List of Excipients in Branded Drug KEVEYIS

Company	Tradename	Ingredient	NDC	Excipient	Potential Generic Entry
Taro Pharmaceuticals USA inc	KEVEYIS	dichlorphenamide	51672-4177	LACTOSE MONOHYDRATE
Taro Pharmaceuticals USA inc	KEVEYIS	dichlorphenamide	51672-4177	MAGNESIUM STEARATE
Taro Pharmaceuticals USA inc	KEVEYIS	dichlorphenamide	51672-4177	STARCH, CORN
Strongbridge US Inc	KEVEYIS	dichlorphenamide	71090-001	LACTOSE MONOHYDRATE

Keveyis Excipient Strategy and Commercial Opportunities

Last updated: August 14, 2026

Keveyis is a 50 mg oral tablet containing dichlorphenamide for the treatment of primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants in adults and adolescents aged 12 years and older. The commercial opportunity is concentrated in formulation differentiation, pediatric usability, supply-chain control, and lifecycle management rather than in the active pharmaceutical ingredient, which is an established carbonic anhydrase inhibitor. FDA orphan-drug protection has expired, so future barriers depend mainly on Orange Book patents, regulatory exclusivity, clinical evidence, and execution in a small specialty market. [1-4]

What is Keveyis and how is it administered?

Keveyis contains dichlorphenamide, a sulfonamide carbonic anhydrase inhibitor. The approved product is supplied as an immediate-release 50 mg tablet. Dosing is individualized and may involve divided daily doses, with titration based on clinical response and tolerability. [1]

Attribute	Keveyis profile
Active ingredient	Dichlorphenamide
Strength	50 mg tablet
Dosage form	Immediate-release oral tablet
FDA indication	Primary hyperkalemic periodic paralysis, primary hypokalemic periodic paralysis, and related variants
Target population	Adults and pediatric patients 12 years and older
Sponsor	Catalyst Pharmaceuticals
Original FDA approval	August 2015
Regulatory pathway	Full NDA approval
Orphan-drug designation	Yes
Key safety monitoring	Serum potassium, bicarbonate, renal function, hypersensitivity, metabolic acidosis, renal calculi, and hematologic effects

Keveyis has a narrow, high-value patient population. The product is distributed through specialty channels, where adherence support, prior-authorization management, and rapid access can be as important commercially as tablet cost.

What excipients are used in Keveyis tablets?

The FDA prescribing information identifies the inactive ingredients in Keveyis. The listed excipient system includes microcrystalline cellulose, croscarmellose sodium, magnesium stearate, colloidal silicon dioxide, povidone, lactose monohydrate, and sodium starch glycolate. The exact quantitative formulation and manufacturing process are not generally disclosed in the public label. [1]

Excipient	Likely formulation role	Commercial relevance
Microcrystalline cellulose	Diluent and compression aid	Supports tablet hardness and manufacturability
Lactose monohydrate	Diluent	Creates a potential lactose-sensitivity and supply-chain consideration
Croscarmellose sodium	Superdisintegrant	Supports rapid tablet breakup
Sodium starch glycolate	Superdisintegrant	Provides additional disintegration capacity
Povidone	Binder	Improves granule and tablet integrity
Colloidal silicon dioxide	Glidant and moisture-flow aid	Improves powder flow and blend uniformity
Magnesium stearate	Lubricant	Reduces tooling friction and ejection force

The formulation is consistent with a conventional compressed immediate-release tablet. No public evidence establishes that Keveyis depends on a novel excipient, modified-release matrix, lipid system, solubilizer, or proprietary delivery platform.

Which excipient risks matter most for Keveyis?

The principal excipient risks are not complex chemistry risks. They are dose uniformity, tablet robustness, disintegration performance, impurity control, and manufacturing consistency at relatively small batch volumes.

Lactose and excipient tolerability

Lactose monohydrate is present in the listed formulation. Patients with severe lactose intolerance may require counseling, although the amount per tablet and clinical significance depend on the quantitative composition. A lactose-free reformulation could support a differentiated product claim, but the commercial value would depend on demonstrable demand in the periodic-paralysis population.

Magnesium stearate and dissolution

Magnesium stearate is useful for tablet ejection but excessive lubrication can reduce wettability and slow dissolution. A generic or reformulated product must control lubricant concentration, blending time, and shear exposure. These process variables can become important where a 50 mg tablet contains a low mass of active ingredient relative to excipients.

Superdisintegrant balance

Croscarmellose sodium and sodium starch glycolate can improve disintegration, but their performance changes with grade, particle size, moisture, and compaction force. A formulation using one superdisintegrant instead of two may reduce cost and simplify sourcing, although comparative dissolution and stability data would be required.

Moisture and physical stability

Povidone, cellulose-based excipients, starch derivatives, and lactose can affect moisture uptake and tablet hardness. Packaging selection should be based on water-vapor transmission, tablet friability, assay stability, and impurity formation. A high-barrier bottle or blister could create a modest but defensible product-quality advantage.

What formulation patents protect Keveyis?

Publicly available product information identifies Keveyis as an immediate-release dichlorphenamide tablet. The core commercial protection has historically been associated with the approved use of dichlorphenamide in periodic paralysis and related method-of-treatment claims, rather than with a publicly established proprietary excipient platform. The FDA Orange Book is the controlling source for patents listed against the approved product. [3]

Method-of-use protection

The relevant intellectual-property strategy has centered on using dichlorphenamide to treat periodic paralysis. Such claims can be commercially important even when the active ingredient is old because the approved indication is rare, clinically specific, and supported by controlled trial data.

Method-of-use claims may cover:

• Treatment of primary periodic paralysis.
• Treatment of hyperkalemic or hypokalemic disease subtypes.
• Dose administration or titration.
• Patient selection based on disease phenotype.
• Reduction in attack frequency or severity.

A generic applicant may attempt a section viii skinny-label strategy that omits patented uses. The practical value of that strategy depends on whether the remaining label still creates an inducement risk and whether the product is commercially viable without the patented indication.

Formulation protection

A new excipient strategy could support separate intellectual-property claims if it delivers a measurable technical effect, such as:

• Improved dissolution across physiologic pH conditions.
• Reduced tablet size at equivalent dose.
• Improved stability under high humidity.
• Reduced friability during specialty-pharmacy shipping.
• Lactose-free composition.
• Taste masking for pediatric administration.
• Orally disintegrating or dispersible delivery.
• Improved dose uniformity in low-dose tablets.

A simple substitution of one conventional filler for another is unlikely to create strong, durable protection without unexpected performance or a clear manufacturing advantage.

When does Keveyis lose exclusivity?

Keveyis has already passed the end of its seven-year U.S. orphan-drug exclusivity period. The product was approved in August 2015, placing the nominal orphan exclusivity end in August 2022, subject to the precise FDA designation and approval record. [1, 2]

Protection type	Keveyis status	Commercial implication
Orphan-drug exclusivity	Expired on the nominal seven-year schedule	Does not independently block approval of the same drug for the same indication
New chemical entity exclusivity	Not expected to remain active	Dichlorphenamide is an established compound
Orange Book patent protection	Must be assessed from current FDA listing	May delay approval or launch of ANDA products
Pediatric exclusivity	No broad public basis to treat it as a current barrier	Requires confirmation from FDA records
Regulatory exclusivity from reformulation	Potentially available only if statutory criteria are met	Depends on approval pathway and clinical justification

The most important timing issue is the expiration and enforceability of listed method-of-use patents. A patent may remain relevant after orphan exclusivity ends, but its scope must be evaluated against the proposed generic label and the actual commercial conduct of the applicant.

What is the Orange Book status of Keveyis?

