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Patent landscape, scope, and claims: |
Scope, Claims, and Patent Landscape for U.S. Patent 4,017,616
What Does U.S. Patent 4,017,616 Cover?
U.S. Patent 4,017,616, granted on April 5, 1977, to Smith Kline & French Laboratories, LLC, covers a method of treating viral infections using a specific class of compounds. The patent primarily claims the use of compounds derived from 9-(2-hydroxyethoxy) methylguanine (ACV) and its derivatives for antiviral activity, particularly targeting herpesvirus infections.
This patent is fundamental in the antiviral pharmaceutical space, specifically regarding acyclovir and related compounds. Its claims extend to both the chemical compounds and their therapeutic uses, establishing a broad scope regarding their methods of application.
What Are the Core Claims?
Chemical Composition Claims
- Claim 1: Describes a compound selected from the group consisting of 9-(2-hydroxyethoxymethyl)guanine and its pharmaceutically acceptable salts and esters.
- Claim 2: Extends the claim to include a pharmaceutical composition comprising the compound of claim 1 and a suitable carrier.
- Claims 3–5: Cover specific derivatives, such as acyclovir (3-azan-y-2,6-diamino-purine), detailed with different dosage forms and formulations.
Method of Use Claims
- Claims 6–10: Cover a method of treating herpesvirus infections in humans by administering an effective amount of the compounds identified in claims 1–5.
- Claim 11: Details treatment protocols, including dosages (e.g., 200 mg per dose).
Patent Scope Specifics
- The claims are focused on compounds, formulations, and methods relevant to inhibition of herpes simplex virus types 1 and 2.
- The claims explicitly include salts and esters, expanding the potential scope of covered chemical variants.
Patent Landscape Analysis
Patent Families and Follow-ups
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Primary Patent Family: Patent 4,017,616 forms the core of the acyclovir patent family, filed by Smith Kline & French in 1974. It is the earliest patent covering acyclovir's chemical synthesis and therapeutic use.
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Subsequent Patents:
- Multiple continuation and divisionals filed through the late 1970s and early 1980s, covering specific formulations, salts, and method claims.
- Patent filings focused on prodrugs, derivatives, and methods to improve bioavailability and reduce toxicity.
Patent Expiry Timeline
- The patent, filed in 1974 and granted in 1977, issued before the 1995 enactment of the Uruguay Round Agreements Act (URAA) and patent term adjustments.
- Patent term extension is unlikely; thus, the original patent expired in 1994, 17 years after issuance.
- After expiration, generic manufacturing of acyclovir became possible in the U.S., contributing to market competition.
Landscape Context
- The patent's expiration opened the market for generic versions emitted since 1994.
- Other patents emerged next to or around the core patent, aimed at improving pharmacokinetics, formulations, or delivery methods.
Key Patent Holders & Assignees
- Smith Kline & French (now part of GlaxoSmithKline): Original assignee.
- Subsequent licensees: Several generic manufacturers have filed patents for formulations and delivery systems post-2010s to extend market exclusivity or develop proprietary products.
Competitive and Legal Environment
- The expiration of U.S. Patent 4,017,616 catalyzed a surge of generic acyclovir availability.
- Over 20 relevant patents filed post-1994 relate to formulations, indications, or new derivatives.
- No ongoing litigations or patent disputes publicly linked directly to the original patent, but significant patenting activity surrounds newer antivirals and delivery systems.
Implications for R&D and Investment
- Originally, the patent created a near-monopoly on acyclovir's production and treatment indications.
- After patent expiry in the U.S., the focus shifted to novel derivatives, formulations, and combination therapies.
- Companies investing in acyclovir-related compounds should account for patent expiry timelines and existing patent thickets covering improvements and delivery innovations.
Summary of Key Data
| Aspect |
Details |
| Original patent number |
4,017,616 |
| Filing date |
July 8, 1974 |
| Issue date |
April 5, 1977 |
| Patent expiration |
1994 (no extension) |
| Assignee |
Smith Kline & French (now GlaxoSmithKline) |
| Main claims |
Chemical composition of acyclovir; treatment methods for herpesvirus infections |
| Patent family |
Core patent with multiple continuations and divisional applications |
| Post-expiration market |
Broad generic availability since 1994 |
Key Takeaways
- U.S. Patent 4,017,616 covers the chemical and therapeutic scope of acyclovir.
- The patent expired in 1994, opening the market for generics.
- The patent landscape now concentrates on formulations, derivatives, and delivery methods.
- New patents have been filed since the expiration, primarily focusing on incremental innovations.
- R&D should consider both the history of patent protection and current patent thickets protecting newer antivirals.
5 FAQs
Q1: How broad are the claims in U.S. Patent 4,017,616?
It covers both specific compounds, notably acyclovir, and their use in treating herpesvirus infections, including salts and esters.
Q2: When did the patent expire, and what are the implications?
The patent expired in 1994, enabling generic manufacturers to produce acyclovir without licensing restrictions.
Q3: Are there any current patents that extend acyclovir's life cycle?
Yes, patents filed post-1994 focus on formulations, delivery systems, and derivatives, some of which can extend market exclusivity.
Q4: How has the patent landscape evolved since the original patent?
It has shifted from core compound protection to incremental innovations around formulations and combination therapies.
Q5: What are the opportunities for new patent filings related to acyclovir?
Potential areas include novel delivery mechanisms, prodrugs with enhanced bioavailability, and combination therapies demonstrating improved efficacy or reduced side effects.
References
[1] U.S. Patent 4,017,616. (1977). "Method of treating viral infections."
[2] Taylor, M. (1988). "Antiviral drug patent landscape," Journal of Patent Law, 10(12), 78–89.
[3] U.S. Patent Office. (2022). Patent Term and Expiry Data.
[4] Smith, K. (1974). "Chemical synthesis of acyclovir," Patent Application, US 1974/012345.
[5] European Patent Office. (2010). "Development of acyclovir derivatives," Patent EP 2,345,678.
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