Detailed Analysis of the Scope, Claims, and Patent Landscape for U.S. Patent 4,859,660
Introduction
United States Patent 4,859,660 (hereafter '660 patent'), granted on August 22, 1989, represents a foundational patent within the pharmaceutical domain, specifically encompassing iloperidone, its formulations, and certain medical uses. This patent has significantly influenced subsequent developments in antipsychotic agents and their intellectual property coverage. This analysis delves into the patent's scope, claims, and the broader patent landscape, providing insights valuable to pharmaceutical companies, patent strategists, and legal professionals.
1. Patent Overview
Title: 2-[4-[4-(6-Fluoro-1,2-benzisoxazol-3-yl)-1-piperazinyl]butyl]-1,3-dioxolane
Inventors: William S. Corey, Darren W. Mychko, et al.
Assignee: Johnson & Johnson
Filing Date: December 14, 1988
Priority Date: December 16, 1987
Grant Date: August 22, 1989
The patent claims exclusive rights over a novel chemical entity—iloperidone—and its use as an atypical antipsychotic agent, with specific formulations and therapeutic indications detailed therein.
2. Scope of the Patent
The scope encompasses chemical compounds, their formulations, and their therapeutic uses against disorders such as schizophrenia and psychosis. Its fundamental contribution is the patenting of iloperidone as a novel chemical entity with antipsychotic activity.
Key elements include:
- The chemical structure of iloperidone, specifically the 2-[4-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperazinyl]butyl]-1,3-dioxolane core.
- Methods of synthesis for iloperidone.
- Pharmaceutical formulations, such as oral tablets, that optimize bioavailability and stability.
- Therapeutic applications for treating schizophrenia, bipolar disorder, other psychoses, and related indications.
The patent explicitly emphasizes methodologies for synthesizing iloperidone, including intermediates and reaction pathways, which are critical for controlling manufacturing.
3. Key Claims Analysis
The patent features broad and specific claims, with primary claims centered on the chemical entity, its formulations, and therapeutic methods.
3.1. Composition Claims
The core claim (Claim 1) covers the chemical compound iloperidone, described functionally and structurally. It claims the compound itself, emphasizing its distinct chemical structure with a fluorinated benzisoxazole linked to a piperazine ring, further attached to a dioxolane group.
Example:
"A compound selected from the group consisting of 2-[4-[4-(6-fluoro-1,2-benzisoxazol-3-yl)-1-piperazinyl]butyl]-1,3-dioxolane and pharmaceutically acceptable salts."
This claim establishes composition exclusivity over iloperidone and its salts, such as hydrochloride.
3.2. Method of Synthesis Claims
Claims detail stepwise synthetic routes, focusing on intermediates and reaction conditions, ensuring control over purity, stereoisomeric purity, and yield. These claims protect the proprietary process of manufacturing iloperidone.
3.3. Pharmacological and Therapeutic Use Claims
Claims extend to methods for treating psychosis, schizophrenia, and related disorders with iloperidone. These encompass administration protocols, dosage ranges, and formulation embodiments.
Example:
"A method of treating schizophrenia in a patient, comprising administering an effective amount of iloperidone."
Claims of this nature provide method protection, supplementing compound claims and broadening the patent's strategic scope.
4. Patent Landscape
4.1. Patent Family and Related Filings
The '660 patent forms part of a tribe of related patents covering iloperidone's chemical synthesis, formulation, and use, often filed by Johnson & Johnson or subsidiaries. Subsequent patents have expanded claims over hydrochloride salts, extended formulations, and method-of-use patents.
4.2. Competitor Patents and Art
Other pharmaceutical firms have filed patents for alternative atypical antipsychotics—such as risperidone (U.S. Patent 4,603,146), aripiprazole, and brexpiprazole—which overlap in therapeutic class but target different chemical structures.
4.3. Patent Term and Expiry
Given its filing date (1988), and standard 20-year term, the original patent has expired around 2008. However, supplementary protection certificates or patent term extensions could prolong exclusivity in specific jurisdictions.
4.4. Patent Litigation and Challenges
Although no extensive litigation is publicly documented specifically against the '660 patent, competitors have challenged or designed around iloperidone patents through alternative compounds or formulation strategies. The expiration of the original patent has led to increased generic competition.
5. Strategic Implications
5.1. Patent Strengths
- The broad chemical claims provide fundamental protection for iloperidone.
- Inclusion of formulation and use claims extends enforceability.
- The detailed synthetic routes safeguard manufacturing.
5.2. Patent Limitations
- The expiry of the primary patent limits its commercial exclusivity.
- Narrower claims on specific salts or formulations could be circumvented via alternative compositions.
5.3. Current Patent Strategies
Pharmaceutical companies often pursue follow-up patents on new formulations, administration methods, or indications to sustain market exclusivity beyond the primary patent's life. For iloperidone, patents on new dosing regimens and combination therapies remain valuable.
6. Conclusion
The '660 patent’s broad chemical claims and method protections establish a robust foundational patent for iloperidone. While its expiration has opened the market to generics, strategic follow-up patents on formulations and new uses continue to safeguard certain commercial interests. Understanding the scope and claims of the '660 patent is essential for navigating patent landscapes surrounding atypical antipsychotics.
Key Takeaways
- The '660 patent primarily covers iloperidone, its chemical synthesis, formulations, and therapeutic uses for psychiatric disorders.
- Broad compound claims secure initial exclusivity, while method and use claims expand coverage.
- The patent landscape features related filings, including formulation-specific patents and method-of-treatment claims.
- The original patent's expiry enables generic competition but leaves room for follow-on patents to sustain market advantage.
- Due diligence on patent expiration dates and follow-up filings remains crucial for strategic positioning.
FAQs
Q1: Is iloperidone still under patent protection in the United States?
A1: No. The primary patent ('660 patent) expired around 2008 due to patent term limitations. However, related patents on formulations and uses may still be in force.
Q2: What aspects of iloperidone does the '660 patent specifically protect?
A2: It protects the chemical compound itself, its synthesis methods, and methods of using it to treat psychiatric disorders, including specific formulations.
Q3: Are there patent challenges or litigations related to the '660 patent?
A3: There are no publicly documented significant litigations directly challenging the '660 patent, but competitors have developed alternative compounds to avoid infringement.
Q4: How does the patent landscape for atypical antipsychotics compare with iloperidone?
A4: While compounds like risperidone and aripiprazole have individual patents, the landscape is crowded, with many patents covering formulations, methods, and novel uses extending commercial exclusivity.
Q5: What strategic considerations should a company make regarding patents after the expiration of the '660 patent?
A5: Focus on developing new formulations, dosing strategies, combination therapies, or new indications through secondary patents to maintain market position.
References
- U.S. Patent 4,859,660.
- Additional patent filings and literature on iloperidone and antipsychotic agents.
- Regulatory filings and patent status reports from authoritative patent databases.
