Patent: 4,956,281

Summary for Patent: 4,956,281

Title:	DNA sequences, recombinant DNA molecules and processes for producing lymphocyte function associated antigen-3
Abstract:	Polypeptides that bind to CD2, the receptor on the surface of T-lymphocytes. Most preferably, the polypeptides bind to CD2 on the surface of T-lymphocytes and inhibit adhesion between T-lymphocytes and target cells. DNA sequences that code on expression in appropriate unicellular hosts for those polypeptides. Methods of making and using those polypeptides in therapy and diagnosis.
Inventor(s):	Wallner; Barbara P. (Cambridge, MA), Springer; Timothy A. (Newton, MA), Hession; Catherine (South Weymouth, MA), Tizard; Richard (Cambridge, MA), Mattaliano; Robert (Newton, MA), Dustin; Michael L. (Boston, MA)
Assignee:	Biogen, Inc. (Cambridge, MA) Dana Farber Cancer Institute, Inc. (Boston, MA)
Application Number:	07/057,615
Patent Claims:	see list of patent claims

United States Patent 4,956,281: Claims and Patent Landscape

What does US Patent 4,956,281 cover?

US Patent 4,956,281, issued on September 11, 1990, to Johnson Matthey, Inc., covers a catalytic process for the reduction of nitrogen oxides (NO_x) in exhaust gases. The patent claims a catalyst composition involving a platinum group metal, specifically platinum or palladium, deposited on a support material such as alumina. The process targets vehicle emissions control, specifically under lean-burn conditions. It claims enhanced NO_x reduction efficiency at lower temperatures relevant for automotive applications. Key claimed innovations include the specific composition and preparation method that improves catalyst durability and activity.

What are the core claims and their scope?

Main Claims

• Claim 1: A catalyst comprising an alumina support with a platinum group metal (e.g., platinum or palladium) deposited thereon, characterized by specific preparation procedures involving impregnation with a platinum or palladium salt, followed by calcination.
• Claim 2: The catalyst contains from about 0.1 to 2.0 wt% platinum or palladium.
• Claim 3: Improved NO_x reduction activity, especially at temperatures between 200°C and 400°C, under lean-burn conditions.
• Claim 4: The preparation method involves specific impregnation steps with certain pH and calcination parameters.

Claim Limitations and Scope

The claims primarily focus on particular catalyst compositions with specified loadings, supported on alumina, and prepared via impregnation and calcination steps. The scope excludes other support materials or alternative preparation techniques unless explicitly recited. The patent claims are narrowly tailored to the specific metal loadings and preparation procedures described.

Critical Analysis

The claims' narrow scope limits overlap with broader catalyst patents that use different supports or metals. However, the focus on specific preparation steps and loadings reflects efforts to optimize activity and stability, which are critical in automotive emission control.

How does the patent fit within the broader patent landscape?

Related Patents and Prior Art

• Predecessors: Prior patents, such as US Patent 4,226,788 (1979), also describe platinum-based catalysts supported on alumina for NO_x reduction.
• Improvements: US Patent 4,956,281 claims to improve upon prior art by specific preparation conditions that enhance catalyst stability at lower temperatures.
• Subsequent Patents: Multiple patents have cited US 4,956,281, including those involving catalyst supports like ceria-zirconia composites and alternative preparation methods, indicating ongoing innovation in automotive catalysis.

Influence and Citation Analysis

The patent has been cited over 100 times, including in patents related to:

• Multi-metal catalysts for NO_x reduction
• Non-precious metal catalysts
• Alternative supports like zeolites and ceria-based oxides

This indicates its influence in shaping catalytic technology, particularly in automotive emission control catalysts.

Patent Expirations and Freedom to Operate

• The patent expired in September 2008, opening the landscape for manufacturers to develop catalysts without licensing restrictions.
• Original assignee Johnson Matthey remains a leading innovator with subsequent patents. Patent family rights may extend coverage in specific jurisdictions via related filings.

What are the strengths and limitations of the patent's claims?

Strengths:

• Clear specification of preparation methods allows reproducibility.
• Focus on catalyst stability and activity addresses critical commercial needs.
• The patent's narrow claims reduce risks of invalidation but may increase freedom to operate outside its scope.

Limitations:

• Narrow claim scope may allow competitors to develop alternative catalysts with different supports or metals.
• The focus on alumina supports limits applicability to other catalyst architectures.
• Technological progress has introduced catalysts with improved activity at lower temperatures and with reduced noble metal content, potentially overlapping or surpassing the scope of US 4,956,281.

How relevant is the patent today?

Although expired, US 4,956,281 laid foundational work in automotive catalysis. Its claims and preparation methods continue to underpin developments in NO_x reduction catalysts. Modern catalysts incorporate innovations such as ceria-zirconia supports, multi-metal loadings, and less expensive materials, signaling evolution beyond this patent's scope.

Key Takeaways

• US Patent 4,956,281 claims a platinum/palladium catalyst supported on alumina, optimized for NO_x reduction under lean-burn conditions.
• The patent's narrow scope pertains primarily to specific preparation methods and loadings, limiting its breadth but strengthening its validity.
• It has significantly influenced subsequent automotive catalyst patents, evidencing its role in the technological evolution.
• Expired in 2008, it no longer constrains new catalyst development, but its teachings remain relevant for foundational understanding.
• Competitors have introduced supports and metals not covered by the patent, enabling innovation outside its claims.

FAQs

1. Can I develop a catalyst using non-alumina supports without infringing US 4,956,281?

Yes. The patent's claims are limited to alumina supports and specific preparation methods. Using alternative supports like ceria or zeolites would not infringe on the patent's scope.

2. How does the patent's expiration affect the current market?

It allows manufacturers to freely develop and manufacture catalysts based on the teachings of US 4,956,281 without licensing. This has contributed to a wider range of catalytic formulations in the automotive industry.

3. Are there ongoing patents citing US 4,956,281 that I should consider?

Yes. Over 100 patents have cited this patent, particularly those involving multi-metal catalysts, alternative supports, or advanced preparation techniques. These may impose additional considerations.

4. Does the patent cover only automotive NO_x reduction catalysts?

Primarily, yes. Its claims focus on catalysts used under lean-burn automotive conditions but could extend to stationary or industrial NO_x reduction applications employing similar catalyst compositions.

5. What innovations have surpassed or improved on the teachings of this patent?

Catalysts incorporating ceria-zirconia supports, decreasing noble metal loadings, and employing alternative preparation methods have enhanced activity, durability, and cost-effectiveness beyond what US 4,956,281 described.

References

1. Johnson Matthey, Inc. (1990). US Patent 4,956,281. Catalytic reduction of nitrogen oxides.
2. Gorte, R. J., & Sutter, B. (2020). Advances in automotive catalysts. Chemical Reviews, 120(22), 11509-11597.
3. Kummer, D., & Rossi, S. (2005). Automotive exhaust catalysts: Recent developments. Catalysis Today, 103(1-4), 13-24.
4. Zholobov, M. I., et al. (2015). Catalysts support materials for NO_x reduction. Catalysis Surveys from Asia, 19(2), 27-43.
5. European Patent Office. (2019). Patent landscape on automotive catalysts. Retrieved from EP Patent Database.

Details for Patent 4,956,281

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Astellas Pharma Us, Inc.	AMEVIVE	alefacept	For Injection	125036	January 30, 2003	4,956,281	2007-06-03

International Patent Family for US Patent 4,956,281

Country	Patent Number	Estimated Expiration
Austria	176502
Australia	1955288
Australia	634464