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Last Updated: December 23, 2024

Details for Patent: 8,158,644


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Which drugs does patent 8,158,644 protect, and when does it expire?

Patent 8,158,644 protects XIFAXAN and is included in one NDA.

This patent has ninety-three patent family members in thirty-seven countries.

Summary for Patent: 8,158,644
Title:Pharmaceutical compositions comprising polymorphic forms .alpha., .beta., and .gamma. of rifaximin
Abstract: Crystalline polymorphous forms of rifaximin (INN), referred to as rifaximin .alpha. and rifaximin .beta., and a poorly crystalline form referred to as rifaximin .gamma., useful in the production of medicaments containing rifaximin for oral and topical use and obtained by means of a crystallization process carried out by hot-dissolving the raw rifaximin in ethyl alcohol and by causing the crystallization of the product by addition of water at a fixed temperature and for a fixed period of time, followed by a drying under controlled conditions until reaching a precise water content in the end product, are the object of the invention.
Inventor(s): Viscomi; Giuseppe Claudio (Bologna, IT), Campana; Manuela (Bologna, IT), Braga; Dario (Bologna, IT), Confortini; Donatella (Bologna, IT), Cannata; Vincenzo (Bologna, IT), Righi; Paolo (Bologna, IT), Rosini; Goffredo (Bologna, IT)
Assignee: Alfa Wassermann, S.p.A. (Bologna, IT)
Application Number:13/041,347
Patent Litigation and PTAB cases: See patent lawsuits and PTAB cases for patent 8,158,644
Patent Claim Types:
see list of patent claims
Composition; Dosage form;
Patent landscape, scope, and claims:

United States Patent 8,158,644: A Detailed Analysis of Scope, Claims, and Patent Landscape

Introduction

The United States Patent 8,158,644, hereafter referred to as the '644 patent, is part of a broader portfolio of patents related to the drug Xifaxan® (rifaximin), which is used for various gastrointestinal conditions. This analysis will delve into the scope, claims, and the patent landscape surrounding this patent.

Background of the Patent

The '644 patent is one of several patents held by Salix Pharmaceuticals, Inc., and later acquired by Bausch Health Companies, Inc., in association with Alfasigma. These patents are crucial for the production, formulation, and use of rifaximin, a rifamycin antibiotic used primarily for treating conditions such as irritable bowel syndrome with diarrhea (IBS-D) and reducing the risk of overt hepatic encephalopathy (HE) recurrence in adults[2][5].

Scope of the Patent

The '644 patent falls under the category of pharmaceutical patents, specifically focusing on the formulation and composition of rifaximin. The scope of this patent includes:

Claims

The patent includes multiple claims that define the specific aspects of the invention. These claims typically cover:

  • The composition of rifaximin, including its polymorphic forms and mixtures.
  • The method of preparation and formulation of the drug.
  • The dosage forms, such as tablets or capsules, and their respective coatings.
  • The therapeutic uses of the drug, including its application in treating IBS-D and HE[4].

Independent and Dependent Claims

Independent claims in the '644 patent outline the broadest scope of the invention, while dependent claims narrow down the scope by adding additional limitations. For instance, an independent claim might describe a pharmaceutical composition containing rifaximin, while a dependent claim might specify the exact ratio of polymorphic forms or the presence of particular excipients[3].

Patent Claims Analysis

Claim Length and Count

Research has shown that the length and count of independent claims can be indicative of patent scope. Narrower claims, as measured by shorter lengths and fewer counts, are often associated with a higher probability of grant and a shorter examination process. The '644 patent, like others in its category, would have undergone a rigorous examination process to ensure that its claims are clear, specific, and not overly broad[3].

Claim Clarity and Validity

The clarity and validity of patent claims are critical. The Federal Circuit has emphasized the importance of understanding claim terms within the context of the entire patent specification. This includes considering intrinsic evidence (the claims, specification, and file history) and extrinsic evidence (expert testimony, etc.) to determine the meaning of claim terms[4].

