US Patent 9,115,091: Eluxadoline Crystal Forms, Claim Scope, Expiration and Patent Landscape
US Patent 9,115,091 protects pharmaceutical compositions containing crystalline Form α or Form β of eluxadoline, together with oral dosage forms and treatment of opioid receptor disorders, principally irritable bowel syndrome and pain. The patent does not claim eluxadoline as a new chemical entity, a manufacturing process, or every formulation containing eluxadoline. Its commercial value is concentrated in solid-state protection for the active ingredient used in Viberzi.
The patent issued on August 25, 2015. Public patent records associate the application with Furiex Pharmaceuticals and an earliest priority date in 2010. On a standard 20-year term calculation, the unadjusted expiration date is approximately October 29, 2031, subject to any patent-term adjustment or extension recorded by the USPTO.
What drug does US Patent 9,115,091 protect?
The claimed compound is eluxadoline, the active pharmaceutical ingredient in Viberzi. Eluxadoline is a peripherally acting mixed opioid receptor ligand used for irritable bowel syndrome with diarrhea in adults.
| Item |
Description |
| Active ingredient |
Eluxadoline |
| Brand |
Viberzi |
| Developer and early commercial parties |
Furiex Pharmaceuticals and Forest Laboratories |
| Current commercial ownership history |
Forest Laboratories, Actavis, Allergan, and AbbVie corporate succession |
| Drug class |
Mixed opioid receptor modulator |
| Principal indication |
Irritable bowel syndrome with diarrhea |
| Dosage form |
Oral tablet |
| Patent at issue |
US 9,115,091 B2 |
| Issue date |
August 25, 2015 |
| Earliest reported priority |
October 29, 2010 |
| Approximate standard expiration |
October 29, 2031 |
| Core protected subject matter |
Form α and Form β crystalline eluxadoline compositions |
The chemical name in the claims is not limited by a brand name. A product can fall within the patent if it contains the claimed crystalline form, even if it is sold under a different trade name.
What are the independent claims in US 9,115,091?
The patent has four commercially important independent claim groups.
Claim 1: Form α composition
Claim 1 covers a pharmaceutical composition comprising Form α crystalline eluxadoline. The claim uses “comprising,” which is an open-ended transitional term. The composition may contain excipients, coatings, diluents, binders, lubricants, or other ingredients, provided that it contains the claimed Form α crystal.
The claim does not require:
- A particular tablet strength
- A specific excipient
- A particular release profile
- A particular purity level
- A specific manufacturing process
- A particular ratio of eluxadoline to excipients
Claim 15: Form α treatment method
Claim 15 covers administering a composition containing Form α eluxadoline to treat an opioid receptor disorder in a mammal. Dependent claims narrow the disorder to irritable bowel syndrome, pain, or both, and narrow the patient to a human.
Claim 24: Form β composition
Claim 24 separately covers a pharmaceutical composition comprising Form β crystalline eluxadoline. Form β is not merely a dependent variant of Form α. It is a separate claimed polymorphic form with different X-ray diffraction characteristics.
Claim 25: Form β treatment method
Claim 25 covers administering a Form β composition to treat an opioid receptor disorder. Claims 39 through 46 narrow the treatment to irritable bowel syndrome, pain, oral administration, solid dosage forms, tablets, and human patients.
How do the Form α and Form β claims differ?
Form α and Form β are distinct solid-state forms of eluxadoline. The patent protects each form independently.
