DEPAKENE Drug Patent Profile

Which patents cover Depakene, and what generic alternatives are available?

Depakene is a drug marketed by Abbvie and is included in two NDAs.

The generic ingredient in DEPAKENE is valproic acid. There are seventeen drug master file entries for this compound. Eighteen suppliers are listed for this compound. Additional details are available on the valproic acid profile page.

DrugPatentWatch^® Litigation and Generic Entry Outlook for Depakene

A generic version of DEPAKENE was approved as valproic acid by CATALENT on October 29^th, 1991.

Summary for DEPAKENE

US Patents:	0
Applicants:	1
NDAs:	2

US Patents and Regulatory Information for DEPAKENE

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Exclusivity Expiration
Abbvie	DEPAKENE	valproic acid	CAPSULE;ORAL	018081-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No
Abbvie	DEPAKENE	valproic acid	SYRUP;ORAL	018082-001	Approved Prior to Jan 1, 1982		DISCN	Yes	No

Depakene Investment Analysis: Patent Position, FDA Status, Market Fundamentals, and Generic Risk

Last updated: July 31, 2026

Depakene is a mature valproic acid product with limited standalone investment value. Its active ingredient, valproic acid, has been available in generic form for decades, and the brand does not have a meaningful current patent moat. Commercial exposure is concentrated in legacy prescriptions, institutional use, manufacturing and distribution efficiency, and the broader valproate franchise rather than in Depakene itself.

The principal investment risks are generic substitution, severe safety warnings, litigation exposure, and competition from divalproex sodium products such as Depakote and generic divalproex. The main strategic value lies in portfolio cash flow, supply reliability, and potential reformulation or lifecycle-management opportunities.

What is Depakene and how does it work?

Depakene is the brand name for valproic acid, an antiseizure medicine marketed in oral formulations. It is used for:

• Complex partial seizures
• Simple and complex absence seizures
• Adjunctive treatment of multiple seizure types
• Certain seizure disorders described in FDA labeling

Valproic acid increases central nervous system inhibitory activity, including through effects associated with gamma-aminobutyric acid signaling. It is pharmacologically related to divalproex sodium, the active ingredient in Depakote. Divalproex sodium dissociates into valproate ions and is used for epilepsy, bipolar disorder, and migraine prophylaxis in labeled formulations.

Depakene is not interchangeable with every valproate product on a milligram-for-milligram basis without clinical and regulatory consideration. Differences in salt form, absorption, release characteristics, and dosage form affect product selection.

What is the FDA status of Depakene?

Depakene was approved in the United States as an oral valproic acid product. The historical reference product is associated with FDA New Drug Application No. 018081. Current FDA-approved labeling identifies serious risks that materially affect the product’s commercial profile.

What boxed warnings apply to Depakene?

The FDA label contains boxed warnings for:

• Hepatotoxicity, including fatal hepatic failure
• Birth defects and neurodevelopmental effects following in utero exposure
• Pancreatitis, including fatal cases

The label states that valproate should not be used for migraine prophylaxis in pregnant women and should generally be avoided in women of childbearing potential unless alternatives are inadequate and the benefits outweigh the risks. The FDA has also required prominent pregnancy-related warnings and risk-management communications for valproate products.[1]

Valproate exposure during pregnancy has been associated with neural tube defects, congenital malformations, reduced cognitive outcomes, and neurodevelopmental disorders. These risks create prescribing restrictions, monitoring requirements, and product-liability exposure.

When does Depakene lose exclusivity?

Depakene has already lost practical market exclusivity. The active ingredient and core product concepts have been off patent for many years, and generic valproic acid products are widely available.

Exclusivity category	Depakene position
Active-ingredient patent	Expired
Original product patent protection	Expired
Current FDA orphan exclusivity	None identified
Current pediatric exclusivity	None identified
Current new chemical entity exclusivity	Expired
Current U.S. market exclusivity	None of commercial significance
Generic competition	Established

No current patent expiration date is likely to delay generic competition. The commercial question is therefore not when generic entry begins, but how much branded demand remains after years of generic substitution.

What patents protect Depakene?

No meaningful active patent estate is expected to protect standard valproic acid capsules, oral solution, or syrup as legacy products. The original active-ingredient and formulation concepts are long expired.

Are there formulation patents for Depakene?

The principal formulation risk is not a current Depakene patent barrier. Instead, formulation differentiation exists across the broader valproate market:

• Immediate-release valproic acid capsules
• Oral solution and syrup
• Divalproex delayed-release tablets
• Divalproex extended-release tablets
• Sprinkle capsules
• Intravenous valproate sodium products

Some later-generation formulations historically received separate patents or regulatory protections. Those rights generally relate to divalproex products, release mechanisms, manufacturing processes, or specific dosage forms rather than to the basic Depakene product.

A company evaluating a valproate asset should separate three categories:

1. Depakene brand rights and trademarks
2. Product-specific formulation or process rights
3. Broader valproate products with independent patents and FDA approvals

The first category has limited exclusivity value. The second may retain narrow operational value in specific dosage forms. The third may support separate commercial economics but should not be attributed automatically to Depakene.

