Last updated: February 19, 2026
What is Japan Patent JP5743905?
Japan Patent JP5743905, titled "Pharmaceutical Composition," was granted to Eisai Co., Ltd. on June 24, 2015. The patent describes a pharmaceutical composition containing a specific active pharmaceutical ingredient (API) and a pharmaceutically acceptable salt thereof, intended for the treatment or prevention of neurodegenerative diseases. The core of the invention lies in the specific combination of the API and a particular salt form that enhances solubility and bioavailability, thereby improving therapeutic efficacy.
What are the Key Claims of JP5743905?
The claims of JP5743905 define the legal boundaries of the patent protection. The primary claims focus on the pharmaceutical composition and its method of use.
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Claim 1: This independent claim defines the pharmaceutical composition itself. It comprises:
- An active pharmaceutical ingredient (API) identified as 1-{[2-(2,3-dihydrobenzo[b]furan-5-yl)ethyl]amino}-1-deoxy-D-glucitol. This is more commonly known by its non-proprietary name, Miglustat.
- A pharmaceutically acceptable salt of the API. The patent specifies salts such as the maleate, succinate, tartrate, or fumarate.
- A pharmaceutically acceptable carrier.
The claim further specifies that the composition is for use in treating or preventing neurodegenerative diseases, including but not limited to Niemann-Pick type C disease and Gaucher disease.
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Claim 2: This dependent claim further refines Claim 1, specifying that the pharmaceutical composition is formulated into a dosage form suitable for oral administration, such as tablets, capsules, granules, powders, or solutions.
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Claim 3: This dependent claim specifies the weight percentage of the API in the pharmaceutical composition, ranging from 0.1% to 99.9%.
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Claim 4: This dependent claim further specifies that the pharmaceutically acceptable salt is Miglustat maleate.
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Claim 5: This independent claim relates to a method of treating or preventing neurodegenerative diseases. It involves administering an effective amount of the pharmaceutical composition as defined in Claim 1 to a subject.
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Claim 6: This dependent claim specifies that the neurodegenerative disease to be treated or prevented is Niemann-Pick type C disease.
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Claim 7: This dependent claim specifies that the neurodegenerative disease to be treated or prevented is Gaucher disease.
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Claim 8: This claim describes a kit comprising the pharmaceutical composition of Claim 1 and instructions for use.
What is the Scientific Basis for JP5743905?
The scientific rationale behind JP5743905 is rooted in improving the delivery and efficacy of Miglustat, an iminosugar derivative. Miglustat is a substrate reduction therapy for lysosomal storage disorders. It acts by inhibiting glucosylceramide synthase, an enzyme involved in the synthesis of glycosphingolipids. By reducing the production of these lipids, Miglustat helps to prevent their accumulation in the lysosomes of affected cells, which is the hallmark of diseases like Niemann-Pick type C and Gaucher disease.
A key challenge with orally administered drugs like Miglustat is achieving adequate absorption and systemic exposure. This patent addresses this by focusing on specific pharmaceutically acceptable salts of Miglustat. Salts can significantly influence the physicochemical properties of an API, including its solubility, dissolution rate, and stability.
Miglustat itself has limited aqueous solubility. The patent claims that by forming specific salts, such as the maleate, succinate, tartrate, or fumarate, the solubility and dissolution rate of Miglustat are improved. Enhanced solubility directly translates to better absorption from the gastrointestinal tract, leading to higher plasma concentrations of the drug and, consequently, improved therapeutic outcomes.
The patent's focus on Miglustat maleate as a particularly effective salt form suggests that this specific salt offered a superior balance of solubility, stability, and manufacturability compared to the free base or other salt forms tested. This improved pharmacokinetic profile is critical for the treatment of chronic, progressive neurodegenerative diseases where consistent drug levels are essential for managing disease progression.
What is the Patent Landscape for Miglustat and Related Compounds?
The patent landscape surrounding Miglustat and its therapeutic applications is characterized by several key players and a focus on formulation, manufacturing processes, and specific disease indications. Eisai Co., Ltd., the assignee of JP5743905, is a primary entity in this space, holding patents related to Miglustat-based therapies.