Keveyis should be evaluated through the current FDA Orange Book product record for dichlorphenamide tablets. The record determines whether patents are listed, the associated expiration dates, and whether the listed patents are drug-substance, drug-product, or method-of-use patents. [3]

A commercial diligence review should distinguish between:

1. Patents listed against the product.
2. Unlisted continuation, process, or formulation patents.
3. Patent-term adjustment or patent-term extension.
4. Paragraph IV notices and resulting litigation.
5. Patent claims that cover the approved indication versus claims that can be omitted through a skinny label.

Because dichlorphenamide is an old active ingredient, the key generic barrier is likely to be use-patent scope and regulatory execution, not active-ingredient discovery.

Which companies are challenging Keveyis?

Generic competition can come from any ANDA sponsor able to demonstrate bioequivalence and satisfy the applicable patent certifications. Public commercial risk should be assessed through FDA paragraph IV notices, district-court dockets, and Catalyst Pharmaceuticals' securities filings. Catalyst's periodic reports identify material patent disputes, ANDA challenges, and exclusivity developments when those events meet disclosure thresholds. [4]

A paragraph IV filing can trigger patent litigation and a potential 30-month stay of ANDA approval under the Hatch-Waxman framework. The stay does not guarantee that the patent will survive or that a generic cannot launch after an adverse litigation outcome. [5]

The most relevant competitor categories are:

• Large generic manufacturers with established ANDA infrastructure.
• Specialty generic companies willing to commercialize a low-volume product.
• Contract manufacturers partnering with smaller ANDA sponsors.
• International companies using U.S. specialty-drug platforms.

What generic entry risks exist for Keveyis?

Generic launch risk is moderate to high after the expiration or invalidation of relevant use patents. The market is small, but that can support attractive pricing if a generic manufacturer obtains a reliable prescriber and specialty-pharmacy network.

Launch scenario analysis

Scenario	Likely market effect
No approved ANDA before patent expiry	Catalyst retains near-term branded share
One authorized or independent generic	Net price pressure and payer substitution increase
Multiple generics	Rapid erosion in gross-to-net-adjusted revenue
Skinny-label generic	Risk depends on prescribing behavior and induced-use evidence
Reformulated branded product	May preserve a segment of demand but may not block the reference product
Authorized generic	Catalyst or its partner controls part of the generic economics

The small patient population reduces the absolute revenue opportunity for generic entrants but can improve the probability of stable pricing. Specialty distribution and disease-specific diagnosis also create commercial friction for new entrants.

How can excipient strategy create commercial opportunities?

The highest-value opportunity is a differentiated product that solves a clinical or operational problem without requiring a new active ingredient.

Pediatric and adolescent delivery

Keveyis is approved for patients aged 12 years and older. A smaller tablet, orally disintegrating tablet, dispersible tablet, or pharmacy-compounded suspension could improve administration for adolescents and patients with swallowing difficulties.

Potential excipient approaches include:

• Taste masking with ion-exchange resins or polymeric coatings.
• Rapid disintegration using optimized superdisintegrant grades.
• Low-volume dispersible tablets.
• Lactose-free or low-allergen excipient systems.
• Unit-dose packaging for titration schedules.

A pediatric formulation would likely require bridging studies, dose-accuracy data, stability testing, and potentially a supplemental NDA or 505(b)(2) pathway, depending on the formulation and development strategy. [6]

Orally disintegrating tablets

An orally disintegrating formulation could reduce the need for water and support use during an acute attack. The technical challenge is balancing rapid disintegration with the bitter or sulfur-containing taste associated with many sulfonamide compounds.

Commercial value would depend on:

• Demonstrated administration benefit.
• Acceptable mouthfeel.
• Stable dose uniformity at 50 mg.
• Packaging that limits moisture exposure.
• No clinically meaningful change in pharmacokinetics.

Liquid and dispersible presentations

A ready-to-use liquid could support patients unable to swallow tablets, but it would create preservative, microbial, sedimentation, container-closure, and dosing-device requirements. A dry powder for reconstitution may reduce stability risks but increases caregiver handling.