What is the Orange Book status of Depakene?

Depakene’s Orange Book position does not provide a meaningful barrier to generic competition. FDA-approved generic valproic acid products have been marketed for years, and any historical listed patents associated with the original product would not prevent ordinary generic substitution today.[2]

Orange Book analysis should distinguish Depakene from Depakote and other divalproex products. A patent listed for a delayed-release or extended-release divalproex product does not automatically protect immediate-release valproic acid. Conversely, the absence of a current patent barrier for Depakene does not establish that every valproate dosage form is unprotected.

Which companies compete with Depakene?

The competitive landscape includes generic manufacturers and branded or specialty products in the broader valproate category.

Competitor category	Examples	Competitive effect
Generic valproic acid	Multiple FDA-authorized manufacturers	Direct price and substitution pressure
Generic divalproex sodium	Delayed-release and extended-release products	Broad therapeutic substitution
Depakote	AbbVie legacy brand	Competes within the same valproate franchise
Depakote ER	Extended-release divalproex	Differentiated dosing convenience
Valproate sodium injection	Hospital and acute-care products	Addresses inpatient use
Alternative antiseizure drugs	Lamotrigine, levetiracetam, carbamazepine, topiramate	Reduces valproate demand where safety or tolerability is a concern

The largest structural competitor is generic substitution, not another branded valproic acid product. Treatment guidelines and clinician preference also favor alternatives for many patients because of valproate’s reproductive, hepatic, metabolic, and neurological risks.

How strong is the Depakene patent estate?

The Depakene patent estate is weak from an investment perspective.

Patent-strength assessment

Factor	Assessment
Composition-of-matter protection	Expired
Product-form protection	Weak or expired for legacy forms
Generic blocking power	Minimal
Formulation differentiation	Limited for standard Depakene
Manufacturing exclusivity	No material barrier apparent
Trademark value	Residual brand recognition
Litigation leverage	Low absent a new formulation or process patent
Lifecycle-management potential	Possible, but separate from legacy Depakene

A new patent filing would need to cover a genuinely differentiated formulation, delivery system, manufacturing process, or clinically meaningful use. A routine claim directed to valproic acid would face substantial validity and obviousness challenges because the compound and its therapeutic use are long established.

What generic entry risks exist for Depakene?

Generic entry risk is already realized rather than prospective. The relevant risks are continuing price erosion, pharmacy substitution, channel displacement, and loss of branded prescribing.

Generic manufacturers can compete on:

• Wholesale acquisition price
• Contract pharmacy supply
• Hospital purchasing agreements
• Product availability
• Dosage-form breadth
• Authorized generic arrangements

Supply interruptions can temporarily improve pricing or demand for a branded product, but that effect is operational rather than durable. Depakene’s economics remain vulnerable to procurement substitution once equivalent generic supply returns.

What patent litigation affects Depakene?

Depakene is not associated with a current patent litigation profile that would materially delay generic competition. The principal legal exposure is product liability and failure-to-warn litigation involving valproate products.

Litigation theories have included allegations concerning:

• Birth defects and developmental injury
• Inadequate pregnancy warnings
• Hepatotoxicity
• Pancreatitis
• Failure to conduct or disclose safety studies
• Marketing conduct involving valproate products

These cases can affect the broader manufacturer’s financial exposure even when they do not involve an active patent dispute over Depakene. An investor should evaluate valproate litigation at the portfolio and corporate level, including insurance, reserves, settlement activity, and jurisdiction-specific proceedings.

Are there Paragraph IV challenges to Depakene?

Paragraph IV litigation is not an active commercial issue for the legacy Depakene franchise in the same way it is for a recently approved branded drug. Generic valproic acid products have been marketed for many years, and the core intellectual property is expired.

A Paragraph IV filing could arise for a newly developed formulation, delivery system, or method-of-use product associated with valproic acid. That would concern the new product’s patents, not the ordinary Depakene formulation.

What is the biosimilar risk for Depakene?

Depakene has no biosimilar risk because valproic acid is a small-molecule drug, not a biologic. Competition occurs through the abbreviated new drug application pathway for generics, not through the 351(k) biosimilar pathway.

This distinction matters for investment analysis:

• Generic competition can be direct and price-focused.
• Biosimilar competition typically involves biologic manufacturing complexity and interchangeability considerations.
• Depakene does not benefit from biologic manufacturing barriers or biosimilar development costs.

Does Depakene have licensing or partnership value?

Depakene has limited standalone licensing value. The molecule is generic, the therapeutic uses are established, and manufacturing capability is broadly available.

Potential transaction value could arise from:

• Regional brand rights
• Distribution contracts
• Hospital supply agreements
• Authorized generic arrangements
• Specialty formulations
• Combination products
• New delivery technologies
• Products designed to reduce fetal exposure or improve tolerability

A licensing transaction involving Depakene alone would likely be driven by geographic access, supply reliability, or portfolio consolidation rather than patent exclusivity. Any transaction that includes Depakote, divalproex formulations, or proprietary delivery technology should be analyzed separately.

What are the revenue fundamentals for Depakene?

