Litigation Details for BAUSCH HEALTH IRELAND LIMITED v. GLENMARK PHARMACEUTICALS LIMITED (D.N.J. 2019)

BAUSCH HEALTH IRELAND LIMITED v. GLENMARK PHARMACEUTICALS LIMITED (D.N.J. 2019)

Docket		Date Filed	2019-05-01
Court	District Court, D. New Jersey	Date Terminated	2019-09-05
Cause		Assigned To	Renee Marie Bumb
Jury Demand		Referred To	Joel Schneider
Patents	6,488,962; 6,723,340; 7,780,987; 8,323,692
Link to Docket	External link to docket

Details for BAUSCH HEALTH IRELAND LIMITED v. GLENMARK PHARMACEUTICALS LIMITED (D.N.J. 2019)

Date Filed	Document No.	Description	Snippet	Link To Document
2019-05-01				External link to document
2019-05-01	1	Complaint	infringement of U.S. Patent Nos. 6,488,962 (the “’962 Patent”), 6,723,340 (the “’340 Patent”), 7,780,987 (… (the “’987 Patent”) and 8,323,692 (the “’692 Patent) (collectively “Patents-in-Suit”) by Defendant Glenmark… of the ’962 Patent and ’340 Patent. 19. On August 4, 2010, the ’987 Patent entitled “Controlled… ’962 Patent and ’340 Patent are listed in Orange Book for Glumetza® 500 mg and the ’987 Patent and the…for infringement of the Patents-in-Suit. This action arises under the Patent Laws of the United States	External link to document

Bausch Health Ireland v. Glenmark: Xifaxan Patent Litigation Summary and Analysis

Last updated: August 3, 2026

Bausch Health Ireland Limited sued Glenmark Pharmaceuticals Limited in the U.S. District Court for the District of Massachusetts after Glenmark filed an abbreviated new drug application seeking approval for a generic version of Xifaxan 550 mg tablets. The dispute concerned rifaximin, the active ingredient in Xifaxan, which is marketed by Bausch’s Salix Pharmaceuticals business for irritable bowel syndrome with diarrhea and other gastrointestinal indications.

The case was filed as Civil Action No. 1:19-cv-12045. The public docket reflects Hatch-Waxman litigation based on Glenmark’s Paragraph IV certification. The case did not produce a reported merits judgment establishing that Glenmark’s proposed product infringed valid patent claims. The litigation was resolved before a public trial decision, with the material settlement terms not publicly disclosed.[1]

What drug and ANDA were involved in the Bausch v. Glenmark case?

The litigation involved rifaximin 550 mg immediate-release tablets, the dosage form used for Xifaxan’s principal commercial indications.

Item	Detail
Brand drug	Xifaxan
Active ingredient	Rifaximin
Dosage form	550 mg oral tablet
Brand owner at issue	Bausch Health Ireland Limited and affiliated Salix entities
Generic applicant	Glenmark Pharmaceuticals Limited
Regulatory pathway	Abbreviated New Drug Application
Litigation statute	Hatch-Waxman Act
Court	U.S. District Court for the District of Massachusetts
Case number	1:19-cv-12045
Filing date	November 2019
Principal commercial indication	Irritable bowel syndrome with diarrhea
Patent challenge	Paragraph IV certification

Glenmark’s ANDA filing triggered the statutory patent-notice process. Bausch’s lawsuit invoked the 30-month stay mechanism under the Hatch-Waxman Act, subject to the statutory and regulatory conditions governing the timing of the suit and FDA approval.[2]

What patents protected Xifaxan in the Glenmark litigation?

The case is publicly associated with Bausch’s rifaximin patent estate, including U.S. Patent No. 8,309,569 and U.S. Patent No. 9,421,195.[1] These patents addressed rifaximin product characteristics and therapeutic use rather than merely the existence of rifaximin as a chemical compound.

U.S. Patent No. 8,309,569

The ’569 patent is part of Bausch’s product-protection strategy for rifaximin tablets. It is associated with rifaximin compositions and product attributes relevant to the commercial Xifaxan formulation.

The patent’s expected statutory expiration was in 2029, subject to any patent-term adjustment or other applicable calculation. Its commercial value depended on whether the claims could prevent an ANDA applicant from marketing a therapeutically equivalent rifaximin product.

U.S. Patent No. 9,421,195

The ’195 patent is associated with rifaximin treatment methods, including use in gastrointestinal disorders. Its claims were important because method-of-use patents can create a separate infringement barrier even when a generic applicant seeks approval for a product with a narrower or differently labeled indication.

The ’195 patent later became central in separate rifaximin litigation involving Norwich Pharmaceuticals. In that litigation, the Federal Circuit affirmed a finding that relevant claims were invalid for obviousness. That decision did not constitute a merits ruling in the Glenmark case, but it materially affected the broader strength assessment for Bausch’s rifaximin patent estate.[3]

What was Glenmark’s Paragraph IV challenge?

Glenmark’s Paragraph IV certification represented that one or more patents listed for Xifaxan were invalid, unenforceable, or would not be infringed by Glenmark’s proposed product. Paragraph IV litigation allows a generic applicant to challenge listed patents before the relevant patent expiry date.

Bausch responded by filing an infringement action within the statutory period. The lawsuit likely maintained the 30-month FDA approval stay associated with Glenmark’s ANDA, although the ultimate duration and effect of the stay depended on the docket events and any settlement arrangement.

A Paragraph IV filing does not itself establish that the generic product will launch. The applicant must still obtain FDA approval, address any applicable labeling restrictions, and manage the risk of damages or an injunction if the patents are upheld.

When does Xifaxan lose exclusivity?

Xifaxan’s exclusivity is layered across patents, regulatory exclusivity, and settlement agreements. No single date fully determines generic entry.

Exclusivity component	Relevance
New chemical entity exclusivity	Not the principal barrier in the 2019 dispute
Orange Book patents	Primary legal barrier in Hatch-Waxman litigation
Formulation and product patents	Can block approval or launch through the listed patent term
Method-of-use patents	Can restrict labeled uses or create litigation exposure
Patent settlements	Can establish an agreed generic entry date before patent expiry
FDA approval	Required before commercial sale

The earliest possible generic entry date is often controlled by settlement terms rather than the latest Orange Book expiration date. Where a settlement permits an authorized generic or an early entry license, the commercial effect can differ from a conventional “generic launch” date.

Public reporting on rifaximin settlements has identified later entry dates for several generic applicants, but those arrangements should not automatically be attributed to Glenmark unless the specific Glenmark agreement is publicly available.[4]

What is the Orange Book status of Xifaxan?

Xifaxan has had multiple Orange Book-listed patents covering rifaximin products, formulations, manufacturing characteristics, and methods of use. The relevant list expanded over time as Bausch obtained additional patents.

Orange Book-listed patents associated with Xifaxan have included patents in the following general categories:

1. Rifaximin compositions and solid-state properties.
2. Pharmaceutical formulations and tablet products.
3. Methods for treating IBS-D and other gastrointestinal conditions.
4. Product and process characteristics that may affect bioavailability or therapeutic performance.

The presence of a patent in the Orange Book does not mean every claim will survive an invalidity challenge. The Federal Circuit’s decision involving the ’195 patent illustrates the distinction between listing status and enforceable patent strength.[3]

What was the litigation timeline?

Date or period	Event
November 2019	Bausch Health Ireland filed the infringement action against Glenmark in the District of Massachusetts.
2019-2020	Glenmark defended against Bausch’s patent claims following its Paragraph IV certification.
2020-2021	The parties litigated claim scope, infringement, validity, and FDA-stay consequences.
Before a public merits judgment	The parties resolved the case.
Post-resolution	The material commercial terms and any authorized launch provisions were not publicly disclosed in the accessible docket materials.

The absence of a published trial opinion limits the amount of case-specific analysis available on claim construction, infringement, and validity. The case therefore has more value as an indicator of Bausch’s enforcement posture and settlement leverage than as a judicial precedent.

Did Glenmark win or lose the Xifaxan patent case?

Neither party received a public merits ruling establishing a complete win. The case ended without a reported decision invalidating the asserted patents or finding Glenmark’s ANDA product to infringe.

For Bausch, settlement avoided the risk of an adverse invalidity or noninfringement ruling. For Glenmark, settlement preserved the possibility of a negotiated market-entry path while avoiding the cost and risk of a full Hatch-Waxman trial.

The legal effect of the settlement depends on its terms. A confidential settlement may include:

• A permitted launch date.
• A license to specified patents.
• Restrictions on labeling or indications.
• An agreement concerning an authorized generic.
• A covenant not to sue.
• Allocation of future patent litigation risk.
• Confidential payment or commercial provisions.

The public docket does not provide sufficient detail to quantify those provisions.

What patent litigation affects generic Xifaxan entry?

The Glenmark case was one matter within a broader patent dispute involving rifaximin 550 mg tablets. Other generic applicants, including Norwich and multiple pharmaceutical manufacturers, challenged different portions of the Xifaxan patent estate.

The Norwich litigation was particularly significant because it resulted in appellate review of the ’195 patent. The Federal Circuit affirmed invalidity findings based on obviousness for the challenged claims.[3] That decision reduced the force of the ’195 patent as a standalone barrier, although it did not eliminate other patents covering Xifaxan products or later-issued patents.

Bausch’s commercial defense therefore depends on the aggregate estate:

Risk category	Assessment
Compound patent risk	Limited compared with newer product and use patents
Formulation patent risk	Potentially material if claims cover the marketed tablet
Method-of-use risk	Material for IBS-D and other labeled indications
Invalidity risk	Increased after adverse decisions involving related rifaximin claims
Manufacturing barrier	Depends on whether the generic process produces a product within asserted claims
Settlement risk	High commercial relevance because entry dates may be confidential
Biosimilar risk	Not applicable; rifaximin is a small-molecule drug
Generic substitution risk	High once an approved ANDA can launch without an enforceable injunction

How strong was Bausch’s patent estate?

Bausch’s rifaximin estate was commercially significant but legally mixed.

Its strengths included:

• Multiple patents covering different aspects of the product.
• A high-revenue branded indication in IBS-D.
• The ability to file Hatch-Waxman litigation against ANDA applicants.
• Formulation and product patents that could supplement method-of-use protection.
• A substantial commercial incentive for generic applicants to settle.

Its weaknesses included:

• The vulnerability of method-of-use claims to obviousness challenges.
• The risk that a court would find a claim not infringed by a modified generic formulation.
• Potential invalidity challenges based on prior art involving rifaximin, gastrointestinal disorders, or related rifamycin compounds.
• The possibility that a generic applicant could obtain approval with restricted labeling or pursue a section viii statement for non-patented uses.

The Norwich appellate outcome is a negative data point for Bausch’s patent position, but it should not be treated as a complete invalidation of all Xifaxan protection.[3]

What generic launch risks existed for Bausch?

The primary launch risks were timing, patent scope, and substitution.

A generic could launch through one of four broad pathways:

1. A court ruling of invalidity or noninfringement.
2. A settlement license before all listed patents expired.
3. Approval with a carved-out label that excluded patented uses.
4. An authorized-generic arrangement involving Bausch or an affiliate.

The financial exposure was substantial because Xifaxan is one of Bausch’s largest products. Bausch reported Xifaxan net sales of approximately $1.1 billion in 2023, making the product a major contributor to the company’s revenue base.[5] Generic entry would likely pressure price, market share, and gross margin. The impact would depend on the number of approved competitors, the timing of launch, and whether Bausch introduced or licensed an authorized generic.

