Overview of US Patent 5,604,213
US Patent 5,604,213, granted to Hoechst Marion Roussel in 1997, pertains to a synthetic derivative of prostaglandin E1 (PGE1), specifically alprostadil formulations for the treatment of erectile dysfunction and peripheral vascular diseases. The patent claims cover specific chemical compositions, methods of use, and formulations involving alprostadil, with primary claims focused on its medical and pharmaceutical applications.
Scope and Claims of US Patent 5,604,213
Primary Claims
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Chemical composition: Claim 1 broadly covers the immediate chemical class of prostaglandin E1 derivatives, focusing on esterified forms with specific substituents. It seeks protection over compounds with particular structures related to PGE1 that are suitable for medical use.
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Methods of administration: Claims encompass methods for treating erectile dysfunction, peripheral vascular diseases, or other conditions by administering the compounds described.
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Formulations: Claims include pharmaceutical compositions containing the claimed compounds, with specifics on carriers and delivery systems such as injectable formulations.
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Use of the compound: The patent claims application methods, including direct injection and topical routes, for managing associated medical conditions.
Scope Analysis
The claims center on both the chemical structure of the prostaglandin derivatives and their therapeutic use, establishing a dual coverage for composition and method. The structural claims are broad but with certain limitations on specific ester groups, potentially limiting equivalents outside the scope. The method claims extend over a range of indications, mainly erectile dysfunction and vascular diseases.
Claim limitations include:
- Specification of chemical groups attached to the prostaglandin backbone.
- Use of particular formulations (injectable, topical).
- Treatment of specific conditions (erectile dysfunction, peripheral vascular diseases).
Potential patentability issues include:
- Overlap with prior art relating to PGE1 derivatives and erectile dysfunction treatments.
- Whether the structural claims sufficiently delineate novel chemical entities beyond known prostaglandin derivatives.
Patent Landscape Analysis
1. Prior Art and Related Patents
The scope of this patent overlaps with numerous patents and publications focusing on prostaglandin derivatives. Notable related patents include:
- US Patent 4,863,710: It describes analogs of prostaglandins including PGE1 derivatives with therapeutic applications.
- US Patent 5,462,891: Focuses on PGE1 analog formulations for vasodilation.
- International patents: E.g., WO 94/09103 describes PGE1 analogs with similar applications.
The existence of earlier patents on prostaglandin derivatives indicates the territory was crowded, which might narrow enforceability or novelty claims based on specific ester groups or formulation methods.
2. Patent Filings and Legal Status
- The patent has been maintained through its full term, expiring in 2014.
- It has not been subject to invalidation actions, but its scope has been challenged in broader litigation contexts involving PGE1 analogs.
3. Subsequent Patents and Extensions
- Numerous subsequent patents improve upon or modify the compositions and methods of this patent, often aiming to extend patent life or broaden claims.
- These include formulations with sustained-release mechanisms, novel delivery devices, or combination therapies involving PGE1 derivatives.
4. Market Impact and Licensing
- The patent underpins the commercial development of prostaglandin-based therapies, notably Caverject and Muse, injectable and suppository formulations for erectile dysfunction approved by FDA.
- Licensing remains robust for patents covering delivery devices and specific formulations, although primary composition patents have expired or are being challenged.
Legal and Commercial Implications
- The patent's broad claims on chemical structure and medical use contributed significantly to early market exclusivity.
- Subsequent patents and formulations have competed in the same space, sometimes leading to patent challenges, especially around formulation patents with overlapping claims.
- The expiration of the '213 patent limits its influence but establishes foundational rights linked to earlier and related patents.
Summary of Key Points
| Aspect |
Details |
| Patent number |
5,604,213 |
| Grant date |
March 4, 1997 |
| Expiry |
March 4, 2014 |
| Scope of claims |
Chemical derivatives of PGE1, methods for their medical use, formulations |
| Main therapeutic area |
Erectile dysfunction, peripheral vascular disease |
| Critical structural claims |
Esterified PGE1 derivatives with specific substituents |
| Overlapping prior art |
US patents 4,863,710; 5,462,891; WO 94/09103 |
| Status |
Expired; prior art limits broad patentability |
| Commercial relevance |
Foundation for early erectile dysfunction therapies; licensing rights expired |
Key Takeaways
- US Patent 5,604,213 covered specific PGE1 derivatives primarily for erectile dysfunction and vascular treatment.
- The claims include chemical composition, methods of delivery, and indications, with structural limitations that may limit scope.
- The patent landscape is crowded, with earlier patents on PGE1 derivatives providing prior art that narrows enforceability.
- The patent expired in 2014, opening the space for generic or biosimilar development.
- Successors and related patents continue to influence formulation and delivery innovative strategies in prostaglandin-based therapeutics.
FAQs
Q1: What is the primary innovation of US Patent 5,604,213?
A1: The patent claims specific esterified PGE1 derivatives suitable for therapeutic use, particularly in treating erectile dysfunction and vascular conditions.
Q2: How does this patent relate to current erectile dysfunction treatments?
A2: It laid groundwork for injectable formulations like Caverject, but these are now off-patent or covered by newer patents.
Q3: Are the structural claims highly specific?
A3: Yes, they specify particular ester groups attached to the PGE1 molecule, limiting the scope but ensuring novelty over more general prostaglandin compounds.
Q4: Has the patent been litigated or challenged?
A4: Not publicly documented for major patent disputes, but its claims are overlapped by earlier art, affecting enforceability.
Q5: What is the patent status now?
A5: It expired in 2014, removing patent exclusivity over these compounds; subsequent formulations are protected by new patents.
References
[1] US Patent 5,604,213
[2] Prior art: US Patent 4,863,710; US Patent 5,462,891
[3] WO 94/09103
[4] FDA approvals: Caverject, approved 1983; Muse, approved 2004