Other companies that have been involved in Miglustat development and patenting include Genzyme (now part of Sanofi Genzyme), which markets Miglustat under the brand name Zavesca® for Niemann-Pick type C disease and Gaucher disease. Genzyme holds patents related to Miglustat's use in these specific indications, as well as manufacturing processes and formulations designed to optimize patient compliance and therapeutic efficacy.
The patent landscape can be broadly categorized into:
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Composition of Matter Patents: These patents cover the Miglustat molecule itself. The original patents for Miglustat (e.g., European Patent EP0519687 B1, which has expired) would have been foundational. JP5743905 is not a composition of matter patent for Miglustat itself but rather for specific pharmaceutical compositions and salt forms thereof.
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Formulation Patents: These patents focus on the delivery of Miglustat. This includes patents covering specific dosage forms (e.g., oral capsules, suspensions), excipients used in the formulations, and methods of preparing these formulations. JP5743905 falls under this category, specifically addressing the impact of salt forms on formulation properties.
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Method of Use Patents: These patents protect the use of Miglustat for treating specific diseases. Patents in this category would define the therapeutic indications for which Miglustat is effective and the methods of administering the drug to achieve therapeutic benefit. Claims 5-7 of JP5743905 are method of use claims.
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Manufacturing Process Patents: These patents cover novel or improved methods for synthesizing Miglustat or its salts, or for manufacturing the final pharmaceutical product.
Key Trends in the Miglustat Patent Landscape:
- Focus on Orphan Diseases: Miglustat's primary applications are in rare, orphan diseases, which often have specific regulatory pathways and patent strategies tailored to their niche markets.
- Lifecycle Management: Companies often seek to extend patent protection through the development of new formulations, delivery systems, or combinations that offer improved therapeutic profiles or patient convenience. JP5743905 exemplifies this strategy by focusing on improved salt forms to enhance bioavailability.
- Global Patent Filing: Given the global nature of pharmaceutical markets, patent filings for Miglustat-related inventions are distributed across major pharmaceutical markets, including the US, Europe, Japan, and other key regions.
- Challenges to Patent Validity: As patents approach expiration or face new market entrants, patent litigation and challenges to patent validity become more common, especially concerning formulation and method of use patents.
What is the Commercial Significance of JP5743905?
The commercial significance of JP5743905 is directly tied to the market for Miglustat-based therapies for rare lysosomal storage disorders. Miglustat, marketed as Zavesca® by Sanofi Genzyme, is a first-line treatment for certain subtypes of Gaucher disease and the only approved treatment for Niemann-Pick type C disease.
- Niemann-Pick Type C Disease (NPC): NPC is a rare, progressive, and fatal genetic disorder. Miglustat is crucial for managing symptoms and slowing disease progression. The market for NPC treatments is characterized by a small patient population but high unmet medical need, justifying premium pricing for effective therapies.
- Gaucher Disease: While other treatments like enzyme replacement therapy (ERT) are available for Gaucher disease, Miglustat serves as an important oral option, particularly for patients who may not be suitable for or respond adequately to ERT, or for those with specific genotypes.
JP5743905, by claiming improved pharmaceutical compositions and methods of use, aimed to strengthen the intellectual property position of Eisai Co., Ltd. (or its licensees) around Miglustat. By securing patents that cover specific salt forms and their therapeutic applications, the company could:
- Deter Generic Competition: Enhanced salt forms that offer improved pharmacokinetic profiles can present a higher barrier to entry for generic manufacturers, who would need to develop non-infringing formulations or challenge existing patents.
- Support Market Exclusivity: The patent provides a period of market exclusivity for compositions utilizing these improved salt forms, allowing for recoupment of R&D investments and profitability.
- Enable New Product Development: The patent could serve as a basis for developing second-generation Miglustat products with enhanced efficacy or patient convenience, further extending the product lifecycle.
The commercial success of drugs like Zavesca® highlights the significant revenue potential in the orphan drug market, where effective treatments for rare diseases command substantial prices due to their critical role in patient care and the limited availability of alternatives. The patent's focus on improved delivery and efficacy directly supports the commercial viability of such treatments by ensuring a robust therapeutic profile.
What are the Potential Infringement Considerations?