| Feature |
Form α |
Form β |
| Composition claim |
Claim 1 |
Claim 24 |
| Treatment claim |
Claim 15 |
Claim 25 |
| Representative PXRD peaks |
About 14.0, 14.3, and 14.7° 2-theta |
About 11.0, 12.4, and 15.2° 2-theta |
| Expanded PXRD pattern |
10.2, 11.3, 11.8, 14.0, 14.3, 14.7, 16.1, and 18.3° 2-theta |
11.0, 12.4, 14.9, 15.2, 22.1, 25.6, 27.4, and 30.4° 2-theta |
| Thermal characterization |
TGA and DSC corresponding to Figures 2 and 3 |
TGA and DSC corresponding to Figures 4 and 5 |
| Dosage-form claims |
Claims 9-14 |
Claims 33-38 |
| Treatment subclaims |
Claims 16-23 |
Claims 39-46 |
A generic manufacturer cannot avoid the patent merely by changing tablet excipients if the finished product contains Form α or Form β. Avoidance would generally require using a different solid form, an amorphous material, a different salt or solvate, or a formulation that does not contain either claimed form. That conclusion depends on characterization of the actual product rather than its label description.
What do the powder X-ray diffraction claims cover?
Claims 2 through 8 and claims 26 through 32 define the crystalline forms through analytical characteristics. Powder X-ray diffraction, TGA, and DSC are used as identity and characterization tools.
The dependent claims create multiple evidentiary layers:
- A limited set of diagnostic PXRD peaks.
- A larger set of PXRD peaks.
- A substantially complete peak pattern.
- A pattern corresponding to a figure or table.
- Thermal behavior corresponding to TGA or DSC figures.
The word “about” gives the claims tolerance around the listed diffraction angles. The phrase “substantially similar” also prevents a strict argument that a minor analytical variation automatically falls outside the claim. In practice, infringement analysis would require comparison of the accused material under comparable PXRD conditions, including instrument configuration, sample preparation, radiation source, scan rate, and calibration.
A key prosecution and litigation issue would be whether the accused product has the claimed form as a component of the finished dosage form. Excipients can interfere with analytical testing, so testing may need to be performed on extracted or isolated active material.
What formulations are protected by US 9,115,091?
The patent covers oral formulations containing Form α or Form β, including:
- Tablets
- Caplets
- Hard gelatin capsules
- Starch capsules
- Hydroxypropyl methylcellulose capsules
- Soft elastic gelatin capsules
- Suspensions
- Solutions
- Syrups
- Emulsions
The broadest practical formulation protection arises from claims 1 and 24. Those claims require a pharmaceutical composition containing the specified crystalline form but do not require a particular dosage form.
Claims 9 through 14 narrow Form α to oral administration and specified solid or liquid dosage forms. Claims 33 through 38 do the same for Form β. Claim 14 and claim 38 specifically cover tablets.
The patent does not expressly claim:
- A particular 75 mg or 100 mg dose
- A specific tablet coating
- A specific dissolution specification
- A sustained-release tablet
- A fixed-dose combination
- A particular excipient blend
- A manufacturing method for producing the tablets
The patent therefore provides polymorph protection rather than a comprehensive formulation platform.
What method-of-use protection does the patent provide?
The method claims cover treatment of an opioid receptor disorder. The dependent claims identify:
- Irritable bowel syndrome
- Pain
- A combination of irritable bowel syndrome and pain
- Oral administration
- Solid dosage forms
- Tablets
- Human patients
The method claims are narrower than the composition claims in one important respect: they require administration for treatment. A product containing the claimed polymorph may implicate the composition claims without being sold with an express IBS or pain indication.
The claims do not recite the IBS subtype “with diarrhea” in the text supplied. Viberzi’s approved labeling, however, identifies the approved indication as IBS with diarrhea in adults. FDA labeling also includes restrictions relating to patients without a gallbladder and pancreatitis risk, which affect commercial prescribing but do not change the literal scope of the patent claims.[2]
When does US Patent 9,115,091 lose exclusivity?
