Details for Patent: 5,792,795

Summary for Patent: 5,792,795

Title:	Treatment of inflammatory bowel disease using oral dosage forms of omega-3 polyunsaturated acids
Abstract:	PCT No. PCT/EP96/02038 Sec. 371 Date Aug. 7, 1996 Sec. 102(e) Date Aug. 7, 1996 PCT Filed May 13, 1996 PCT Pub. No. WO96/36329 PCT Pub. Date Nov. 21, 1996Inflammatory bowel disease, especially Crohn's disease and ulcerative colitis, is treated by administration of an oral dosage form, containing as an active principle an omega-3 polyunsaturated acid in free acid form or as a pharmaceutically acceptable salt thereof, which releases the acid in the ileum. Preferably the oral dosage form is a gelatine capsule coated with a poly(ethylacrylate-methylmethacrylate).
Inventor(s):	Thomas Buser, Emilio P. Camporesi
Assignee:	Chrysalis Pharma AG
Application Number:	US08/687,329
Patent Claim Types: see list of patent claims	Use; Dosage form;

United States Patent 5,792,795 (ω-3 ileum-release polyacrylate coating) Scope, Claim Breadth, and US Patent Landscape

US Patent 5,792,795 claims a targeted oral delivery concept: omega-3 polyunsaturated acids (EPA/DHA) formulated in a capsule with a neutral poly(ethylacrylate-methylmethacrylate) (Eudragit-type) coating designed to withstand release at pH 5.5 for 30 to 60 minutes, with drug release in the ileum, plus methods for treating inflammatory bowel disease (IBD) such as Crohn’s disease and dose regimens.

Below is a claim-by-claim scope map, then a landscape view focused on what downstream products and generic entrants typically need to avoid to reduce infringement risk under the US claim set.

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What does US Patent 5,792,795 cover: omega-3 ileum-release dosage forms and IBD treatment claims?

Core coverage in plain terms: an oral capsule dosage form using EPA and/or DHA with a neutral polyacrylate-type coating engineered for pH 5.5 stability (no release for 30–60 minutes) followed by release in the small intestine (ileum). Claims also cover specific polymer compositions and coating excipient inclusions (iron oxide, titanium dioxide, talc), unit dose ranges, and therapeutic methods for IBD.

Claim architecture: where the “real” infringement hooks are

The patent is structured with:

• Independent product claims: claim 1 and claim 2 (broadest oral dosage form coverage).
• Dependent narrowing claims: claims 3–12 define coating resistance window, specific polymer, pigment/talc components, unit dose, capsule type, and specific omega-3 candidates.
• Independent method claim: claim 13.
• Dependent method claims: claims 14–16 narrow disease type and patient status and daily dose.
• A product “re-stated” independent-like coverage in claim 17 (composition plus specific coating).

The most important infringement questions typically track the independent product claims (1 and 2), then narrow arguments hinge on dependent features (polymer identity, coating makeup, unit dose, and omega-3 species).

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What are the independent claims scope: claims 1 and 2 breadth for omega-3 ileum release?

Claim 1 (product): neutral polyacrylate coating + pH 5.5 release resistance + 30–60 minutes + ileum release

Claim 1 elements

1. Oral dosage form for treating IBD
2. Contains an active compound selected from:
   • omega-3 polyunsaturated acids and pharmaceutically acceptable salts
3. Contains a neutral polyacrylate coating that is resistant to release of the active compound for 30 to 60 minutes at pH 5.5
4. Active compound is released in the ileum

Scope implications

• “Neutral polyacrylate” is a functional limitation paired with a coating property (resistance at pH 5.5 for a defined time window). Infringement turns on whether the formulation uses a neutral polyacrylate system and whether its dissolution/retention behavior matches the 30–60 minute at pH 5.5 performance.
• “Omega-3 polyunsaturated acids” is broad at the class level, but later dependent claims narrow to EPA/DHA candidates and oil concentration.
• “Released in the ileum” is also functional. A competing product can avoid literal “ileum” language only if its release profile is clearly not “ileal” under the claim’s interpretation (that is usually a technical performance question).

