Details for Patent: 8,852,636

Summary for Patent: 8,852,636

Title:	Pharmaceutical compositions for the coordinated delivery of NSAIDs
Abstract:	The present invention is directed to drug dosage forms that release an agent that raises the pH of a patient's gastrointestinal tract, followed by a non-steroidal anti-inflammatory drug. The dosage form is designed so that the NSAID is not released until the intragastric pH has been raised to a safe level. The invention also encompasses methods of treating patients by administering this coordinated release, gastroprotective, antiarthritic/analgesic combination unit dosage form to achieve pain and symptom relief with a reduced risk of developing gastrointestinal damage such as ulcers, erosions and hemorrhages.
Inventor(s):	John R. Plachetka
Assignee:	Nuvo Pharmaceuticals (ireland) Designated Activity Co
Application Number:	US14/045,156
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 8,852,636
Patent Claim Types: see list of patent claims	Use; Composition; Dosage form;

US Patent 8,852,636: Claim Scope, Expiration, Orange Book Position, and Vimovo Patent Landscape

US Patent No. 8,852,636 covers coordinated oral delivery of esomeprazole and naproxen. Its core requirement is a dosage form that releases esomeprazole in the stomach while retaining naproxen behind a pH-dependent coating until the surrounding medium reaches at least pH 3.5. The patent covers both tablets and capsules, with dependent claims directed to dosage ranges, arthritis treatment, excipients, and pH adjustment.

The patent was granted on October 7, 2014, to Pozen Inc. Its patent term was tied to an early-2000s priority chain and expired in November 2023. As of March 2025, US Patent 8,852,636 is no longer an enforceable patent barrier to an otherwise approvable generic product.

What does US Patent 8,852,636 protect?

The patent protects a dual-release composition combining:

1. Esomeprazole, a proton-pump inhibitor, released in the stomach.
2. Naproxen, an NSAID, retained in a coated core until exposure to a medium with a pH of at least 3.5.
3. A unit dosage form administered orally as either a tablet or capsule.

The commercial concept corresponds to the formulation used for Vimovo, marketed as delayed-release naproxen and immediate-release esomeprazole tablets.

The central distinction is not merely the presence of both active ingredients. The claims require a particular spatial and release configuration:

• Naproxen must occupy a core or multiple cores.
• The naproxen-containing core must be surrounded by a pH-dependent coating.
• The coating must not release naproxen below pH 3.5.
• Esomeprazole must be located in one or more layers outside the naproxen core.
• The esomeprazole layer cannot contain naproxen.
• The esomeprazole layer cannot itself be surrounded by an enteric coating.
• Esomeprazole must release in the stomach after ingestion.

A product containing esomeprazole and naproxen in a conventional admixture would not satisfy the principal composition claims unless it also met the claimed core, coating, location, and release limitations.

What are the independent claims?

Claims 1, 5, 7, and 11 are the principal independent claims.

Claim	Category	Covered dosage form or use
1	Composition	Tablet with naproxen in a coated core and esomeprazole outside the core
5	Method	Treating pain or inflammation with the claim 1 composition
7	Composition	Capsule with naproxen in a coated core and esomeprazole outside the core
11	Method	Treating pain or inflammation with the claim 7 composition

Claim 1: tablet formulation

Claim 1 requires a unit-dose tablet containing esomeprazole and naproxen. Naproxen must be in a core surrounded by a coating that delays release until pH 3.5 or higher. Esomeprazole must be in an external layer that releases in the stomach and is not enterically coated.

The claim is narrower than a generic combination-product claim because it requires a specific dosage architecture. The tablet limitation excludes capsules and other dosage forms from literal infringement of claim 1, although those forms may fall within claim 7.

Claim 7: capsule formulation

Claim 7 is directed to a capsule rather than a tablet. The capsule contains a naproxen core surrounded by a pH-dependent coating. Esomeprazole is outside the core and is released in the stomach.

Claim 7 creates a separate independent coverage path for multiparticulate and encapsulated products. A capsule product would not need to satisfy the tablet limitation in claim 1, but it would need to satisfy the corresponding capsule limitations in claim 7.

Claims 5 and 11: treatment methods

Claims 5 and 11 cover administering the respective composition to treat pain or inflammation. Claims 6 and 12 narrow the use to osteoarthritis or rheumatoid arthritis.

The treatment claims require use of the claimed formulation, not merely administration of separate esomeprazole and naproxen products. A generic applicant could avoid literal infringement by using a materially different formulation, although the commercial and regulatory analysis would depend on the approved label and product design.

How do the dependent claims narrow the patent?

Claims 2 through 4 narrow the tablet embodiment. Claims 8 through 10 narrow the capsule embodiment.

