DIROXIMEL FUMARATE Drug Patent Profile

Which patents cover Diroximel Fumarate, and when can generic versions of Diroximel Fumarate launch?

Diroximel Fumarate is a drug marketed by Zydus and is included in one NDA.

The generic ingredient in DIROXIMEL FUMARATE is diroximel fumarate. There is one drug master file entry for this compound. One supplier is listed for this compound. Additional details are available on the diroximel fumarate profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Diroximel Fumarate

A generic version of DIROXIMEL FUMARATE was approved as diroximel fumarate by ZYDUS on November 12^th, 2025.

Summary for DIROXIMEL FUMARATE

US Patents:	0
Applicants:	1
NDAs:	1
Raw Ingredient (Bulk) Api Vendors:	48
Clinical Trials:	8
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for DIROXIMEL FUMARATE
DailyMed Link:	DIROXIMEL FUMARATE at DailyMed

Recent Clinical Trials for DIROXIMEL FUMARATE

Identify potential brand extensions & 505(b)(2) entrants

Sponsor	Phase
Ministre de la Sant	PHASE2
University Hospital, Lille	PHASE2
King's College London	NA

See all DIROXIMEL FUMARATE clinical trials

Anatomical Therapeutic Chemical (ATC) Classes for DIROXIMEL FUMARATE

L04AX	Other immunosuppressants
L04A	IMMUNOSUPPRESSANTS
L04	IMMUNOSUPPRESSANTS
L	Antineoplastic and immunomodulating agents

Paragraph IV (Patent) Challenges for DIROXIMEL FUMARATE

Tradename	Dosage	Ingredient	Strength	NDA	ANDAs Submitted	Submissiondate
VUMERITY	Delayed-release Capsules	diroximel fumarate	231 mg	211855	1	2020-12-23

US Patents and Regulatory Information for DIROXIMEL FUMARATE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Zydus	DIROXIMEL FUMARATE	diroximel fumarate	CAPSULE, DELAYED RELEASE;ORAL	218596-001	Nov 12, 2025	AB	RX	No	No

EU/EMA Drug Approvals for DIROXIMEL FUMARATE

Company	Drugname	Inn	Product Number / Indication	Status	Generic	Biosimilar	Orphan	Marketing Authorisation	Marketing Refusal
Biogen Netherlands B.V.	Vumerity	diroximel fumarate	EMEA/H/C/005437Vumerity is indicated for the treatment of adult patients with relapsing remitting multiple sclerosis (see Section 5.1 for important information on the populations for which efficacy has been established).	Authorised	no	no	no	2021-11-15

Diroximel Fumarate Market Dynamics, Patent Exclusivity, Revenue Trajectory, and Generic Risk

Last updated: September 9, 2026

Diroximel fumarate, marketed by Biogen as Vumerity, is an oral disease-modifying therapy for relapsing forms of multiple sclerosis. The product has gained share from Tecfidera because it delivers the same active metabolite, monomethyl fumarate, with fewer gastrointestinal tolerability concerns. Its commercial trajectory remains positive, but growth is constrained by competition from Tecfidera generics, newer high-efficacy multiple sclerosis therapies, and eventual generic entry.

Vumerity generated approximately $600 million in annual revenue in 2023, based on Biogen’s reported quarterly product sales. The principal commercial risk is not biosimilar substitution. It is Paragraph IV generic competition after the remaining formulation and composition patents expire or are successfully challenged.

What is diroximel fumarate and how does Vumerity work?

Diroximel fumarate is an oral fumarate prodrug. After administration, it is rapidly converted to monomethyl fumarate, the pharmacologically active metabolite also associated with Tecfidera, or dimethyl fumarate.

Vumerity is approved for:

• Clinically isolated syndrome
• Relapsing-remitting multiple sclerosis
• Active secondary progressive multiple sclerosis

The FDA approved Vumerity on Oct. 29, 2019. The product is supplied as delayed-release capsules in 231 mg strength. The recommended maintenance dose is 462 mg twice daily after a short titration period.[1]

How does Vumerity compare with Tecfidera?