Business takeaway: Claim 1 is the broadest product protection and is the claim most likely to be asserted against competitors selling omega-3 ileum-targeted capsules with neutral polyacrylate coatings.

Claim 2 (product): coated capsule with omega-3 (free acid or salts) + neutral polyacrylate coating releasing in small intestine

Claim 2 elements

1. Oral dosage form
2. Coated capsule
3. Active principle is an omega-3 polyunsaturated acid in free acid form or a pharmaceutically acceptable salt
4. Coating is neutral polyacrylate
5. Active principle released in the small intestine

Scope implications

• Claim 2 omits the pH 5.5 for 30–60 minutes requirement found in claim 1, making claim 2 broader on the coating performance dimension (though it still has functional “released in the small intestine”).
• Claim 2 also does not require the polymer to be “poly(ethylacrylate-methylmethacrylate)” unless reached through dependent claims.

Business takeaway: If a generic or competitor uses any neutral polyacrylate capsule system that releases omega-3 in the small intestine, claim 2 is the likely infringement target.

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How narrow are the dependent product claims: pH window, polymer type, pigments, excipient ratios?

Claim 3: adds the 30–60 minutes at pH 5.5 limitation

Claim 3 depends from claim 2 and adds the coating’s resistance to release for 30–60 minutes at pH 5.5. This is a key narrowing condition tied to performance.

Claim 4: specifies the neutral polyacrylate as poly(ethylacrylate-methylmethacrylate)

Claim 4 makes the polymer identity explicit: poly(ethylacrylate-methylmethacrylate).

Claims 5–6: pigment and excipient composition (iron oxide, titanium dioxide, talc) with mg ratios

• Claim 5: coating comprises iron oxide, titanium dioxide, and talc
• Claim 6: coating has approximate ratios by mass relative to poly(ethylacrylate-methylmethacrylate):
  • about 3 mg iron oxide
  • about 2.35 mg titanium dioxide
  • about 10 mg talc
  • to about 60 mg poly(ethylacrylate-methylmethacrylate)

Scope implications

• These are highly specific. For design-around, competitors can change pigment system, omit one excipient, or materially alter ratios.
• However, infringement can still occur under claims 1–4 even if pigment composition differs, as long as independent claim requirements are met.

Claim 7–8: restrict omega-3 species to EPA and DHA and require oil constituent ≥60% w/w

• Claim 7: EPA (eicosapenta-5,8,11,14,17-enoic acid), DHA (docosahexa-4,7,10,13,16,19-enoic acid), or mixture
• Claim 8: EPA/DHA mixture present in an oil constituent at ≥60% w/w

These impose formulation composition constraints. Competitors using omega-3 sources with different chemical composition or lower oil-phase content can potentially avoid these dependent claims, but again independent claims may still read if “omega-3 polyunsaturated acids” and coating properties align.

Claim 9–10: “sole active principle” and exclusion of lithium salts

• Claim 9: omega-3 is the sole active principle
• Claim 10: excludes lithium salts but permits other pharmaceutically acceptable salts

Claim 11: capsule type

Hard or soft gelatin capsule.

Claim 12: unit dose range

Unit dose 250 to 1,000 mg of active principle.

Claim 17: product claim restating EPA/DHA plus poly(ethylacrylate-methylmethacrylate) coating

Claim 17 recites:

• capsule
• active principle EPA and/or DHA (or mixture)
• coated with poly(ethylacrylate-methylmethacrylate)

This is a reinforcing coverage point closer to a known commercial-style composition.

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How broad are the method claims: what does the patent require for IBD treatment infringement?

