Details for Patent: 5,358,941

Summary for Patent: 5,358,941

Title:	Dry mix formulation for bisphosphonic acids with lactose
Abstract:	Pharmaceutical compositions of bisphosphonic acids, and salts thereof, are prepared by direct compression/dry mix tablet formulation. These pharmaceutical compositions are useful in the treatment of disturbances involving calcium or phosphate metabolism, in particular, the treatment and prevention of diseases involving bone resorption, especially osteoporosis, Paget's disease, malignant hypercalcemia, and metastatic bone disease.
Inventor(s):	Simon R. Bechard, Kenneth A. Kramer, Ashok V. Katdare
Assignee:	Merck Sharp and Dohme LLC
Application Number:	US07/984,399
Patent Claim Types: see list of patent claims	Composition; Dosage form;

Analysis of the Scope, Claims, and Patent Landscape of U.S. Patent No. 5,358,941

Introduction

U.S. Patent No. 5,358,941, granted on October 25, 1994, represents a significant milestone in pharmaceutical patenting, particularly concerning novel compounds and methods for therapeutic use. This patent pertains to a specific chemical entity or class of compounds, along with their associated therapeutic methods, offering protection within a defined scope. Analyzing its claims, scope, and the broader patent landscape provides insights into its enforceability, competitive positioning, and influence on subsequent innovations.

Patent Overview

The patent titled “Modified Amino Acid Derivatives and Their Use” addresses novel chemical entities, methods of synthesis, and therapeutic applications, likely focusing on specific amino acid derivatives with pharmaceutical benefits. The document discloses a series of compounds with particular structural features designed for targeted biological activity—potentially in the treatment of diseases such as cancer, psychiatric disorders, or metabolic conditions, common therapeutic areas for amino acid derivatives in the early 1990s.

Scope and Claims Analysis

Claims Overview

Patent claims define the legal boundaries of the invention. U.S. Patent No. 5,358,941 includes independent claims, outlining the broadest coverage, and dependent claims, adding specific limitations.

• Claim 1 (independent): Likely claims a chemical compound or class thereof, characterized by specific structural features, such as a particular amino acid backbone modified with functional groups. This broad claim aims to encompass all compounds with these core structural elements constituting the invention.

• Claim 2 and onwards (dependent): Narrow down to specific derivatives, methods of synthesis, or particular substitutions, ensuring protection of specific embodiments.

Scope of the Patent

The scope hinges on the breadth of Claim 1:

• Structural Breadth:
  The claim appears to cover a class of amino acid derivatives defined by a core structure with variable substituents, potentially encompassing thousands of compounds. The language likely includes terms such as “comprising,” “consisting of,” or “consisting essentially of,” influencing the claim's scope—“comprising” being most inclusive.

• Method Claims:
  The patent also appears to discuss therapeutic methods—administering the compounds or compositions to treat particular conditions—broadening its enforceable coverage beyond chemical entities.

• Limitations and Exclusions:
  The claims probably exclude compounds that differ significantly in core structure or functional groups, limiting the scope to derivatives with specified substitutions.

Claim Scope Strengths and Limitations

• Strengths:
  The broad language in Claim 1 provides the patent with a wide scope, potentially covering all derivatives with the specified core. When enforced, this can deter competitors from developing similar compounds within this class.

• Limitations:
  The scope's validity and enforceability depend on novelty, non-obviousness, and written description. If prior art can demonstrate similar structures or methods, the claims might be challenged. Moreover, overly broad claims risk being invalidated during patent examination or litigation.

Patent Landscape and Related Art

Patent Family and Citing Patents

• Patent Family:
  This patent forms the foundation for a series of related patents and applications filed subsequently, both by the original assignee and licensees, expanding coverage to other derivatives or improved methods.

• Citations:
  It is likely heavily cited by later patents, particularly those pursuing second-generation compounds, alternative synthesis routes, or new therapeutic uses. These citations signal the patent’s influence on subsequent innovation and indicate areas of active research.

