Details for Patent: 10,765,667

Which drugs does patent 10,765,667 protect, and when does it expire?

Patent 10,765,667 protects XIFAXAN and is included in one NDA.

This patent has thirty patent family members in fifteen countries.

Summary for Patent: 10,765,667

Title:	Methods for treating irritable bowel syndrome (IBS)
Abstract:	The present invention provides new methods and kits for treating IBS; treating IBS in females; treating IBS in older subjects; and treating IBS in non-white subjects.
Inventor(s):	Forbes; William (Raleigh, NC), Bortey; Enoch (Chapel Hill, NC)
Assignee:	Salix Pharmaceuticals, Inc. (Bridgewater, NJ)
Application Number:	16/738,392
Patent Claim Types: see list of patent claims	Use;

United States Patent 10,765,667: A Detailed Analysis of Scope, Claims, and Patent Landscape

Introduction

The United States Patent 10,765,667, hereafter referred to as the '667 patent, is one of the key patents in the ongoing litigation between Salix Pharmaceuticals and Norwich Pharmaceuticals. This patent is part of a broader portfolio related to the drug Xifaxan® (rifaximin), which is used to treat various gastrointestinal conditions. Here, we will delve into the scope, claims, and the surrounding patent landscape of the '667 patent.

Background of Xifaxan® and Rifaximin

Xifaxan® (rifaximin) is a rifamycin antibiotic that is primarily used to treat irritable bowel syndrome with diarrhea (IBS-D) and hepatic encephalopathy (HE). The drug has been a significant commercial success, and its patent protection has been a focal point of litigation involving generic manufacturers like Norwich Pharmaceuticals[2][5].

Scope of the '667 Patent

The '667 patent is directed to methods of treating IBS-D using a specific dosing regimen of rifaximin. Specifically, it claims the administration of 550 mg of rifaximin three times a day (totaling 1,650 mg per day) for a period of 14 days. This dosing regimen is critical for the effective treatment of IBS-D symptoms[4][5].

Claims of the '667 Patent

The claims of the '667 patent are centered around the method of treatment for IBS-D using the aforementioned dosing regimen. Here are some key aspects of the claims:

• Dosing Regimen: The patent specifies the administration of 550 mg of rifaximin three times a day for 14 days.
• Treatment of IBS-D: The claims are limited to the treatment of irritable bowel syndrome with diarrhea.
• Formulation: The patent covers the use of rifaximin in its specified form and dosage[4][5].

Patent Landscape: Related Patents

The '667 patent is part of a larger patent portfolio that includes several other patents related to Xifaxan®. Here are some of the key related patents:

• Polymorph Patents: U.S. Patents 7,612,199 and 7,902,206 cover specific polymorphic forms of rifaximin, which are crucial for the drug's stability and efficacy[2][5].
• HE Patents: U.S. Patents 8,624,573, 9,421,195, and 10,335,397 are directed to the treatment of hepatic encephalopathy using rifaximin[2][5].
• Other IBS-D Patents: U.S. Patent 8,309,569 also covers methods of treating IBS-D, similar to the '667 patent but potentially with different aspects or claims[4][5].

Litigation and Validity

The '667 patent has been at the center of a significant litigation between Salix Pharmaceuticals and Norwich Pharmaceuticals. Here are the key points from the litigation:

• District Court Ruling: The United States District Court for the District of Delaware held that the '667 patent, along with other IBS-D and polymorph patents, was invalid as obvious. However, it found that the HE patents were valid and infringed by Norwich[1][5].
• Federal Circuit Appeal: Salix appealed the invalidity holdings, but the Federal Circuit affirmed the district court's decision regarding the invalidity of the '667 and other related patents. However, it also affirmed the denial of Norwich’s motion to modify the judgment, preventing Norwich from launching its generic product until the HE patents expire in 2029[1][5].

Clinical Trials and Disclosure

The development and patenting of the '667 patent involved extensive clinical trials to establish the efficacy and safety of the specified dosing regimen. These trials are federally mandated to be disclosed on ClinicalTrials.gov, which can sometimes create challenges for patent applicants due to the public nature of these disclosures and the rules under the America Invents Act[4].

Impact on Generic Manufacturers

The invalidation of the '667 patent, along with other IBS-D and polymorph patents, would typically allow generic manufacturers like Norwich to enter the market. However, the affirmation of the HE patents and the denial of Norwich’s motion to modify the judgment have delayed their entry until the HE patents expire in 2029. This highlights the complex interplay between different patents within a portfolio and their impact on market competition[1][5].

Conclusion

The United States Patent 10,765,667 is a critical component of Salix Pharmaceuticals' patent portfolio for Xifaxan®. While it has been held invalid as obvious, the broader patent landscape and ongoing litigation continue to shape the market dynamics for this drug. Understanding the scope, claims, and litigation history of this patent is essential for both innovators and generic manufacturers navigating the complex world of pharmaceutical patents.

Key Takeaways

• Scope and Claims: The '667 patent covers a specific dosing regimen for treating IBS-D with rifaximin.
• Related Patents: Part of a larger portfolio including polymorph and HE patents.
• Litigation: Held invalid as obvious, but HE patents remain valid and infringed.
• Impact on Generic Manufacturers: Delayed market entry due to valid HE patents.
• Clinical Trials and Disclosure: Federally mandated disclosures can impact patent strategy.

FAQs

1. What is the '667 patent directed to? The '667 patent is directed to methods of treating irritable bowel syndrome with diarrhea (IBS-D) using a specific dosing regimen of rifaximin.

2. What is the dosing regimen specified in the '667 patent? The patent specifies the administration of 550 mg of rifaximin three times a day (totaling 1,650 mg per day) for a period of 14 days.

3. Why was the '667 patent held invalid? The '667 patent was held invalid as obvious by the district court and affirmed by the Federal Circuit.

4. What other patents are related to the '667 patent? The related patents include polymorph patents (U.S. Patents 7,612,199 and 7,902,206) and HE patents (U.S. Patents 8,624,573, 9,421,195, and 10,335,397).

5. When can generic manufacturers enter the market for Xifaxan®? Generic manufacturers can enter the market after the HE patents expire in 2029, following the denial of Norwich’s motion to modify the judgment.

Sources

1. CAFC Panel Splits on Reasonable Expectation of Success Analysis - IP Watchdog
2. Salix Pharms., Ltd. v. Norwich Pharms., Inc. - Robins Kaplan LLP
3. Rifaximin Tablets - FDA
4. Federal Court Invalidates Dosing Patent Based On Clinical Trials - JD Supra
5. Salix Pharms., Ltd. v. Norwich Pharms. Inc. - JD Supra

Drugs Protected by US Patent 10,765,667

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 Pharms	XIFAXAN	rifaximin	TABLET;ORAL	021361-002	Mar 24, 2010		RX	Yes	Yes	10,765,667					TREATMENT OF IRRITABLE BOWEL SYNDROME WITH DIARRHEA (IBS-D) IN ADULTS 65 YEARS OF AGE OR OLDER
Salix Pharms	XIFAXAN	rifaximin	TABLET;ORAL	021361-002	Mar 24, 2010		RX	Yes	Yes	10,765,667					TREATMENT OF IRRITABLE BOWEL SYNDROME WITH DIARRHEA (IBS-D) IN ADULTS 65 YEARS OF AGE OR OLDER AND SYMPTOMS THEREOF

International Family Members for US Patent 10,765,667

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2009219240
Australia	2010292043
Brazil	112012005627