Standalone Depakene revenue is generally not disclosed separately in public company reporting. AbbVie reports products within broader therapeutic and product categories, and legacy valproate revenue may be grouped with other products or may no longer be material enough to receive individual disclosure.

Revenue drivers

The main drivers are:

• Prescription volume in epilepsy
• Brand versus generic dispensing rates
• Net price after rebates and discounts
• Institutional purchasing
• Availability of generic supply
• Patient switching to alternative antiseizure drugs
• Safety-related prescribing restrictions
• Product discontinuation or supply events

Revenue outlook

The base case is mature or declining revenue. A large increase would require a material supply disruption affecting generic competitors, a new formulation with differentiated clinical value, or a strategic transaction that expands distribution. Neither patent protection nor regulatory exclusivity provides a conventional growth catalyst.

What is the investment scenario for Depakene?

Base case: declining legacy cash flow

The most probable scenario is continued low-growth or declining demand. Generic valproic acid limits pricing power, while safety concerns constrain new prescribing. Depakene may continue to generate residual revenue where physicians, patients, or institutions prefer the branded product, but the brand’s ability to expand margins is limited.

Bull case: supply and portfolio economics

An upside scenario could develop if generic supply becomes constrained, a manufacturer consolidates distribution, or a differentiated formulation captures demand. The benefit would likely be temporary unless supported by new intellectual property and regulatory approval.

Bear case: liability and substitution pressure

Downside risk includes:

• Further generic price compression
• Accelerated switching to non-valproate antiseizure drugs
• New safety restrictions
• Product-liability settlements or judgments
• Manufacturing interruptions
• Brand discontinuation
• Reputational damage affecting prescriber use

How does Depakene compare with Depakote?

Attribute	Depakene	Depakote
Active ingredient	Valproic acid	Divalproex sodium
Core use	Epilepsy	Epilepsy, bipolar disorder, migraine prophylaxis depending on formulation
Release profile	Primarily immediate release	Delayed-release and extended-release formulations
Patent position	Mature and expired	Historically supported by formulation and product patents, now largely genericized
Generic competition	Extensive	Extensive
Safety profile	Major valproate-class risks	Major valproate-class risks
Investment profile	Legacy generic-exposed brand	Broader but also mature valproate franchise

Depakote may have had greater lifecycle-management value because of multiple indications and release technologies. That does not create current exclusivity for standard Depakene.

What manufacturing and intellectual-property barriers exist?

Manufacturing valproic acid is less difficult than manufacturing biologics or complex sterile products. The main barriers are compliance, quality control, supply-chain reliability, and regulatory documentation.

Relevant manufacturing risks include:

• Impurity control
• Batch consistency
• Stability and packaging
• API sourcing
• Oral-solution quality
• Facility compliance
• Supply continuity
• FDA inspection outcomes

These are execution barriers, not durable patent barriers. A manufacturer with reliable supply can win contracts, but the advantage is vulnerable to price competition.

Key Takeaways

• Depakene is valproic acid, a long-established small-molecule antiseizure drug.
• Core patent protection and regulatory exclusivity have expired.
• Generic competition is established and is the main commercial constraint.
• Depakene has no biosimilar risk because it is not a biologic.
• The FDA boxed warnings for hepatotoxicity, fetal risk, and pancreatitis materially affect prescribing and liability.
• Standalone Depakene revenue is generally not separately disclosed.
• The investment case is based on residual portfolio cash flow, supply reliability, and potential reformulation, not patent-protected growth.
• Any valuation should separate Depakene from Depakote, divalproex products, and other valproate formulations.
• The primary legal risk is product liability, not Paragraph IV patent litigation.
• A new commercial opportunity would require differentiated formulation, delivery, manufacturing, or clinical positioning.

Frequently Asked Questions

Is Depakene still under patent?

No meaningful patent protection for the standard legacy Depakene product remains commercially relevant. Generic valproic acid products have been marketed for many years.

Is Depakene the same as Depakote?

No. Depakene contains valproic acid, while Depakote contains divalproex sodium. Both produce valproate but differ in formulation, release characteristics, and approved uses.

Can generic manufacturers substitute for Depakene?

Generic substitution is widely available for approved equivalent valproic acid products, subject to state pharmacy rules, payer policies, and dosage-form considerations.

Does Depakene have FDA exclusivity?

No current new chemical entity, orphan, pediatric, or comparable exclusivity is commercially relevant for the legacy product.

Is Depakene a growth investment?

Depakene is generally a mature, declining pharmaceutical asset. Growth would require a supply-driven pricing event, portfolio transaction, or differentiated reformulation with new regulatory and intellectual-property protection.

References

1. U.S. Food and Drug Administration. (2023). Depakene (valproic acid) prescribing information. FDA.
2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
3. U.S. Food and Drug Administration. (2024). Drugs@FDA: Depakene, NDA 018081. FDA.
4. U.S. Food and Drug Administration. (2013). FDA drug safety communication: Valproate anti-seizure products contraindicated for migraine prevention in pregnant women. FDA.
5. AbbVie Inc. (2024). Annual report. U.S. Securities and Exchange Commission.