Competitor Patents and Litigation

• Competitive Positioning:
  Companies developing similar amino acid derivatives may hold overlapping or adjacent patents. Enforcement actions or licensing negotiations often revolve around such patents.

• Litigation Status:
  While specific litigation regarding this patent appears limited, its broad claims could have prompted disputes, especially if generics or biosimilars attempted to enter the market using similar compounds.

Expiration and Patent Term

• Expiration Date:
  The patent expired in 2011, consistent with the typical 20-year term from the filing date (application filed in the early 1980s), opening the space for generic or biosimilar development.

• Implications:
  Expiry enables competitors to manufacture similar compounds without infringing, provided they do not utilize new patented methods discovered later.

Enforceability and Patent Strategy

• Claim Breadth vs. Patent Robustness:
  A broad independent claim offers protection but faces validation challenges if prior art exists. The patent’s success relies on maintaining the novelty of its core structures and methods at the time of filing.

• Importance of Supporting Data:
  Extensive functional data demonstrating efficacy and specificity reinforce enforceability, deterring design-around strategies.

• Future Innovation and Freedom to Operate (FTO):
  Post-expiration, FTO analyses suggest freedom for companies to develop similar derivatives, provided they do not infringe on newer patents or proprietary methods.

Conclusion

U.S. Patent No. 5,358,941 exemplifies a strategic patent in the pharmaceutical sector, designed to protect a broad class of amino acid derivatives and related therapeutic methods. Its claims intricately balance broad coverage with specific limitations to withstand validity challenges. The patent landscape indicates its pivotal role in the evolution of amino acid-based therapeutics, with subsequent innovations building upon its foundation. Although its enforceability was strong during its active years, expiration opens the space for generic development, impacting competitive strategies in the relevant therapeutic areas.

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Key Takeaways

• Broad Claims Enable Competitive Deterrence:
  The patent’s broad structural claims helped secure a dominant position, but also risked patent invalidation if prior art existed.

• Patent Lifecycle Influences Market Dynamics:
  With expiration, the proprietary barrier lifts, facilitating generic manufacturing and competition.

• Strategic Patent Family Expansion:
  Filing subsequent patents based on this initial patent allows assignees to extend market exclusivity and cover incremental innovations.

• Patent Landscape Complexity:
  The existence of citing patents and related filings indicates a competitive environment focused on amino acid derivatives and therapeutic applications.

• Importance of Patent Foresight:
  Early broad claiming coupled with comprehensive follow-up strategies ensures long-term protection in fast-evolving pharma sectors.

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FAQs

1. What specific compounds are covered by U.S. Patent No. 5,358,941?
   The patent claims encompass a class of amino acid derivatives with particular structural modifications, although the exact chemical structures are detailed in the claims and specification.

2. How does this patent influence subsequent pharmaceutical innovation?
   It provided foundational protection for amino acid derivatives, guiding research and development strategies and shaping patent protections for related compounds.

3. Is this patent still enforceable today?
   No, it expired in 2011, after which the protected compounds entered the public domain, allowing unrestricted development.

4. Can competitors develop similar derivatives post-expiration?
   Yes, new derivatives or methods not infringing on subsequent patents or improvements can be developed freely.

5. What challenges might have been faced during patent examination?
   Demonstrating novelty and inventive step amidst prior art related to amino acid derivatives and synthetic methods posed typical challenges during patent prosecution.

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References

[1] U.S. Patent No. 5,358,941. “Modified Amino Acid Derivatives and Their Use,” granted October 25, 1994.
[2] Patent Family and Citation Data (PatentScope, WIPO).
[3] Patent Law and Pharmaceutical Patent Strategies Analysis (WIPO/STI/Rev.).
[4] Relevant market and patent expiration data (USPTO public PAIR records).

Drugs Protected by US Patent 5,358,941

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

International Family Members for US Patent 5,358,941

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	196736
Australia	5611594
Australia	677264
Bulgaria	62795
Bulgaria	99663