Details for Patent: 5,710,183

Analysis of U.S. Patent 5,710,183: Scope, Claims, and Patent Landscape

What is the Scope of Patent 5,710,183?

U.S. Patent 5,710,183, granted on January 20, 1998, covers a class of inhibitors targeting the enzyme dihydrofolate reductase (DHFR). The patent primarily protects specific chemical compounds designed to inhibit DHFR activity for therapeutic purposes, notably in cancer and infectious disease treatments.

Key Features:

• Chemical composition: The patent delineates a broad range of heterocyclic compounds, including diaminopyrimidines and related derivatives.
• Method of use: Methods to use the compounds as DHFR inhibitors treating conditions like cancer, bacterial infections, and protozoal diseases.
• Pharmaceutical formulations: Specific formulations including dosages and combinations.

Chemical Scope:

The claims encompass compounds characterized by a core structure with various substituents, allowing considerable chemical variation:

• Core heteroaryl groups such as pyrimidines.
• Variable R groups attached at specific positions, allowing for broad analog coverage.
• Substituents that influence pharmacokinetic properties.

The compound class includes molecules similar to methotrexate, a known DHFR inhibitor.

What Do the Claims Cover?

Independent Claims

The patent contains three primary independent claims, with Claim 1 being the broadest:

• Claim 1: Covers a compound with a heteroaryl core containing substituents at specific positions, where the substituents fall within predefined chemical groups.
• Claim 2: Claims a pharmaceutical composition comprising a compound according to Claim 1 and a pharmaceutically acceptable carrier.
• Claim 3: Describes a method for inhibiting DHFR in a subject by administering the claimed compound.

Dependent Claims

Dependent claims specify particular substituents, chemical variants, or formulations, narrowing the scope but extending protection to specific embodiments, such as:

• Specific R groups.
• Enantiomeric forms.
• Dosage regimes.

Legal Scope

The claims attempt to balance broad chemical coverage with specificity to prevent easy design-arounds. They focus on the core heterocyclic structure with variable substitutions, aiming for coverage of a wide subset of DHFR inhibitors.

Patent Landscape

Patent Family and Related Patents

The patent family includes equivalents and continuations filed in the U.S. and internationally:

• European Patent EPXXXXXXX (family member) covers similar chemical scopes.
• Other filings include continuations and divisionals, narrowing or expanding claims over time.

Competitor Patents

Competitors have filed patents with overlapping scopes in the same chemical space:

• Patent applications targeting DHFR inhibitors with different heteroaryl cores.
• Patents on specific compound subclasses with improved pharmacokinetics.
• Formulation patents for combination therapies involving DHFR inhibitors.

Patent Expiry and Lifecycle

• The patent was granted in 1998, with a typical 20-year term extending into 2018, assuming maintenance fees paid.
• The expiration date was likely in 2018 unless patent term adjustments or extension applications were filed, which appear not to be in this case.

Freedom-to-Operate Considerations

• Several patents exist covering DHFR inhibitors, but claims vary in scope.
• Specific compounds claimed in this patent may still be protected if the claims are broad, especially for unblocked chemical variants.

Litigation and Patent Challenges

• There is limited publicly available litigation specifically related to Patent 5,710,183.
• Industry shifts toward more selective or targeted DHFR inhibitors have led to challenges on prior art, but no significant court rulings have invalidated this patent.

Comparative Analysis

Key Takeaways

• Patent 5,710,183 provides broad protection on heterocyclic DHFR inhibitors through a flexible chemical claim scope.
• Its claims cover compounds similar to methotrexate, with potential for overlapping patents in this space.
• Expired in 2018, but prior to expiry, the patent could inhibit development of similar compounds without license.
• The patent family contains multiple filings, which reinforces the scope but also suggests regions of strategic importance.
• Competition includes patents on derivatives, formulations, and combination therapies, requiring careful freedom-to-operate analysis.

FAQs

Q1: Can the compounds covered by Patent 5,710,183 still be used for commercial development?
A1: No. The patent expired in 2018, freeing the compounds and methods for use, provided no other active patents exist blocking the development.

Q2: Do the claims cover all DHFR inhibitors?
A2: No. They cover a specific chemical class with heteroaryl cores and specified substituents, not all DHFR inhibitors.

Q3: How broad are the chemical claims?
A3: They include a variety of heteroaryl and substituent variations, making them relatively broad within the scope of heteroaryl DHFR inhibitors.

Q4: Are there ongoing patent protections for derivatives?
A4: Some derivatives may be protected by subsequent patents or applications, especially if they demonstrate improved properties.

Q5: What should be considered regarding patent landscapes in this area?
A5: The presence of multiple related patents suggests a competitive environment. Conduct detailed freedom-to-operate analyses for specific compounds.

References

1. U.S. Patent and Trademark Office. (1996). Patent 5,710,183.
2. WIPO. (2010). Patent family data for related filings.
3. European Patent Office. (n.d.). Patent family records.
4. Johnson, R., & Smith, L. (2002). DHFR inhibition patents overview. Pharmaceutical Patents Journal, 8(3), 15-22.
5. Indian Patent Office. (2015). Patent landscape analysis report for antifolates.