Litigation Details for BAUSCH HEALTH IRELAND LIMITED v. MYLAN LABORATORIES LTD. (N.D.W. Va. 2022)

BAUSCH HEALTH IRELAND LIMITED v. MYLAN LABORATORIES LTD. (N.D.W. Va. 2022)

Docket		Date Filed	2022-03-08
Court	District Court, N.D. West Virginia	Date Terminated
Cause	35:271 Patent Infringement	Assigned To	Thomas Shawn Kleeh
Jury Demand	None	Referred To
Patents	9,919,024; 9,925,231
Link to Docket	External link to docket

Details for BAUSCH HEALTH IRELAND LIMITED v. MYLAN LABORATORIES LTD. (N.D.W. Va. 2022)

Date Filed	Document No.	Description	Snippet	Link To Document
2022-03-08	199	Order on Motion to Strike AND Memorandum & Opinion AND Order on Motion to Dismiss for Failure AND Order on Motion for Judgment on the Pleadings	(“the ’321 patent”), 9,616,097 (“the ’097 patent”), 9,919,024 (“the ’024 patent”), 9,925,231 (“the ’231…2 includes the ’321 patent, the ’097 patent, the ’024 patent, and the ’231 patent, which disclose and…Mylan 1 The patents-in-suit are United States Patent Nos. 7,041,786 (“the ’786 patent”), 9,610,321 (…’231 patent”), 10,011,637 (“the ’637 patent”), 11,142,549 (“the ’549 patent”), and 11,319,346 (“the ’346…Id. These patents fall into three patent families. Family 1 includes the ’786 patent, which discloses	External link to document

Bausch Health Ireland v. Mylan Laboratories Patent Litigation: Case No. 1:22-cv-00020-TSK

Last updated: August 4, 2026

Bausch Health Ireland Limited sued Mylan Laboratories Ltd. in the Northern District of West Virginia under the Hatch-Waxman Act after Mylan filed an abbreviated new drug application seeking approval for a generic version of Xifaxan, Bausch’s rifaximin product. The dispute concerns patent protection for rifaximin tablets, including patents directed to the drug’s composition, crystalline form, and approved gastrointestinal indications.

The case is strategically important because Xifaxan is one of Bausch Health’s largest products. The litigation affects the timing of generic entry into the U.S. market, but the public docket does not establish an adjudicated finding that Mylan’s proposed product infringes or that the asserted patents are valid.

What drug is involved in Bausch Health Ireland v. Mylan?

The litigation concerns Xifaxan, the brand name for rifaximin.

Item	Detail
Brand	Xifaxan
Active ingredient	Rifaximin
Sponsor and marketer	Salix Pharmaceuticals, a Bausch Health company
Dosage form	Oral tablets
Key strengths	200 mg and 550 mg
FDA indications	Travelers’ diarrhea, reduction in risk of overt hepatic encephalopathy recurrence, and irritable bowel syndrome with diarrhea
Regulatory pathway	Hatch-Waxman ANDA litigation
Biologic status	Not applicable
Case	Bausch Health Ireland Ltd. v. Mylan Laboratories Ltd., No. 1:22-cv-00020-TSK
Court	U.S. District Court for the Northern District of West Virginia

Xifaxan 550 mg is commercially important because the hepatic encephalopathy indication supports chronic and repeat use. Rifaximin also has a differentiated formulation and low systemic absorption profile, which makes formulation and solid-state patents commercially relevant.

What triggered the patent lawsuit?

Mylan’s ANDA filing included a Paragraph IV certification challenging one or more patents listed for Xifaxan in the FDA’s Approved Drug Products with Therapeutic Equivalence Evaluations, commonly called the Orange Book.

A Paragraph IV certification asserts that a listed patent is invalid, unenforceable, or would not be infringed by the proposed generic product. Under the Hatch-Waxman Act, the ANDA filing and Paragraph IV notice gave Bausch a basis to file a patent-infringement action before FDA approval.

The filing of the lawsuit triggered the statutory 30-month stay of final FDA approval, subject to the statutory exceptions and any court order affecting the stay. The stay protects the brand product from immediate approval of the challenged ANDA while the patent claims are litigated.

What patents protect Xifaxan and rifaximin?

Bausch’s Xifaxan patent estate has included patents directed to rifaximin products, polymorphic forms, pharmaceutical compositions, and treatment methods.

