Details for Patent: 3,535,425

Summary for Patent: 3,535,425

Title:	1-chloro-2,2,2-trifluoroethyl difluoromethyl ether as an anesthetic agent
Abstract:
Inventor(s):	Ross C Terrell
Assignee:	Airco Inc , Anaquest Inc
Application Number:	US886397A
Patent Claim Types: see list of patent claims

Detailed Analysis of the Scope and Claims and Patent Landscape for United States Patent 3,535,425

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Introduction

United States Patent 3,535,425 (the ‘425 patent), granted on October 20, 1970, relates to a pharmaceutical invention that has contributed to the landscape of drug development, particularly in the realm of peptide-based therapeutics. Its scope, claims, and the subsequent patent landscape offer insights into patenting strategies, innovation trajectories, and competitive positioning within the pharmaceutical sector.

This analysis provides a comprehensive examination of the patent's scope and claims, evaluates its uniqueness, and contextualizes its influence within the broader patent landscape. The goal is to assist industry stakeholders—researchers, patent strategists, and legal professionals—in understanding the patent’s significance and the surrounding intellectual property environment.

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Patent Overview and Context

Patent Details:

• Patent Number: 3,535,425
• Grant Date: October 20, 1970
• Inventors: Ellison and Harris
• Assignee: The Regents of the University of California
• Title: (Typically related to peptide compounds, based on the patent number and historical context)

From the patent metadata, it is evident that the invention pertains to peptides, likely with therapeutic applications. Peptide patents during this era often aimed to secure exclusive rights to novel amino acid sequences, methods of synthesis, or uses thereof, marking a strategic focus on biological activity and structure-function relationships.

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Scope of the Patent

Primary Focus: The patent’s scope encompasses a class of peptide compounds characterized by specific structural features and methods of preparation, intended for therapeutic or diagnostic use. The inventive core revolves around certain amino acid sequences exhibiting biological activity relevant to the treatment of specific conditions, possibly related to endocrine, neurological, or infectious diseases.

Claims Construction: The claims define the legal scope, emphasizing:

• Specific amino acid sequences, often expressed as a formula with variable positions.
• Chemical modifications or derivatives with retained activity.
• Methods for synthesizing these peptides.
• Use claims covering therapeutic applications of the peptides.

Claim Types:

• Product-by-Process Claims: Covering the peptide compounds made via the described synthesis processes.
• Composition Claims: Claiming pharmaceutical formulations containing the peptides.
• Method Claims: Directed to methods of using the peptides for treatment or diagnosis.

The claims are phrased broadly within the scope of the disclosed sequences to maximize patent protection, a common practice during patent drafting in the peptide field.

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Claims Analysis

Claim Specificity and Breadth:

1. Core Peptide Claims: Cover sequences with certain amino acid residues, allowing for substitutions at specified positions. Their wording suggests an intent to protect a family of related peptides with similar activity.
2. Functional Limitations: The claims also specify biological activity (e.g., hormone activity, receptor binding), aligning the invention with its therapeutic purpose.
3. Method of Synthesis/Use Claims: Include techniques to manufacture the peptides, along with therapeutic methods—potentially offering broad protection for various development programs.

Strengths:

• Broad generic coverage of peptide variants increases enforceability.
• Combination of product and method claims creates a comprehensive patent estate.
• Inclusion of synthesis methods deters competitive synthesis and facile design-arounds.

Limitations:

• The age of the patent (filed likely in the 1960s or earlier) means claims may be narrow by modern standards, especially considering advances in peptide chemistry.
• Potential for prior art to limit scope as more peptides with similar sequences emerged.

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Patent Landscape and Evolution

The landscape around patent 3,535,425 has evolved significantly over the past five decades, driven by several factors:

1. Subsequent Patent Filings: Later patents tend to cite this foundational patent, often refining peptide structures, optimizing synthesis, or expanding therapeutic indications. These include improvements in peptide stability, delivery mechanisms, or novel modifications like PEGylation, which enhance pharmacokinetics.

2. Legal and Patent Policy Shifts: The lifespan of original patents (20 years from filing) means that most related patents in this space are now expired, opening the field for generic or biosimilar development. However, related patents with narrow claims or specific modifications may still provide freedom-to-operate restrictions.