Claims	Limitation
2	Single naproxen-containing core in the tablet
3	Esomeprazole amount of 5 mg to 100 mg
4	Naproxen amount of 200 mg to 600 mg
8	Multiple coated naproxen particles in the capsule
9	Esomeprazole amount of 5 mg to 100 mg
10	Naproxen amount of 200 mg to 600 mg
13 and 16	At least one carrier
14 and 17	Specified auxiliary agents
15 and 18	At least one pH-adjusting ingredient

The dependent claims provide fallback positions around common commercial formulations. The 5 mg-to-100 mg esomeprazole range is broad and includes the 20 mg strength used in Vimovo. The 200 mg-to-600 mg naproxen range includes the 375 mg and 500 mg strengths associated with Vimovo.

The excipient claims are broad. They cover ordinary pharmaceutical ingredients such as lubricants, disintegrants, stabilizers, wetting agents, buffers, coloring agents, flavoring agents, and pH modifiers. These claims add formulation detail but generally provide less meaningful differentiation than the core release architecture.

What technical elements are most important for infringement?

The pH 3.5 release threshold

The pH-dependent coating is the principal technical limitation. Naproxen cannot be released before the surrounding medium reaches pH 3.5 or higher.

This language is functional rather than purely compositional. In an infringement dispute, dissolution testing and product-development records would likely be important. Relevant evidence could include:

• Dissolution profiles across acidic and near-neutral media.
• Coating composition and thickness.
• In vitro release specifications.
• Stability data.
• Batch-release testing.
• Regulatory product specifications.
• Manufacturing records showing the coating process.

A product that releases naproxen at pH 2 or below would have a strong noninfringement position for the literal pH limitation. A product that releases naproxen only after exposure to pH 3.5 or higher would present a closer case.

Esomeprazole outside the naproxen core

The claim requires esomeprazole to be in one or more layers outside the naproxen core. This limitation targets a layered or multiparticulate arrangement rather than a homogeneous blend.

A product in which both active ingredients are co-located in the same matrix could avoid literal infringement. The analysis would depend on whether the product nevertheless contains a distinct naproxen core and an external esomeprazole layer.

No enteric coating around the esomeprazole layer

The claim requires the external esomeprazole layer to release in the stomach and not be surrounded by an enteric coating. This is a significant design constraint.

Conventional proton-pump-inhibitor products often use enteric protection because PPIs are acid labile. The patented configuration instead places esomeprazole outside the naproxen core and permits gastric release. A generic developer using enterically coated esomeprazole may have an argument that the claim is not met, although the complete dosage form and any doctrine-of-equivalents theory would require separate analysis.

What products are commercially associated with the patent?

The patent family is associated with the Vimovo product concept, a prescription combination of naproxen and esomeprazole magnesium.

Product characteristic	Vimovo-type formulation
Active ingredients	Naproxen and esomeprazole magnesium
Dosage form	Delayed-release tablet
Naproxen strengths	375 mg and 500 mg
Esomeprazole strength	20 mg
Release design	Immediate gastric release of esomeprazole with delayed naproxen release
FDA application	NDA 022462
Therapeutic uses	Osteoarthritis and rheumatoid arthritis signs and symptoms

The FDA labeling describes Vimovo as a fixed-dose combination of naproxen, an NSAID, and esomeprazole magnesium, a proton-pump inhibitor. The product is designed to reduce the risk of naproxen-associated gastric ulcers in specified patients requiring chronic NSAID therapy, rather than to provide interchangeable gastroprotection for every NSAID user. [2]

When did US Patent 8,852,636 expire?

US Patent 8,852,636 expired in November 2023 based on its priority and patent-term history. The patent was granted on October 7, 2014, but its enforceable term was not measured as 20 years from the grant date.

Event	Date
Earliest priority in the patent family	November 2003
Patent granted	October 7, 2014
Expected patent-term expiration	November 2023
Current status as of March 2025	Expired by term

Patent expiration removes the ability to enforce the claims against post-expiration manufacture, use, sale, or offer for sale in the United States. It does not erase historical infringement exposure during the enforceable term.

Patent expiration also does not automatically establish FDA approval. A generic applicant must still satisfy the applicable ANDA requirements, demonstrate pharmaceutical equivalence and bioequivalence, and address any remaining listed patents or regulatory exclusivities.

What is the Orange Book status of the patent?

US Patent 8,852,636 was part of the US patent estate associated with the naproxen/esomeprazole combination. The Orange Book analysis must distinguish three categories:

1. Listed patents covering the approved drug or formulation.
2. Unexpired patents that could support a Paragraph IV certification.
3. Expired patents that no longer block commercial entry.

As of the patent’s November 2023 expiration, the '636 patent no longer provided an active patent-based barrier to an ANDA launch. Any remaining Orange Book entry would have historical significance unless another unexpired patent covered the same approved product.

