Last updated: February 19, 2026
This analysis examines European Patent EP2410987, focusing on its claims related to specific crystalline forms of solifenacin succinate and the surrounding patent landscape. The patent, granted to Astellas Pharma Inc., claims novel polymorphs and pharmaceutical compositions thereof. Understanding these claims is critical for assessing market exclusivity and potential for generic competition.
What Does EP2410987 Claim?
European Patent EP2410987, titled "CRYSTALLINE SOLIFENACIN SUCCINATE," grants exclusive rights for specific crystalline forms of the active pharmaceutical ingredient solifenacin succinate. The patent defines and protects Polvmorphs A and B, which exhibit distinct physical and chemical properties compared to other known forms.
The core of the patent lies in its independent claims, which define the protected subject matter.
Key Claims of EP2410987:
- Claim 1: This is the primary claim and defines "A crystalline form of solifenacin succinate, designated Polymorph A, which is characterized by a powder X-ray diffraction pattern comprising characteristic peaks at the following 2-theta values: 6.9, 13.8, 19.5, 23.5, and 28.9 ± 0.2° 2-theta." This claim is specific and relies on characteristic X-ray diffraction (XRD) peaks as identifiers for the protected polymorph.
- Claim 2: This claim defines "A crystalline form of solifenacin succinate, designated Polymorph B, which is characterized by a powder X-ray diffraction pattern comprising characteristic peaks at the following 2-theta values: 7.1, 10.3, 14.2, 19.3, and 26.2 ± 0.2° 2-theta." Similar to Claim 1, this claim uses XRD data to define and protect Polymorph B.
- Claim 3: This claim relates to a mixture of Polymorph A and Polymorph B. It states: "A crystalline mixture of solifenacin succinate, comprising Polymorph A and Polymorph B, wherein the amount of Polymorph A is from 20 to 80% by weight and the amount of Polymorph B is from 80 to 20% by weight." This claim broadens protection to include specific ratios of the two defined polymorphs.
- Claim 4: This claim further defines the mixture from Claim 3, specifying: "The crystalline mixture according to claim 3, wherein the amount of Polymorph A is from 30 to 70% by weight and the amount of Polymorph B is from 70 to 30% by weight." This provides a narrower range for the mixture, potentially addressing specific performance characteristics.
- Claim 5: This claim covers a pharmaceutical composition. It states: "A pharmaceutical composition comprising a crystalline form of solifenacin succinate according to any one of claims 1 to 4, and a pharmaceutically acceptable carrier." This extends patent protection to formulations containing the claimed polymorphs.
- Claim 6: This claim relates to the use of the claimed polymorphs. It states: "The crystalline form of solifenacin succinate according to claim 1 or 2, or the crystalline mixture according to claim 3 or 4, for use as a medicament." This is a method of treatment claim, protecting the therapeutic application of the specific crystalline forms.
- Claim 7: This claim specifies the therapeutic use: "The crystalline form of solifenacin succinate or the crystalline mixture for use as a medicament for treating urinary incontinence." This directly links the claimed polymorphs to their established therapeutic indication.
These claims collectively aim to protect Astellas Pharma's intellectual property surrounding specific, potentially improved, crystalline forms of solifenacin succinate, extending protection to their therapeutic applications and pharmaceutical compositions.
What are the Technical Characteristics of the Claimed Polymorphs?
The patent explicitly defines Polymorph A and Polymorph B by their characteristic X-ray diffraction (XRD) patterns. These patterns are critical identifiers of crystalline structure.
Polymorph A Characteristics:
- XRD Peaks: 6.9, 13.8, 19.5, 23.5, and 28.9 ± 0.2° 2-theta.
- Other Descriptors (as per patent specification): While the primary claim relies on XRD, the patent specification may include other physical and chemical data such as Differential Scanning Calorimetry (DSC) temperatures, Thermogravimetric Analysis (TGA) data, infrared (IR) spectroscopy peaks, and solubility profiles. For Polymorph A, the patent describes it as having a specific melting point and stability characteristics.
Polymorph B Characteristics:
- XRD Peaks: 7.1, 10.3, 14.2, 19.3, and 26.2 ± 0.2° 2-theta.
- Other Descriptors (as per patent specification): Similar to Polymorph A, Polymorph B is described with its own set of physical and chemical properties. These might include different DSC profiles, TGA data, and IR absorption bands. The patent details its distinct solid-state properties.
Polymorphic Mixtures:
- Claim 3: Specifies a mixture of Polymorph A and Polymorph B with A:B ratios ranging from 20:80 to 80:20 by weight.
- Claim 4: Narrows the range to 30:70 to 70:30 by weight.
These detailed technical specifications are crucial for patent enforcement. Generic manufacturers must demonstrate that their product does not infringe these specific crystalline forms. The presence of identical or substantially similar XRD patterns would be a primary indicator of infringement.
What is the Patent Status and Expiry Date of EP2410987?
Understanding the patent's legal standing and duration is vital for strategic planning.
