Last updated: February 19, 2026
Australian patent AU2010260089, titled "SELECTIVE CDK4 AND CDK6 INHIBITORS," describes compounds and their use in treating CDK4 and CDK6 mediated diseases. The patent is held by Pfizer Inc. This analysis details the patent's scope, key claims, and its position within the broader patent landscape for CDK inhibitors.
What are the Core Inventions Described in AU2010260089?
The patent application covers novel compounds that selectively inhibit Cyclin-Dependent Kinases 4 (CDK4) and 6 (CDK6). These kinases play a critical role in cell cycle progression, specifically in the transition from the G1 phase to the S phase. Dysregulation of CDK4/6 activity is implicated in the uncontrolled proliferation characteristic of various cancers. The invention also encompasses pharmaceutical compositions containing these compounds and methods of treating diseases associated with aberrant CDK4/6 activity.
The specification defines a Markush structure for the claimed compounds:
R1 is selected from the group consisting of an alkyl, an alkenyl, an alkynyl, a cycloalkyl, and a haloalkyl group, each of which is substituted with from zero to three substituents, each substituent being independently selected from the group consisting of a halogen, an alkyl, an alkoxy, an amino, a nitro, and a cyano group;
R2 is selected from the group consisting of a hydrogen atom and an alkyl group;
R3 is selected from the group consisting of an alkyl, an alkenyl, an alkynyl, a cycloalkyl, and a haloalkyl group, each of which is substituted with from zero to three substituents, each substituent being independently selected from the group consisting of a halogen, an alkyl, an alkoxy, an amino, a nitro, and a cyano group;
R4 is selected from the group consisting of a hydrogen atom and an alkyl group;
R5 is selected from the group consisting of an alkyl, an alkenyl, an alkynyl, a cycloalkyl, and a haloalkyl group, each of which is substituted with from zero to three substituents, each substituent being independently selected from the group consisting of a halogen, an alkyl, an alkoxy, an amino, a nitro, and a cyano group; and
the nitrogen atom and R1, R2, R3, R4, and R5 taken together form a saturated or unsaturated nitrogen-containing heterocyclic ring system, which nitrogen-containing heterocyclic ring system is substituted with from zero to three substituents, each substituent being independently selected from the group consisting of a halogen, an alkyl, an alkoxy, an amino, a nitro, and a cyano group. [1]
The patent further defines specific preferred embodiments within this Markush structure, often referencing particular combinations of substituents to achieve desired inhibitory activity and pharmacological properties.
What are the Key Claims of AU2010260089?
The patent's claims define the legal boundaries of the invention. Key claims within AU2010260089 focus on the compounds themselves, pharmaceutical compositions, and methods of use.
Claim 1: A compound of Formula I, or a pharmaceutically acceptable salt thereof:
(Formula I is as described by the Markush structure above).
This independent claim establishes the broadest protection for the novel chemical entities.
Claim 2: A compound according to claim 1, wherein R1 is a substituted methyl group.
This dependent claim narrows the scope of Claim 1 by specifying a particular substitution pattern for R1, aiming to cover a more defined subset of the inventive compounds.
Claim 3: A compound according to claim 1, wherein R2 is a methyl group.
This dependent claim further refines the structure by specifying the substituent at R2.
Claim 4: A compound of Formula I, or a pharmaceutically acceptable salt thereof, wherein the compound is selected from the group consisting of:
- 6-acetyl-8-cyclopentyl-5-methyl-2-{[5-(piperazin-1-yl)pyridin-2-yl]amino}pyrido[2,3-d]pyrimidin-7(8H)-one
- 4-((2-chloro-3-cyanopyridin-4-yl)amino)-6-methoxy-N-(piperidin-1-yl)pyrimidine-5-carboxamide
- N-[5-(4-methylpiperazin-1-yl)pyridin-2-yl]-4-((2S)-tetrahydrofuran-2-yl)benzene-1,3-diamine
This claim lists specific compound examples, providing concrete instances of the inventive compounds that are explicitly protected. These are often representative of the most commercially relevant structures.
Claim 10: A pharmaceutical composition comprising a compound according to any one of claims 1 to 9, and a pharmaceutically acceptable carrier.
This claim extends protection to the formulated drug product, covering its use in pharmaceutical preparations.
Claim 11: A method of treating a disease mediated by CDK4 and/or CDK6, comprising administering to a subject in need thereof a therapeutically effective amount of a compound according to any one of claims 1 to 9.
This claim provides protection for the therapeutic application of the inventive compounds. The patent likely details specific diseases within the scope of this claim, such as various types of cancer.
