US Patent 9,616,097: Scope, Claim Construction, Expiration and Plecanatide Patent Landscape

US Patent No. 9,616,097 protects a specific oral formulation of plecanatide, the 16-amino-acid guanylate cyclase-C agonist marketed as Trulance. The claims are directed to 3 mg and 6 mg unit doses containing the peptide, a low-moisture inert carrier, and a lubricant, with minimum purity and storage-stability requirements. The patent is formulation-focused rather than a broad composition-of-matter patent covering plecanatide itself.

The principal commercial risk is that an ANDA applicant seeking to copy the 3 mg or 6 mg Trulance dosage form could practice every limitation of claim 1, including the carrier, lubricant, purity, and stability limitations. A generic developer may reduce exposure by using a different excipient system, lubricant concentration, dosage form, or packaging configuration.

What does US Patent 9,616,097 protect?

US 9,616,097 protects an oral dosage formulation containing:

Claim element	Required limitation
Active ingredient	A GCC agonist peptide consisting of SEQ ID NO:1
Peptide structure	A (4,12; 7,15) bicyclic peptide
Dose	3.0 mg or 6.0 mg per unit dose
Carrier	An inert low-moisture carrier
Lubricant	A lubricant, with magnesium stearate specifically claimed in claim 8
Purity	At least 91% chromatographic purity after storage for at least three months
Form	Oral dosage formulation
Stability	Extended stability under specified temperature and humidity conditions in claim 5

SEQ ID NO:1 is the plecanatide peptide used in Trulance. The bicycle designation identifies the two disulfide connectivity relationships between cysteine residues 4 and 12 and residues 7 and 15. This structural limitation excludes unrelated GCC agonist peptides and materially narrows the claims compared with a generic claim to all GCC agonists.

The patent does not broadly cover every plecanatide formulation. It requires the particular dose, carrier category, lubricant, and stability or purity characteristics stated in the claims.

How do claims 1 through 12 define the protected formulation?

Claim 1: the core combination

Claim 1 is the independent claim. An accused product would generally need to contain all of the following:

Plecanatide or the claimed SEQ ID NO:1 peptide.
A 3 mg or 6 mg amount per unit dose.
An oral dosage formulation.
An inert low-moisture carrier.
A lubricant.
At least 91% chromatographic purity after storage for at least three months.

The phrase "consisting of" may create a meaningful claim-construction issue. In patent drafting, "consisting of" generally excludes additional ingredients that materially alter the basic and novel characteristics of the claimed formulation. It does not necessarily exclude trace impurities, processing aids, or excipients that do not materially affect the claimed formulation. The precise effect would depend on the specification, prosecution history, and the asserted interpretation in litigation.

The stability and purity language is particularly important. Claim 1 does not merely require a formulation that initially contains high-purity plecanatide. It requires the stated purity after storage. An infringement analysis would therefore depend on analytical testing, the selected chromatographic method, storage conditions, and the meaning of "after storage for at least three months."

Claims 2 and 3: purity and acid content

Claim 2 narrows the purity requirement to at least 92% to 95%. The wording creates a drafting ambiguity because "92% to 95%" can be read as a bounded range, while "no less than 92% to 95%" is not technically precise. A court may examine the specification and prosecution record to determine whether the claim covers:

At least 92%;
A range of 92% through 95%; or
At least 95%.

Claim 3 limits inorganic acids and carboxylic acids to less than 0.2%. This limitation appears directed to chemical stability. Acidic excipients, residual process materials, and degradation products could become relevant in an infringement or validity dispute.

Claims 4, 6 and 7: dosage form and packaging

Claim 4 covers solid forms including:

Powder;
Granule;
Sachet;
Troche;
Tablet; and
Capsule.

Claim 6 narrows the formulation to a capsule or tablet. Claim 7 adds a blister pack or strip. These claims create separate design-around routes. A product in a bottle rather than a blister pack may avoid claim 7 while still potentially implicating claims 1, 4 or 6.

The packaging limitation is unlikely to protect the active formulation independently. It is relevant only when combined with the underlying capsule or tablet and the other limitations.

Claims 8 and 9: lubricant

Claim 8 specifies magnesium stearate. Claim 9 limits the lubricant to 0.25% by weight. A formulation using a different lubricant, such as sodium stearyl fumarate, may avoid these dependent claims but could remain exposed to claim 1 if the alternative material is still legally characterized as a lubricant.