The Orange Book can change through patent delisting, expiration, product discontinuation, or changes in listed patent status. The controlling commercial question is whether any unexpired, properly listed patent remains relevant to the specific ANDA product and its proposed labeling. [3]

What Paragraph IV challenges affected the Vimovo patent estate?

Generic applicants targeting Vimovo would generally have had four certification options under the Hatch-Waxman framework:

• Paragraph I: no patent information had been submitted.
• Paragraph II: the patent had expired.
• Paragraph III: the applicant would wait until patent expiration.
• Paragraph IV: the patent was invalid, unenforceable, or would not be infringed.

During the enforceable period of the Vimovo patent estate, a Paragraph IV certification could trigger litigation under 35 U.S.C. § 271(e)(2). The resulting 30-month stay would depend on the timing of the NDA holder’s suit and the specific listed patent.

After November 2023, the '636 patent could support a Paragraph II or Paragraph III position rather than a commercially meaningful Paragraph IV challenge. A Paragraph IV dispute directed solely to an expired patent would not ordinarily delay approval or launch.

Historical litigation analysis must be conducted across the entire Vimovo family because a generic applicant could challenge several patents in one ANDA. The relevant risk was therefore not limited to the '636 patent. Related formulation and dosage-form patents could have created overlapping litigation positions even where one patent was vulnerable.

Which patents formed the broader Vimovo patent landscape?

The broader estate included patent family members directed to combinations of a proton-pump inhibitor and an NSAID, specific release configurations, dosage forms, and related formulation features.

Publicly identified family and related patents include:

Patent	General relevance
US 6,926,907	Earlier combination-product patent associated with the naproxen/PPI concept
US 7,332,183	Related continuation or family coverage
US 8,557,285	Later formulation or dosage-form coverage
US 8,852,636	Tablet and capsule configurations analyzed here
US 9,192,644	Later family coverage relating to combination formulations
US 9,675,669	Later formulation-related patent
US 10,092,541	Later family coverage associated with the combination product

The exact enforceability of each patent depends on terminal disclaimers, patent-term adjustment, patent-term extension, maintenance fees, prosecution history, and Orange Book listing history. A family member’s expiration did not necessarily establish the expiration date of every related patent.

How strong was the patent estate?

The '636 patent had moderate historical strength against products that copied the Vimovo architecture and weaker strength against materially redesigned products.

Strengths

• The claim language identifies a commercially meaningful release sequence.
• The tablet and capsule embodiments are covered in separate independent claims.
• The claims include both composition and method-of-treatment protection.
• The 5 mg-to-100 mg esomeprazole and 200 mg-to-600 mg naproxen ranges encompass common commercial strengths.
• The claim requires a technical dissolution characteristic that can be tested.

Vulnerabilities

• The patent relies heavily on structural and functional limitations that a generic developer could potentially redesign.
• The pH 3.5 threshold creates a measurable noninfringement pathway.
• The external, non-enterically coated esomeprazole layer may not cover conventional enteric-PPI architectures.
• The patent’s term has expired.
• The broad excipient claims may add limited practical protection where the core release architecture is avoided.

The highest-risk design-around would likely use a different location or release mechanism for esomeprazole, a different naproxen protection strategy, or a separate dosage form. Whether such a design remains bioequivalent to the reference product would be a regulatory question separate from patent infringement.

What generic launch risks existed?

Before expiration, generic launch risk had several components:

Risk	Relevance
Patent litigation	Suit following a Paragraph IV certification
30-month stay	Potential delay in ANDA approval
Formulation redesign	May avoid the claims but complicate bioequivalence
Label carve-out	May affect method-of-use claims
Multiple listed patents	Separate patents could preserve blocking power
Manufacturing reproducibility	The pH-dependent coating is a critical quality attribute
Launch-at-risk exposure	Potential damages and injunction risk before patent expiration

After expiration of the '636 patent, the principal risks shifted from patent enforcement to regulatory approval, manufacturing scale-up, bioequivalence, product quality, and competition.

What manufacturing and intellectual-property barriers remain?

The patent is expired, but the technical manufacturing problem remains relevant. A commercial product must consistently produce:

• Immediate and reproducible gastric release of esomeprazole.
• Delayed naproxen release at the required intestinal pH.
• Adequate separation of the two active ingredients.
• Acceptable stability for an acid-sensitive proton-pump inhibitor.
• Uniform coating thickness and dissolution performance.
• Batch-to-batch control across both active ingredients.

The most important manufacturing controls are likely coating uniformity, dissolution testing, active-ingredient segregation, moisture control, and stability of esomeprazole.