Attribute	Vumerity	Tecfidera
Active prodrug	Diroximel fumarate	Dimethyl fumarate
Active metabolite	Monomethyl fumarate	Monomethyl fumarate
Manufacturer	Biogen	Biogen originally; generic manufacturers now compete
FDA approval	2019	2013
Dosage form	Delayed-release capsule	Delayed-release capsule
Principal commercial rationale	Improved gastrointestinal tolerability	Earlier market entry and lower-cost generic availability
Generic status	No established US generic launch through mid-2024	Multiple generic approvals and launches
Biosimilar exposure	None	None

The EVOLVE-MS-2 trial reported fewer gastrointestinal adverse events with Vumerity than with Tecfidera. Biogen has used that tolerability distinction to retain patients who might otherwise switch to dimethyl fumarate generics.[2]

What is the financial trajectory for Vumerity?

Vumerity has moved from launch-stage revenue to a material Biogen franchise. Its growth initially reflected conversion from Tecfidera and uptake among patients seeking improved tolerability. Later growth depended more heavily on retention, payer access, and switching from Tecfidera generics.

Vumerity revenue timeline

Period	Commercial development	Approximate revenue signal
2019	US launch in November	Initial launch sales
2020	Early adoption affected by COVID-era diagnosis and treatment disruption	More than $100 million
2021	Broader neurologist adoption and Tecfidera switching	Approximately $300 million
2022	Continued uptake and improved prescribing familiarity	Approximately $500 million
2023	Mature growth phase with a larger installed base	Approximately $600 million
2024	Growth expected to moderate as the product matures and MS competition increases	Quarterly sales remained broadly stable to positive through reported periods

Reported figures vary by accounting period and geographic treatment. Biogen’s annual reports identify Vumerity revenue separately, while some market analyses combine US and international sales or use constant-currency calculations.[3]

What drives Vumerity revenue growth?

Four factors support sales:

1. Physician preference for a fumarate with improved gastrointestinal tolerability.
2. Switching from Tecfidera in patients with gastrointestinal complaints.
3. Continued use of oral therapy before escalation to higher-efficacy agents.
4. Biogen’s established multiple sclerosis sales infrastructure.

The main restraints are:

• Low-cost dimethyl fumarate generics.
• High-efficacy monoclonal antibodies and oral therapies.
• Treatment sequencing toward earlier use of more potent agents.
• Payer pressure on branded oral drugs.
• Potential generic diroximel fumarate competition after patent challenges.

Vumerity therefore occupies a defensive position within Biogen’s MS portfolio. It is less exposed to immediate erosion than Tecfidera was, but it is not insulated from the broader shift toward high-efficacy treatment.

When does diroximel fumarate lose regulatory exclusivity?

Vumerity did not receive conventional five-year new chemical entity exclusivity because its active metabolite, monomethyl fumarate, was already associated with an approved fumarate product. The relevant FDA exclusivity protection was based on new clinical investigations supporting approval rather than a new active moiety.

The principal US regulatory exclusivity period expired in 2022. Patent protection, rather than FDA exclusivity, is the central barrier to generic approval and launch.

FDA exclusivity and patent timing

Protection	Approximate status
FDA approval	Oct. 29, 2019
Three-year clinical-investigation exclusivity	Expired in 2022
Five-year NCE exclusivity	Not the primary protection for Vumerity
Patent protection	Extends beyond regulatory exclusivity, subject to validity and infringement outcomes
Pediatric exclusivity	No publicly established six-month extension identified as the principal commercial barrier

A generic applicant could submit an ANDA after the regulatory exclusivity period, but launch timing still depends on the Orange Book patents, Paragraph IV notices, litigation, settlement terms, and any applicable 30-month stay.

What patents protect Vumerity?

Vumerity is protected by patents directed to the diroximel fumarate compound, pharmaceutical compositions, dosage forms, and related methods of treatment. The principal US patent family publicly associated with the product includes U.S. Patent No. 10,300,075 and later continuation or related patents.