The exact 0.25% limitation in claim 9 is narrow. A formulation using 0.20%, 0.30%, or another concentration could avoid literal infringement, although the doctrine of equivalents could become relevant depending on the technical effect and prosecution history.

Claims 10 through 12: carrier and particle size

Claim 10 specifies microcrystalline cellulose. Claim 11 requires the inert carrier to constitute at least 96% by weight. Claim 12 limits the carrier particle size to 50 to 900 microns.

These limitations identify the likely commercial formulation architecture: a peptide dispersed in a predominantly microcrystalline-cellulose excipient system with magnesium stearate as lubricant. A competing formulation using mannitol, lactose, starch, or another carrier could reduce literal infringement risk, subject to whether the substitute qualifies as an "inert low-moisture carrier" under claim 1.

What is the patent expiration date for US 9,616,097?

Item	Information
Patent	US 9,616,097 B2
Technology	Oral GCC agonist formulation
Patent type	Formulation and stability patent
Priority basis	2013 priority filing identified in the patent family
US nonprovisional filing	2014 patent application filing
Issue date	April 11, 2017
Expected ordinary expiration	March 24, 2034
Product association	Plecanatide, marketed as Trulance

The expected expiration date is based on the 20-year term measured from the relevant US nonprovisional filing date, subject to any patent-term adjustment or terminal disclaimer reflected in the official patent record. The earlier provisional priority filing generally does not reduce the 20-year term under the modern US patent-term regime.

The patent should be distinguished from earlier plecanatide composition-of-matter patents, which may expire earlier. A formulation patent can therefore remain commercially relevant after the primary peptide patent has expired.

What is the Orange Book status of US 9,616,097?

US 9,616,097 has been associated with the Trulance patent estate and is relevant to FDA-regulated generic entry analysis. The Orange Book status of a listed patent should be assessed together with the listed use code, patent expiration date, and any patent-term adjustment shown in the FDA records.[1]

An Orange Book listing does not establish validity or infringement. It does, however, create a Hatch-Waxman certification issue for an ANDA applicant. A generic applicant may need to provide a Paragraph IV certification if it seeks approval before the listed patent expires and contends that the patent is invalid, unenforceable, or not infringed.[2]

The commercial effect depends on whether the patent is listed for the drug product, the approved indication, or a specific formulation or method of use. Formulation patents generally create a more targeted barrier than composition-of-matter patents because a generic applicant may attempt to use a different formulation.

When does plecanatide lose exclusivity?

Plecanatide has several layers of exclusivity:

Exclusivity layer	Commercial relevance
Composition-of-matter patents	Protect the peptide structure and may expire before the formulation patents
Formulation patents	Protect specific dose, excipient, purity and stability combinations
Method-of-use patents	May protect treatment of chronic idiopathic constipation or irritable bowel syndrome with constipation
FDA regulatory exclusivity	Depends on the NDA and approval pathway
Orange Book-listed patents	Trigger ANDA patent certifications and possible litigation

Trulance was approved by the FDA in January 2017 for adults with chronic idiopathic constipation. The FDA later approved it for adults with irritable bowel syndrome with constipation.[3] The principal patent barrier for a generic may extend beyond the first composition-of-matter expiration because later-issued formulation and use patents can create separate litigation and launch risks.

US 9,616,097 is significant because its expected term extends to 2034, subject to the official term calculation. A generic applicant may nevertheless obtain an approval with a carve-out, a non-infringing formulation, or a court judgment before that date.

What formulation patents protect Trulance?

The principal protected formulation concept is a low-moisture solid oral dosage form containing 3 mg or 6 mg of plecanatide. The claims concentrate on four technical features:

Moisture control through the inert carrier.
Chemical stability of the peptide.
High chromatographic purity after storage.
A manufacturing-friendly solid dosage form using microcrystalline cellulose and magnesium stearate.

Claim 11 is commercially important because it requires at least 96% carrier by weight. This leaves relatively little room for active ingredient, lubricant, coatings, stabilizers, or other excipients. The limitation may correspond closely to a marketed tablet composition, but it also creates a potential non-infringement path if the competing product uses a materially different excipient balance.

Claim 5 is broader in duration but narrower in conditions. It covers stability for at least 18 months under one of three conditions:

30°C and 65% relative humidity;
25°C and 60% relative humidity; or
2°C to 8°C.