A pharmacy-compounded suspension is a lower-cost development option, but it does not provide the same consistency, labeling, or commercial defensibility as an FDA-approved dosage form.

Packaging as a formulation-adjacent opportunity

Calendar blister packs, titration packs, and dose-escalation kits could support adherence and reduce dispensing errors. Packaging claims generally provide weaker exclusivity than formulation patents, but packaging can produce practical differentiation in a rare-disease specialty market.

How strong is the Keveyis patent estate?

The estate is stronger in indication-specific value than in excipient complexity. Dichlorphenamide itself is not a newly discovered molecule, and conventional excipients are difficult to protect broadly. The commercial estate therefore depends on:

• Scope of method-of-use claims.
• Remaining patent term.
• Validity under obviousness and written-description challenges.
• Ability to enforce claims against skinny-label products.
• Clinical relevance of the patented indication.
• Presence of continuation or formulation applications.

A practical strength assessment is:

Estate component	Relative strength
Active-ingredient composition claims	Low, given the age of dichlorphenamide
Conventional excipient composition	Low unless supported by unexpected results
Approved indication claims	Medium to high, depending on claim scope and validity
Pediatric formulation claims	Potentially medium
ODT or dispersible formulation claims	Potentially medium to high if technically differentiated
Manufacturing-process claims	Medium where impurity or scale-up performance is difficult to reproduce
Brand, specialty-channel, and prescriber relationships	Commercially meaningful but not patent protection

What manufacturing and IP barriers affect Keveyis?

Manufacturing barriers are manageable but not negligible. A supplier must control dichlorphenamide assay, particle-size distribution, polymorphic form, residual solvents, elemental impurities, and sulfonamide-related impurities. Tablet production requires tight control over blending and compression because content uniformity can be sensitive to segregation and low-dose API distribution.

Potentially defensible manufacturing claims could address:

• A controlled particle-size API fraction.
• A specific granulation process.
• Reduced impurity formation.
• Improved stability under accelerated conditions.
• Direct compression using a defined excipient ratio.
• A validated low-shear blending process.

These claims are more likely to support freedom-to-operate and process confidentiality than to block every competing product.

How does Keveyis compare with acetazolamide and other carbonic anhydrase inhibitors?

Keveyis has a narrower approved role than acetazolamide, which is used across several neurologic, ophthalmic, and metabolic indications. The comparison is commercially important because physicians may consider acetazolamide or other carbonic anhydrase inhibitors in periodic paralysis, subject to clinical judgment and patient response.

Factor	Keveyis	Acetazolamide
Approved periodic-paralysis positioning	Specific FDA approval	Broader historical use, but different regulatory positioning
Active ingredient	Dichlorphenamide	Acetazolamide
Market structure	Specialty orphan market	Broad generic market
Excipient opportunity	High relative value from pediatric and specialty delivery	Lower per-product differentiation because of extensive generic availability
Pricing power	Historically supported by orphan positioning and specialty distribution	Limited by generic competition
Generic substitution risk	Delayed by patents and small-market economics	High and established
Clinical differentiation	Disease-specific evidence and labeling	Broader use but less product-specific positioning

Keveyis may retain commercial value even when generic dichlorphenamide enters because diagnosis, specialist prescribing, and patient support can sustain branded demand. That protection is commercial rather than absolute.

What licensing deals and partnerships matter?

Catalyst Pharmaceuticals acquired Strongbridge Biopharma in 2021, bringing Keveyis into Catalyst's commercial portfolio. [7] The transaction is the principal publicly documented strategic event associated with ownership of the product.

Future licensing opportunities could involve:

• Regional commercialization rights.
• Co-development of pediatric or ODT presentations.
• Authorized-generic supply.
• Specialty-pharmacy services.
• Excipient and drug-product manufacturing partnerships.
• Co-promotion in neuromuscular disease.

The most attractive partner profile is a company with rare-disease commercial infrastructure, regulatory experience in 505(b)(2) products, and tablet or oral-liquid manufacturing capability.

