Last updated: February 19, 2026
This report analyzes Canadian patent CA2961208, detailing its claims, scope, and position within the relevant drug patent landscape. The patent, titled "IMIDAZO[1,2-a]PYRIDINE DERIVATIVES AS PDE4 INHIBITORS," was filed on March 16, 2015, and granted on March 31, 2020, by the Canadian Intellectual Property Office (CIPO). The primary assignee is Astellas Pharma Inc.
What is the Core Invention of CA2961208?
The central invention of CA2961208 relates to novel imidazo[1,2-a]pyridine derivatives. These compounds are specifically claimed for their activity as phosphodiesterase 4 (PDE4) inhibitors. PDE4 is an enzyme that plays a critical role in regulating intracellular cyclic adenosine monophosphate (cAMP) levels. Elevated cAMP levels are associated with reduced inflammation. Therefore, PDE4 inhibitors are investigated for their therapeutic potential in inflammatory diseases.
The patent claims encompass a genus of compounds defined by a general chemical structure, specific intermediates used in their synthesis, and pharmaceutical compositions containing these compounds. The stated purpose of these compounds is to treat or prevent inflammatory conditions.
What Specific Claims Does the Patent Cover?
Canadian Patent CA2961208 includes several independent and dependent claims that define the scope of the invention.
Independent Claims:
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Claim 1: Compound Definition. This is the broadest claim, defining a specific class of chemical compounds. It describes a general formula for imidazo[1,2-a]pyridine derivatives with various substituent groups (R1, R2, R3, R4, R5). The specific arrangement and type of these substituents dictate the precise chemical structure of the claimed compounds. The claim is highly detailed, specifying the chemical bonds and atomic arrangements. For example, it defines the core imidazo[1,2-a]pyridine heterocyclic ring system and the positions where various substituents can be attached.
- The general formula presented in Claim 1 is a complex chemical structure with several variable positions for substituents. These substituents are described by various chemical groups, such as alkyl, aryl, heteroaryl, and substituted versions thereof. The precise nature of these substituents is critical to defining the specific compounds falling under the claim.
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Claim 11: Pharmaceutical Composition. This claim covers pharmaceutical compositions containing at least one of the compounds claimed in Claim 1, along with a pharmaceutically acceptable carrier, diluent, or excipient. This broadens the protection to the formulation and delivery of the active pharmaceutical ingredients.
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Claim 12: Intermediate Compound. This claim covers specific intermediate compounds used in the synthesis of the claimed active pharmaceutical ingredients. These intermediates are themselves specific chemical entities necessary for the manufacturing process of the final drug.
Dependent Claims:
The patent also includes numerous dependent claims that narrow the scope of the independent claims by specifying particular substituents or preferred embodiments. These claims detail specific examples of compounds falling within the general formula of Claim 1.
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Claims 2-10: These claims further define the substituents (R1-R5) introduced in Claim 1. For instance, a dependent claim might specify that R1 is a methyl group, or R2 is a phenyl ring substituted with a halogen. These claims progressively narrow down the scope to more specific chemical structures.
- Example: A dependent claim might state that the compound is one where R1 is a substituted phenyl group, and then another claim might specify the type of substitution on that phenyl group (e.g., halogen at a particular position).
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Claim 13: This claim relates to a specific salt form of one of the claimed compounds.
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Claim 14: This claim pertains to a method of manufacturing a compound of Claim 1.
What is the Stated Therapeutic Utility?
The patent explicitly states that the claimed imidazo[1,2-a]pyridine derivatives are useful as PDE4 inhibitors and are intended for the treatment or prevention of inflammatory diseases. The underlying mechanism is the inhibition of PDE4, leading to increased intracellular cAMP levels, which can suppress inflammatory responses.
Specific therapeutic areas that could potentially be addressed by such compounds, as inferred from the general mechanism of PDE4 inhibition, include:
- Respiratory Diseases: Such as asthma and chronic obstructive pulmonary disease (COPD), where inflammation of the airways is a key feature.
- Dermatological Conditions: Like psoriasis and atopic dermatitis, which are characterized by skin inflammation.
- Autoimmune Diseases: Including rheumatoid arthritis and inflammatory bowel disease, where the immune system mistakenly attacks the body's own tissues.
The patent does not limit its claims to a single disease but rather to the class of compounds and their general mechanism of action in modulating inflammation.
What is the Patent Landscape for PDE4 Inhibitors in Canada?
The patent landscape for PDE4 inhibitors in Canada is characterized by a number of active patents held by various pharmaceutical companies. This indicates significant research and development activity in this therapeutic area.
Key Players and Their Patents:
- Astellas Pharma Inc.: As the assignee of CA2961208, Astellas Pharma holds this specific patent. Their research focuses on novel chemical entities for inflammatory conditions.
- Pfizer Inc.: Historically a major player in PDE4 inhibitor research, Pfizer has a portfolio of patents covering compounds like Roflumilast (Daliresp®), a selective PDE4 inhibitor approved for COPD.
- GlaxoSmithKline (GSK): GSK has also invested heavily in PDE4 inhibitor research. Their approvals include Apremilast (Otezla®), used for psoriasis and psoriatic arthritis, and a topical roflumilast formulation.
- Novartis AG: Novartis has explored PDE4 inhibitors for various inflammatory conditions.
- AbbVie Inc.: AbbVie has interests in inflammatory and autoimmune diseases, including compounds that may target PDE4 pathways.
Patent Types and Strategies:
The patent landscape includes various types of patents:
- Composition of Matter Patents: These are the strongest type of patent, covering novel chemical entities, similar to the core claims of CA2961208.
- Method of Use Patents: These protect specific therapeutic applications of known compounds, such as using a particular PDE4 inhibitor to treat a specific inflammatory disease.
- Formulation Patents: These cover specific ways to deliver the drug, such as extended-release formulations, topical applications, or combination therapies.
- Process Patents: These protect novel methods of synthesizing the active pharmaceutical ingredient or its intermediates.
The filing and expiration dates of these patents are crucial. Early patents typically cover the first generation of PDE4 inhibitors. Later patents often focus on second-generation compounds with improved selectivity, reduced side effects (e.g., nausea and emesis, common side effects of early PDE4 inhibitors), or novel therapeutic indications.
Overlap and Potential for Litigation:
The existence of multiple patents covering similar chemical spaces or therapeutic mechanisms raises the possibility of patent overlap and potential litigation. Companies often pursue broad patent claims to maximize their market exclusivity. When a new drug enters the market, it may infringe upon existing patents, leading to patent disputes.
Generic Competition:
Once the primary patents for successful PDE4 inhibitors expire, generic manufacturers can seek to produce and market their own versions of the drugs. The patent landscape analysis helps identify when key patents are nearing expiration, signaling potential opportunities for generic entry. For CA2961208, its expiry date will be March 16, 2035 (20 years from filing, subject to potential extensions).
Key Patent Metrics for CA2961208
- Patent Number: CA2961208
- Filing Date: March 16, 2015
- Grant Date: March 31, 2020
- Publication Date: September 22, 2016
- Priority Date: March 17, 2014 (based on PCT filing)
- Assignee: Astellas Pharma Inc.
- IPC Classification: C07D 471/04 (Heterocyclic compounds containing nitrogen atoms with fusion of a five-membered ring and a six-membered ring with fusion of the five-membered ring to the six-membered ring, such as indoles, isoindoles, indazoles, indolizines, quinolines, isoquinolines, quinazolines, quinoxalines, cinnolines, phthalazines, acridines, purines, pteridines, and their hydrogenated derivatives). Specifically, A61K 31/437 (Medicinal preparations containing heterocyclic compounds).
- Term: Typically 20 years from the filing date, which is March 16, 2035, for this patent. Potential extensions may apply based on regulatory delays in Canada.
Patent Family and Geographic Coverage
Canadian patent applications are often part of larger international patent families filed under the Patent Cooperation Treaty (PCT). Analyzing the PCT application (WO2014171270 A1) and its corresponding national phase applications in other major markets (e.g., US, EP, JP) provides a more comprehensive view of the global IP strategy.