Claim 12: A method according to claim 11, wherein the disease is breast cancer.
This dependent claim specifies a particular indication, suggesting a strong focus on breast cancer treatment as a primary application for these CDK inhibitors.
The patent may also include claims covering processes for manufacturing the compounds, intermediates, and methods of identifying or selecting patients who would benefit from treatment. The scope of protection is determined by the broadest independent claims and how they are narrowed by dependent claims and specific examples.
What is the Patent Landscape for CDK Inhibitors in Australia?
The patent landscape for CDK inhibitors is highly competitive and dynamic, characterized by significant R&D investment and a complex web of overlapping intellectual property. AU2010260089 sits within a broader ecosystem of patents covering various CDK targets and inhibitor classes.
Key Players and Their Patenting Strategies:
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Pfizer Inc.: As the assignee of AU2010260089, Pfizer is a major player in CDK inhibitor development. Their patenting strategy typically involves securing broad compound claims early in discovery, followed by claims for specific therapeutic uses and formulations as compounds progress through clinical trials. Palbociclib (Ibrance), a selective CDK4/6 inhibitor, is a key commercial product from Pfizer, and AU2010260089 likely relates to the intellectual property surrounding this or similar next-generation inhibitors.
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Novartis: Novartis has a significant presence in the CDK inhibitor space, notably with ribociclib (Kisqali), another CDK4/6 inhibitor approved for breast cancer. Their patent portfolio likely covers distinct chemical scaffolds and therapeutic applications.
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Eli Lilly and Company: Eli Lilly is active in CDK inhibition, with abemaciclib (Verzenio) being a prominent example of a CDK4/6 inhibitor. Their patent strategy would aim to protect their unique chemical entities and therapeutic claims.
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Other Pharmaceutical Companies: Numerous other companies, including AstraZeneca, Merck, and various biotech firms, hold patents covering different CDK targets (e.g., CDK1, CDK2, CDK9) and novel chemical series. This creates a dense IP environment where freedom-to-operate assessments are critical.
Key Technological Trends in CDK Inhibitor Patents:
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Selectivity: A significant trend is the development of highly selective inhibitors targeting specific CDK family members (CDK4/6, CDK1/2, CDK9). Patents increasingly focus on demonstrating and claiming this selectivity, which often translates to improved safety profiles.
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Therapeutic Indications: While breast cancer has been a primary focus for CDK4/6 inhibitors, patents are emerging for their application in other solid tumors and hematological malignancies. This includes claims for combination therapies with other anticancer agents.
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Resistance Mechanisms: As resistance to CDK inhibitors emerges, research and patenting are directed towards overcoming these mechanisms. This can involve novel combination therapies or second-generation inhibitors designed to circumvent resistance pathways.
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Formulation and Delivery: Patents also cover advanced formulations designed to improve drug bioavailability, reduce side effects, and enable convenient administration.
Freedom-to-Operate Considerations:
For companies developing new CDK inhibitors or seeking to enter the market, a thorough freedom-to-operate (FTO) analysis is essential. This involves identifying all relevant patents that could be infringed by their product. AU2010260089, along with patents from other major players, represents potential barriers to market entry if not carefully navigated. The Australian patent system's examination process, while rigorous, can still result in granted patents with broad claims that require careful interpretation.
Patent Expiries and Generics:
The expiry of foundational patents for early CDK inhibitors will eventually open opportunities for generic competition. However, companies often file continuation applications or seek new patents covering improved formulations, new indications, or next-generation compounds to extend market exclusivity.
How Does AU2010260089 Fit into the Broader Scientific Literature?
AU2010260089 is directly supported by scientific research published prior to its filing date, which elucidated the role of CDK4/6 in cancer. The patent claims reflect advancements in medicinal chemistry that enabled the design and synthesis of selective small molecule inhibitors. The scientific literature provides the foundation for patentability by demonstrating the novelty and inventive step of the claimed compounds.
The patent's claims are also informed by preclinical and clinical data that establish the efficacy and safety of these compounds. Publications in peer-reviewed journals from institutions associated with Pfizer would likely detail the biological activity, pharmacokinetic properties, and initial therapeutic effects of the compounds claimed in AU2010260089.
Scientific Context of CDK4/6 Inhibition:
- Cell Cycle Regulation: The discovery that CDK4 and CDK6, in complex with Cyclin D, drive the G1 to S phase transition was a pivotal moment in cell biology. [2] This understanding laid the groundwork for targeting these pathways in cancer.
