmaceutical equivalence, bioequivalence, CMC, labeling
Lactose-free tablet	505(j) if equivalent	Inactive-ingredient justification, dissolution, bioequivalence
New ODT	505(b)(2) or ANDA depending on sameness	Dosage-form comparability, palatability, performance
Sprinkle product	Usually 505(b)(2)	Administration, stability, dose recovery, clinical bridging
Extended-release product	505(b)(2)	New pharmacokinetic and clinical-performance evidence
Combination product	505(b)(2) or new drug application	Combination-specific safety and efficacy package

A 505(b)(2) product may obtain differentiated labeling or dosage-form protection but requires more development capital than a standard ANDA. An ODT or sprinkle formulation is commercially attractive only if it solves a defined adherence or administration problem.

How strong is the NOURIANZ patent estate?

The estate appears technically moderate rather than structurally difficult for generic competition. The conventional excipient system does not create a meaningful standalone barrier. The remaining risk is concentrated in active-ingredient patent families, method-of-use claims, formulation claims, and manufacturing know-how.

Strength factor	Assessment
Novel excipient protection	Low
Formulation complexity	Low to moderate
API manufacturing complexity	Moderate
Clinical differentiation	Moderate
ANDA development burden	Manageable
Biosimilar barrier	Not applicable
Patent litigation risk	Requires current Orange Book and docket review
Commercial substitution risk	Moderate, because the product is adjunctive and branded physician familiarity may persist

The main technical barrier may be API sourcing rather than tablet manufacture. An API supplier must demonstrate impurity control, polymorph or solid-state consistency where relevant, residual-solvent control, and a stable regulatory filing supported by a Type II drug master file or equivalent documentation.

What manufacturing and excipient opportunities exist?

The largest business opportunities are upstream and contract-manufacturing opportunities:

• Supply of pharmaceutical-grade lactose monohydrate, croscarmellose sodium, corn starch, hypromellose, and coating pigments.
• Development of a preblended direct-compression excipient system optimized for istradefylline dissolution.
• Contract manufacture of 20 mg and 40 mg film-coated tablets.
• API and finished-dose supply for markets where patent barriers have expired.
• Regional licensing of an ODT, dispersible tablet, or lactose-free product.
• Packaging systems that protect tablets from moisture and preserve color and assay through shelf life.

An excipient supplier is unlikely to obtain meaningful molecule-specific exclusivity from a standard ingredient alone. The stronger commercial position comes from a validated platform, proprietary grade, regulatory support package, or long-term supply agreement.

How does NOURIANZ compare with competing Parkinson’s adjunctive products?

Product class	Main differentiation	Excipient opportunity
Istradefylline	A2A antagonism; once-daily oral adjunct	Low-cost generic tablet; ODT or sprinkle product
Rasagiline and selegiline	MAO-B inhibition	Conventional tablets, orally disintegrating systems
Entacapone-containing products	COMT inhibition	Combination tablets and dose simplification
Opicapone	Once-daily COMT inhibition	Film-coated tablets and modified-release development
Amantadine ER	Extended exposure; dyskinesia and “off” management	Modified-release and capsule technologies
Levodopa delivery systems	Core replacement therapy	Complex delivery and device-linked formulations

NOURIANZ has a relatively simple dosage form compared with extended-release amantadine products or device-based levodopa systems. That lowers manufacturing cost but limits formulation-based differentiation.

What generic launch scenarios exist for NOURIANZ?

Early launch after patent clearance

A first-wave ANDA sponsor could launch when FDA approval is available and no enforceable patent blocks entry. Price erosion would depend on the number of approved applicants and the size of the branded patient base.

Authorized generic or settlement launch

Kyowa Kirin could license a generic, authorize a third-party product, or settle Paragraph IV litigation with a specified launch date. Such an arrangement would reduce litigation uncertainty but could compress the value of independent generic entry.

Differentiated 505(b)(2) launch

A company could pursue an ODT, sprinkle, or lactose-free product. This strategy would avoid direct price competition only if the dosage form obtains physician, payer, or patient adoption.

Regional launch

Markets outside the U.S. may offer earlier opportunities where compound or formulation patents have expired, local registration standards differ, or the product is not actively commercialized. Geographic freedom-to-operate must be determined country by country.

What is the revenue exposure for Kyowa Kirin and generic entrants?

Kyowa Kirin does not generally report NOURIANZ revenue as a separately disclosed segment in the same way as its largest oncology and rare-disease products. Public revenue exposure therefore cannot be reliably calculated from consolidated company reporting alone.[4]

For a generic entrant, commercial potential depends on:

• U.S. prescription volume for adjunctive “off” episode treatment.
• The number of approved ANDA competitors.
• Reimbursement and tier placement.
• Persistence of branded prescribing.
• The cost of istradefylline API.
• Whether Kyowa Kirin maintains promotional support.
• The timing and terms of any patent settlement.

The most attractive business case is a low-cost tablet with reliable API supply and a first-to-market or early-market position. A premium excipient strategy is unlikely to support higher pricing unless it enables a clinically relevant dosage-form advantage.

Key Takeaways

• NOURIANZ is an immediate-release istradefylline tablet available in 20 mg and 40 mg strengths.
• Its excipient system is conventional and does not create a major technical barrier to generic manufacture.
• Lactose, corn starch, croscarmellose sodium, magnesium stearate, hypromellose, talc, titanium dioxide, and iron oxide are the key formulation materials.
• U.S. NCE exclusivity began with the 2019 approval and generally ended in 2024.
• Current Orange Book listings, continuation patents, litigation, and settlements determine actual generic-entry timing.
• Biosimilar risk is not relevant because istradefylline is a small-molecule drug.
• The strongest near-term opportunity is a conventional ANDA tablet supported by secure API sourcing.
• ODT, sprinkle, dispersible, and lactose-free products offer greater differentiation but likely require a 505(b)(2) strategy or additional development work.
• Excipient suppliers can create value through validated grades, preblended systems, regulatory packages, and supply agreements rather than ordinary commodity ingredients.
• Kyowa Kirin’s product-specific revenue exposure is not separately disclosed in a way that supports a precise public estimate.

FAQs

Can a generic NOURIANZ tablet use different excipients?

Yes. An ANDA applicant may use different inactive ingredients if the product meets pharmaceutical-equivalence, bioequivalence, quality, safety, and labeling requirements.

Is lactose-free istradefylline commercially attractive?

It may address a defined patient preference, but the opportunity is limited unless the formulation delivers measurable tolerability, adherence, or market-access benefits.

Can an excipient supplier patent a NOURIANZ generic formulation?

A supplier may patent a genuinely novel composition, manufacturing process, or performance advantage. Ordinary use of lactose, starch, croscarmellose sodium, magnesium stearate, and hypromellose is unlikely to create molecule-specific exclusivity.

Would an istradefylline orally disintegrating tablet be an ANDA product?

Not necessarily. If the dosage form differs materially from the reference product, FDA may require a 505(b)(2) application rather than a conventional ANDA.

What is the principal non-excipient barrier to generic NOURIANZ?

The principal risks are current Orange Book patents, Paragraph IV litigation, API sourcing, impurity control, and the timing of any settlement or authorized-generic arrangement.

References

1. U.S. Food and Drug Administration. (2019). NOURIANZ (istradefylline) tablets: Prescribing information. Kyowa Kirin, Inc.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Center for Drug Evaluation and Research.

3. U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/

4. Kyowa Kirin Co., Ltd. (2024). Integrated report and financial results materials. Tokyo, Japan.