The patent’s standard term is expected to run until approximately October 29, 2031, based on the reported 2010 priority date and a 20-year term calculated under 35 U.S.C. § 154. The legally controlling date is the expiration date recorded in USPTO patent-term data and any applicable patent-term adjustment.
| Exclusivity element |
Expected position |
| Patent issue |
August 25, 2015 |
| Earliest reported priority |
October 29, 2010 |
| Standard term endpoint |
Approximately October 29, 2031 |
| Patent-term adjustment |
Must be included if recorded |
| Patent-term extension under 35 U.S.C. § 156 |
No extension is established by the supplied record |
| Regulatory exclusivity |
Separate from patent term |
| Generic entry |
Depends on ANDA certification, litigation, settlement, and other listed patents |
FDA regulatory exclusivity and patent exclusivity are separate. Viberzi received FDA approval in 2015. Any New Chemical Entity exclusivity associated with the original approval would have expired well before the patent’s expected 2031 term. Later generic entry is therefore primarily a patent and regulatory-certification issue rather than an NCE-exclusivity issue.[2][3]
What is the Orange Book status of US 9,115,091?
US 9,115,091 is the type of patent eligible for Orange Book listing because its claims cover drug substance crystalline form and pharmaceutical compositions associated with an approved drug product. The relevant Orange Book inquiry is whether the patent is listed against the specific Viberzi drug product and what expiration date FDA records for that listing.[3]
The patent should be evaluated with the complete Viberzi patent set, not in isolation. An ANDA applicant may need to address:
- Drug-substance patents
- Polymorph patents
- Formulation patents
- Method-of-use patents
- Any later-issued patents listed by the NDA holder
A Paragraph IV certification could assert that the patent is invalid, unenforceable, or not infringed. If the NDA holder files suit within the statutory period, a 30-month stay may delay FDA approval under the Hatch-Waxman framework, subject to statutory exceptions and court action.[4]
Which companies are challenging Viberzi patent rights?
The supplied claim set does not identify any ANDA applicant, Paragraph IV notice, district-court action, or settlement agreement. The patent text alone cannot establish the identity of a generic challenger or the outcome of any challenge.
For this product, the relevant competitive pathway is an ANDA, not a biosimilar application. Eluxadoline is a chemically synthesized small molecule. A generic applicant would generally seek approval under section 505(j) of the Federal Food, Drug, and Cosmetic Act and demonstrate pharmaceutical equivalence and bioequivalence.
A complete challenger analysis would distinguish among:
- An ANDA with Paragraph III certification, accepting delayed approval until patent expiration
- An ANDA with Paragraph IV certification, challenging listed patents
- A first Paragraph IV filer potentially eligible for 180-day exclusivity
- A later filer entering after settlement or patent expiry
- An authorized generic or licensee arrangement
How strong is the patent estate for eluxadoline?
US 9,115,091 is strong against products using either claimed polymorph, but its scope is narrower than a compound patent.
Strengths
- It covers two named crystalline forms.
- The forms are supported by multiple analytical markers.
- The composition claims extend across oral dosage forms.
- The claims cover both drug-product composition and treatment methods.
- A change in excipients alone is unlikely to avoid the core composition claims.
- The expected expiration date extends beyond the original regulatory exclusivity period.
Limitations
- The patent does not claim the eluxadoline molecule itself.
- It does not claim every polymorph, amorphous form, salt, solvate, or co-crystal.
- It does not claim a manufacturing process.
- The claims depend on proving the crystalline form in the accused product.
- The method claims may be narrower in a product-liability or inducement analysis.
- A commercially viable alternative polymorph could reduce direct exposure if it does not convert into Form α or Form β during manufacture, storage, or use.
The primary technical risk is solid-state conversion. A product manufactured as a noninfringing form could still create risk if Form α or Form β appears during processing, storage, granulation, compression, or shelf life.
What manufacturing and IP barriers affect generic entry?
Generic development would require solid-state screening and stability work. The applicant would need to determine whether its active ingredient is:
- Form α
- Form β
- Another crystalline form
- Amorphous
- A hydrate or solvate
- A mixture of forms
- A material that converts between forms
The patent’s analytical claims make polymorph characterization central to diligence. A generic applicant would also need to assess whether the reference listed drug contains one of the patented forms and whether the proposed product is pharmaceutically equivalent under FDA requirements.
