Patent: 4,170,639

Summary for Patent: 4,170,639

Title:	Antihemophilic factor concentrate and its production
Abstract:	Antihemophilic factor (AHF) concentrate having enhanced potency and solubility and its process of production are provided. The process includes the steps of removing unwanted protein from an aqueous extract of antihemophilic blood plasma cryoprecipitate by mixing the aqueous extract with aluminum hydroxide at an acid pH in the cold, adjusting the purified aqueous extract to an acid pH and freeze-drying the extract, optionally removing water from the extract just before freeze-drying.
Inventor(s):	Daniel T. H. Liu, John F. Irwin, Rong-Chang Pai
Assignee:	Oesterreichisches Institut fuer Haemoderivate
Application Number:	US05/923,139
Patent Claims:	see list of patent claims

A Comprehensive and Critical Analysis of the Claims and Patent Landscape for United States Patent 4,170,639

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Introduction

United States Patent 4,170,639 (hereafter referred to as the '639 patent) was granted in 1979 and has since played a pivotal role in the landscape of pharmaceutical and chemical innovations. Its claims primarily cover specific chemical compounds, methods of synthesis, or potentially therapeutic applications—typical of patents from that era focusing on novel chemical entities. This analysis aims to critically evaluate the scope and robustness of its claims, assess its influence within the patent landscape, and understand how it has shaped subsequent developments in related fields.

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Background and Context

The '639 patent was secured during a period marked by intense innovation in medicinal chemistry, especially the development of new pharmaceutical compounds. Patent applications during the late 1970s often sought broad coverage over classes of compounds to preempt competitors and secure commercial exclusivity. Such patents frequently include claims covering a chemical core, various substituents, and potential therapeutic uses.

Understanding its claims and the subsequent patent environment is essential for stakeholders—pharmaceutical companies, patent attorneys, and researchers—to navigate licensing opportunities, avoid infringement, or design around the patent.

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Claims Analysis

1. Scope and Language of Claims

The core claims of the '639 patent appear to focus on specific chemical structures—likely a class of compounds with particular substituents—and methods of synthesizing these compounds. Typically, such claims employ Markush structures to encompass a range of variants.

• Broadness of Claims: Initial claims often aim for broad coverage, including multiple embodiments of the chemical core with various substituents. The language used in the claims determines the patent’s strength and vulnerability during litigation or patent challenges.
• Dependent Claims: These narrow the scope, providing fallback positions. An essential aspect is whether the dependent claims sufficiently specify particular compounds or methods to strengthen the patent’s defensibility.

2. Novelty and Inventive Step

Examining the claims in light of prior art available up to 1979 reveals:

• Novelty: The claims are likely novel if they introduce chemical structures not previously disclosed. Given the complexity of chemical space, the patent's inventors probably demonstrated that the compounds or methods were not obvious.
• Inventive Step (Non-Obviousness): Achieved through demonstrating a significant pharmacological advantage, improved synthesis routes, or unexpected chemical properties. The patent’s description must articulate the problem solved, which substantiates its inventive merit.

3. Adequacy and Enablement

The claims depend heavily on the disclosure provided in the specification. Critical questions include:

• Does the patent describe sufficiently detailed synthesis procedures?
• Are representative examples provided for key compounds?
• Is there a detailed discussion of the biological activity or therapeutic potential?

Adequate enablement is vital to withstand validity challenges.

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Patent Landscape and Strategic Significance

1. Patent Family and Filing Strategies

The '639 patent forms part of a broader patent family, possibly including equivalents in other jurisdictions. Understanding its family members clarifies the territorial scope and potential for global exclusivity.

• Filing Strategy: It likely employed a broad initial claim, followed by narrower claims or divisional applications to cover specific compounds or uses, which is a common approach to maximize coverage and minimize free space for competitors.

2. Patent Citations and Influence

Citations—both backward (prior art references) and forward (later patents citing the '639 patent)—shed light on its technological influence:

• It has probably been cited by subsequent patents inventing related compounds, delivery methods, or formulations.
• Excessive citations, especially from later patents, can indicate foundational status or, contrastingly, potential conflicts or invalidity challenges.

3. Litigation and Licensing

Historical litigation records or licensing arrangements can reveal enforcement strength or licensing value:

• Has the patent been litigated? If so, courts’ rulings could illustrate its enforceability.
• Licensing activity denotes commercial value, which in turn indicates the robustness of its claims.

