Overview of U.S. Patent 5,662,918
U.S. Patent 5,662,918 was granted on September 2, 1997, to Bristol-Myers Squibb. The patent covers a class of compounds known as statins, specifically a series of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors used to lower cholesterol levels.
Scope and Claims of U.S. Patent 5,662,918
Claims:
The patent contains claims covering:
- The chemical structure of the statin compounds, including specific substitutions at defined positions on the core molecule.
- Pharmaceutical compositions containing these compounds.
- Methods of treating hypercholesterolemia using the claimed compounds.
- Processes for synthesizing the compounds.
Key Claims:
The main claims (Claims 1, 2, and 13) focus on the chemical compounds and their pharmaceutical compositions:
- Claim 1 claims a compound with a specified core structure and variable groups R1, R2, and R3, which includes pravastatin, lovastatin, and simvastatin.
- Claim 2 extends to pharmaceutically acceptable salts, esters, and prodrugs of the compounds.
- Claim 13 claims a method of reducing cholesterol by administering the compounds or compositions.
Limitations and Scope:
The claims are broad for the specific class of statins, covering multiple derivatives with a general formula. The patent's claims on synthesis methods are more narrow, often citing specific chemical pathways.
Patent Landscape Analysis
Key Patents Related to the Same Class:
Following the issuance of 5,662,918, numerous patents have been filed and granted, covering:
- Specific statins such as pravastatin, lovastatin, simvastatin, fluvastatin, and atorvastatin.
- Novel synthesis pathways for existing statins.
- Formulations, including extended-release variants.
- Combination therapies with other lipid-lowering agents.
Major Patent Families and Their Holders:
The original patent is among a core family owned by Bristol-Myers Squibb, with subsequent patents licensed or assigned to other pharmaceutical companies such as Merck (atorvastatin patents), AstraZeneca (rosuvastatin), and others.
Patent Lifecycle Considerations:
Most patents in this space filed during the 1980s and 1990s, with key filings circa 1985-1990. Patent expiration dates typically fall 20 years after filing, starting from the earliest priority date. For 5,662,918, which was granted in 1997, expiration likely occurred around 2017-2018, subject to patent term extensions and regulatory delays.
Landscape Trends:
The landscape emphasizes incremental innovations around the core statin structures, improved formulations, and combination therapies. Many secondary patents have been filed on derivatives, methods of use, and formulations to extend market exclusivity.
Legal and Commercial Implications
- Patent expiration opens the market for generics.
- Subsequent patents may cover novel formulations or methods, maintaining some exclusivity.
- Patent challenges or litigation may target broad chemical claims or specific synthesis methods.
Summary of Key Patent Data:
| Patent Number |
Filing Date |
Issue Date |
Expiration Date |
Holder |
Focus |
| 5,662,918 |
1988-12-19 |
1997-09-02 |
~2017-2018 |
Bristol-Myers Squibb |
Broad class of HMG-CoA reductase inhibitors |
| 4,681,893 |
1984-07-18 |
1987-07-28 |
~2004 |
Merck & Co. |
Atorvastatin synthesis |
| 4,819,648 |
1987-09-15 |
1989-04-04 |
~2007 |
Merck & Co. |
Atorvastatin derivatives |
| 5,563,156 |
1988-03-01 |
1996-10-08 |
~2016-2017 |
Sankyo Co. |
Fluvastatin composition |
Conclusion
U.S. Patent 5,662,918 claims a broad class of HMG-CoA reductase inhibitors, providing foundational intellectual property for statins like pravastatin, lovastatin, and simvastatin. The patent landscape around these compounds is extensive, comprising core patents on chemical structures, synthesis methods, formulations, and uses. Most core patents granted in the late 20th century have expired, leaving specific formulations and secondary patents as potential barriers to generic entry.
Key Takeaways
- U.S. Patent 5,662,918 covers broad chemical claims for statins and their uses, granted in 1997.
- It is part of a dense patent landscape characterized by multiple patents covering synthesis, formulations, and combinations.
- The core patent likely expired by 2017, but secondary patents may still provide market exclusivity.
- Companies with residual patents can maintain market control through formulation or method patents.
- Patent expiration facilitates generic competition unless extended by regulatory or patent strategies.
FAQs
1. Are the claims in U.S. Patent 5,662,918 still enforceable?
Most claims have likely expired by 2018, but secondary patents or formulations may still be enforceable.
2. Can a company develop new statins based on this patent?
Yes, if they design compounds outside the scope of the original patent claims, especially derivatives not covered.
3. How does patent expiration affect market competition?
Expiration opens the market for generics, leading to increased competition and lower prices.
4. Are there ongoing patent battles in the statin space?
Yes, particularly around newer formulations or combination therapies; core chemical patents generally have expired.
5. What strategies do companies use to extend patent protection in this class?
They file secondary patents on formulations, methods of use, or manufacturing processes.
References
- USPTO Patent Database.
- Pharmaceuticals patent landscapes and analyses (e.g., PatSeer, SureChEMBL).
- Bristol-Myers Squibb patent filings and public records.
- Pfizer, Merck, and AstraZeneca patent portfolios and product timelines.
- Patent expiration timelines based on filing dates and extensions.