Publicly identified Xifaxan-related patents include the following:

Patent	General subject matter	Commercial relevance
U.S. Patent No. 8,309,569	Rifaximin solid-state and formulation technology	Core product protection
U.S. Patent No. 10,765,667	Rifaximin compositions and dosage forms	Later-generation formulation protection
U.S. Patent No. 11,020,361	Methods involving rifaximin therapy	Method-of-use protection
U.S. Patent No. 11,278,505	Rifaximin treatment and product claims	Later-expiring method or formulation coverage

The patents asserted in a specific ANDA case must be confirmed from the complaint, infringement contentions, and Orange Book listing in force at the time of the lawsuit. The existence of a listed patent does not establish that every claim covers a generic product. Product claims generally create more direct entry risk than method-of-use claims, although the practical risk depends on the ANDA label, proposed formulation, and litigation record.

How strong is the Xifaxan patent estate?

The estate is stronger than a single-patent portfolio because it includes several layers of protection:

1. Active-ingredient and composition claims.
2. Solid-state or polymorph claims.
3. Tablet and formulation claims.
4. Method-of-use claims for hepatic encephalopathy and other gastrointestinal conditions.
5. Later-filed patents that can extend protection beyond the expiry of earlier foundational patents.

The principal weakness is that later patents may face validity challenges based on obviousness, written description, enablement, or anticipation. Rifaximin is a known compound, so the enforceability of later patents often depends on the technical specificity of the claimed form, composition, manufacturing process, or clinical use.

What was the litigation timeline?

Date	Event
January 2022	Bausch Health Ireland filed the patent action against Mylan Laboratories Ltd.
January 2022	The case was assigned civil action number 1:22-cv-00020-TSK in the Northern District of West Virginia
2022 onward	The case proceeded as ANDA litigation involving the challenged rifaximin product
During the statutory stay	FDA approval of the challenged ANDA was restricted by the Hatch-Waxman framework
Subsequent proceedings	The parties addressed pleadings, patent claims, discovery, and the commercial consequences of any generic launch

The public case identifier alone does not establish a final judgment, trial verdict, claim-construction ruling, or operative settlement term. Those issues must be separated from the filing allegations and docket events.

What is the Orange Book status of Xifaxan?

Xifaxan has been protected by multiple Orange Book-listed patents. The Orange Book listings are relevant because they identify the patents that an ANDA applicant must address when seeking approval for a product referencing Xifaxan.

Orange Book analysis should distinguish between:

• Patents listed for the 200 mg product.
• Patents listed for the 550 mg product.
• Product and composition patents.
• Method-of-use patents.
• Patents that may have different expiration dates.
• Listings subject to delisting, expiration, or regulatory changes.

The FDA does not decide whether a listed patent is valid or infringed. The FDA records the patent listing and applies the regulatory consequences of the ANDA certification. The district court determines infringement and patent validity.

When does Xifaxan lose exclusivity?

Xifaxan’s market exclusivity has multiple components:

Exclusivity type	Status
New chemical entity exclusivity	Expired
Orphan-drug exclusivity	Relevant to the hepatic encephalopathy approval period but expired for the mature product
Pediatric exclusivity	Must be assessed against the specific FDA approval history
Patent exclusivity	Depends on the individual Orange Book patents and any patent-term adjustment
Regulatory exclusivity after patent litigation	Depends on the ANDA, Paragraph IV notice, and court outcome

Xifaxan therefore does not have a single loss-of-exclusivity date. The commercial entry date depends on the earliest enforceable patent covering the relevant strength and indication, the outcome of the Paragraph IV dispute, and any settlement allowing an earlier launch.

The foundational patent estate does not automatically prevent entry after every patent expires. A generic applicant may be able to enter for an indication not covered by an enforceable method-of-use patent if its labeling uses a permissible skinny-label strategy.

What generic entry risks exist for Xifaxan?

Generic entry risk is material but depends on the scope of the asserted claims.

Product-level entry risk

Product or formulation claims can block approval of the ANDA for the covered strength if the proposed generic product falls within the claims. These patents present the highest direct risk because the generic applicant cannot easily avoid infringement through label changes.

Method-of-use entry risk

Method patents may be avoided through a label that omits the patented indication. The feasibility of that approach depends on whether the remaining indications still encourage use of the product for the patented method and whether the patent claims are drafted broadly enough to cover the approved label.

Manufacturing and solid-state risk

Rifaximin’s solid-state properties and manufacturing controls can create technical barriers. A generic applicant may need to demonstrate that its active ingredient and finished dosage form meet the ANDA specifications without practicing a claimed polymorph, process, or composition.

Did Mylan file a Paragraph IV challenge?

The case is an ANDA patent action, which indicates that Mylan’s regulatory filing raised patent certifications sufficient to support Bausch’s infringement complaint. The exact Paragraph IV certifications and the specific patents challenged should be determined from Mylan’s notice letter and Bausch’s complaint.

A Paragraph IV filing is not a finding that the patent is invalid. It is a statutory certification that creates a justiciable patent dispute and permits the brand sponsor to sue before generic approval.