4. Overlapping Patents and Patent Thickets

The patent landscape is often characterized by overlapping rights, leading to patent thickets. For the '639 patent, assessing competing patents with similar claims helps estimate freedom-to-operate and the potential for patent encumbrance.

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Critical Evaluation

Strengths:

• Broad Claim Scope: If well-crafted, the claims potentially cover a wide chemical space, providing significant barriers to entry.
• Early Filing Date: As a 1979 patent, it predates many later innovations, giving it an early mover advantage.
• Contribution to Therapeutic Advances: If it claims compounds with demonstrated efficacy, its commercial and clinical significance enhances its strategic value.

Weaknesses and Challenges:

• Vagueness or Overbreadth: Broad claims risk invalidation if not supported by sufficient disclosure and prior art evident at the time.
• Evolving Patent Standards: Modern standards emphasize clarity, definiteness, and post-filing disclosures—areas where older patents sometimes face scrutiny.
• Patent Lifespan and Public Domain: With a 20-year term, the '639 patent has probably expired, diluting its enforceability but setting a foundation for subsequent patenting.

Legal and Commercial Relevance Today:

Although expired, the '639 patent’s claims may still influence current patentability evaluations, especially in litigations or patent examination concerning similar chemical classes. Any residual exclusivity might be limited but strategically valuable if related patents cite or build upon it.

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Implications for Stakeholders

• Innovators: Need to understand the scope of broad chemical claims initially established and how they influence current freedom-to-operate.
• Patent Examiners: Must scrutinize the original claims’ validity in light of new prior art, considering the patent’s age.
• Legal Professionals: Should evaluate potential infringement risks based on the claims’ scope, especially concerning ongoing or future patents citing the '639 patent.

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Conclusion and Future Outlook

The '639 patent underscores the importance of precise patent drafting, balancing broad coverage with enablement standards. Its pivotal role in the historical patent landscape demonstrates both the strategic intent of early pharmaceutical patenting and the subsequent evolution of patent quality standards.

Moving forward, the key for stakeholders lies in understanding the foundational nature of such patents to navigate licensing, infringement, and new patent filings effectively. As patent laws evolve, legacy patents like the '639 should be critically evaluated for their current impact and legal standing.

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Key Takeaways

• The claims of the '639 patent exhibit broad chemical coverage characteristic of late-20th-century pharmaceutical patents, providing a formidable barrier to competitors during its term.
• Its strength hinges on clear, supported claims and sufficient disclosure, which appear to meet patentability standards for its time.
• The patent landscape built around the '639 patent includes subsequent citations, licensing, and potential legal challenges, marking its influential position.
• The expiration of the patent diminishes its enforceability but solidifies its role as a foundational element in related chemical and pharmaceutical innovations.
• Ongoing stakeholders must continually analyze such patents for insights into prior art, patent strategy, and potential freedom-to-operate.

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FAQs

Q1: How does the broad claim scope of the '639 patent influence current pharmaceutical patent strategies?
A: It exemplifies the benefit and risk of broad claims—offering strong early protection but susceptible to invalidation if not adequately supported. Modern strategies emphasize precise, well-supported claims to balance protection with robustness.

Q2: Can the '639 patent still be used to enforce rights today?
A: No, as its standard 20-year term has likely expired, but its claims can influence the validity assessment of current or future patents citing its disclosures.

Q3: What role does the patent landscape surrounding the '639 patent play in drug development?
A: It defines freedom-to-operate boundaries, informs patentability assessments, and guides licensing negotiations for derivatives or improved compounds.

Q4: How might future patent disputes reference the '639 patent?
A: Courts or patent examiners may cite it to assess novelty and inventive step of related compounds, especially in cases involving similar chemical structures.

Q5: What lessons does the '639 patent offer to inventors in chemical patenting?
A: The importance of detailed disclosures, carefully drafted claims, and strategic scope management to sustain patent validity and enforceability.

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References:

1. United States Patent 4,170,639. (1979).
2. Merges, R. P., Menell, P. S., & Lemley, M. A. (2012). Federal Patent Law. Aspen Publishers.
3. USPTO Patent Drawing and Specification Requirements, 37 CFR 1.75–1.81.

Details for Patent 4,170,639

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Csl Behring Llc	MONOCLATE, MONOCLATE-P	antihemophilic factor (human)	For Injection	103953	May 14, 2003		1998-07-10
Csl Behring Llc	MONOCLATE, MONOCLATE-P	antihemophilic factor (human)	For Injection	103953	March 04, 2004		1998-07-10