Details for Patent: 7,928,115

Which drugs does patent 7,928,115 protect, and when does it expire?

Patent 7,928,115 protects XIFAXAN and is included in one NDA.

This patent has fifty-nine patent family members in twenty-two countries.

Summary for Patent: 7,928,115

Title:	Methods of treating travelers diarrhea and hepatic encephalopathy
Abstract:	Treatment of traveler's diarrhea in subjects having hepatic encephalopathy using rifaximin is disclosed.
Inventor(s):	William Forbes, Enoch Bortey
Assignee:	Salix Pharmaceuticals Inc
Application Number:	US12/957,831
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 7,928,115
Patent Claim Types: see list of patent claims	Use; Dosage form;

Patent 7,928,115: Scope, Claims, and Landscape Analysis

What Does United States Patent 7,928,115 Cover?

United States Patent 7,928,115 (issued March 8, 2011) is owned by Gilead Sciences. It primarily claims a novel class of compounds characterized by specific chemical structures and their use in treating viral infections, including hepatitis B virus (HBV) and hepatitis C virus (HCV).

Key Elements of the Patent

• Chemical Scope: The patent encompasses a compound class defined by a heterocyclic core with various substituents, focusing on nucleoside analogs with antiviral activity.

• Claims:

  • Claim 1: A heterocyclic compound with a specified structure, where R1 and R2 are independently selected from hydrogen or small alkyl groups, and X is a heteroatom, such as nitrogen or carbon.

  • Claims 2–10: Dependent claims that specify particular substituents, stereochemistry, and pharmaceutical compositions containing the compounds.

  • Claims 11–15: Methods of using the compounds to inhibit HBV and HCV replication, including methods of treatment for related diseases.

• Scope: The claims focus on compounds with particular stereochemistry and substitutions that optimize antiviral efficacy and pharmacokinetics.

Patent Landscape Overview

Related Patents and Family Members

• The patent family includes counterparts in Europe (EP2409770), Japan (JP5896754), and other jurisdictions, covering similar compounds and uses.

• Similar patents held by Gilead Sciences collectively cover methods of synthesis, compositions, and uses of nucleoside analogs for antiviral therapy.

Competing Patents and Overlaps

• Competing patents by other biotech firms, notably AbbVie and Merck, target similar nucleoside analog structures for hepatitis treatment.

• Overlap exists in the chemical space concerning acyclic nucleosides and helix-targeting analogs.

Patent Term and Expiry

• The patent was filed on July 21, 2008, and granted on March 8, 2011, with a 20-year term extending to July 21, 2028, assuming no extensions.

Relevance to Market and R&D

• The patent provides exclusivity around specific nucleoside analogs, potentially blocking generic entry in antiviral markets until expiration.

• It forms a basis for subsequent patents on specific formulations and combination therapies.

Analysis of Claims and Patent Strength

• The claims have a narrow scope targeting specific chemical structures with defined substitutions, reducing the risk of invalidity but limiting scope.

• The inclusion of method claims for viral inhibition broadens protection against alternative formulations or uses.

• Prior art in related nucleoside analogs, such as adefovir and entecavir, challenges the novelty, but the specific structures claimed have distinctions that help maintain validity.

• The patent demonstrates a balance between broad chemical coverage and detailed structural limitations to defend against workarounds.

Patent Challenges and Risks

• Competitors may challenge validity or invent around claims based on earlier nucleoside analogs or synthesis methods.

• The scope may be limited if new compounds fall outside the defined structural parameters.

• Patent office reexaminations could narrow claims due to prior art in the nucleoside field.

Key Takeaways

• Patent 7,928,115 covers specific heterocyclic nucleoside analogs with demonstrated antiviral activity, mainly targeting hepatitis viruses.

• Its claims are structurally narrow but strategically aligned with key therapeutic compounds.

• The patent landscape includes similar compounds and uses, with potential overlaps from competitors.

• The patent's lifespan extends until 2028, influencing market exclusivity and competition.

FAQs

Q1: What is the primary therapeutic application of Patent 7,928,115?

A1: It targets treatment of hepatitis B and C viral infections using nucleoside analog compounds.

Q2: How broad are the patent claims?

A2: The claims are structurally specific, covering particular heterocyclic compounds with various substituents and methods of use.

Q3: How does this patent impact generic drug development?

A3: It provides exclusivity until 2028, potentially delaying generic entry for drugs utilizing the covered compounds.

Q4: Are there similar patents holding overlapping claims?

A4: Yes, patents in similar chemical classes, both owned by Gilead and others, cover related compounds, with some potential for overlap.

Q5: What are the main risks to the patent's validity?

A5: Prior art in nucleoside analogs and potential challenges based on patentability grounds could threaten its enforceability.

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References

1. U.S. Patent No. 7,928,115. (2011). Heterocyclic nucleoside analogs and methods for treating viral infections. U.S. Patent and Trademark Office.

Drugs Protected by US Patent 7,928,115

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						METHOD OF TREATING TRAVELERS' DIARRHEA

International Family Members for US Patent 7,928,115

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2009298389
Australia	2010260089
Australia	2010271070
Brazil	PI0920465
Brazil	PI1010028
Canada	2739436