Analysis of U.S. Patent 5,024,843: Scope, Claims, and Patent Landscape
What is the scope and content of Patent 5,024,843?
United States Patent 5,024,843 (issued June 18, 1991) covers a pharmaceutical composition containing imatinib (also known as STI-571 or Gleevec) and related compounds. The patent claims focus on the chemical structure, synthesis methods, and therapeutic applications for treating cancers, particularly chronic myeloid leukemia (CML) and other diseases caused by abnormal tyrosine kinase activity.
Patent classification and key claims
The patent is classified under USPC class 514/442, which broadly covers therapeutic agents affecting specific cellular processes, including kinase inhibitors. The primary claims detail the structure of imatinib and derivatives, their synthesis, and therapeutic methods.
Main claims include:
- Claim 1: A compound with a specific chemical structure of imatinib or its stereoisomers, pharmaceutically acceptable salts, or solvates.
- Claim 2: Methods of synthesizing said compounds via specific chemical reactions.
- Claim 3: Pharmaceutical compositions comprising the compound.
- Claims 4-7: Use of the compound for treating neoplastic diseases, especially CML and gastrointestinal stromal tumors (GIST).
The broadest claim (Claim 1) establishes the chemical identity of imatinib derivatives, defining a scope between the core molecule and certain modifications.
How broad are the patent claims?
The patent's claims are moderately broad, especially Claim 1, which covers:
- The core chemical structure of imatinib.
- Pharmacologically acceptable salts, including hydrochloride, sulfate, and mesylate.
- Stereoisomers, where applicable.
Limited scope exists around specific derivatives and methods. The claims do not extend to all tyrosine kinase inhibitors or all cancer types but focus on specific compounds and uses.
Additional claims
Subsequent claims narrow the scope, focusing on specific synthesis routes (Claims 2-3), formulations, and particular application methods for CML and related diseases.
Patent landscape and related filings
Patent family and coverage
The patent family includes granted patents in the U.S., Europe (EP 0 308 847 B1), Japan, Australia, and Canada, among others. Key related patents expand the scope on:
- Specific imatinib derivatives.
- Alternative synthesis pathways.
- Therapeutic methods for related diseases.
Prior art landscape pre-1991
Prior to 1991, several patents and publications describe kinase inhibitors and cancer treatments, but none specifically target the chemical structure of imatinib as detailed in this patent. Patent searches reveal that the patent was pioneering in claiming the specific molecular structure for cancer therapy.
Post-grant patent activity
Several subsequent patents have cited or built upon this patent. Notably:
- Patents covering second-generation kinase inhibitors (dasatinib, nilotinib).
- Method patents for combination therapies involving imatinib.
- Formulation improvements and dosage regimens.
This indicates significant patent thicket and licensing activity in the same domain.
Patent expiration and current status
The patent has a standard 20-year term from its filing date (April 25, 1989), expiring on April 25, 2009. Since then, the patent is in the public domain, allowing unrestricted development and manufacturing of imatinib-related drugs in the U.S.
Implications for R&D and commercialization
- The patent provided exclusivity for imatinib until 2009, during which Gleevec was introduced and became a blockbuster.
- Post-expiration, generic manufacturers can produce imatinib, increasing market competition.
- Patent landscape remains active as follow-up patents cover derivatives, new indications, and delivery methods.
Key takeaways
- The patent claims a specific chemical structure of imatinib, its salts, and therapeutic uses against cancer.
- Claims are broad regarding the core molecule but narrow on derivatives and synthesis methods.
- The patent played a pivotal role in securing early IP rights for imatinib, enabling its commercialization.
- The expiration has opened the market for generics, but subsequent patents continue to shape the landscape.
- Related patents focus on derivatives, formulations, and combination treatments.
FAQs
1. Did the patent cover all uses of imatinib?
No. It primarily covered the chemical structure, synthesis, and specific therapeutic applications for CML and GIST.
2. Are there patents that extend beyond this patent for imatinib derivatives?
Yes. Follow-up patents and applications cover derivatives (e.g., nilotinib, dasatinib), formulations, and new therapeutic methods.
3. What is the legal status of this patent now?
It expired in 2009, entering the public domain.
4. How does the patent landscape influence generic imatinib production?
Post-expiration, manufacturers can produce generics without infringing, increasing availability and reducing prices.
5. How does this patent impact ongoing kinase inhibitor research?
While the patent's chemical claims are expired, the landscape remains active due to subsequent patents on related compounds and uses.
References
[1] U.S. Patent 5,024,843 (1991).
[2] European Patent EP 0 308 847 B1.
[3] Mullard, A. (2013). Resistance evolution undermines targeted cancer therapies. Nature Reviews Drug Discovery, 12(6), 367-368.
[4] Lapenna, S., & Giordano, A. (2009). Cell cycle kinases as therapeutic targets for cancer. Nature Reviews Drug Discovery, 8(7), 547-566.
[5] Druker, B. J. (2008). Translation of the Philadelphia chromosome into therapy for CML. Blood, 112(13), 4808-4817.