A generic applicant would need to assess whether its formulation satisfies one of these conditions and whether the stability result is an inherent property of the commercial product.

How strong is the patent estate for plecanatide?

US 9,616,097 has moderate-to-strong commercial value as a formulation patent but is narrower than a composition-of-matter patent.

Strengths

It covers the actual 3 mg and 6 mg commercial dose strengths.
It identifies plecanatide by sequence and disulfide connectivity.
It includes both formulation composition and measurable stability or purity requirements.
It can remain in force after earlier peptide patents expire.
It may be listed in the Orange Book, creating a statutory ANDA certification and litigation mechanism.

Vulnerabilities

The active peptide is specifically defined, limiting the patent to plecanatide formulations.
The carrier and lubricant requirements provide potential design-around options.
The purity limitation may depend on analytical methodology.
The stability limitation may be challenged for lack of enablement, written description, indefiniteness, or failure to show that the full claim scope achieves the stated result.
Claim 1 may be vulnerable to anticipation or obviousness if earlier publications disclosed plecanatide tablets, low-moisture carriers, magnesium stearate, and comparable stability results.
Claim 2 contains potentially unclear range language.

The strongest litigation position would generally arise when the accused product uses plecanatide, a 3 mg or 6 mg unit dose, microcrystalline cellulose, magnesium stearate, and a comparable high-purity stability profile.

Which companies are challenging the Trulance patent estate?

No publicly established Paragraph IV litigation involving US 9,616,097 is identified in the patent and FDA materials cited here. Trulance is marketed by Bausch Health through its Salix Pharmaceuticals business. The lack of a known public challenge does not eliminate future ANDA risk. Generic companies can file Paragraph IV certifications without an immediate public market launch, and litigation may not occur until the NDA holder receives a formal notice letter.

The competitive field includes:

Product	Active ingredient	Company	Regulatory pathway
Trulance	Plecanatide	Salix Pharmaceuticals/Bausch Health	NDA
Linzess	Linaclotide	AbbVie/Ironwood Pharmaceuticals	NDA
Generic plecanatide	Plecanatide	Potential ANDA applicants	ANDA
Generic linaclotide	Linaclotide	Multiple generic applicants	ANDA

Linzess is a competitive GCC agonist product but does not practice the plecanatide sequence limitation in US 9,616,097. Its patent estate is separate.

What Paragraph IV risks exist for Trulance?

A Paragraph IV applicant could challenge the patent through one or more theories:

The claims are anticipated by prior art disclosing plecanatide oral formulations.
The combination of plecanatide, microcrystalline cellulose, and magnesium stearate is obvious.
The purity and stability limitations are inherent in known formulations.
The claim language does not adequately define the chromatographic method or storage protocol.
The claims lack written-description support across the full range of carriers, lubricants, dosage forms, and stability conditions.
The proposed generic formulation omits one or more limitations.

For the patent holder, the main infringement theory would be that the ANDA product will necessarily contain the claimed ingredients and will inherently meet the purity and stability limitations. For the ANDA applicant, the strongest route would be a formulation design-around supported by comparative analytical data.

Under the Hatch-Waxman framework, a Paragraph IV notice can trigger patent litigation and a statutory 30-month stay of FDA approval in appropriate circumstances.[2] The actual stay and litigation posture depend on the timing of the ANDA notice, patent listing, and NDA holder response.

Does plecanatide face biosimilar risk?

Plecanatide is a synthetic peptide drug rather than a conventional therapeutic protein. Competitive entry would generally be expected through the abbreviated new drug application framework rather than the 351(k) biosimilar pathway used for biologic products.[4]

The practical risk is therefore generic, not biosimilar, competition. FDA approval would require pharmaceutical equivalence and bioequivalence or an otherwise accepted abbreviated pathway. Because plecanatide acts locally in the gastrointestinal tract and has low systemic exposure, the regulatory strategy may rely heavily on product characterization, formulation controls, and FDA-specific bioequivalence requirements.

What manufacturing and intellectual-property barriers affect generic entry?

Manufacturing barriers include:

Controlled peptide synthesis and disulfide-bond formation.
Removal of peptide-related impurities.
Control of moisture during blending, compression, encapsulation and packaging.
Reproducible chromatographic purity.
Stability through the labeled shelf life.
Consistent dose uniformity at the low active-ingredient loading.

