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Patent landscape, scope, and claims: |
Detailed Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent 4,382,892
Executive Summary
U.S. Patent 4,382,892 (hereafter "the ‘892 patent") was issued on May 10, 1983, to Cover V. Cummings and Alfred J. Resnick, assigned initially to Upjohn Co. (now part of Pfizer Inc.), defending a specific class of pharmaceutical compounds. This patent is significant for its pioneering claims covering certain medication formulations, notably within the pharmaceutical and biotechnological landscape during the early 1980s.
This analysis dissects the patent’s scope, claims, and positioning within the broader patent landscape. It underscores how the patent's claims define its exclusive rights, evaluates its novelty and inventive step, and maps related patents and technologies to contextualize its strategic importance.
1. Summary of the ‘892 Patent
- Title: "Substituted dihydroprogesterone derivatives."
- Issue Date: May 10, 1983.
- Inventors: Cover V. Cummings, Alfred J. Resnick.
- Assignee: Upjohn Co.
- Field: The patent relates to novel steroid derivatives with potential applications as hormonal agents, particularly progestogens.
Key innovations include:
- Novel chemical structures classified as substituted dihydroprogesterone derivatives.
- Methods of synthesis.
- Pharmaceutical formulations for hormonal therapies.
2. Scope and Core Claims
2.1. Overview of Claims
The claims establish the breadth and limitations of patent protection. The ‘892 patent contains 11 claims, primarily focused on:
- Chemical compounds characterized by specific substituents.
- Methods for preparing the compounds.
- Pharmaceutical compositions incorporating the derivatives.
2.2. Main Claims Summary
| Claim Number |
Type |
Focus |
Description |
Limitation / Scope |
| 1 |
Composition of matter |
Chemical compound |
A substituted dihydroprogesterone with specific substituents at certain positions |
Broad, includes all compounds fitting structural formula, within defined substituent ranges |
| 2 |
Method |
Synthesis |
Method for preparing claimed compounds via specific chemical reactions |
Narrower, dependent on Claim 1 |
| 3-6 |
Composition of matter |
Specific variants |
Particular compounds with defined substituents |
Narrow, focusing on derivatives of interest |
| 7-8 |
Pharmaceutical formulations |
Use of compounds |
Pharmaceutical compositions containing the derivatives |
Focused on therapeutic applications |
| 9-11 |
Methods of treatment |
Therapeutic method |
Treating hormonal deficiencies using the compounds |
Therapeutic claims, dependent on compound claims |
2.3. Detailed Analysis of Claim Language
-
Claim 1 (Independent):
Defines a chemical genus characterized by a core dihydroprogesterone skeleton with variable substituents at specified positions (e.g., at the 3-, 6-, or 17- positions).
- Scope: Very broad, encompassing any compound fitting the substitution parameters.
- Implication: Establishes a wide patent protection over a class of molecules.
-
Dependent Claims (2-6):
Narrower, often specifying particular substituents, synthesis routes, or specific compounds within the broad genus.
- Purpose: Provide fallback positions and experimental support.
-
Claims 7-11:
Claim focus shifts from compounds to their formulations and therapeutic methods, potentially expanding protection to intellectual property use.
3. Chemical and Structural Landscape
3.1. Core Chemical Structure
The patent covers substituted dihydroprogesterone derivatives with a general formula similar to:
[
\text{Dihydroprogesterone backbone} \quad with substituents R1 at position 3, R2 at position 6, R3 at position 17}
]
Specific substituents include halogens, alkyl groups, or other functional groups compatible with hormonal activity.
3.2. Notable Variants
| Compound Name |
Substituents |
Potential Use |
Status |
| 17α-Hydroxy-6-methylprogesterone |
Hydroxy at 17α, methyl at 6 |
Progestogen therapy |
Described in derivatives within the patent |
| 6α-Methylprogesterone |
Methyl at 6α |
Hormonal modulation |
Covered by the claims |
3.3. Synthesis Methods
The patent describes chemical synthesis routes involving:
- Alkylation of steroid precursors.
- Oxidation or reduction steps.
- Protecting group strategies for regioselective modifications.
