The European Patent Office (EPO) plays a pivotal role in shaping pharmaceutical innovation through its rigorous examination processes and legal frameworks. European Patent EP2708219, granted to Algernon Pharmaceuticals for the use of Repirinast in treating renal fibrosis and kidney disease, exemplifies the intersection of therapeutic repurposing, claim drafting strategies, and patent lifecycle management. This analysis delves into the patent’s scope, claim structure, and broader implications within the European pharmaceutical patent landscape.
Overview of EP2708219 and Its Technical Foundations
Therapeutic Context and Patent Eligibility
EP2708219 claims the use of Repirinast—a mast cell stabilizer originally marketed for asthma—either alone or in combination with telmisartan, an angiotensin receptor blocker, for renal fibrosis and kidney disease[12]. The patent’s allowance by the EPO underscores the office’s recognition of novel therapeutic applications for existing compounds, provided they meet the criteria of novelty, inventive step, and industrial applicability under Article 52–57 of the European Patent Convention (EPC)[11].
Preclinical data from a unilateral ureteral obstruction (UUO) mouse model demonstrated a 51% reduction in fibrosis with Repirinast alone and an additive effect when combined with telmisartan[12]. Such evidence aligns with EPO guidelines requiring experimental validation for method-of-use claims, particularly when repurposing known drugs[10].
Structural Analysis of Claims Under EPC Guidelines
Two-Part Claim Structure and Dependency
EP2708219 adheres to Rule 43 EPC, which mandates a two-part claim structure for independent claims: a prior-art portion and a characterizing portion[10]. For example:
Independent Claim 1:
Prior-art portion: "Use of a compound for treating renal fibrosis..."
Characterizing portion: "...wherein the compound is Repirinast."
Dependent claims further specify embodiments, such as combination therapies with telmisartan or dosage ranges, ensuring compliance with Rule 43(2) EPC’s prohibition on redundant claim categories[10]. The patent avoids clarity objections by defining Repirinast through its International Nonproprietary Name (INN) and chemical structure, satisfying Article 84 EPC’s requirement for concise and unambiguous language[4][10].
Product-by-Process Considerations
While EP2708219 does not explicitly use product-by-process claims, its method-of-use claims share similarities with EPO guidelines for Swiss-type formulations. For instance, claims involving Repirinast’s synthesis or formulation would require demonstrating that process steps impart novel technical properties to the final product[3]. The EPO’s strict stance on structural vs. functional definitions—emphasizing that "product-by-process claims are only allowable if structural definition is impossible"—likely influenced Algernon’s decision to focus on therapeutic use rather than manufacturing processes[3][10].
Patent Landscape and Strategic Implications
Secondary Patenting and Market Exclusivity
EP2708219 represents a secondary patent, extending market exclusivity beyond Repirinast’s original asthma indication. This aligns with industry trends where 70% of pharmaceutical patents filed in Europe are secondary, covering formulations, dosing regimens, or combination therapies[8]. The PLOS ONE study on Chilean patent filings highlights that secondary patents contribute 4–5 years of additional exclusivity on average, with some cases extending protection by over a decade[8]. Algernon’s strategy mirrors this approach, leveraging preclinical data to secure a patent term through 2038, excluding potential supplementary protection certificates (SPCs)[12].
Supplementary Protection Certificates (SPCs) and Unitary Patents
Under EU Regulation 469/2009, Algernon may apply for an SPC to extend EP2708219’s term by up to five years post-patent expiry, contingent on regulatory approval[13]. The 2023 EPO reforms introducing unitary SPCs could further streamline protection across EU member states, reducing administrative burdens for multinational enforcement[13]. However, the "manufacturing waiver" (Regulation 2019/933) permits EU-based generics to produce SPC-protected drugs for export, potentially limiting Algernon’s market control in non-EU regions[13].
Challenges and Enforcement Risks
Opposition Proceedings and Inventive Step
Opponents may challenge EP2708219 under Article 100(a) EPC for lack of inventive step, arguing that combining Repirinast with telmisartan was obvious given prior art on angiotensin receptor blockers in renal disease[10]. The EPO’s Problem-Solution Approach requires Algernon to demonstrate that the combination yields synergistic effects unforeseeable from existing literature. The UUO model data showing additive efficacy will be critical in rebutting such challenges[12].