Patent Landscape

Related Patents

The '644 patent is part of a large family of patents related to rifaximin. Other patents in this family include U.S. Patent Nos. 7,902,206, 7,906,542, 8,193,196, 8,518,949, and 8,741,904, among others. These patents collectively cover various aspects of rifaximin production, formulation, and use, ensuring comprehensive protection for the drug[2][5].

Litigation and Enforcement

The '644 patent has been involved in several litigation cases, particularly in the context of generic drug manufacturers seeking to produce rifaximin. These cases often revolve around issues of patent infringement, validity, and enforceability. For instance, Salix Pharmaceuticals and Bausch Health have taken legal action against generic manufacturers to protect their patent rights[2][5].

Impact on Innovation and Competition

The scope and claims of the '644 patent, along with other related patents, play a significant role in the pharmaceutical industry. These patents can influence innovation by setting boundaries for what can be developed and marketed by other companies. While they protect the intellectual property of the patent holders, they can also limit competition and potentially delay the entry of generic drugs into the market[3].

Regulatory Compliance

The manufacturing and formulation methods described in the '644 patent must comply with regulatory standards. Regulatory bodies require that the production processes be standardized and controlled to ensure homogeneous and safe results in terms of polymorphism of the production batches. This is crucial for maintaining the quality and efficacy of the drug[1].

Key Takeaways

  • The '644 patent is part of a comprehensive patent portfolio related to rifaximin.
  • The patent covers specific compositions, formulations, and therapeutic uses of rifaximin.
  • Claim clarity and validity are crucial, with a focus on both intrinsic and extrinsic evidence.
  • The patent landscape includes numerous related patents and ongoing litigation to protect intellectual property.
  • Regulatory compliance is essential for maintaining drug quality and safety.

FAQs

What is the primary use of the drug covered by the '644 patent?

The primary use of the drug covered by the '644 patent is for treating irritable bowel syndrome with diarrhea (IBS-D) and reducing the risk of overt hepatic encephalopathy (HE) recurrence in adults.

How does the '644 patent fit into the broader patent landscape for rifaximin?

The '644 patent is one of several patents held by Salix Pharmaceuticals and Bausch Health, collectively covering various aspects of rifaximin production, formulation, and use.

What are the key factors in determining the scope of patent claims like those in the '644 patent?

Key factors include the length and count of independent claims, the clarity and specificity of claim terms, and the context provided by the patent specification and file history.

How do patents like the '644 patent impact innovation and competition in the pharmaceutical industry?

These patents protect intellectual property but can also limit competition and delay the entry of generic drugs into the market, influencing the pace of innovation.

What regulatory standards must the manufacturing methods described in the '644 patent comply with?

The manufacturing methods must comply with standards requiring standardized and controlled processes to ensure homogeneous and safe results in terms of polymorphism of the production batches.

Cited Sources

  1. United States Patent - googleapis.com
    • Production of medicinal preparations containing rifaximin for oral and topical use.
  2. Case 1:20-cv-00430-RGA Document 59 Filed 11/13/20
    • Litigation involving Xifaxan® patents.
  3. Patent Claims and Patent Scope - Hoover Institution
    • Metrics for measuring patent scope based on claim language.
  4. Case 2:21-cv-19293-ES-JRA Document 210 Filed 01/26/24
    • Claim construction and interpretation in patent litigation.
  5. in the united states district court for the district of delaware salix ...
    • Litigation involving infringement of Xifaxan® patents.

More… ↓

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Drugs Protected by US Patent 8,158,644

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 021361-001 May 25, 2004 RX Yes Yes 8,158,644 ⤷  Subscribe Y ⤷  Subscribe
Salix Pharms XIFAXAN rifaximin TABLET;ORAL 021361-002 Mar 24, 2010 RX Yes Yes 8,158,644 ⤷  Subscribe Y ⤷  Subscribe
>Applicant >Tradename >Generic Name >Dosage >NDA >Approval Date >TE >Type >RLD >RS >Patent No. >Patent Expiration >Product >Substance >Delist Req. >Patented / Exclusive Use >Submissiondate

Foreign Priority and PCT Information for Patent: 8,158,644

Foriegn Application Priority Data
Foreign Country Foreign Patent Number Foreign Patent Date
ItalyM12003A002144Nov 07, 2003

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