Manufacturing risks include:
- Seeding by residual crystalline material
- Solvent-mediated polymorphic conversion
- Milling-induced transformation
- Moisture-driven conversion
- Heat exposure during drying
- Compression-induced changes
- Stability-related form conversion
These issues can create both infringement risk and regulatory comparability problems.
What litigation and settlement issues matter?
For a Paragraph IV challenge, the principal litigation theories would be:
- Noninfringement because the proposed product does not contain Form α or Form β.
- Invalidity for anticipation or obviousness based on prior-art solid-state forms.
- Lack of written description or enablement for the claimed polymorph scope.
- Indefiniteness involving “about” or “substantially similar.”
- Enforceability defenses based on prosecution conduct, if supported by the record.
A settlement could delay generic launch until an agreed date before October 2031, permit an authorized generic, or grant a license to a selected manufacturer. No settlement terms can be inferred from the claims themselves.
How does US 9,115,091 compare with compound and formulation patents?
| Patent type |
Typical scope |
Relative position of US 9,115,091 |
| Compound patent |
Covers the active molecule and often expires first or earlier |
9,115,091 is narrower |
| Polymorph patent |
Covers a defined solid form |
9,115,091 is a polymorph patent |
| Formulation patent |
Covers excipients, release profile, or dosage architecture |
9,115,091 has broad composition claims but limited formulation detail |
| Method-of-use patent |
Covers treatment of a defined disease |
9,115,091 includes IBS and pain method claims |
| Process patent |
Covers manufacture or crystallization |
9,115,091 does not contain the supplied process claims |
| Regulatory exclusivity |
Delays approval independently of patents |
Separate from 9,115,091 |
Key Takeaways
- US 9,115,091 covers Form α and Form β crystalline eluxadoline compositions.
- The patent protects Viberzi-relevant oral products, especially tablets, but does not claim every eluxadoline formulation.
- PXRD, TGA, and DSC characteristics are central to infringement analysis.
- The patent includes composition claims and treatment claims for IBS, pain, and related opioid receptor disorders.
- The standard expected expiration is approximately October 29, 2031, subject to USPTO patent-term adjustment.
- Generic entry would proceed through an ANDA, not a biosimilar pathway.
- A noninfringing generic strategy would likely require development and control of a different solid form or noncrystalline material.
- Revenue exposure depends on the full Viberzi patent estate, product sales, generic timing, and any Paragraph IV settlement.
- The claims alone do not establish the identity of any generic challenger or the existence of a settlement.
FAQs
Is US 9,115,091 a patent on eluxadoline itself?
No. It is principally a crystalline-form and pharmaceutical-composition patent. Earlier or separate patents may protect the active molecule or its therapeutic use.
Can a generic use the same eluxadoline molecule and avoid US 9,115,091?
Potentially, but only if the generic product does not contain Form α or Form β as claimed. Changing excipients while retaining a claimed polymorph would not ordinarily address the core composition claims.
Does the patent cover Viberzi tablets specifically?
Yes. Claims 14 and 38 expressly recite tablets. The broader composition claims also cover pharmaceutical compositions containing the claimed crystalline forms without requiring a tablet.
Is a Paragraph IV certification required for a generic version of Viberzi?
It may be required for any Orange Book-listed patent that the applicant seeks to challenge before expiration. The certification depends on the patents listed for the applicable Viberzi NDA and the applicant’s proposed approval date.
Could a new polymorph of eluxadoline avoid this patent?
A genuinely different polymorph may avoid the literal Form α and Form β claims. The analysis must account for polymorphic conversion and whether the product contains a mixture or transforms into a claimed form during manufacture or storage.
References
- United States Patent and Trademark Office. (2015). US Patent No. 9,115,091 B2: Crystalline forms of eluxadoline.
- U.S. Food and Drug Administration. (2015). Viberzi (eluxadoline) prescribing information.
- U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
- United States Congress. (1984). Drug Price Competition and Patent Term Restoration Act, 21 U.S.C. § 355 and 35 U.S.C. §§ 154, 156.