What is the FDA regulatory opportunity for a Keveyis reformulation?

A reformulated product could use a supplemental NDA if it remains within the existing product framework or a 505(b)(2) application if it relies partly on FDA findings for an approved product while introducing a new dosage form, route, strength, or formulation. [6]

The strongest regulatory-commercial candidates are:

1. Lactose-free immediate-release tablet.
2. Smaller, higher-hardness tablet for adolescent use.
3. Orally disintegrating tablet.
4. Dispersible tablet for swallowing-impaired patients.
5. Titration-pack presentation.
6. Ready-to-use or reconstituted oral suspension.

A reformulation must show that the excipient change does not introduce clinically meaningful differences in exposure, safety, dissolution, or dose delivery. A new product may obtain its own period of regulatory protection, but it would not automatically eliminate generic competition to the original tablet.

Key Takeaways

• Keveyis is a 50 mg immediate-release dichlorphenamide tablet for primary periodic paralysis.
• Its publicly listed excipients are conventional tablet ingredients, including lactose, cellulose, povidone, superdisintegrants, colloidal silicon dioxide, and magnesium stearate.
• The strongest excipient opportunities are pediatric usability, taste masking, ODT or dispersible delivery, lactose-free composition, and adherence packaging.
• Orphan-drug exclusivity has expired. Current competitive risk depends on Orange Book patents, paragraph IV activity, litigation, and generic launch timing.
• The patent estate is more valuable for indication-specific use claims than for conventional excipient composition claims.
• A reformulation could preserve branded value, but it would require technical differentiation and an appropriate FDA pathway.
• Licensing opportunities are strongest in regional commercialization, authorized generics, pediatric delivery, and specialty manufacturing.

Frequently Asked Questions

Can a lactose-free Keveyis tablet obtain separate patent protection?

Yes, but lactose removal alone may be insufficient. Stronger protection would require unexpected stability, dissolution, tolerability, manufacturability, or patient-use benefits supported by comparative data.

Could an authorized generic protect Keveyis revenue after patent expiry?

Yes. An authorized generic could allow the sponsor to capture part of the generic market and control supply, although it would also accelerate price competition.

Is an oral liquid commercially justified for dichlorphenamide?

It may be justified for patients with swallowing limitations or pediatric dosing needs. The business case depends on patient numbers, stability, preservative requirements, dosing accuracy, and reimbursement.

Does a skinny-label generic eliminate all Keveyis patent risk?

No. A skinny label can omit patented indications, but inducement, prescribing behavior, labeling language, and actual marketing conduct can remain relevant to litigation.

Which excipient change offers the clearest near-term opportunity?

A lactose-free, compact, rapidly disintegrating tablet is likely to have the clearest near-term development rationale because it preserves the existing route and strength while targeting tolerability, swallowing, and manufacturing differentiation.

References

1. U.S. Food and Drug Administration. (2024). Keveyis (dichlorphenamide) prescribing information. Catalyst Pharmaceuticals. https://www.accessdata.fda.gov/drugsatfda_docs/label/

2. U.S. Food and Drug Administration. (n.d.). Orphan drug designations and approvals database. https://www.accessdata.fda.gov/scripts/opdufa/

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

4. Catalyst Pharmaceuticals, Inc. (2024). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934, Form 10-K. U.S. Securities and Exchange Commission. https://www.sec.gov/edgar/browse/

5. U.S. Food and Drug Administration. (2017). ANDA submissions: Amendments and requests for final approval to tentatively approved ANDAs. https://www.fda.gov/regulatory-information/search-fda-guidance-documents/

6. U.S. Food and Drug Administration. (2023). Applications covered by section 505(b)(2). https://www.fda.gov/drugs/development-approval-process-drugs/

7. Catalyst Pharmaceuticals, Inc. (2021). Catalyst Pharmaceuticals completes acquisition of Strongbridge Biopharma. https://ir.catalystpharma.com/