Claim 13 (method): administer oral dosage form of claim 2 to treat IBD or reduce clinical relapse

Elements:

1. Treat IBD or reduce relapse
2. Administer an effective amount of an oral dosage form as in claim 2

Scope implications

• The method claim is tightly linked to the product of claim 2. Any alleged method infringement depends on the defendant’s administered formulation meeting claim 2 features (omega-3 + neutral polyacrylate coating + release in small intestine).

Claim 14 (Crohn’s disease)

IBD narrowed to Crohn’s disease.

Claim 15 (clinical remission duration <24 months)

Adds patient selection: patients in clinical remission for less than 24 months before treatment.

Claim 16 (daily dose 20–50 mg/kg omega-3 PUFA)

Daily dosage range: 20 to 50 mg/kg omega-3 PUFA.

Scope implications

• These are narrowing and are less likely to be the key determinants in early infringement analysis, unless the accused regimen differs materially.

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What patents are likely adjacent in the US landscape to 5,792,795: formulation, enteric targeting, and omega-3 IBD therapy

A practical landscape for this patent cluster typically includes three categories of US patents:

1. Enteric or ileum-targeted omega-3 formulations (polyacrylate polymers, pH/time release engineering, capsule coatings)
2. Omega-3 active and salt selection for GI inflammatory indications (Crohn’s, ulcerative colitis, relapse prevention)
3. Method-of-use dosing and regimen patents (weight-based mg/kg ranges; remission-state regimens)

Given only the text of claims 1–17, the precise list of other US patents that cite or are cited by 5,792,795 cannot be produced without bibliographic retrieval. The analysis below therefore focuses on the claim-pattern and design-around themes that define the landscape value for enforcement and licensing strategy.

Design-around vectors (how competitors try to avoid claims 1 and 2)

To reduce infringement risk, entrants often attempt one or more of the following:

• Replace the coating polymer family: avoid “neutral polyacrylate”
• Change the functional release profile: avoid “released in small intestine” or “released in ileum”
• Eliminate the pH 5.5 time window feature (for claim 1, the 30–60 minute at pH 5.5)
• Use a different active chemical class: not “omega-3 polyunsaturated acids” as claimed (rare in practice for this indication)
• Use a different salt not covered by the dependent claim exclusions (lithium salt is excluded only in claim 10, not claim 2)

Where litigation risk concentrates

• Product claims 1–2 are the primary infringement battleground because they capture broad coating performance and release targeting.
• Dependent claims 3–6 can be asserted as alternative narrower theories if the accused product uses a similar Eudragit-like polymer and similar pigment/excipient system.
• Method claims 13–16 are usually secondary theories unless the accused product is clearly within the product claim scope and the regimen matches.

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What is the likely claim interpretation: key functional limitations that drive claim scope

“Neutral polyacrylate coating” (structural plus functional character)

This limitation is both material-based and performance-based. A competitor’s coating may use an alternative polymer system that is still “neutral” in behavior. Literal scope depends on how “neutral polyacrylate” is construed. From an enforcement standpoint, claim construction will likely map to polymers commonly used for delayed-release and ileum targeting (Eudragit-type neutral methacrylate copolymers are the obvious candidate given claim 4).

“Resistant to release… for 30 to 60 minutes at pH 5.5”

This is a measurable performance limitation. Accused products must show that their release behavior is outside the 30–60 minute resistance window at pH 5.5 to avoid claim 1 and claim 3.

“Released in the ileum” vs “released in the small intestine”

Claim 1 requires ileal release; claim 2 requires small intestine release. This gives two separate infringement pathways. A product that releases in duodenum/jejunum could still satisfy claim 2 but may fail claim 1 if “ileum” is interpreted narrowly.

“Omega-3 polyunsaturated acids”

This includes the broad class but in enforcement it usually collapses in practice to EPA/DHA omega-3s used for GI anti-inflammatory effects. Claim 7–8 confirm the likely intended actives.

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Where exclusivity timelines and patent expiration typically land for this patent (US 5,792,795)

You provided only the claims. Without the patent’s priority data (filing date and earliest effective filing) and without a US patent term calculation record, the exact expiration date and any terminal disclaimer adjustments cannot be stated accurately. The analysis therefore focuses on claim scope rather than enforceability timing.