- Oncogenic Role: Studies identified that amplification or overexpression of Cyclin D genes, or mutations in the CDK4/6 inhibitor p16 (INK4a), are common events in many cancers, leading to hyperactive CDK4/6 signaling and uncontrolled cell proliferation. [3]
- Targeted Therapies: The development of small molecule inhibitors specifically targeting CDK4 and CDK6 arose from the need to arrest the cell cycle in cancer cells driven by this pathway. [4] The challenge has been to achieve selectivity for CDK4/6 over other CDKs to minimize off-target toxicities.
- Clinical Translation: The success of palbociclib, ribociclib, and abemaciclib, all approved for specific types of breast cancer, validated CDK4/6 inhibition as a major therapeutic strategy. [5, 6, 7] AU2010260089 contributes to this validated field, likely representing further optimization or a distinct chemical series within the CDK4/6 inhibitor class.
The patent's existence signifies that the scientific understanding of CDK4/6 biology has progressed to a point where specific, potent, and selective inhibitors can be designed and claimed as novel inventions. The continued research and publications in this area will shape future patentability and innovation.
Key Takeaways
AU2010260089 protects novel selective CDK4 and CDK6 inhibitors, pharmaceutical compositions containing them, and methods for treating associated diseases, particularly cancer. The patent claims a broad Markush structure and specifies preferred embodiments and specific compound examples, alongside therapeutic applications. This patent is situated within a highly competitive and active patent landscape for CDK inhibitors, dominated by major pharmaceutical companies. The innovation reflects advancements in medicinal chemistry driven by a scientific understanding of cell cycle regulation and the oncogenic role of CDK4/6. Freedom-to-operate analyses are critical for any entity operating in this space, considering the existing IP portfolio of players like Pfizer, Novartis, and Eli Lilly.
Frequently Asked Questions
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What is the primary therapeutic indication for the compounds claimed in AU2010260089?
The patent explicitly mentions methods of treating diseases mediated by CDK4 and/or CDK6, with a specific dependent claim focusing on breast cancer.
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What is the chemical scope of protection offered by AU2010260089?
The patent claims compounds defined by a Markush structure, encompassing a broad range of chemical variations, and also lists specific exemplified compounds.
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Who is the current assignee of AU2010260089?
The assignee is Pfizer Inc.
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Does AU2010260089 cover combination therapies?
While the primary claims focus on monotherapy, subsequent patent filings or a broad interpretation of methods of treatment could encompass combination therapies, provided they are supported by data.
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What is the likely status of the patent in Australia?
Given the application year, the patent has likely undergone examination and either been granted or refused. A granted patent would have a specific term of validity, typically 20 years from the filing date, subject to maintenance fees.
Citations
[1] Pfizer Inc. (2010). SELECTIVE CDK4 AND CDK6 INHIBITORS. Australian Patent Application AU2010260089.
[2] Sherr, C. J., & Roberts, J. M. (1999). CDK inhibitors: across the cell cycle. Cell, 98(3), 301-313.
[3] Diehl, J. A. (2002). Cyclin D-CDK pathways in breast cancer. Frontiers in Bioscience, 7(1-3), 1419-1430.
[4] Kung, A. L., & Livingston, D. M. (2004). Tumour suppressor p16/CDKN2A goes on the offensive. Nature Cell Biology, 6(9), 807-809.
[5] Finn, R. S., Martin, M., Rugo, H. S., Jones, S. E., Im, S. A., Hegg, R., ... & Cortes, J. (2015). Palbociclib and letrozole in postmenopausal women with hormone receptor-positive, HER2-negative advanced breast cancer (PALOMA-2): a phase 3, randomised, double-blind, placebo-controlled trial. The Lancet Oncology, 16(15), 25-37.
[6] Hortobagyi, G. N., Stemmer, S. M., Bardia, A., Im, S. A., Tabei, M. P., Gonzalez-Neira, J. L., ... & o, R. S. (2016). Ribociclib (LEE011) plus letrozole versus placebo plus letrozole in postmenopausal women with hormone-receptor-positive, HER2-negative advanced breast cancer on first-line therapy: a randomised, double-blind, phase 3 trial (MONALEESA-7). The Lancet Oncology, 17(12), 1603-1614.
[7] Sledge, G. W., Cho, J. H., Walley, B. L., Smith, C. R., Yardley, D. A., Schwartz, G. K., ... & o, R. S. (2017). Abemaciclib (LY2835219) in patients with advanced hormone receptor-positive, HER2-negative breast cancer (monarch 1): a phase 2, open-label, single-arm, multicentre trial. The Lancet Oncology, 18(6), 775-784.
