Understanding the Scope and Claims of United States Patent 6,495,541: A Detailed Analysis
Introduction to Rucaparib and US Patent 6,495,541
Rucaparib, a powerful poly (ADP-ribosyl) transferase (PARP) inhibitor, was first prepared and patented by the University of Newcastle in England in 2000. It was later approved by the U.S. Food and Drug Administration (FDA) in April 2015 for the treatment of ovarian cancer and launched in the United States under the trade name Rubraca in December 2016[1].
Overview of US Patent 6,495,541
US Patent 6,495,541, filed on January 10, 2000, and expired on January 10, 2020, is a core patent in the Rucaparib patent portfolio. This patent is crucial for understanding the initial protection and subsequent strategies for extending patent protection.
Core Claims and Composition
The patent claims protection for a compound and a composition comprising that compound. Specifically, it discloses the synthesis, 1H-NMR, and mass spectrometry of 8-fluoro-2-(4-methylaminomethylphenyl)-1,3,4,5-tetrahydro-azaheterocyclic heptene [5,4,3-CD] indole-6-one, which is Rucaparib. This compound is identified as a potent PARP inhibitor and is used for treating cancer, as well as improving the curative effects of stroke, head trauma, and neurodegenerative diseases[1][4].
Technical Details and Examples
The patent includes detailed technical descriptions, such as Example IIII, which outlines the synthesis and characterization of Rucaparib. This example provides specific data on the pharmacokinetics of the compound, including its plasma and tumor concentrations in mice, which are critical for understanding its therapeutic efficacy[1].
Patent Strategy and Portfolio
Basic Patents
The initial stage of the patent portfolio involves basic patents for general and specific compounds. US Patent 6,495,541 is the foundational patent in this category, providing broad protection for the compound itself and its composition.
Peripheral Patents
Following the basic patents, the applicant filed several peripheral patents to expand and strengthen the protection. These include patents for:
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Indications: Patents such as US7351701 and US7531530, filed on July 23, 2004, protect the application of Rucaparib for treating BRCA1 and/or BRCA2 expression deficient cancer cells. Later patents like US8071579 and US8143241, filed on August 12, 2007, further specify the use of PARP inhibitors for similar cancer treatments[1].
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Formulation Research: Patents like US9987285, filed on August 17, 2015, focus on formulation research, including the development of tablets and dry granular tablets. This patent highlights the use of camphorsulfonate formulations, which offer better tensile strength compared to maleate formulations, ensuring the tablets meet the required strength standards[1].
Patent Scope and Claims Analysis
Independent Claim Length and Count
The scope of a patent can be measured using metrics such as independent claim length and independent claim count. Narrower claims, as seen during the examination process, are associated with a higher probability of grant and a shorter examination process. This is relevant as the examination process tends to narrow the scope of patent claims, ensuring clarity and validity[3].
Forward Citations and Patent Maintenance
Patents with narrower claims at publication tend to have more forward citations, indicating their influence on subsequent innovations. Additionally, these patents often require fewer maintenance payments, suggesting a more focused and valuable intellectual property[3].
International and National Filings
PCT and National Entries
The patent application for Rucaparib has been filed under the Patent Cooperation Treaty (PCT), allowing for international protection. For example, the Canadian patent CA 2955495, filed on August 17, 2015, and granted on September 19, 2023, protects high dosage strength tablets of Rucaparib. This demonstrates the global strategy for patent protection[2].
Ownership and Licensing
Current and Past Owners
The ownership of the Rucaparib patents has changed over time. For instance, the Canadian patent CA 2955495 is currently owned by Pharma & Schweiz GmbH, while it was previously owned by Clovis Oncology, Inc.[2].
Impact on Innovation and Market
Extending Patent Protection
The strategy of filing basic and peripheral patents effectively extends the protection period of Rucaparib. This approach ensures that the drug remains under patent protection for a longer period, allowing the patent holder to maintain market exclusivity and recoup investment in research and development[1].
Market Domination
By securing a robust patent portfolio, pharmaceutical companies can dominate the market for specific treatments. For Rucaparib, this means maintaining a competitive edge in the treatment of ovarian cancer and other BRCA-related cancers, which is crucial for both patient care and business sustainability.
Key Takeaways
- Core Patent: US Patent 6,495,541 is the foundational patent for Rucaparib, providing initial protection for the compound and its composition.
- Peripheral Patents: Subsequent patents for indications, formulations, and other aspects extend the protection period and strengthen the patent portfolio.
- International Protection: Filing under PCT and national entries ensures global protection for Rucaparib.
- Ownership: Changes in ownership, such as from Clovis Oncology to Pharma & Schweiz GmbH, reflect the evolving landscape of intellectual property management.
- Market Impact: A robust patent portfolio helps in maintaining market exclusivity and dominating the market for specific treatments.
FAQs
What is Rucaparib and its primary use?
Rucaparib is a PARP inhibitor used primarily for the treatment of ovarian cancer, particularly in patients with BRCA1 and/or BRCA2 expression deficient cancer cells.
When was US Patent 6,495,541 filed and expired?
US Patent 6,495,541 was filed on January 10, 2000, and expired on January 10, 2020.
How does the patent portfolio for Rucaparib extend its protection period?
The protection period is extended through a combination of basic patents for the compound and subsequent peripheral patents for indications, formulations, and other aspects.
What is the significance of camphorsulfonate formulations in Rucaparib tablets?
Camphorsulfonate formulations offer better tensile strength compared to maleate formulations, ensuring the tablets meet the required strength standards for effective use.
Who are the current owners of the Rucaparib patents?
The current owners of the Rucaparib patents include Pharma & Schweiz GmbH, with past ownership by Clovis Oncology, Inc.
Sources
- Analysis of Strategy for Extending Patent Protection of Rucaparib - SCIRP.
- Patent 2955495 Summary - Canadian Patents Database - brevets-patents.ic.gc.ca.
- Patent Claims and Patent Scope - SSRN.
- US6495541B1 - Tricyclic inhibitors of poly(ADP-ribose) polymerases - Google Patents.
- Patent Extension Application for RUBRACA® US Patent No. 6495541 - regulations.gov.
