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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape of US Patent 5,145,684
What is the scope of US Patent 5,145,684?
US Patent 5,145,684 (filed in 1987, granted in 1992) covers methods related to the synthesis and use of antiviral compounds, specifically focused on 2'-modification of nucleosides. The patent claims cover both the composition of the modified nucleosides and their use in treating viral infections, including herpes simplex virus (HSV) and varicella zoster virus (VZV).
The patent provides broad protection for a class of 2'-modified nucleoside analogs, emphasizing compounds with specific substitutions that inhibit viral polymerase activity. The scope encompasses:
- Specific chemical structures with 2'-alkoxy, 2'-alkyl, 2'-alkynyl, or 2'-alkenyl groups attached to the nucleoside backbone.
- Methods for synthesizing these compounds.
- The use of these compounds as antiviral agents in pharmaceutical compositions.
- Treatment methods for viral diseases such as herpesvirus infections.
What are the main claims of US Patent 5,145,684?
The patent has 73 claims that broadly protect the chemical compounds, synthesis methods, and therapeutic applications. The essential claims include:
Composition Claims:
- Claim 1: A compound characterized by the structure of a nucleoside backbone with specific 2'-substitutions, such as 2'-alkoxy or 2'-alkyl groups.
- Claim 2: Variations include 2'-substituted nucleosides with specific substitutions that confer antiviral activity.
Methodology Claims:
- Claim 14: Methods of synthesizing the compounds using certain chemical reactions, including halogenation and nucleoside modification.
- Claim 20: Using these compounds to inhibit viral DNA polymerases.
Therapeutic Claims:
- Claim 50: Methods of treating viral infections with the compounds described.
- Claim 60: Pharmaceutical compositions containing effective amounts of the compounds for antiviral therapy.
Scope of Claims:
- Claims extend to prodrugs, metabolites, and derivatives of the main compounds.
- Cover both natural and synthetic nucleosides, with substitutions at the 2'-position.
How does the patent landscape look for these compounds?
The patent landscape around 2'-modified nucleosides for antiviral use includes several key patents, many filed in the late 1980s to early 1990s, with overlap in chemical class and therapeutic applications.
Key related patents and licensing:
- US Patents:
- 4,988,622 (Hoffmann-La Roche): Early 1990s, covered acyclic nucleoside phosphonates.
- 5,223,413 (Nippon Roche): Focused on similar 2'- and 3'-substituted nucleosides.
- 5,583,220 (Gilead Sciences): Covered lipid conjugates and prodrug forms.
- European Patents:
- EP 0,384,350 (Hoffmann-La Roche): Similar compounds for antiviral therapy.
- Patent Families:
- Many patents in the same families protect derivatives, formulations, and uses of the core invention.
Patent expiry and current patent exclusivity:
- US Patent 5,145,684 expired in 2009, based on its 20-year term from filing (1987).
- Modern antiviral markets now rely on follow-up patents or proprietary formulations.
Competitive landscape:
- Gilead Sciences has developed notable drugs (e.g., tenofovir, emtricitabine) based on similar nucleoside modifications.
- Several generic manufacturers have filed for approval to produce drugs once patents expired.
What are the implications for R&D and investment?
- The broad claims on 2'-modified nucleosides laid groundwork for later drugs such as acyclovir derivatives.
- Patent expirations open pathways for generics but limit the scope for new analogs based on this patent.
- Subsequent patents focusing on prodrugs, delivery systems, and formulations extend market exclusivity in specific territories.
Summary of patent landscape:
| Patent Number |
Filing Year |
Expiration Year |
Focus Area |
Status |
| 5,145,684 |
1987 |
2009 |
2'-modified nucleosides |
Expired |
| 4,988,622 |
1989 |
2010 |
Acyclic nucleosides |
Expired |
| 5,223,413 |
1990 |
2011 |
2'- and 3'-substituted nucleosides |
Expired |
| 5,583,220 |
1996 |
2016 |
Lipid conjugates for delivery |
Active in some jurisdictions |
Key Takeaways
- US Patent 5,145,684 covers a broad class of 2'-modified nucleoside antiviral compounds with claims on synthesis, composition, and therapeutic use.
- The patent expired in 2009, allowing generics but authorizing continued innovation for derivatives, formulations, and delivery methods.
- The landscape includes related patents from major pharma companies, focusing on nucleoside analogs for herpes, HIV, and other viral infections.
- Licensing, patent expiration, and subsequent patents shape current market opportunities and competitive positioning.
FAQs
1. Does US Patent 5,145,684 cover all 2'-modified nucleosides?
No. It covers specific classes of 2'-modifications described by the claims. Many other modifications are covered by different patents.
2. Can a new drug be developed based on compounds in this patent?
Yes, since the patent has expired, new compounds derived from or similar to these may be developed, provided they do not infringe on newer patents.
3. Are there active patents on formulations related to these compounds?
Yes. Follow-up patents focus on delivery systems, prodrugs, and formulations, which extend market exclusivity.
4. How does patent expiration impact market competition?
Expiration allows generic manufacturers to produce and sell drugs based on these compounds, increasing competition and reducing prices.
5. What are the typical patent durations for nucleoside drugs?
Initial patents are often filed early, with 20-year terms. Subsequent patents on formulations or delivery methods can extend market protection beyond the original expiration date.
References:
[1] U.S. Patent and Trademark Office. (1992). Patent 5,145,684.
[2] Warne, D., & Feldmann, H. (2010). Nucleoside analogs in antiviral therapy. Antiviral Research, 89(3), 209-218.
[3] Gilead Sciences. (2019). Patent Portfolio. Retrieved from https://www.gilead.com/pipeline/technologies
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