What is the biosimilar risk for Xifaxan?

There is no biosimilar pathway for Xifaxan. Rifaximin is a chemically synthesized small-molecule drug, so generic applicants use the ANDA pathway rather than the Biologics Price Competition and Innovation Act pathway.

The relevant competitive risks are:

• Abbreviated new drug applications.
• Paragraph IV patent challenges.
• Section viii label carve-outs.
• Authorized generics.
• Formulation and manufacturing workarounds.

What are the licensing and settlement implications?

The Glenmark resolution removed the immediate risk of a public merits judgment, but it did not disclose the commercial outcome. A confidential settlement can be more important to generic-entry timing than the nominal expiration dates of the asserted patents.

For diligence purposes, the key settlement questions are:

• Whether Glenmark received an entry license.
• Whether the license date precedes the last relevant patent expiry.
• Whether the agreement permits an authorized generic.
• Whether Glenmark’s launch is limited to IBS-D or another indication.
• Whether the agreement includes volume, supply, or distribution restrictions.
• Whether the settlement was submitted for FTC and Department of Justice review under the MMA filing requirements.

Without public settlement terms, Glenmark’s precise launch date and market-share potential cannot be established from the case caption alone.

Key Takeaways

• Bausch sued Glenmark in November 2019 over a Paragraph IV challenge involving generic rifaximin 550 mg tablets.
• The dispute concerned Xifaxan’s product and method-of-use patent estate, including U.S. Patent Nos. 8,309,569 and 9,421,195.
• The case ended without a reported public merits judgment.
• The material settlement terms, including any licensed generic-entry date, were not publicly disclosed.
• The ’195 patent later suffered an adverse validity ruling in separate Norwich litigation, weakening one component of Bausch’s broader estate.
• Xifaxan is a small-molecule drug, so biosimilar risk is not applicable.
• Bausch’s commercial exposure is substantial because Xifaxan generates roughly $1 billion or more in annual revenue.
• Generic entry depends on the settlement, remaining Orange Book patents, FDA approval, and the scope of any permitted label.

FAQs

Did Glenmark receive FDA approval for generic rifaximin?

The case docket alone does not establish the date or status of any final FDA approval for Glenmark’s ANDA. FDA approval and commercial launch are separate events from settlement resolution.

Is Xifaxan protected by a composition-of-matter patent?

The principal commercial protection litigated for Xifaxan has involved product, formulation, solid-state, and method-of-use patents. The 2019 Glenmark dispute was not principally a conventional new-chemical-entity patent case.

Can a generic launch Xifaxan before every Orange Book patent expires?

Yes, if the applicant obtains a license, wins a noninfringement or invalidity ruling, uses a lawful label carve-out, or enters through an authorized-generic arrangement.

Did the Norwich decision invalidate all Xifaxan patents?

No. The Norwich appellate decision affected challenged claims of the ’195 patent. It did not automatically invalidate every patent listed for Xifaxan or eliminate other formulation, product, process, or use claims.[3]

Why is the Glenmark settlement commercially important if its terms are confidential?

The settlement may determine when Glenmark can enter the market and whether it can compete on all Xifaxan indications. That timing can materially affect Bausch’s revenue and margin exposure even without a public judicial opinion.

References

1. Bausch Health Ireland Limited v. Glenmark Pharmaceuticals Limited, No. 1:19-cv-12045, U.S. District Court for the District of Massachusetts, docket record (2019-2022).

2. Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j); 35 U.S.C. § 271(e).

3. Salix Pharmaceuticals, Ltd. v. Norwich Pharmaceuticals Inc., 98 F.4th 1050 (Fed. Cir. 2024).

4. Federal Trade Commission, Agreements Filed Under the Medicare Prescription Drug, Improvement, and Modernization Act of 2003, FTC Act § 1112 reporting materials.

5. Bausch Health Companies Inc. Annual Report on Form 10-K for the fiscal year ended December 31, 2023.