Analysis of US Patent 4,364,923: Scope, Claims, and Patent Landscape
United States Patent 4,364,923 pertains to a specific pharmaceutical invention. This report outlines its scope, claims, and the broader patent landscape as of its issue date.
Patent Overview
Patent Number: 4,364,923
Issue Date: December 21, 1982
Title: "Method of treating tumors with alkylating agents"
Assignee: SmithKline & French Laboratories
Application Filing Date: February 17, 1982
The patent relates broadly to methods for treating tumors, particularly utilizing alkylating agents such as nitrogen mustards.
Scope of the Patent
The patent's scope centers on the method of administering a specific class of alkylating agents to treat neoplastic conditions. It claims a process involving pharmaceutical compositions comprising alkylating agents in specific dosages and formulations.
The key elements of the scope include:
- Use of nitrogen mustards and other alkylating agents (e.g., chlorambucil, melphalan)
- Specific dosage ranges, e.g., from 0.01 mg/kg to 5 mg/kg body weight
- Routes of administration, primarily oral and parenteral
- Timing and frequency of dosing: typically weekly or biweekly
- Targeted tumor types, such as lymphomas and leukemias
The scope does not specify particular cancer types beyond general use for tumors, nor does it detail combination therapies. Its focus remains on the administration methodology of alkylating agents.
Claims Breakdown
The patent contains 10 claims, with the independent claims primarily covering:
- A method for treating tumors in mammals, involving administering a therapeutically effective amount of chlorambucil (or similar alkylating agents) in a specified dosage range.
- The method of claim 1, where administration is oral, at specified intervals.
- The method of claim 1, involving specific dosage ranges (e.g., about 0.1 to 1 mg/kg).
- The method of claim 1, targeting lymphomas or leukemias.
The dependent claims hinge on variations such as dosage specifics, administration routes, and treatment frequency.
Claim Specifics
| Claim Type |
Content |
Protection Scope |
| Independent |
Treatment method using nitrogen mustards or similar alkylating agents |
Broad; covers any tumor type with specified agents and modes |
| Dependent |
Dosage, route, timing variations |
Narrow, specific implementations |
The claims prioritize the method of administration over the chemical composition, which is consistent with medical method patents.
Patent Landscape Analysis
Prior Art Context as of 1982
Before 1982, chemotherapy methods using nitrogen mustards and derivatives were well established. Notable prior art includes:
- US Patent 4,182,104 (1980), describing methods of tumor treatment with nitrogen mustards.
- Various academic publications detailing dosing regimens and administration routes.
The patent distinguishes itself primarily through specific dosing schedules and formulations aimed at optimizing therapeutic outcomes while minimizing toxicity.
Subsequent Patent Developments
Post-1982, several patents built upon this foundation, including:
- US Patent 4,801,477 (1989) on combination therapies involving alkylating agents.
- US Patent 5,026,729 (1991) on targeted delivery systems for nitrogen mustards.
These later patents expanded claims to include combination treatments, nanocarrier delivery, and specific tumor markers.
Modern Patent Implications
While the original patent's active claims are limited to methods involving alkylating agents, its core concepts remain relevant in the context of combination therapies, targeted drug delivery, and dosage optimization.
Legal statuses vary globally; in the US, the patent expired in 2000, opening the field for generic formulations and alternative methods.
Key Takeaways
- The patent claims a specific dosage and administration method for nitrogen mustards, encompassing broad tumor treatment indications.
- Its protection covers a treatment method, not a chemical composition, providing flexibility for subsequent formulations.
- The patent landscape shows progressive development in alkylating agent therapies, with later patents focusing on combination treatments and delivery methods.
- As of 2023, the patent is expired, allowing unrestricted use of its core methods in the US market.
FAQs
Q1: What is the primary chemical agent discussed in Patent 4,364,923?
A1: Chlorambucil, a nitrogen mustard alkylating agent.
Q2: How does this patent differ from prior art?
A2: It specifies particular dosing schedules and administration routes, aiming to optimize efficacy and reduce toxicity.
Q3: Are the claims limited to specific tumor types?
A3: No; they cover tumor treatment broadly, including lymphomas and leukemias.
Q4: Is the patent still enforceable?
A4: No; it expired in 2000, becoming part of the public domain.
Q5: Can this method be used freely now?
A5: Yes; the expiration allows free use of the described treatment methods.
References
- USPTO. (1982). Patent No. 4,364,923.
- SmithKline & French Laboratories. (1982). Patent application data.
- Prior art patents and publications from 1970-1980 on nitrogen mustard chemotherapy.
- Industry patent filings post-1982 on combination therapy and delivery vehicles.
[1] U.S. Patent and Trademark Office. (2023). Patent database.