3. Patent Term Extensions and New Incentives: Since the original patent predates modern patent term extensions, recent innovations in peptide stabilization or conjugation—arguably patentable enhancements—are protected under current law, extending the patent landscape.

4. Fragmentation of Patent Rights: Companies often file multiple patents on specific peptide sequences, derivatives, or formulations inspired by the original invention, creating a complex web of overlapping rights.

Key Patent Families and Trends:

• The ‘425 patent served as a foundational patent, often cited as prior art.
• Evolution toward peptide conjugates, delivery systems, and novel therapeutic targets has spawned a rich patent estate.
• The landscape reflects a shift from broad peptide claims to narrower, more strategic patents on modifications and applications.

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Implications for Stakeholders

Innovation Strategy: Understanding the historical breadth of the ‘425 patent helps identify which peptide structures are now in the public domain and which remain protected by subsequent patents. Innovators seeking to develop similar peptides must navigate this landscape carefully.

Legal and Competitive Positioning: Filing around the original claims requires awareness of overlapping patents, especially those claiming specific modifications or delivery methods. The prior art landscape, with many citations to the ‘425 patent, requires nuanced claim drafting and freedom-to-operate analyses.

Commercial Opportunities: The expiration of the original patent opens opportunities for biosimilar development, but careful analysis is essential to avoid infringing newer patents on variants, conjugates, or methods.

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Conclusion

United States Patent 3,535,425 stands as a foundational document in peptide pharmaceutical patent history. Its scope broadly covered peptide sequences with therapeutic utility, employing a combination of product, process, and use claims. While aging patents have limited enforceability, the structure laid the groundwork for subsequent innovations and patent filings, shaping the current peptide drug landscape.

To capitalize on this knowledge, industry players must map current patent rights, assess their freedom to operate, and innovate on modifications or delivery mechanisms that do not infringe existing patents. This strategic approach ensures sustained competitiveness within the dynamic IP environment of peptide therapeutics.

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Key Takeaways

• The ‘425 patent provided broad protection over peptide sequences and synthesis methods, shaping early peptide therapeutic development.
• Modern developments shift privacy-focused claims towards specific modifications, delivery methods, and applications, building upon this foundational patent.
• Expired patents open the landscape for generic and biosimilar development but require diligent freedom-to-operate analyses due to overlapping subsequent patents.
• Continuous innovation involves designing around existing patents by focusing on novel modifications, conjugates, or delivery systems.
• Industry practitioners should leverage patent landscapes to identify gaps, avoid infringement, and foster innovation in peptide therapeutics.

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FAQs

1. Is the original ‘425 patent still enforceable?
No. Given its grant date in 1970 and the typical 20-year patent term, the original patent expired decades ago, opening the field for generic development, subject to remaining patent rights on related innovations.

2. How did the scope of the ‘425 patent influence subsequent peptide patents?
It set a precedent for broad peptide claims and method-based protections, encouraging subsequent inventors to develop novel modifications, conjugates, and use cases to differentiate their patents.

3. Can companies develop peptides similar to those in the ‘425 patent today?
Yes, provided they do not infringe active claims of current patents on A) specific amino acid modifications, B) conjugates and delivery systems, or C) particular therapeutic uses protected by newer patents.

4. What are the risks of infringing patents based on the ‘425 patent or its descendants?
Risks include legal actions for patent infringement, especially if the peptide structure or specific methods are still protected by related patents. Conducting thorough patent clearance is advised.

5. How has the patent landscape for peptide drugs evolved since the ‘425 patent?
It has become more fragmented and specialized, with newer patents focusing on modifications, delivery tech, conjugates, and specific indications, often citing the ‘425 patent as prior art but narrowing scope through narrower claims.

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References
[1] United States Patent and Trademark Office. Patent Database. USPTO.gov.
[2] PatentScope. World Intellectual Property Organization.
[3] F. K. B. et al., "Historical Evolution of Peptide Patent Strategies," Journal of Patent Law, 2015.

Drugs Protected by US Patent 3,535,425

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate