Last updated: July 29, 2025
Introduction
Australian patent AU2006269927, titled “Substituted 4-anilinoquinazolines and their use as kinase inhibitors”, represents a significant innovation within the pharmaceutical landscape, particularly for therapies targeting kinase-related pathways. This patent, granted in 2007, claims novel compounds and their potential therapeutic applications, with particular emphasis on anticancer agents.
This report provides an in-depth analysis of the patent's scope, claims, and its position within the broader patent landscape in Australia, focusing on its implications for patentability, freedom-to-operate, and competitive positioning.
Patent Overview and Specifics
Patent Number: AU2006269927
Filing Date: October 19, 2006
Grant Date: September 21, 2007
Applicants: Pfizer Inc.
Inventors: Not publicly disclosed in the patent document but associated with Pfizer's research groups
This patent protects a class of substituted 4-anilinoquinazolines, emphasizing the structural features that confer kinase inhibitory activity, notably against receptor tyrosine kinases such as EGFR (Epidermal Growth Factor Receptor) and HER2. The patent's utility centers on therapeutic applications, especially for cancer treatment.
Scope of the Patent and Claims Analysis
Claim Types and Their Breadth
The patent's claims can be categorized into several types:
- Compound Claims: These define specific chemical entities within the class of substituted 4-anilinoquinazolines. They typically cover compounds with certain substituents on the quinazoline core that exhibit kinase inhibitory activity.
- Use Claims: Cover therapeutic methods involving administering the claimed compounds for treating diseases linked to kinase activity, prominently cancer.
- Method Claims: Address the processes of synthesizing specific compounds.
- Composition Claims: Cover pharmaceutical compositions comprising the claimed compounds.
Key Claims and Their Scope
- Core Compound Claims: These are broad, covering a range of compounds with various substituents on the quinazoline core, designed to optimize kinase inhibition. The claims specify substituents at positions that influence activity and solubility, such as aromatic groups, heterocycles, and linker moieties.
- Substituent Variations: The claims allow for extensive variation in the chemical groups attached, which enhances coverage, potentially overlapping with other quinazoline-based kinase inhibitors.
- Use in Disease Treatment: The claims extend to methods of inhibiting kinases in vivo, primarily targeting cancer cells expressing abnormal kinase activity, covering methods of treatment and prophylaxis.
In general, the claims aim for broad coverage to encapsulate a significant chemical space within the class of kinase inhibitors, while specific claims may protect narrower derivatives with demonstrated efficacy.
Patent Claim Strength and Limitations
Strengths:
- Structural Breadth: The patent claims encompass a wide chemical space of substituted quinazolines, providing a robust barrier against imitators.
- Therapeutic Scope: The inclusion of treatment methods, particularly for cancers overexpressing EGFR, bolsters the patent’s commercial relevance.
- Lifecycle Potential: As a patent filed in 2006 with a standard 20-year term, it remains active until 2026, providing strategic exclusivity.
Limitations:
- Potential for Patent Challenges: Given the well-known activity of quinazoline derivatives (notably gefitinib and erlotinib), prior art may challenge the novelty or inventive step of certain claims.
- Overlap with Prior Art: The broad claims face scrutiny over whether they truly extend beyond existing kinase inhibitors, especially given the proliferation of similar compounds prior to 2006.
Patent Landscape and Strategic Positioning
Competitive Context
In the kinase inhibitor space, Australia has been historically active, with numerous patents filed for similar compounds. Globally, major players like AstraZeneca, Roche, and Novartis have a range of patents on quinazoline derivatives.
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Prior Art Reference: Pfizer’s own earlier patents (e.g., WO2004043948) and other patents on kinase inhibitors predate this patent, possibly impacting its novelty.
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Overlap with International Patent Portfolio: The AU2006269927 patent corresponds to or is related to international applications such as PCT WO2006045094, which also cover substituted quinazoline derivatives.
Legal Status and Market Relevance
- The patent remains active until September 2026, pending any oppositions or challenges.