Representative Vumerity patent estate

Patent or patent family	General subject matter	Commercial significance
U.S. Patent No. 10,300,075	Diroximel fumarate and related fumarate chemistry	Core compound protection
Related continuation patents	Compound, compositions, and pharmaceutical use claims	Potentially extends claim coverage beyond the core patent
Formulation patents	Delayed-release oral dosage forms and capsule compositions	Can complicate generic substitution
Method-of-use patents	Treatment of relapsing forms of multiple sclerosis	May remain relevant where a generic label includes or carves out protected uses

Patent expiration dates depend on the specific patent, patent-term adjustment, terminal disclaimers, and any patent-term extension. Public patent records place important Vumerity protection into the 2030s for certain continuation and formulation claims, while the earliest core patent protection expires earlier.

A generic applicant does not need to wait for every patent to expire. It can challenge listed patents through a Paragraph IV certification or omit protected indications through a section viii statement.

What formulations are protected by Vumerity patents?

The formulation estate is commercially important because Vumerity is a delayed-release capsule, not simply an immediate-release oral fumarate. Relevant claim categories can include:

• Diroximel fumarate in defined dosage ranges.
• Delayed-release or enteric-release delivery.
• Capsule compositions.
• Excipients and release-control systems.
• Stability and degradation controls.
• Dosing regimens that limit gastrointestinal exposure.
• Treatment methods using specified doses.

Formulation patents are often more difficult for generic applicants to design around when the delivery profile is central to the product’s tolerability advantage. Their practical value depends on claim breadth and whether the FDA permits a substitutable product with a materially different formulation.

What is the Orange Book status of Vumerity?

Vumerity is an FDA-approved small-molecule drug and is eligible for Orange Book patent listing. Its generic pathway is an ANDA, not a biosimilar application under section 351(k) of the Public Health Service Act.

The Orange Book status has three commercial implications:

1. Listed patents can trigger Paragraph IV litigation.
2. A timely infringement action can create a 30-month stay of final ANDA approval.
3. A generic applicant may attempt a section viii carve-out for protected methods of use.

Because Vumerity’s central value proposition is a specific oral formulation and tolerability profile, composition and formulation patents are likely to matter more than method-of-use patents alone.

Which companies are challenging Vumerity patents?

Publicly reported generic activity has centered on ANDA applicants seeking approval for diroximel fumarate delayed-release capsules. The applicant roster and litigation posture can change as additional ANDAs are filed or settled.

The main potential challengers are generic manufacturers with established oral solid-dose capabilities, including companies that already market dimethyl fumarate or other multiple sclerosis products. The competitive set may include large generic companies and specialty manufacturers rather than biotechnology companies.

A Paragraph IV challenge would normally produce one of three outcomes:

• The generic company wins or invalidates the asserted patents.
• The case settles with a licensed launch date.
• The generic company loses and remains blocked until patent expiry or a later settlement.

No broad biosimilar-style competitive wave is expected because diroximel fumarate is a chemically synthesized small molecule.

What patent litigation affects Vumerity?

Vumerity litigation risk is primarily a US ANDA issue. The likely defendants are Biogen and, depending on patent ownership and licensing arrangements, other entities holding or controlling relevant rights.

The litigation questions are:

• Whether the asserted patent claims are valid.
• Whether the proposed generic formulation infringes.
• Whether continuation patents are properly listed.
• Whether a generic label can omit protected uses.
• Whether settlement agreements provide an authorized or licensed launch date.
• Whether patent-term adjustment extends the effective barrier.

The existence of a Paragraph IV notice does not establish a launch date. A lawsuit can delay approval, but a court ruling, settlement, or dismissal can materially change timing.

Have Vumerity generic settlements been disclosed?

Publicly disclosed settlement details should be treated separately from patent expiry. Pharmaceutical settlements can permit an earlier launch than the latest patent expiration date while preserving royalties, supply rights, or other commercial restrictions.

The most important settlement terms would be:

• Authorized launch date.
• Royalty obligations.
• Scope of licensed claims.
• Restrictions on formulation or indication.
• Acceleration provisions if a third-party generic enters.
• Whether the settlement is reported to the Federal Trade Commission.

A definitive generic launch forecast cannot rely solely on the latest Orange Book expiration date. Litigation and settlement outcomes can move entry forward by several years.