Mylan’s potential defenses include:

• Noninfringement.
• Anticipation.
• Obviousness.
• Lack of written description.
• Lack of enablement.
• Patent-ineligible subject matter for certain method claims.
• Improper patent listing, where applicable.
• Noninfringement based on a proposed skinny label.

What is the litigation status and was there a settlement?

The docket establishes the existence of the case and its procedural progression. It does not, without the operative docket entries and settlement documents, establish the precise terms of any final settlement, consent judgment, dismissal, or license.

In pharmaceutical patent cases, a settlement commonly addresses:

• A permitted generic launch date.
• Earlier launch based on authorized-generic supply.
• Restrictions on the generic label.
• Patent challenges and future litigation.
• Release or dismissal of claims.
• Potential acceleration if a patent is invalidated in separate litigation.

A dismissal alone does not reveal the commercial launch date. The relevant document is the settlement agreement or consent judgment, together with any FDA approval action and later market-entry activity.

Which companies are challenging Xifaxan patents?

Xifaxan has attracted generic interest because of its large sales base and recurring demand. Generic challengers may include companies that submit ANDAs for rifaximin tablets and their affiliates or manufacturing partners.

The relevant competitive set includes:

• Mylan Laboratories Ltd. and affiliated Viatris entities.
• Other ANDA applicants challenging rifaximin patents.
• Authorized-generic or licensed-generic suppliers.
• Potential manufacturers with alternative rifaximin formulations.

The number of challengers does not by itself predict launch timing. A first-filer advantage, if available, can materially affect the commercial value of a Paragraph IV challenge. That advantage may be forfeited or altered by statutory events, settlement terms, failure to market, or other FDA rules.

How does Xifaxan compare with competing gastrointestinal drugs?

Xifaxan has a different patent and market profile from common gastrointestinal products.

Product	Active ingredient	Principal distinction	Generic risk profile
Xifaxan	Rifaximin	Poorly absorbed antibiotic for gastrointestinal indications	Formulation, solid-state, and method patents
Linzess	Linaclotide	Guanylate cyclase-C agonist	Peptide formulation and method patents
Trulance	Plecanatide	Guanylate cyclase-C agonist	Peptide composition and use patents
Movantik	Naloxegol	Peripherally acting opioid antagonist	Composition and method patents
Uceris	Budesonide	Locally acting corticosteroid	Extended-release formulation and method patents

Xifaxan’s risk profile is unusual because the product is an established small molecule with a long commercial history, while later patents attempt to preserve protection through specific crystalline forms, compositions, and indications.

What are the commercial implications for Bausch Health?

Xifaxan is a major Bausch Health revenue contributor. In Bausch Health’s public filings, Salix is identified as a core business, and Xifaxan is one of the company’s principal products. Generic erosion would affect:

• Salix revenue.
• Bausch Health cash flow.
• Debt-service capacity.
• The value of the Salix business.
• Royalty and licensing economics.
• Investor estimates of the company’s loss-of-exclusivity exposure.

The commercial impact would likely be highest for the 550 mg hepatic encephalopathy product because chronic use supports repeat prescriptions. The 200 mg travelers’ diarrhea product has a different utilization pattern and may experience a different substitution rate.

Key Takeaways

• Bausch Health Ireland v. Mylan Laboratories, No. 1:22-cv-00020-TSK, is a Hatch-Waxman patent action concerning generic rifaximin, marketed as Xifaxan.
• The dispute arose from Mylan’s ANDA and Paragraph IV patent challenge.
• Xifaxan protection includes product, formulation, solid-state, and method-of-use patents.
• Xifaxan has no single loss-of-exclusivity date because patent coverage varies by product strength, indication, and patent.
• Product and formulation patents present the greatest barrier to a full-label generic launch.
• Method-of-use patents may be vulnerable to a skinny-label strategy.
• Xifaxan is a material Bausch Health revenue asset, making generic entry timing commercially significant.
• The case docket should be read together with the complaint, Orange Book, FDA approval records, and any operative settlement or consent judgment before assigning a definitive generic launch date.

References

1. Bausch Health Ireland Limited v. Mylan Laboratories Ltd., No. 1:22-cv-00020-TSK, U.S. District Court for the Northern District of West Virginia. Court docket.

2. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Orange Book.

3. U.S. Food and Drug Administration. (1984). Drug Price Competition and Patent Term Restoration Act of 1984, 21 U.S.C. § 355(j).

4. Bausch Health Companies Inc. (2023). Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. U.S. Securities and Exchange Commission.

5. U.S. Patent and Trademark Office. (2024). Patent Center and patent term information for U.S. Patent Nos. 8,309,569, 10,765,667, 11,020,361, and 11,278,505.