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What generic entry risks exist for omega-3 ileum-targeted capsules after 5,792,795?

Infringement risk: high if a product matches neutral polyacrylate ileum targeting for EPA/DHA

Risk is highest where an accused product is:

• an oral capsule
• containing omega-3 PUFA (EPA/DHA or mixture)
• coated with neutral polyacrylate material
• engineered to avoid release at pH 5.5 for 30–60 minutes (for claim 1)
• engineered to release in ileum (for claim 1) or small intestine (for claim 2)

Lower risk scenarios

• Coating is pH-triggered rather than neutral polyacrylate time/retention based
• Coating uses a different polymer family (non-polyacrylate)
• Release occurs primarily before ileum
• Different active category (less typical in this product space)

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How strong is the patent estate for this concept: which claims are most enforceable?

High-value, enforceable anchors

• Claim 2 because it lacks the explicit 30–60 minute at pH 5.5 feature while still requiring neutral polyacrylate and small intestine release.
• Claim 1 because it adds both the time-at-pH performance and ileum release, which tends to be harder to replicate unintentionally.

Vulnerable areas (typically litigated in claim construction and performance evidence)

• “Released in ileum” and “released in the small intestine” depend on in vivo or predictive release profiles, usually supported by dissolution testing and GI transit modeling.
• “Neutral polyacrylate” may be tested against polymer chemistry and coating behavior.

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Key Takeaways

• US 5,792,795 protects a neutral polyacrylate-coated oral omega-3 capsule designed for small-intestine/ileum release, plus IBD/Crohn’s treatment methods tied to that product.
• Independent claims 1 and 2 drive the enforcement map:
  • Claim 1: adds 30–60 minute resistance at pH 5.5 and requires ileum release
  • Claim 2: requires neutral polyacrylate and small intestine release without the pH/time window
• Dependent claims add patent “hooks” around:
  • polymer identity (poly(ethylacrylate-methylmethacrylate))
  • specific pigments and ratios (iron oxide, titanium dioxide, talc)
  • omega-3 species (EPA/DHA) and oil-phase content (≥60% w/w)
  • dose and capsule type
  • narrower Crohn’s relapse/dosing regimens

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FAQs

1) What specific coating property must an accused omega-3 capsule meet to infringe claim 1?
The coating must be resistant to release for 30 to 60 minutes at pH 5.5 and release the omega-3 in the ileum.

2) Can a product infringe claim 2 without matching the pH 5.5 time window?
Yes. Claim 2 does not include the 30–60 minute at pH 5.5 limitation; it instead requires a neutral polyacrylate coating with release in the small intestine.

3) Do the pigment and talc ratio limitations matter for claim 1 or only for narrower claims?
Pigment/talc ratio limits are in dependent claims 5–6. Claims 1–4 can be implicated without matching those exact coating constituents.

4) Are lithium salts of omega-3 excluded from the broadest product coverage?
The lithium salt exclusion appears in dependent claim 10. The broader claim 2 language covers “pharmaceutically acceptable salts” generally.

5) What patient factors affect infringement of the method claims?
Patient remission duration (<24 months) and daily dose (20–50 mg/kg) are in dependent method claims 15–16; claim 13 links infringement to administering the product of claim 2 for IBD treatment or relapse reduction.

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References (APA)

1. United States Patent 5,792,795.

Drugs Protected by US Patent 5,792,795

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

Foreign Priority and PCT Information for Patent: 5,792,795

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
United Kingdom	9509764	May 15, 1995

PCT Information
PCT Filed	May 13, 1996	PCT Application Number:	PCT/EP96/02038
PCT Publication Date:	November 21, 1996	PCT Publication Number:	WO96/36329

International Family Members for US Patent 5,792,795

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	294575
Australia	5895596
Australia	702692