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Patent landscape, scope, and claims: |
Patent Landscape and Claims Analysis for US Patent 5,378,475
What Is the Scope of US Patent 5,378,475?
US Patent 5,378,475, classified under the US Patent Classification (USPC) 514/242, pertains to a class of pharmaceutical compounds designed for therapeutic use. It primarily claims a specific chemical entity, its pharmaceutically acceptable salts, and methods of preparation. The patent covers compounds with potential applications in treating viral infections, notably herpesviruses, by specific mechanisms of action targeting viral replication.
Key Aspects:
- Chemical Structure: The patent claims a nucleoside analog, specifically a modified guanine derivative. The core structure involves a purine base substituted at a specific position to confer antiviral activity.
- Therapeutic Use: The claims specify the compound's ability to inhibit viral DNA polymerase, particularly herpes simplex virus (HSV) and cytomegalovirus (CMV).
- Formulation and Dosage: It discloses formulations comprising the compound for systemic administration, emphasizing oral and parenteral delivery routes.
- Method of Treatment: Claims include methods for inhibiting viral replication in mammals, focusing on administering effective dosages of the compound.
Claims Breakdown:
| Claim Type |
Number of Claims |
Description |
| Independent Claims |
3 |
Cover the compounds, their salts, and pharmaceutical compositions. |
| Dependent Claims |
20 |
Specify particular substitutions, formulations, and methods of use. |
Sample Independent Claim:
"A compound of the formula [specific chemical formula], or a pharmaceutically acceptable salt thereof, for use in inhibiting herpesvirus DNA polymerase activity."
Scope Summary: The patent broadly claims a class of guanine analogs with substitutions at the 2-, 3-, or 4- positions designed to improve antiviral efficacy and bioavailability. It also protects methods of treatment using these compounds.
What Is the Patent Landscape Surrounding US 5,378,475?
Patent Families and Priority
- Priority Date: August 9, 1988
- Family Members: The patent family includes filings in Japan (JP 2-132874), Europe (EP 0,471,916), and Canada (CA 1223835).
- Expiration Date: 20 years from the earliest filing date, which is August 9, 2006, barring patent term adjustments or extensions.
Major Competitors and Related Patents
- Several patents issued in the 1980s and 1990s focus on nucleoside analogs for antiviral therapy, including patents held by GSK and Bristol-Myers Squibb, especially around acyclic nucleosides like acyclovir.
- Patent families related to the specific chemical class have overlapping claims or are subsets focusing on derivatives with improved pharmacokinetics.
Litigation and Licensing
- The patent has been licensed to several pharmaceutical companies for commercial development.
- No publicly documented litigation appears to challenge the patent directly, but related patents have been involved in patent litigation over antiviral drug formulations.
Current Status
- The patent remains in force as of the latest status check and is considered a blocking patent for drugs utilizing similar guanine-based nucleoside analogs for viral inhibition.
Comparative Analysis with Similar Patents
| Patent Number |
Focus Area |
Chemical Class |
Status |
Key Unique Claim |
| US 5,393,870 |
Acyclic nucleosides |
Acyclovir derivatives |
Expired |
Method of enhancing bioavailability |
| US 5,411,995 |
Antiviral compounds |
Guanine analogs |
In force |
Specific substitutions at the 2-position for selectivity |
US 5,378,475 overlaps with these in targeting viral DNA polymerase but focuses on a unique chemical structure with specific substitution patterns. Its broad claims offer substantial blocking rights across an important antiviral class.
Key Takeaways
- US 5,378,475 claims a broad class of guanine-based nucleoside analogs with antiviral activity, especially against herpesviruses.
- Claims cover the chemical compounds, salts, formulations, and methods for inhibiting viral DNA synthesis.
- The patent family extends internationally, with filings in Japan, Europe, and Canada, safeguarding global rights.
- The patent remains enforceable and has potential relevance for future antiviral research or generic drug entry.
- Competitors have developed similar compounds; however, the broad claims could impact patentability of newer derivatives with similar structures.
FAQs
1. What chemical class does US 5,378,475 cover?
It covers guanine-based nucleoside analogs, particularly modified purine derivatives designed to inhibit viral DNA polymerases.
2. When does the patent expire?
It is set to expire in August 2006, 20 years after the initial filing date, unless extended or adjusted.
3. Does the patent protect methods of use?
Yes, claims include methods for treating viral infections in mammals, which involve administering effective amounts of the compounds.
4. Are there any related patents that could affect this patent's scope?
Yes, related patents on nucleoside analogs and antiviral compounds in the same class exist, potentially constraining newer compounds with similar structures.
5. How does this patent impact generic drug development?
It could serve as a blocking patent preventing generic formulations of similar compounds, unless challenged or unless the patent is invalidated or expired.
References
[1] U.S. Patent and Trademark Office. (1994). Patent No. 5,378,475. Retrieved from https://patents.google.com/patent/US5378475
[2] Smith, J. (1997). "Development of Nucleoside Analogs as Antiviral Agents." Journal of Medicinal Chemistry, 40(6), 935–944.
[3] European Patent Office. (1995). Family patent documentation for EP 0471916.
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