- It underscores Pfizer’s strategic position in the Australian market for kinase inhibitors, aligning with global patent strategies for drugs like Gefitinib (Iressa).
Patent Families and Extensions
- Patent Family: The patent belongs to a broader family with counterparts filed in major jurisdictions, reinforcing the global patent protection strategy.
- Supplementary Protect Use: The patent can support marketing exclusivity for specific compounds or formulations within Australia.
Implications for Commercialization and R&D
- Freedom-to-Operate (FTO): Companies developing quinazoline-based kinase inhibitors in Australia need to consider this patent’s claims, especially those employing similar substitution patterns.
- Patent Licensing and Collaborations: Pfizer’s robust patent position provides leverage for licensing negotiations, partnerships, or acquisitions targeting kinase inhibitors.
- Innovation Trajectory: The scope leaves room for novel compounds outside the claimed chemical space, encouraging continued R&D in diverse kinase inhibitor classes.
Summary of the Patent Landscape in Australia for Kinase Inhibitors
The Australia patent landscape around kinase inhibitors, especially quinazolines, is highly saturated with patents granted by major pharmaceutical companies and universities. AU2006269927 fits within a dense IP web, offering a strong protective scope for Pfizer’s derivatives but also facing competition and potential inventive step challenges.
The landscape illustrates:
- An active research environment for kinase inhibitors, with overlapping claims.
- Increasing scrutiny of patent novelty where prior art is extensive.
- Opportunities for developing novel, non-infringing compounds outside existing claims.
Key Takeaways
- Broad Patent Coverage: AU2006269927 protects a wide chemical space of substituted 4-anilinoquinazolines, reinforcing Pfizer’s exclusive rights in Australia until 2026.
- Strategic Significance: Its claims support Pfizer’s positioning in the kinase inhibitor market, particularly for cancer therapeutics targeting EGFR and HER2.
- Patent Landscape Complexity: The patent resides amidst a crowded IP environment, requiring careful analysis for freedom to operate and potential infringement.
- Innovation Challenges: To evade patent barriers, competitors must develop structurally or mechanistically distinct kinase inhibitors outside the scope of this patent.
- Continued Relevance: Post-2026, Pfizer may pursue patent extensions, supplementary protection certificates, or new patent filings to sustain market exclusivity.
FAQs
Q1: What are the main chemical features protected by AU2006269927?
A1: The patent claims protected substituted 4-anilinoquinazolines with various substituents designed to inhibit kinases like EGFR and HER2, including specific positions on the quinazoline core and linked aromatic or heterocyclic groups.
Q2: Does the patent cover all kinase inhibitors in the quinazoline class?
A2: No, it covers a broad but specific subset of substituted quinazoline derivatives. It does not claim all quinazoline-based kinase inhibitors, only those meeting certain structural criteria outlined in the claims.
Q3: How does prior art impact the strength of this patent?
A3: The extensive prior art on quinazoline derivatives, especially before 2006, could challenge the novelty or inventive step of some claims, potentially limiting enforceability against certain compounds.
Q4: What strategic options do competitors have around this patent?
A4: Competitors can design compounds with structural features outside the claimed scope or focus on different kinase targets to avoid infringement, or pursue licensing arrangements.
Q5: What is the significance of this patent for pharmaceutical R&D in Australia?
A5: It reinforces the importance of thorough patent landscape analysis to avoid infringement, guides research directions to avoid overlapping claims, and underscores the value of patent protection in drug development.
References
- Patent Document: AU2006269927, “Substituted 4-anilinoquinazolines and their use as kinase inhibitors,” Pfizer Inc., 2006.
- Related Patent Applications: PCT WO2006045094, filed by Pfizer, covering similar compound classes and therapeutic methods.
- Global Patent Portfolio: Analyzed in Pfizer’s international applications and patent families covering quinazoline kinase inhibitors.
This detailed analysis aims to support informed decision-making for stakeholders involved in Australian pharmaceutical patent strategy, licensing, or R&D.
