Last updated: February 23, 2026
What is the scope of patent EP3791861?
EP3791861 is a European patent granted for a selective serotonin reuptake inhibitor (SSRI) compound. The patent primarily covers a novel class of substituted phenylpiperazine derivatives with specific substitution patterns, demonstrated to inhibit serotonin reuptake effectively. The patent claims extend to pharmaceutical compositions, methods of synthesis, and their use in treating psychiatric disorders such as depression and anxiety.
The patent's scope encompasses:
- Chemical compounds: Substituted phenylpiperazine derivatives with particular structural features.
- Methods of use: Treatment methods involving administrating these compounds for psychiatric conditions.
- Pharmaceutical compositions: Formulations containing these derivatives.
- Synthesis processes: Specific methods for manufacturing the compounds.
The claims are constructed to protect both the compounds and their therapeutic applications, including salts, isomers, and prodrugs derived from the core compounds.
What are the main claims of EP3791861?
The patent includes independent claims and multiple dependent claims. The most significant claims are:
Independent Claims:
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Compound claims: A chemical entity characterized by a substituted phenylpiperazine structure, with precise substitution patterns on the phenyl and piperazine rings. For example, claim 1 defines a compound with specific substituents at designated positions on the phenyl and piperazine rings.
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Use claims: Method of treating depression or other psychiatric conditions by administering a compound as defined in claim 1.
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Composition claims: Pharmaceutical formulations containing the claimed compounds combined with pharmaceutically acceptable excipients.
Dependent Claims:
- Variations of the core structure with specific substitutions.
- Particular salts and stereoisomers.
- Specific synthesis methods.
- Controlled release formulations for sustained therapeutic levels.
Claim Scope Analysis:
The claims are narrowly focused on specific substituted phenylpiperazine derivatives that demonstrate serotonin reuptake inhibition. The chemical scope is broad enough to cover minor structural variations as long as they meet the functional criteria outlined.
What is the patent landscape surrounding EP3791861?
The patent landscape includes:
Patent family and jurisdiction coverage:
- Patent family includes counterparts filed in multiple jurisdictions, extending protection beyond Europe, notably in the US and Japan.
- Patent expiry is expected around 2035-2038, considering patent term adjustments.
Summary tables
| Aspect |
Details |
| Patent number |
EP3791861 |
| Filing date |
July 18, 2018 |
| Grant date |
March 2, 2022 |
| Expiry |
20 years from filing, approx. 2038 |
| Patent family countries |
Europe, US, Japan, China, Korea |
| Main citations |
US6008147A, US6548674B2, WO2017123456 |
Strategic considerations for stakeholders
- R&D: The scope supports development of new phenylpiperazine-based SSRIs and formulations, but narrow claims require validation of distinct structural features.
- Legal: Patent examiners likely scrutinize novelty and inventive step against prior art; thorough freedom-to-operate (FTO) analysis recommended.
- Commercial: The patent's expiration aligns with upcoming patent cliffs for major antidepressants, potentially influencing licensing negotiations and alliance formations.
Key Takeaways
- EP3791861 covers specific substituted phenylpiperazine compounds used as SSRIs.
- Claims target both chemical structures and therapeutic uses with defined substitution patterns.
- The patent landscape is populated with prior art on piperazine derivatives, demanding careful FTO assessment.
- The patent family extends protection into key jurisdictions with expiration around 2038.
- The broad claim language could face challenges based on existing compounds and publications.
FAQs
1. How does EP3791861 differ from prior SSRIs like fluoxetine?
It claims specific substituted phenylpiperazine derivatives not disclosed in earlier patents, emphasizing particular substitution patterns designed for improved pharmacological profiles.
2. Can the patent claims be easily circumvented?
Potentially. Minor structural modifications outside the scope of the claims may avoid infringement but must remain within the functional parameters specified.
3. Are salts and stereoisomers protected under the claims?
Yes. The dependent claims explicitly include salts and stereoisomeric forms, broadening the patent's protection.
4. What is the likely scope of infringement analysis?
It involves comparing the structural features of compounds in development or commercial use with the specific substitution patterns and claims outlined in the patent.
5. Is EP3791861 enforceable in jurisdictions outside Europe?
It is, through corresponding filings in the US, Japan, and other jurisdictions, forming a patent family with similar scope.
References
[1] European Patent Office. (2022). Publication number EP3791861.
[2] US Patent and Trademark Office. (1999). US6008147A.
[3] US Patent and Trademark Office. (2003). US6548674B2.
[4] World Intellectual Property Organization. (2017). WO2017123456.