How strong is the Vumerity patent estate?

The estate is moderately strong commercially but not impenetrable.

Strengths

• Vumerity has multiple patent categories rather than a single compound patent.
• The product’s delayed-release delivery system supports formulation-based differentiation.
• Biogen has substantial resources to litigate ANDA challenges.
• The product has a clear clinical rationale based on gastrointestinal tolerability.
• Generic substitution may require more than simple active-ingredient replication.

Weaknesses

• FDA regulatory exclusivity has already expired.
• The active metabolite is not novel to Vumerity.
• Small-molecule patents face conventional invalidity and obviousness challenges.
• Generic manufacturers can seek narrow labels or alternative formulations.
• Tecfidera generics establish payer and physician familiarity with fumarate therapy.
• Patent continuations can face written-description, obviousness-type double-patenting, or terminal-disclaimer issues.

The estate is more valuable as a portfolio than as a single blocking patent. The commercial outcome will depend on whether at least one enforceable formulation or composition claim survives through the expected generic approval window.

What generic entry risks exist for Vumerity?

Generic entry creates a high-risk erosion scenario because multiple sclerosis drugs are chronic therapies and pharmacy substitution can occur rapidly once a therapeutically equivalent product is approved.

Generic launch scenarios

Scenario	Timing	Commercial effect
Patent win for Biogen	After final patent expiry	Vumerity retains branded share until launch
Settlement with licensed entry	Before latest patent expiry	Gradual or accelerated price erosion
Patent invalidation	Potentially soon after ANDA litigation	Rapid price and volume pressure
Section viii carve-out	Depends on label and prescriber behavior	Partial rather than full substitution
Authorized generic	Before independent generic launch	Biogen may retain some economics but reduce branded sales

A single generic entrant can reduce net pricing. Multiple entrants usually produce sharper erosion as pharmacy benefit managers add substitution incentives. Vumerity’s premium over dimethyl fumarate generics must be justified by tolerability, adherence, and total treatment economics.

How does Vumerity compare with competing multiple sclerosis drugs?

Product	Class	Competitive position
Vumerity	Fumarate prodrug	Oral option with improved GI profile versus Tecfidera
Tecfidera and generics	Fumarate	Lower-cost oral alternative
Bafiertam	Monomethyl fumarate	Competes on active metabolite and oral convenience
Aubagio and generics	Teriflunomide	Oral, lower-cost, different safety and efficacy profile
Gilenya and generics	S1P modulator	Oral high-efficacy alternative
Kesimpta	Anti-CD20 antibody	High-growth, self-administered biologic
Ocrevus	Anti-CD20 antibody	High-efficacy infusion therapy
Tysabri	Integrin inhibitor	High-efficacy therapy with distinct safety monitoring

Bafiertam is the closest branded pharmacologic competitor because it also delivers monomethyl fumarate. Its commercial impact has been limited relative to the larger threat from low-cost dimethyl fumarate and high-efficacy biologics.

What licensing deals support diroximel fumarate commercialization?

Alkermes developed and licensed diroximel fumarate to Biogen under a collaboration announced in 2017. Biogen obtained worldwide rights to develop and commercialize the product, while Alkermes retained economic participation through milestone and royalty arrangements.[4]

The agreement gives Biogen commercial control and provides Alkermes with a royalty-based revenue stream without the same level of manufacturing and sales expense. Alkermes has identified Vumerity royalties as part of its commercial portfolio in company disclosures.

The licensing structure has two implications:

• Biogen captures product revenue but carries commercialization and litigation costs.
• Alkermes receives lower-risk royalty economics that remain exposed to generic entry and contract duration.

What is the geographic coverage for Vumerity?

Vumerity was developed for global commercialization, with Biogen responsible for major markets. The United States is the largest patent and generic-risk jurisdiction because of its ANDA system, Orange Book listings, and high specialty-pharmacy concentration.

Commercial protection also depends on:

• European patent validation and supplementary protection certificates.
• National patent litigation.
• Local reimbursement decisions.
• Market-specific generic or hybrid application pathways.
• Regulatory approval of delayed-release formulations.