Other possible barriers include trade secrets, know-how, supplier qualification, product-specific analytical methods, and regulatory exclusivity. These rights are distinct from the expired claims of US 8,852,636.

How does the patent compare with conventional naproxen or esomeprazole products?

Product type	Likely relationship to claim 1
Naproxen tablet alone	Does not contain esomeprazole; outside the claim
Esomeprazole capsule alone	Does not contain naproxen; outside the claim
Separate naproxen and esomeprazole prescriptions	Not a single claimed unit dosage form
Homogeneous naproxen/esomeprazole blend	May avoid the core-and-layer limitations
Enterically coated esomeprazole with separate naproxen layer	May avoid the no-enteric-coating limitation
Vimovo-type layered tablet	Closely aligned with claim 1
Multiparticulate capsule with coated naproxen particles	Potentially aligned with claims 7 and 8

What is the commercial exposure?

The patent protected a combination product intended for patients who needed naproxen but were at risk of NSAID-associated gastric ulcers. Commercial exposure therefore depended on both NSAID demand and the premium for combining gastroprotection with analgesic therapy.

The key commercial impact of patent expiry was the removal of a formulation-based barrier around a branded combination product. The effect on revenue depended on:

• The branded product’s remaining market share.
• Number and timing of approved generic competitors.
• Generic substitution rules.
• Wholesale and payer contracting.
• Manufacturing cost.
• Whether generics matched the reference product’s strength and labeling.

The patent itself no longer supports a current royalty or infringement premium in the United States. Any remaining value would arise from know-how, regulatory infrastructure, trademarks, manufacturing capability, or other unexpired rights.

Key Takeaways

• US Patent 8,852,636 covers esomeprazole outside a pH-dependent naproxen core.
• Claim 1 is directed to tablets; claim 7 is directed to capsules.
• The naproxen coating must delay release until the surrounding medium reaches at least pH 3.5.
• Esomeprazole must release in the stomach and must not be surrounded by an enteric coating.
• Claims 3, 4, 9, and 10 cover commercial dosage ranges that include 20 mg esomeprazole and 375 mg or 500 mg naproxen.
• Claims 5, 6, 11, and 12 cover treatment of pain or inflammation, including osteoarthritis and rheumatoid arthritis.
• The patent expired in November 2023.
• The '636 patent no longer presents an active US patent barrier to generic entry.
• Historical Paragraph IV risk had to be assessed against the full Vimovo patent estate, not this patent alone.
• Current commercial barriers are more likely to involve FDA approval, bioequivalence, coating manufacture, stability, and competition than enforceable rights under the '636 patent.

FAQs

Does US Patent 8,852,636 cover Vimovo?

Yes. The claim architecture is directed to a naproxen/esomeprazole dosage form with gastric esomeprazole release and delayed naproxen release, matching the principal design of Vimovo.

Can a generic use 500 mg naproxen and 20 mg esomeprazole after expiration?

Patent expiration removes the '636 patent barrier, but the product must still satisfy FDA approval requirements, including pharmaceutical equivalence, bioequivalence, quality standards, and applicable Orange Book certifications.

Does the patent cover separate naproxen and esomeprazole tablets?

No. The claims require a single unit dosage form containing both active ingredients in the claimed configuration.

Would an enterically coated esomeprazole layer fall within claim 1?

Not literally if the esomeprazole layer is surrounded by an enteric coating, because claim 1 expressly requires that the layer not be surrounded by an enteric coating.

Is the patent still enforceable against a US generic launch?

No. US Patent 8,852,636 expired by patent term in November 2023. Historical infringement before expiration remains legally distinct from post-expiration commercial activity.

References

1. U.S. Patent No. 8,852,636. (2014). Pharmaceutical compositions comprising a proton pump inhibitor and a non-steroidal anti-inflammatory drug. United States Patent and Trademark Office.

2. U.S. Food and Drug Administration. (2010). Vimovo prescribing information: Naproxen and esomeprazole magnesium delayed-release tablets. FDA.

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

4. U.S. Food and Drug Administration. (2024). Orange Book: Approved drug products with therapeutic equivalence evaluations. FDA, Center for Drug Evaluation and Research.

5. United States Code, 35 U.S.C. § 271(e)(2). (2024). Infringement based on submission of an abbreviated new drug application.

Drugs Protected by US Patent 8,852,636

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate

International Family Members for US Patent 8,852,636

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1411900		C300481	Netherlands
European Patent Office	1411900		91858	Luxembourg
European Patent Office	1411900		1190013-1	Sweden
European Patent Office	1411900		CA 2012 00036	Denmark
European Patent Office	1411900		2011/016	Ireland
European Patent Office	1411900		SPC/GB11/015	United Kingdom
European Patent Office	1411900		C01411900/01	Switzerland