United States Patent 8,735,372: A Detailed Analysis of Scope, Claims, and Patent Landscape
Introduction
United States Patent 8,735,372, assigned to Gilead Sciences, Inc., is a significant patent in the realm of hepatitis C treatments, particularly concerning the drug sofosbuvir. This patent is part of a broader patent landscape that has been the subject of various legal and scientific analyses.
Patent Overview
Patent Number and Type
The patent number is 8,735,372, and it is classified as a prodrug patent. Prodrugs are inactive compounds that undergo metabolic conversion in the body to release the active drug[4].
Family and Expiry
This patent belongs to the Sofia family and is set to expire on March 21, 2028, which is three years past the expiry date of the base patent for sofosbuvir[2].
Claims and Scope
Prodrug Claims
The patent claims phosphoramidate prodrugs of nucleoside derivatives, specifically designed for the treatment of viral infections in mammals. These prodrugs help in the metabolic activation of the base compound once it enters the body. The claims include various salts, hydrates, solvates, and stereoisomers of these prodrugs, as well as processes for their preparation[5].
Specific Compounds
The patent describes the use of these prodrugs in conjunction with the nucleoside compound sofosbuvir, which is the backbone of Gilead’s hepatitis C treatments. The prodrugs are designed to enhance the bioavailability and efficacy of sofosbuvir by facilitating its activation within the body[2].
Patent Landscape
Related Patents
The patent 8,735,372 is part of a larger family of patents related to sofosbuvir, including patents on the base molecule, crystalline structures, and formulations. Here are some key related patents:
- Base Patent (7,429,572): This patent covers the core molecule of sofosbuvir and has been challenged on grounds of anticipation and obviousness[2].
- Crystalline Structure Patents (8,633,309 and 9,284,342): These patents cover various crystalline forms of sofosbuvir, extending the monopoly period by several years[2].
- Formulation Patent (8,889,159): This patent relates to the specific dosage form of sofosbuvir, further broadening the patent protection[2].
Global Patent Family
The sofosbuvir patent family includes multiple patents filed in various jurisdictions, creating a complex global patent landscape. These patents are tracked through international systems such as the Global Dossier, which provides access to the file histories of related applications from participating IP Offices[1].
Legal Challenges
Anticipation and Obviousness
The patent 8,735,372 has faced challenges on grounds of anticipation and obviousness. Critics argue that the use of prodrugs with nucleoside treatments is an obvious choice and has been practiced for decades, thus questioning the novelty and inventive step of the patent[2].
Litigation and Oppositions
Several litigation procedures and pre-grant oppositions have been initiated against this and related patents. For example, the Initiative for Medicines, Access & Knowledge (I-MAK) has filed challenges against Gilead’s sofosbuvir patents, arguing that they do not meet the criteria for patentability[2].
Economic and Public Health Impact
Monopoly Extension
The prodrug patents, including 8,735,372, extend Gilead’s monopoly over sofosbuvir by several years, delaying the entry of generic versions into the market. This extension can have significant economic implications, as it allows Gilead to maintain high prices for the drug, affecting access to treatment for patients[2].
Access to Medicines
The patent landscape around sofosbuvir has been a subject of debate in the context of public health. The high cost of the drug, protected by a robust patent portfolio, has limited access to hepatitis C treatment in many parts of the world. Efforts to challenge these patents aim to facilitate the entry of generic versions, thereby increasing access to affordable treatment[4].
Conclusion
United States Patent 8,735,372 is a critical component of Gilead’s patent strategy for sofosbuvir, extending the company’s control over the drug through the use of prodrugs. The patent’s claims and scope are part of a broader landscape that includes multiple related patents, each contributing to the complex and often contentious environment surrounding hepatitis C treatments.
Key Takeaways
- Prodrug Patents: The patent covers phosphoramidate prodrugs of nucleoside derivatives, enhancing the bioavailability of sofosbuvir.
- Patent Expiry: The patent is set to expire on March 21, 2028.
- Legal Challenges: The patent has faced challenges on grounds of anticipation and obviousness.
- Global Patent Family: The sofosbuvir patent family is extensive and global, tracked through systems like the Global Dossier.
- Economic and Public Health Impact: The patent extends Gilead’s monopoly, affecting the cost and accessibility of hepatitis C treatment.
FAQs
Q: What is the main claim of United States Patent 8,735,372?
A: The main claim is for phosphoramidate prodrugs of nucleoside derivatives, specifically for the treatment of viral infections in mammals.
Q: Why are prodrug patents important in the context of sofosbuvir?
A: Prodrug patents extend the monopoly period by facilitating the metabolic activation of the base compound, enhancing its bioavailability and efficacy.
Q: What are the grounds on which this patent has been challenged?
A: The patent has been challenged on grounds of anticipation and obviousness, arguing that the use of such prodrugs is not novel or inventive.
Q: How does this patent impact access to hepatitis C treatment?
A: The patent, along with other related patents, delays the entry of generic versions of sofosbuvir into the market, maintaining high prices and limiting access to affordable treatment.
Q: What is the Global Dossier, and how does it relate to this patent?
A: The Global Dossier is a service that provides access to the file histories of related applications from participating IP Offices, helping track the global patent family of sofosbuvir.
Sources
- USPTO - Search for patents: https://www.uspto.gov/patents/search
- I-MAK - US Cases on Hepatitis C Medicines: https://www.i-mak.org/cases/us-cases-hepatitis-c/
- USPTO - Patent Claims Research Dataset: https://www.uspto.gov/ip-policy/economic-research/research-datasets/patent-claims-research-dataset
- WHO - SOFOSBUVIR Report: https://cdn.who.int/media/docs/default-source/essential-medicines/intellectual-property/sofosbuvir-report.pdf?sfvrsn=5a6c06ea_2
- Unified Patents Portal - US-8735372-B2: https://portal.unifiedpatents.com/patents/patent/8735372