US entry risk is likely to produce the largest immediate revenue effect. European erosion may be more fragmented because national launch timing and reimbursement differ by country.

What manufacturing and intellectual-property barriers affect generic entry?

Generic manufacturers must reproduce a delayed-release oral product with acceptable stability, dissolution, bioequivalence, and capsule performance. The chemistry itself is unlikely to be the largest barrier. The more important issues are:

• Controlling conversion and degradation of diroximel fumarate.
• Matching release characteristics.
• Demonstrating bioequivalence under FDA requirements.
• Avoiding formulation patent claims.
• Establishing adequate commercial-scale supply.
• Securing an ANDA free of blocking litigation.

These barriers can delay entry but rarely create durable protection if the generic can design around the claims.

What is the long-term commercial outlook for diroximel fumarate?

Vumerity should remain a meaningful Biogen product through the latter part of the decade if patent litigation delays generic entry. Growth is likely to moderate because the product is already established, Tecfidera generics limit category pricing, and MS prescribing is shifting toward high-efficacy therapies.

The base commercial thesis is:

• Near term: stable to modest growth from retention and Tecfidera switching.
• Medium term: increasing exposure to formulation and continuation-patent litigation.
• Long term: sharp erosion after a substitutable generic launch.
• Royalty impact: Alkermes revenue declines with Vumerity net sales but may remain positive through licensed generic or settlement economics.

Vumerity is not a biosimilar-risk asset. Its principal value is the combination of branded tolerability differentiation, Biogen’s MS franchise infrastructure, and a multi-layered small-molecule patent estate.

Key Takeaways

• Diroximel fumarate is marketed as Vumerity by Biogen.
• FDA approval occurred in October 2019.
• Vumerity’s commercial rationale is improved gastrointestinal tolerability relative to Tecfidera.
• Regulatory exclusivity expired before the key patent barriers.
• The product has a multi-layered estate involving compound, formulation, and method-of-use claims.
• The main competitive threat is ANDA-based generic entry, not biosimilar competition.
• Vumerity generated approximately $600 million in 2023 revenue based on reported product sales.
• Tecfidera generics constrain pricing and reduce the size of the fumarate market opportunity.
• High-efficacy MS therapies, particularly anti-CD20 products, limit long-term volume growth.
• Patent litigation and settlement terms are more important than regulatory exclusivity in determining launch timing.

FAQs About Diroximel Fumarate

Is Vumerity the same drug as Tecfidera?

No. Vumerity contains diroximel fumarate, while Tecfidera contains dimethyl fumarate. Both are converted to monomethyl fumarate, but they are different active ingredients and formulations.

Is there a generic version of Vumerity?

No broadly established US generic launch had occurred through mid-2024. Generic approval and launch depend on ANDA filings, Orange Book patents, Paragraph IV litigation, and settlement terms.

Is Vumerity a biologic or a biosimilar?

No. Vumerity is a chemically synthesized small-molecule drug. Generic competition proceeds through the ANDA pathway, not the biosimilar pathway.

What is the closest competitor to diroximel fumarate?

The closest pharmacologic competitor is monomethyl fumarate, marketed as Bafiertam. The larger commercial competitors are Tecfidera generics and high-efficacy MS therapies such as Kesimpta and Ocrevus.

Who owns the commercial rights to Vumerity?

Biogen holds worldwide commercial rights under its collaboration with Alkermes. Alkermes developed the product and receives economic participation under the licensing arrangement.

References

1. U.S. Food and Drug Administration. (2019). Vumerity (diroximel fumarate) prescribing information.
2. Naismith, R. T., Wundes, A., Ziemssen, T., et al. (2020). Efficacy and safety of diroximel fumarate in patients with relapsing-remitting multiple sclerosis: EVOLVE-MS-2. Multiple Sclerosis Journal.
3. Biogen Inc. (2024). 2023 annual report on Form 10-K.
4. Alkermes plc. (2017). Alkermes and Biogen enter collaboration for novel oral treatment for multiple sclerosis.
5. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
6. United States Patent and Trademark Office. (2024). Patent Center and Patent Examination Data System records for diroximel fumarate patent families.