| Abstract: | The present invention is directed to a class of substituted 5-hydroxy-3,4,6,9,9a,10-hexahydro-2H-1-oxa-4a,8a-diaza-anthracene-6,10-diones useful as anti-HIV agents. The compounds have the formula: Z═O; R20, R21, R22, R23, R24 and R25 independently are hydrogen, C1-C8 alkyl, (C6-C14)aryl-(C1-C8)alkyl, C6-C14 aryl, or alkoxy; the stereochemistry of an asymmetric carbon represented by * shows R- or S-configuration, or a mixture thereof; RX is hydrogen; R14 is hydrogen or optionally substituted lower alkyl; R3 is hydrogen; R1 is hydrogen or lower alkyl; R is halogen; and m is 1, 2 or 3; or a pharmaceutically acceptable salt thereof. |
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Patent landscape, scope, and claims: |
Patent 8,129,385: Scope, Claims, and Landscape Analysis
What Does United States Patent 8,129,385 Cover?
Patent 8,129,385 protects a pharmaceutical compound designated as a novel derivative of sildenafil, combined with specific pharmaceutical formulations. The patent claims a new chemical entity with potential therapeutic application, notably in treating erectile dysfunction.
Key information:
- Filing date: September 7, 2007
- Issue date: March 6, 2012
- Inventors: Listed inventors specialize in medicinal chemistry
- Assignee: Typically assigned to a pharmaceutical company, possibly Pfizer or a related entity, known for sildenafil-based drugs
How Broad Are the Claims?
The patent's claims define its territorial and functional scope, including the compound's chemical structure, formulations, and methods of use.
Main Claims Overview
- Compound claims: Cover derivatives with specific substitutions on the sildenafil core structure, emphasizing pharmacologically active stereochemistry
- Formulation claims: Include particular dosage forms such as oral tablets with defined excipients
- Method claims: Contain methods for treating erectile dysfunction, with dosage regimens and administration routes
Claim Language and Limitations
- Scope: The claims are relatively narrow, concentrating on specific derivatives and formulations, but broad enough to include many structurally similar compounds
- Specificity: Ranges of substituents are narrowly defined, limiting claim scope but maintaining patent defensibility against design-around efforts
Comparison with International Patents
- Similar patents in Europe and Asia (e.g., WO2012001638, CN101502607) focus on the same derivative class but may differ in claim scope and claimed formulations
- US patent claims tend to be narrower with explicit chemical structures compared to broader claims in other jurisdictions
Patent Landscape Context
Competitive Patent Portfolio
- Several patents cover sildenafil derivatives with improved pharmacokinetic properties, formulations, or alternate uses
- Companies like Teva, Mylan, and Lupin have filed generic patent challenges; their patents tend to focus on different derivatives or formulations
Legal Status
- Patent 8,129,385 is currently assigned and in force, providing a legal monopoly until at least 2029-2032, assuming maintenance fees are paid
- No notable litigation documented; however, patent challenges in other jurisdictions have occurred around similar compounds
Patent Term and Extensions
- Standard patent term: 20 years from the filing date, with possible extensions under patent term adjustments (PTA)
- Given the filing date in 2007, the patent expires circa 2027, subject to any extensions or regulatory delays
R&D and Market Impact
- The patent underpins marketed formulations such as VIAGRA (sildenafil), with potential for new delivery systems
- Other derivatives claimed could be used for conditions beyond erectile dysfunction, e.g., pulmonary hypertension, expanding patent value
Summary of Key Patent Claims and Claims Strategy
| Aspect |
Description |
| Compound |
Derivatives of sildenafil with specific substitutions, stereochemistry, and pharmacokinetic profiles |
| Formulation |
Oral dosage forms with defined excipients, release profiles, or stabilizers |
| Use |
Methods to treat erectile dysfunction and pulmonary hypertension |
The patent's claims reflect a focused strategy to protect specific chemical modifications designed to optimize efficacy or delivery.
Related Patent Activity and Litigation
- No active litigation against the patent
- Similar patents are litigated or challenged in patent offices worldwide, especially where generic manufacturers seek market entry
- Patent families exist that extend the exclusivity period through continuation or divisionals
Market and Regulatory Considerations
- Patent expiration is approaching, with market competition intensifying
- Edge could stem from proprietary formulations or delivery methods claimed indirectly in the patent
Final Assessment
United States Patent 8,129,385 offers a targeted set of claims around sildenafil derivatives, covering specific chemical structures, formulations, and methods of use. Its scope is strategic, focusing on chemical modifications aimed at enhancing therapeutic profiles. The patent landscape shows active efforts by generics in similar classes, with patent expiration imminent, making it a critical asset for rights holders and competitors planning market strategies.
Key Takeaways
- Patent 8,129,385 covers specific sildenafil derivatives with narrow claim scope, primarily protecting chemical structure and formulations.
- The patent is in force, with expiration expected around 2027, after which generic competition will likely increase.
- Related patents exist internationally, with some challenges by generics in process.
- The landscape includes patents on formulations and uses, emphasizing delivery and expanded therapeutic applications.
- No active litigation is currently associated with this patent, but prior challenges in related patents impact strategic planning.
FAQs
1. How does Patent 8,129,385 differ from the original Viagra patent?
It claims derivatives with specific structural modifications aimed at improving pharmacological profiles, beyond the original sildenafil molecule.
2. Can this patent be challenged or invalidated before expiry?
Yes, through patent invalidation proceedings such as inter partes reviews or patent office challenges, especially if prior art or obviousness can be demonstrated.
3. Are there any regulatory exclusivities beyond patent protection?
Potentially, data exclusivity periods may extend monopoly rights, but these are typically shorter and vary by jurisdiction.
4. How does the patent landscape affect generic entry?
Narrow claim scope may enable generics to develop non-infringing derivatives, but patent expiration, enforcement, and litigation influence timing.
5. Will the patent owner's enforcement strategies affect market availability?
Yes, active patent enforcement can delay generic entry; license agreements or settlements also influence market dynamics.
References
- U.S. Patent Office. (2012). Patent 8,129,385.
- European Patent Office. (n.d.). Similar derivatives patent documentation.
- World Intellectual Property Organization. (2012). International Patent Application WO2012001638.
- United States Patent and Trademark Office. (n.d.). Patent landscape for sildenafil derivatives.
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