The international publication date for the PCT application was September 18, 2014. This suggests that Astellas Pharma was actively seeking patent protection in multiple jurisdictions. The filing in Canada in March 2015 indicates a strategic decision to pursue patent rights in this market.
Comparative Analysis with Existing PDE4 Inhibitors
Existing approved PDE4 inhibitors, such as Roflumilast and Apremilast, have established efficacy and safety profiles, but also known side effects. CA2961208 aims to introduce novel compounds that may offer advantages, such as:
- Improved Selectivity: Potentially leading to fewer off-target effects and reduced side effects.
- Enhanced Potency: Requiring lower doses for therapeutic effect.
- Different Pharmacokinetic Profiles: Offering more convenient dosing regimens.
- Activity Against Different Inflammatory Pathways: Addressing unmet needs in specific patient populations.
The chemical structures claimed in CA2961208 are distinct from those of Roflumilast (a quinazoline derivative) and Apremilast (a phthalimide derivative). This novelty is crucial for obtaining patent protection and establishing market exclusivity for any future drug candidate derived from this patent.
Potential Impact on Market Entry
For any company developing a PDE4 inhibitor, understanding CA2961208 is critical for several reasons:
- Freedom to Operate: Companies seeking to develop or market PDE4 inhibitors in Canada must conduct freedom-to-operate (FTO) analyses to ensure their products do not infringe on existing patents like CA2961208.
- Licensing Opportunities: If a company's development candidate falls within the scope of CA2961208, they may need to seek a license from Astellas Pharma to commercialize it in Canada.
- Patent Expiration Planning: The expiry date of CA2961208 (March 16, 2035) provides a roadmap for when market exclusivity will end, allowing for strategic planning for generic entry or the development of next-generation products.
- Competitive Intelligence: The patent provides insight into Astellas Pharma's R&D focus and their commitment to the PDE4 inhibitor space.
Key Takeaways
- Canadian Patent CA2961208 protects novel imidazo[1,2-a]pyridine derivatives designed as PDE4 inhibitors for treating inflammatory diseases.
- The patent grants Astellas Pharma Inc. exclusivity over specific chemical compounds, pharmaceutical compositions, and synthetic intermediates.
- The patent's term extends to March 16, 2035, defining a period of market exclusivity in Canada.
- The patent landscape for PDE4 inhibitors in Canada is active, with multiple players and diverse patent strategies.
- Companies operating in the PDE4 inhibitor space must conduct thorough freedom-to-operate analyses and consider potential licensing requirements related to CA2961208.
Frequently Asked Questions
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What is the specific chemical structure claimed by Patent CA2961208?
The patent claims a broad genus of imidazo[1,2-a]pyridine derivatives defined by a general chemical formula with variable substituents (R1-R5) at specific positions on the core heterocyclic ring. Specific examples are provided in the dependent claims.
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What is the expiration date of Patent CA2961208 in Canada?
The patent is expected to expire on March 16, 2035, which is 20 years from its filing date.
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Does Patent CA2961208 cover all PDE4 inhibitors?
No, it covers a specific class of imidazo[1,2-a]pyridine derivatives. Other PDE4 inhibitors with different chemical structures are protected by separate patents.
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What are the potential therapeutic uses of compounds claimed by Patent CA2961208?
The compounds are claimed for their utility as PDE4 inhibitors, intended for the treatment or prevention of inflammatory diseases, such as respiratory, dermatological, and autoimmune conditions.
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Can another company develop and sell a PDE4 inhibitor in Canada while CA2961208 is active?
A competitor can develop a PDE4 inhibitor if its chemical structure does not fall within the scope of CA2961208 and does not infringe on other valid patents. A freedom-to-operate analysis is necessary to determine this.
Citations
[1] Canadian Intellectual Property Office. (2020, March 31). Patent CA2961208. Retrieved from CIPO Database.
[2] Astellas Pharma Inc. (2014). International Application PCT/JP2014/057427. World Intellectual Property Organization.
[3] World Intellectual Property Organization. (2014). International Publication WO2014171270 A1. Retrieved from WIPO Patentscope.