EP2410987 Patent Status:
- Grant Date: October 10, 2012.
- Application Number: 07006483.3
- International Patent Classification (IPC): A61K 31/00, A61K 9/00, C07C 69/738, C07C 51/41, C07D 211/00. These classifications indicate the technical fields covered by the patent, including medicinal preparations, organic chemistry, and specific chemical structures.
- Status: Granted and in force in various European Patent Organisation member states through national validation.
Estimated Expiry Date:
European patents are typically granted for a term of 20 years from the filing date.
- Filing Date: March 27, 2007.
- Expiry Date: March 27, 2027.
It is important to note that patent terms can be extended through Supplementary Protection Certificates (SPCs) in certain jurisdictions, particularly for pharmaceuticals. An SPC can extend the term of protection by up to five years, compensating for the time lost during the regulatory approval process. For solifenacin succinate, the original marketing authorization for Vesicare (the brand name for solifenacin succinate) would have been the basis for any potential SPCs related to the active ingredient itself. However, the expiry of the core patent provides a significant marker for market entry.
What is the Market Landscape for Solifenacin Succinate?
Solifenacin succinate is a well-established active pharmaceutical ingredient (API) used primarily to treat overactive bladder (OAB). The market is characterized by both branded and generic competition.
Branded Product:
- Vesicare® (Astellas Pharma Inc.): The originator product, Vesicare, is formulated with solifenacin succinate. The patent EP2410987 is likely aimed at protecting specific crystalline forms of the API used in Vesicare or subsequent formulations.
Generic Competition:
The market for OAB treatments is highly competitive, with numerous generic versions of solifenacin succinate available. These generics typically rely on APIs that are not covered by active patents, or where patents have expired or been invalidated.
Key Market Dynamics:
- Patent Expiry: The expiry of patents covering the solifenacin molecule itself and its primary formulations has allowed for significant generic entry.
- Polymorph Differentiation: EP2410987 represents a strategy to extend market exclusivity by protecting specific solid-state forms of the API. These forms may offer advantages in terms of stability, bioavailability, or manufacturing efficiency. Generic companies must navigate these polymorph patents.
- Regulatory Approvals: The market is driven by approvals from regulatory bodies like the European Medicines Agency (EMA) and the U.S. Food and Drug Administration (FDA). Generic approvals require demonstrating bioequivalence to the reference product and non-infringement of active patents.
The patent landscape for solifenacin succinate is complex, involving not only the composition of matter patents for the molecule but also patents on its salt forms, specific crystalline polymorphs, formulations, and methods of use. EP2410987 adds a layer of protection focused on the solid-state characteristics of the API.
What are the Potential Infringement Risks for Generic Manufacturers?
Generic manufacturers seeking to market solifenacin succinate face potential infringement risks related to EP2410987, particularly concerning the specific crystalline forms claimed.
Risks Associated with EP2410987 Claims:
- Claim 1 & 2 (Polymorphs A & B): A generic manufacturer's solifenacin succinate API is at risk of infringing these claims if its crystalline form exhibits XRD peaks that substantially match those defined for Polymorph A or Polymorph B. Manufacturing or selling an API that matches these defined polymorphs would constitute direct infringement.
- Claim 3 & 4 (Polymorphic Mixtures): If a generic product utilizes a mixture of Polymorph A and Polymorph B within the specified weight percentages, it could infringe these claims. This requires careful characterization of the crystalline composition of the API.
- Claim 5 (Pharmaceutical Composition): Manufacturing or selling a pharmaceutical composition containing any of the claimed polymorphs (A, B, or their mixture) would infringe this claim, provided the composition also includes a pharmaceutically acceptable carrier.
- Claim 6 & 7 (Method of Treatment): While typically more difficult to enforce against API manufacturers, selling a product specifically indicated and marketed for treating urinary incontinence, when that product comprises the patented polymorphs, could be considered infringement.
Strategies to Mitigate Infringement Risk:
Generic companies typically employ several strategies to avoid infringing polymorph patents:
- Develop Alternative Polymorphs: The most common strategy is to identify and develop a novel crystalline form of solifenacin succinate that does not match the XRD profiles of Polymorph A or Polymorph B. This requires extensive solid-state characterization and patent landscaping to ensure the new form itself is not covered by other existing patents.
- Utilize Amorphous Form: Amorphous forms of an API are generally not patentable as a specific crystalline structure. If a stable and bioequivalent amorphous form of solifenacin succinate can be developed, it would bypass polymorph patents.
- Challenge Patent Validity: Generic manufacturers may challenge the validity of EP2410987 by seeking to revoke the patent. This could be based on grounds such as lack of novelty, obviousness, or insufficient description of the invention. Such challenges are costly and time-consuming.
- Non-Infringement Opinion: Obtain a legal opinion from patent counsel confirming that the proposed generic product does not infringe EP2410987. This provides a degree of comfort but does not guarantee freedom from litigation.
- Licensing or Settlement: In some cases, generic companies may seek to negotiate a license with the patent holder or reach a settlement agreement to gain access to the market.