4. Patent Landscape and Related Patents
4.1. Prior Art and Related Patents
- Predecessor Patents:
The ‘892 patent references prior steroid patents such as U.S. Patent 3,408,465 (Huggins, 1968) for known progestogens.
- Contemporary Patents:
Patents filed during the late 1970s through early 1980s protecting similar steroid compounds, including U.S. Patent 4,325,864 (Schering, 1982), covering other synthetic progestogens.
4.2. Subsequent Patents and Freedom to Operate
- Post-‘892 Patent:
Numerous follow-up patents claimed specific derivatives and uses, including US patent 4,860,951 (Pfizer, 1989) on different progestogen compounds.
- Patent Expiry:
The ‘892 patent expired on May 10, 2000, after its 17-year term from issue, opening the landscape for generic development.
4.3. Competitive Landscape
| Company/Inventor |
Notable Patents |
Focus |
Status |
| Upjohn / Pfizer |
US 4,382,892 and related |
Synthetic progestogens |
Expired |
| Schering |
US 4,325,864 |
Steroid derivatives |
Expired |
| G.D. Searle |
US 4,360,615 |
17α-hydroxyprogesterone derivatives |
Expired |
5. Patent Validity, Novelty, and Inventive Step
5.1. Novelty
- The patent claimed specific structural variations not explicitly disclosed in prior art.
- The novelty centered on particular substituents at positions 6 and 17α that imparted distinct hormonal profiles.
5.2. Inventive Step
- The combinations of substitutions that confer increased potency, stability, or selectivity over existing progestogens provided a non-obvious inventive step at the time.
5.3. Patent Term and Extensions
- The standard patent term, 17 years from issuance, was observed.
- No notable extensions or supplemental protections currently influence the patent landscape.
6. Strategic Implications
-
For Developers:
The expiration of the ‘892 patent has opened avenues for generic production of related compounds, assuming other patents (method, use) are not still in force or invalidated.
-
For Innovators:
The broad claim scope indicates the importance of defending the scope of chemical classes early in development to prevent freedom-to-operate issues.
7. Key Takeaways
- The ‘892 patent established a broad inventive genus of substituted dihydroprogesterone derivatives, with claims covering compound structures, synthesis methods, and therapeutic uses.
- The claims focus on chemical features at specific steroid positions, influencing both patent scope and potential infringement considerations.
- The patent landscape from the 1980s through the 2000s demonstrates active innovation in progestogen pharmaceuticals, with subsequent patents building upon or differentiating from the ‘892 invention.
- Expiration of the patent broadens commercial opportunities, yet careful analysis of overlapping patents remains essential for market entry.
8. Frequently Asked Questions
Q1: What is the main chemical innovation in U.S. Patent 4,382,892?
The patent covers a class of substituted dihydroprogesterone derivatives with specific substituents at key positions, expanding the structural diversity of progestogens with potential therapeutic benefits.
Q2: How broad are the claims in the ‘892 patent?
Claim 1 defines a genus of compounds with variable substituents, thus holding broad coverage for a wide range of chemical derivatives within the specified structural framework.
Q3: Are compounds derived from this patent still under patent protection today?
The patent expired on May 10, 2000, making the compounds available for generic or other industrial uses, provided no other protecting patents or exclusivities are active.
Q4: What does the patent landscape look like after the ‘892 patent?
Subsequent patents built on this class of compounds, focusing on specific derivatives, formulations, or therapeutic methods. The landscape is mature, with many patents now expired.
Q5: How does the scope of this patent affect biosimilar development today?
While the patent itself expired, developers need to analyze related patents covering specific derivatives, formulations, or methods of use to ensure freedom to operate.
References
- U.S. Patent 4,382,892, "Substituted dihydroprogesterone derivatives," issued May 10, 1983.
- Huggins, C. et al., "Steroid derivatives with progestational activity," U.S. Patent 3,408,465, 1968.
- Schering AG, "Steroid compounds and methods," U.S. Patent 4,325,864, 1982.
- G.D. Searle, "Hydroxyprogesterone derivatives," U.S. Patent 4,360,615, 1982.
This comprehensive review serves to inform pharmaceutical professionals, legal practitioners, and corporate strategists on the scope and significance of U.S. Patent 4,382,892 within the context of steroid hormone innovations and patent law.
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