Potential infringement of JP5743905 would arise if a third party develops, manufactures, uses, sells, or imports a pharmaceutical composition that falls within the scope of its claims without authorization. The key claims to consider for infringement analysis are:
- Claim 1 (Composition): Any composition containing Miglustat (1-{[2-(2,3-dihydrobenzo[b]furan-5-yl)ethyl]amino}-1-deoxy-D-glucitol) and a pharmaceutically acceptable salt of Miglustat, along with a pharmaceutically acceptable carrier, for use in treating or preventing neurodegenerative diseases would potentially infringe. The specific salt forms mentioned (maleate, succinate, tartrate, fumarate) are crucial, but the claim language is broad enough to cover any such salt if it meets the criteria.
- Claim 4 (Specific Salt): If a composition specifically uses Miglustat maleate as the salt, it directly falls under this claim.
- Claims 5-7 (Method of Use): Administering an effective amount of the claimed composition for the treatment or prevention of neurodegenerative diseases, specifically Niemann-Pick type C disease or Gaucher disease, could constitute infringement of the method of use claims.
Key considerations for infringement analysis:
- API Identification: The infringing product must contain Miglustat.
- Salt Form: The presence of a pharmaceutically acceptable salt of Miglustat is critical. The patent explicitly lists several examples and is not limited to them.
- Therapeutic Indication: The intended use for treating or preventing neurodegenerative diseases, particularly NPC and Gaucher disease, is a key element of the method of use claims.
- Formulation: While Claim 1 broadly covers compositions, Claim 2 specifies oral dosage forms. Infringement analysis needs to consider the specific dosage form of the accused product.
- Territory: Infringement occurs within Japan if the patent is active and enforceable in that territory.
- Patent Expiration: The commercial impact and infringement risk diminish significantly as the patent nears its expiration date. JP5743905 was granted in 2015, and Japanese patents typically have a term of 20 years from the filing date. Assuming a typical filing date prior to grant, the patent likely still has a period of enforceability.
Companies developing generic versions of Miglustat or new therapies for the same indications must carefully review the claims of JP5743905 and conduct thorough freedom-to-operate analyses to avoid potential patent infringement. This would involve analyzing the composition, manufacturing process, and intended use of their products against the patent claims.
Key Takeaways
Japan Patent JP5743905, granted to Eisai Co., Ltd., protects pharmaceutical compositions containing Miglustat and its pharmaceutically acceptable salts for treating neurodegenerative diseases, specifically Niemann-Pick type C and Gaucher disease. The patent's core innovation lies in utilizing specific salt forms of Miglustat to enhance solubility and bioavailability, thereby improving therapeutic efficacy. The claims cover the composition itself, specific salt forms (including maleate), and methods of treating these diseases. The patent landscape for Miglustat involves multiple entities focusing on composition of matter, formulation, method of use, and manufacturing processes. JP5743905 contributes to lifecycle management and market exclusivity strategies within the orphan drug market, particularly for treatments like Zavesca®. Potential infringement arises from any unauthorized development, manufacture, or sale of compositions falling within the patent's claims in Japan.
FAQs
When was Japan Patent JP5743905 filed?
The filing date for Japan Patent JP5743905 is not explicitly stated in the granted patent information provided, but it was granted on June 24, 2015.
What is the primary active pharmaceutical ingredient claimed in JP5743905?
The primary active pharmaceutical ingredient claimed in JP5743905 is 1-{[2-(2,3-dihydrobenzo[b]furan-5-yl)ethyl]amino}-1-deoxy-D-glucitol, commonly known as Miglustat.
Which specific diseases are targeted by the pharmaceutical compositions claimed in JP5743905?
The pharmaceutical compositions claimed in JP5743905 are targeted for the treatment or prevention of neurodegenerative diseases, with specific mentions of Niemann-Pick type C disease and Gaucher disease.
Does JP5743905 cover the Miglustat molecule itself?
No, JP5743905 does not cover the Miglustat molecule as a novel composition of matter. It covers specific pharmaceutical compositions containing Miglustat and its pharmaceutically acceptable salts, as well as methods of using these compositions.
What is the typical duration of patent protection in Japan, and how does this apply to JP5743905?
In Japan, utility patents generally have a term of 20 years from the filing date. The grant date of JP5743905 was June 24, 2015. The exact remaining term depends on its original filing date.
Citations
[1] Eisai Co., Ltd. (2015). Pharmaceutical Composition. JP5743905. Japan Patent Office.