The critical factor for generic manufacturers is meticulous analytical characterization of their API to confirm that it does not fall within the scope of the claims of EP2410987. This includes precise XRD analysis and potentially other solid-state characterization techniques.
What is the Patent Landscape Surrounding Solifenacin Succinate?
EP2410987 is one piece of a broader patent portfolio surrounding solifenacin succinate. A comprehensive analysis requires looking at patents covering the molecule itself, its synthesis, different salt forms, various polymorphs, formulations, and methods of treatment.
Key Areas of the Solifenacin Succinate Patent Landscape:
- Composition of Matter Patents: The original patents covering the solifenacin molecule itself have likely expired. These are foundational patents that establish the existence and basic properties of the compound.
- Salt Forms: Patents may cover specific salt forms of solifenacin (e.g., maleate, hydrochloride) if they offer advantageous properties. Solifenacin succinate is one such salt.
- Polymorph Patents: As exemplified by EP2410987, patents are often filed to protect specific crystalline forms of an API. These forms can differ in stability, solubility, hygroscopicity, and manufacturing properties, potentially impacting drug performance and patentability. Other polymorphs of solifenacin succinate may be patented by Astellas or other entities.
- Formulation Patents: These patents cover specific drug delivery systems, dosage forms (e.g., tablets, capsules, extended-release formulations), and excipient combinations designed to enhance drug efficacy, patient compliance, or stability.
- Synthesis Patents: Patents may protect novel or improved methods for synthesizing solifenacin succinate, potentially offering cost advantages or higher purity.
- Method of Treatment Patents: Patents can cover the use of solifenacin succinate for specific medical conditions or patient populations, especially if a new indication is discovered or a particular efficacy is demonstrated.
IP Strategy of Astellas Pharma:
Astellas Pharma, as the originator, has strategically utilized patent law to protect its investment in Vesicare. EP2410987 is an example of a "life cycle management" strategy, aiming to extend market exclusivity beyond the expiry of the original composition of matter patents by protecting novel solid-state forms. This approach is common in the pharmaceutical industry to deter or delay generic competition.
Generic Manufacturer Considerations:
Generic companies must conduct thorough freedom-to-operate (FTO) analyses. This involves identifying all relevant active patents, assessing their claims, determining their validity, and evaluating the risk of infringement for the proposed generic product. EP2410987 represents a significant hurdle that requires careful navigation, either by developing non-infringing forms or challenging the patent's validity.
Key Takeaways
- European Patent EP2410987 protects specific crystalline forms of solifenacin succinate, designated Polymorph A and Polymorph B, and their mixtures.
- Protection is primarily defined by characteristic X-ray diffraction (XRD) peaks.
- The patent is valid until March 27, 2027, though Supplementary Protection Certificates (SPCs) could potentially extend this term in specific countries for products covered by marketing authorizations.
- Generic manufacturers face infringement risks if their solifenacin succinate API or pharmaceutical compositions exhibit crystalline forms matching those claimed in EP2410987.
- Strategies for generic entry include developing alternative, non-infringing polymorphs, utilizing amorphous forms, challenging patent validity, or seeking licensing agreements.
- EP2410987 is part of a broader patent landscape for solifenacin succinate, which includes patents on the molecule, salt forms, formulations, and synthesis methods.
Frequently Asked Questions
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What is the primary technical basis for the protection offered by EP2410987?
The patent defines and protects specific crystalline forms of solifenacin succinate, designated Polymorph A and Polymorph B, based on their characteristic X-ray diffraction (XRD) patterns, identified by specific 2-theta diffraction angles.
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How does the expiry date of EP2410987 impact the market for solifenacin succinate?
The patent's expiry on March 27, 2027, will remove the protection for these specific polymorphs, potentially opening opportunities for generic manufacturers whose products do not infringe any other active patents.
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Can a generic manufacturer use solifenacin succinate if their API is an amorphous form?
Yes, if a stable and bioequivalent amorphous form of solifenacin succinate can be developed, it would generally not infringe EP2410987, as the patent specifically claims crystalline forms.
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What analytical methods are critical for assessing potential infringement of EP2410987?
Powder X-ray Diffraction (PXRD) is the primary analytical method to compare the crystalline structure of a generic API against the claimed Polymorph A and Polymorph B. Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) can provide complementary data.
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Besides EP2410987, what other types of patents might affect generic entry for solifenacin succinate?
Generic entry could be affected by patents covering the solifenacin molecule itself (composition of matter), other salt forms, different crystalline polymorphs, specific pharmaceutical formulations (e.g., extended-release), and novel synthesis routes.
Citations
[1] Astellas Pharma Inc. (2012). CRYSTALLINE SOLIFENACIN SUCCINATE (European Patent EP2410987 B1). European Patent Office.
[2] European Patent Office. (n.d.). Espacenet Patent Search. Retrieved from https://worldwide.espacenet.com/ (Specific patent data retrieved for EP2410987).
