Analysis of Patent 5,167,242: Scope, Claims, and Landscape
What is the scope of Patent 5,167,242?
Patent 5,167,242 covers a pharmaceutical composition and method involving a specific compound for the treatment of proliferative diseases, particularly cancer. The patent's scope encompasses:
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Chemical composition: The active ingredient is a particular 2-phenylaminopyrimidine derivative.
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Uses: Treatment of proliferative diseases, including various cancers such as leukemia, melanoma, and solid tumors.
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Formulations: It includes pharmaceutical formulations suitable for oral, injectable, or topical administration.
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Methods of making: The patent details synthesis procedures for producing the compound.
The patent claims overlap with compounds and methods aimed at kinase inhibition, especially targeting the epidermal growth factor receptor (EGFR) family.
What are the main claims of Patent 5,167,242?
The patent contains 16 claims, with the core claims focused on:
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Claim 1: A compound with a specified chemical structure—2-phenylaminopyrimidine derivatives with particular substitutions—claimed for use in inhibiting kinase activity.
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Claim 2: The same compound substantially free of impurities.
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Claims 3-5: Methods for synthesizing the compound, including specific reaction steps.
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Claims 6-8: Pharmaceutical compositions comprising the compound in combination with carriers or excipients.
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Claims 9-12: Methods of treating proliferative diseases by administering an effective amount of the compound.
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Claims 13-16: Variations covering specific derivatives, formulations, and use cases.
The claims are broad in composition but specific in chemical substitution patterns, aiming to cover a class of compounds intended for kinase inhibition.
How does the patent landscape look for this technology?
Patent Infringement and Freedom to Operate (FTO)
Since the patent claims a broad class of kinase inhibitors, multiple subsequent patents have entered the landscape, including:
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Secondary patents: Covering specific derivatives, formulations, and manufacturing methods.
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Blocking patents: Held by major pharmaceutical firms like Pfizer, Novartis, and AstraZeneca, focusing on EGFR inhibitors such as gefitinib and erlotinib.
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Complementary patents: Covering combination therapies involving the compounds described in 5,167,242.
Related Patent Families
The patent falls within a family of filings originating from research institutions and pharmaceutical companies interested in kinase inhibitors. Related patents include:
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US 5,660,871: Covering other pyrimidine derivatives for kinase inhibition.
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EP 0571024: European counterpart focusing on specific chemical variations.
Patent Lifecycle and Expiry
The patent was filed in 1991 and issued in 1992. Its 20-year term expired in 2012, opening opportunities for generic manufacturing. However, follow-up patents and method-of-use claims may still restrict commercial activity.
Litigation and Litigation Risks
No major litigation challenges are publicly documented specific to 5,167,242. However, infringement risks persist due to overlapping claims in the kinase inhibitor space, especially for compounds structurally similar to those claimed.
Market and R&D Implications
The expiration of the patent opened the market for generic versions of compounds covered, but the patent's influence persists in patent thickets guarding the broader kinase inhibitor class. Companies conducting R&D benefit from freedom to operate—yet must navigate existing patent claims carefully.
Key differences from comparable patents
| Patent Number |
Focus |
Claims |
Filing Year |
Expiry Year |
Key Differentiator |
| 5,167,242 |
Pyrimidine derivatives for kinase inhibition |
Broad class of 2-phenylaminopyrimidines |
1991 |
2012 |
Early patent covering a specific chemical class |
| 5,660,871 |
Encompassing broader kinase inhibitors |
Series of related derivatives |
1994 |
2014 |
Slightly expanded chemical scope |
| EP 0571024 |
European counterpart |
Specific chemical variations |
1994 |
2014 |
European-focused patent |
Summary and implications
Patent 5,167,242 established a foundation for kinase inhibitor development targeting proliferative diseases. Its broad claims provided early protection for a class of compounds later expanded upon by subsequent patents. The patent's expiration has reduced litigation risks specific to its claims but leaves a complex landscape with overlapping patents that still influence research and commercialization strategies.
Key Takeaways
- Patent 5,167,242 covers specific 2-phenylaminopyrimidine kinase inhibitors with claims focused on chemical composition, synthesis, and use in cancer treatment.
- The patent's 20-year term ended in 2012, opening the market for generics, but surrounding patent filings maintain a dense legal landscape.
- Companies active in kinase inhibitors must track overlapping patents to ensure freedom to operate.
- Subsequent patents have extended protection on derivatives, formulations, and combination therapies.
- The patent landscape for kinase inhibitors remains active, with ongoing filings and legal considerations shaping industry strategy.
FAQs
1. Does Patent 5,167,242 cover all kinase inhibitors?
No. It covers specific pyrimidine derivatives within the kinase inhibitor class, not all kinase inhibitors.
2. Are there infringement risks for compounds similar to those in Patent 5,167,242?
Yes. Similar compounds falling within the chemical scope may face patent infringement unless they are sufficiently distinct or the patent has expired.
3. Has the patent been litigated?
No public records indicate significant litigation involving Patent 5,167,242.
4. Can generic manufacturers produce compounds claimed by this patent?
Yes, after the patent's expiry in 2012, generic production became feasible, subject to current patent landscape constraints.
5. How does this patent relate to modern EGFR inhibitors?
It laid early groundwork for kinase inhibitor chemistry but does not cover the latest drugs like osimertinib, which are protected by newer patents.
References
- U.S. Patent and Trademark Office. (1992). Patent 5,167,242.
- European Patent Office. (1994). EP 0571024.
- PatentScope. (2012). Patent expiry and family data.
- Novartis. (2004). Patent filings on kinase inhibitors.
- WHO. (2020). Cancer treatment innovations and patent landscape.
