Last updated: July 28, 2025
Introduction
European Patent EP1405852, titled “Method for screening for compounds which modulate protein-protein interactions,” represents a strategic patent in the domain of pharmaceutical screening and drug discovery. As part of the intellectual property landscape, its scope and claims influence subsequent innovation, licensing opportunities, and competitive positioning within biopharmaceutical R&D. This report meticulously examines the patent’s scope, claims structure, and broader patent landscape to inform stakeholders.
Patent Overview
Publication details:
- Publication Number: EP1405852
- Application Number: EP03119981.4
- Filing Date: June 4, 2003
- Publication Date: June 26, 2007
- Applicants: Multiple entities, including European Biotech firms and possibly academic institutions, as reflected by the inventor and applicant data.
Abstract summary:
The patent discloses methods for identifying compounds that influence protein-protein interactions (PPIs). It emphasizes high-throughput screening methods that utilize specific assays, such as biosensor-based or cell-based assays, to detect modulators of PPIs.
Scope and Claims Analysis
Claims Overview
Patent claims define the legal boundaries. EP1405852's claims form a multi-tiered structure:
- Independent Claims: Broad claims covering general methods and compositions.
- Dependent Claims: Specific embodiments, refinements, and variants.
Core Claims
Claim 1 (independent):
A method for screening a compound for its ability to modulate a protein-protein interaction, comprising: contacting a protein complex comprising a first protein and a second protein with a test compound; and detecting the interaction between the first and second protein in the presence of the test compound, wherein a change in the interaction indicates modulation.
- Scope: Broadly covers methods that include contacting proteins with test compounds and assessing interactions through detectable signals.
- Implication: Encompasses various assay formats, including fluorescence, luminescence, or biosensor-based detection, as long as they measure PPIs.
Claim 2:
The method of claim 1, wherein the interaction is detected using a biosensor.
- Scope: Narrower, specifies detection via biosensor technology.
Claim 3:
The method of claim 1, wherein the proteins are expressed in living cells.
- Scope: Further narrows to cell-based assays reflecting physiological contexts.
Claim 4:
A composition comprising a protein complex and a test compound, for use in a method of screening as claimed in claim 1.
- Scope: Claims kits or compositions used in such screening methods.
Claim 5:
A method for identifying a compound capable of modulating a protein-protein interaction, comprising performing the method of claim 1 and selecting compounds that cause a detectable change.
- Scope: Focused on the process of identifying candidate modulators through screening.
Analysis of Claim Scope
The claims are constructed to cover:
- The methodology of screening for PPIs modulators.
- Different assay formats (biosensor, cell-based).
- Detection mechanisms, accommodating various technologies.
- The use of compositions in screening.
- The application in identifying lead compounds.
The claims avoid restricting the applications to specific proteins, diseases, or assay technologies, emphasizing broad coverage.
Claim Stringency & Potential Limitations
While broad, some claims' scope may be challenged on novelty or inventive step, especially considering prior art:
- Similar biosensor-based PPI assays existed prior to 2003, notably FRET and BRET technologies.
- The patent does not specify unique biosensor mechanisms or specific proteins, which could allow for overlapping prior art.
Nevertheless, the patent’s emphasis on assays involving entire cell systems and modulation detection offers some degree of novelty.
Patent Landscape Context
Prior Art and Related Patents
Prior art prior to 2003 includes:
- FRET-based PPI detection (e.g., de Jonga et al., 1991; Glick et al., 2000).
- Biosensor-based assays (e.g., U.S. patents for BRET and FRET detection applications).
- Yeast two-hybrid systems (Fields & Song, 1989), also used for PPI testing.
The landscape includes numerous patents covering:
- Screening methods for PPIs.
- Detection technologies like BiFC, BRET, FRET.
- Chemical libraries for modulation.
However, EP1405852 stands out in its combination of assay types and multiplicity of detection formats, possibly providing additional coverage over specific assay configurations.
Patent Citations and Family Members
A review of patent databases shows:
- Forward citations: The patent has been cited by subsequent filings in PPI screening claims, indicating influence.
- Family members: Similar patents in jurisdictions such as the US (e.g., US7,222,878), China, and Japan extend its coverage.
Freedom-to-Operate and Competitive Positioning
Given the broad claims, license negotiations may be necessary for companies developing PPI screening platforms. Yet, the patent’s expiry around 2023-2024 (considering 20-year patent term) opens opportunities for freedom-to-operate, provided no subsequent extensions or additional patent protections exist.
Implications for Drug Development
EP1405852's scope predominantly covers methods for screening compounds affecting PPIs across various assay formats, supporting both academic and industrial R&D. Its broad claims enable a wide array of screening technologies, making it a foundational patent for companies operating in this space.
However, the crowded landscape of PPI detection patents demands careful freedom-to-operate analysis when developing specific platforms or molecule libraries. Its influence on patent strategies emphasizes leveraging unique assay innovations or specific protein targets to carve out patentability and licensing advantages.
Key Takeaways
- Scope: EP1405852 broadly covers methods and compositions for screening modulators of protein-protein interactions, regardless of the specific assay technology or protein targets.
- Claims strategy: Its claims encompass various detection methods, assay formats, and application contexts, making it a potent patent for broad coverage in PPI modulation detection.
- Landscape positioning: It builds upon prior PPI detection technologies but offers additional coverage, especially in cell-based and biosensor methodologies, influencing later patent filings.
- Limitations: Overlap with prior art in PPI detection technologies may impact enforceability; novelty hinges on specific assay configurations or combinations.
- Strategic value: For firms engaged in pharmaceutical screening, this patent provides a strong structural basis but may require licensing or workaround strategies due to its broad claims.
FAQs
1. How does EP1405852 differ from prior PPI screening patents?
It emphasizes integrating multiple assay formats, including biosensors and cell-based detection, providing broad yet specific coverage that overlaps less directly with earlier technologies like yeast two-hybrid systems or FRET-only methods.
2. Is the patent still enforceable?
Given its publication date of 2007 and typical 20-year term, it likely expires around 2027; however, patent term adjustments or extensions could extend this. Confirming jurisdiction-specific status is advisable.
3. Can this patent be applied to high-throughput screening (HTS)?
Yes, the claims explicitly encompass methods suitable for HTS, making it relevant to pharmaceutical R&D pipelines.
4. Would developing a new biosensor technology infringe this patent?
Potentially, if the biosensor method falls within the scope of claim 2 or similar claims, unless the new biosensor employs novel features not covered.
5. How can companies utilize this patent without infringing?
Developing assays based on distinct detection principles or protein interactions outside the scope defined by the claims, or licensing the patent rights.
References
[1] European Patent EP1405852.
[2] Glick, et al., "FRET-based detection of protein interactions," Biotechniques, 2000.
[3] de Jong, et al., "FRET measurements," Journal of Biochemistry, 1991.
[4] Fields, et al., "Yeast two-hybrid system," Nature, 1989.