Cross-Jurisdictional Enforcement
As a bundle of national patents, EP2708219’s enforcement varies across EPC member states. For example, German courts apply a "core invention" doctrine, narrowly interpreting claim scope, while French courts emphasize literal claim language[4]. Algernon’s decision to file through the EPO rather than individual national offices balances cost efficiency with the risk of fragmented validity rulings[11].
Comparative Analysis with Similar Patents
Case Study: Hepatitis C and Tuberculosis Patents
The WIPO patent landscape report on hepatitis C (HCV) and tuberculosis (TB) drugs reveals parallel strategies to EP2708219. For instance, Gilead’s sofosbuvir patents include method-of-use claims for HCV genotype variations, leveraging clinical trial data to justify novelty[9]. Similarly, bedaquiline’s secondary patents on nanoparticle formulations illustrate the EPO’s tolerance for functional claims when supported by technical evidence[9]. Unlike these examples, EP2708219 avoids formulation claims, focusing instead on therapeutic application—a strategic choice minimizing clarity objections[3][10].
Conclusion
EP2708219 exemplifies the EPO’s balanced approach to incentivizing drug repurposing while safeguarding patent quality. Its claims adhere to strict structural and clarity requirements, and its reliance on preclinical data aligns with EPO evidentiary standards. Within the broader patent landscape, secondary patents like EP2708219 underscore the pharmaceutical industry’s reliance on incremental innovation to sustain exclusivity. Future challenges, including SPC reforms and opposition risks, will shape its commercial viability, but its grant marks a significant milestone in renal fibrosis treatment.
Key Takeaways
- EP2708219’s claims leverage method-of-use data to meet EPO novelty and inventive step requirements.
- Secondary patenting strategies extend market exclusivity by 5–12 years, contingent on robust preclinical/clinical evidence.
- Supplementary Protection Certificates and unitary patent reforms enhance cross-jurisdictional protection but face generics competition via manufacturing waivers.
FAQs
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How does the EPO assess method-of-use patents for repurposed drugs?
The EPO requires experimental data demonstrating a surprising technical effect, even for known compounds[10][12].
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Can combination therapy claims face obviousness challenges?
Yes, unless synergistic effects are proven beyond additive outcomes[8][10].
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What is the impact of the 2023 SPC reforms on EP2708219?
Unitary SPCs streamline multi-country extensions but require compliance with centralized EUIPO procedures[13].
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How do product-by-process claims differ from method-of-use claims?
Product-by-process claims define a product by its manufacturing steps, while method-of-use claims focus on therapeutic application[3][10].
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What enforcement risks exist for EP2708219 in Europe?
Divergent national interpretations of claim scope and the manufacturing waiver pose significant challenges[11][13].
“The claims shall define the matter for which protection is sought. They shall be clear and concise and be supported by the description.”
– Article 84, European Patent Convention[4]
References
- https://www.sec.gov/Archives/edgar/data/1160308/000119312517038542/d324677dex1063.htm
- https://www.iponz.govt.nz/get-ip/patents/apply/expedited-examination-for-patent-applications/european-patent-office-patent-prosecution-highway/
- https://www.gje.com/resources/navigating-product-by-process-claims-at-the-european-patent-office/
- https://en.wikipedia.org/wiki/Claims_under_the_European_Patent_Convention
- https://curity.io/resources/learn/scopes-vs-claims/
- https://curity.io/resources/learn/scopes-claims-and-the-client/
- https://www.wipo.int/publications/en/series/index.jsp?id=137
- https://journals.plos.org/plosone/article?id=info%3Adoi%2F10.1371%2Fjournal.pone.0124257
- https://www.treatmentactiongroup.org/wp-content/uploads/2021/11/hcv_tb_longacting_patent_trends.pdf
- https://www.epo.org/en/legal/guide-epc/2023/ga_c4_2_6.html
- https://en.wikipedia.org/wiki/European_Patent_Office
- https://www.globenewswire.com/news-release/2025/04/08/3057466/0/en/Algernon-Pharmaceuticals-Receives-Notice-of-Allowance-from-European-Patent-Office-for-Repirinast-for-Kidney-Disease.html
- https://single-market-economy.ec.europa.eu/industry/strategy/intellectual-property/patent-protection-eu/supplementary-protection-certificates-pharmaceutical-and-plant-protection-products_en
Last updated: 2025-04-23