The high-carrier formulation presents a technical challenge because the peptide represents a small fraction of the tablet or capsule mass. Manufacturing scale-up must control blend uniformity and segregation. Blister or strip packaging may also be important for moisture protection, although packaging alone does not establish infringement of the patent.

The patent landscape therefore creates two separate barriers. The first is legal: the listed patent claims and any unexpired composition or method patents. The second is technical: a generic formulation must maintain peptide purity and potency under ordinary commercial storage conditions.

What generic launch scenarios exist?

Scenario	Likely result
Generic copies 3 mg or 6 mg formulation with microcrystalline cellulose and magnesium stearate	High infringement exposure
Generic uses a different carrier and lubricant	Lower literal-infringement risk
Generic uses a different dose strength	May avoid claims 1 and 6, but regulatory substitution may be limited
Generic uses a liquid formulation	May avoid solid-form claims 4, 6 and 7, but claim 1 analysis remains
Generic files Paragraph IV	Litigation and possible 30-month stay
Generic files with a Paragraph III certification	Approval delayed until patent expiration
Generic uses a section viii carve-out	Relevant only if the patent is listed for a removable method of use

The most credible early-entry route would be a non-infringing solid formulation that uses plecanatide but substitutes the carrier and lubricant while demonstrating equivalent quality and bioequivalence.

Key Takeaways

US 9,616,097 is a formulation patent covering oral 3 mg and 6 mg plecanatide products.
Its core limitations are plecanatide sequence, low-moisture inert carrier, lubricant, high purity and storage stability.
Dependent claims specifically cover microcrystalline cellulose, magnesium stearate, 0.25% lubricant, at least 96% carrier and 50 to 900 micron carrier particle size.
The expected ordinary expiration date is March 24, 2034, subject to the official patent-term calculation.
The patent is materially narrower than a composition-of-matter patent and offers several formulation design-around opportunities.
A generic product using the same dose, microcrystalline cellulose, magnesium stearate and comparable stability profile would face the greatest Paragraph IV risk.
Plecanatide competition is expected to arise through the ANDA pathway rather than the biosimilar pathway.
No publicly established Paragraph IV litigation involving US 9,616,097 is identified in the cited materials.

FAQs

What drug is covered by US Patent 9,616,097?

The patent covers oral formulations containing plecanatide, a bicyclic GCC agonist peptide marketed as Trulance.

Does US 9,616,097 cover all plecanatide products?

No. The claims require specific doses, formulation components and purity or stability properties. A plecanatide product using materially different ingredients may avoid literal infringement.

Is microcrystalline cellulose required by claim 1?

No. Claim 1 requires an inert low-moisture carrier. Microcrystalline cellulose is expressly required only by dependent claim 10.

Is magnesium stearate required by claim 1?

No. Claim 1 requires a lubricant. Magnesium stearate is specified in claim 8, and 0.25% lubricant is specified in claim 9.

Can a generic launch before 2034?

Potentially. A generic applicant could pursue a Paragraph IV challenge, obtain a judgment of invalidity or non-infringement, or develop a formulation that avoids the asserted claims. Patent expiration remains the straightforward entry date if no earlier legal or regulatory route succeeds.

References

U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book. FDA.
U.S. Food and Drug Administration. (2017). Abbreviated new drug application submissions: Refuse-to-receive standards. FDA.
U.S. Food and Drug Administration. (2017). Trulance (plecanatide) prescribing information. FDA.
U.S. Food and Drug Administration. (2020). New drug application and abbreviated new drug application regulations. FDA.
United States Patent and Trademark Office. (2017). U.S. Patent No. 9,616,097: Pharmaceutical compositions comprising guanylate cyclase-C agonists. USPTO.
21 U.S.C. § 355. (2024). New drug applications and abbreviated applications.
35 U.S.C. §§ 154, 271. (2024). Patent term and infringement provisions.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Salix	TRULANCE	plecanatide	TABLET;ORAL	208745-001	Jan 19, 2017		RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial	Y				⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2011302006	⤷ Start Trial
Australia	2013232306	⤷ Start Trial
Australia	2016216716	⤷ Start Trial
Australia	2018286626	⤷ Start Trial
Australia	2020270511	⤷ Start Trial
Canada	2810243	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,616,097

Which drugs does patent 9,616,097 protect, and when does it expire?

Summary for Patent: 9,616,097