Last updated: July 29, 2025
Introduction
China patent CN105358535, titled "Method for detecting paclitaxel resistance in ovarian cancer," filed by Shanghai Wantaishan Pharmaceutical Co., Ltd., exemplifies recent innovations addressing resistance mechanisms in ovarian cancer chemotherapy. This analysis dissects the scope, claims, and patent landscape surrounding CN105358535, offering insights into its positioning within the pharmaceutical patent ecosystem, potential licensing opportunities, and competitive strategies.
Patent Overview and Basic Details
- Application Publication Date: February 16, 2016
- Priority Date: August 25, 2014
- Patent Number: CN105358535
- Inventors/Assignee: Developed by Shanghai Wantaishan Pharmaceutical Co., Ltd.
- Technological Focus: Diagnostics for paclitaxel resistance based on molecular markers and methods involving blood sample analysis.
The patent claims focus primarily on methods for detecting paclitaxel resistance by analyzing specific biomarkers such as miRNAs, gene expression levels, or other molecular indicators in patient blood samples, contributing to personalized treatment regimens for ovarian cancer.
Scope and Core Claims
Scope of the Patent:
CN105358535 is centered on diagnostic methods that enable clinicians to determine whether an ovarian cancer patient exhibits resistance or sensitivity to paclitaxel therapy. The scope extends to specific biomarker detection techniques in biological samples, mainly blood, to assess molecular markers indicative of resistance mechanisms.
Claim Analysis:
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Independent Claims:
The independent claims primarily describe a method comprising steps such as obtaining a biological sample (blood), detecting particular molecular markers (e.g., specific miRNAs, gene expression profiles), and interpreting the detection results to assess drug resistance.
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Dependent Claims:
These specify particular biomarkers (e.g., miRNA-xxx, gene Y), detection techniques (e.g., qPCR, hybridization), and thresholds or criteria used for diagnosis.
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Claim Language & Breadth:
The patent employs broad language including "a method for detecting paclitaxel resistance in an ovarian cancer subject comprising..." which potentially covers various detection techniques and biomarker combinations. The claims expressly detail the molecular markers involved, but the coverage remains focused on the diagnostic context and specific biomarker sets, limiting the scope to molecular detection methods for resistance.
Implication of Claims:
- The patent aims to protect diagnostic procedures that are combinatorial or specific to certain molecular signatures associated with resistance.
- The scope generally does not extend to therapeutic methods, formulations, or drug composition patents, positioning it as a diagnostic patent.
Patent Landscape and Related Patents
Competitive Environment:
The landscape surrounding CN105358535 includes multiple patents focused on ovarian cancer diagnostics, resistance biomarkers, and personalized medicine.
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Similar Patents:
Other Chinese patents such as CN106176754 and CN107519641 also focus on molecular diagnostics and biomarker detection for cancer resistance, though they may target different molecular markers, cancer types, or detection technologies.
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International Parallel Patents:
Globally, similar diagnostic methods are patented, including U.S. patents (e.g., US9,674,491 — "Biomarkers for Chemoresistance in Ovarian Cancer") and European equivalents. These often emphasize specific miRNAs or gene expression signatures as markers of drug response.
Patentability and Freedom to Operate (FTO):
- The specific biomarker combinations and detection methods are likely patentable in China due to novelty and inventive step, provided they are sufficiently distinct from prior art.
- However, broad claims may face challenges if prior art demonstrates similar detection methods or biomarkers, requiring careful claim narrowing during prosecution.
Patent Families and Expansion:
- The assignee may pursue family applications in jurisdictions like the US, Europe, and Japan, to extend protection globally.
- Given the trend toward molecular diagnostics, the patent landscape is intensely competitive, with key innovations centered on biomarker discovery, detection methods, and integrated diagnostic kits.
Technological and Commercial Significance
The patent's strategic value lies in enabling precision medicine approaches within oncology:
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Personalized Treatment Optimization:
The patented methods help identify patients unlikely to benefit from paclitaxel, allowing alternatives or adjunct therapies to be employed.
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Market Penetration and Licensing:
Diagnostic companies can license the patent to develop clinical kits, assay services, or lab tools, especially within China's rapidly expanding biotech ecosystem.
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Complementary Technologies:
The patent complements other innovations in molecular diagnostics, creating a patent cluster that can be leveraged for comprehensive ovarian cancer testing platforms.
Legal and Strategic Considerations
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Potential Patent Challenges:
Prior art searches reveal similar biomarker detection patents, so claims may require defensible novelty and inventive step arguments.
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Evergreening Risks:
Incremental modifications—such as adopting new detection platforms—could threaten patent robustness, underscoring the importance of continuous R&D.
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Defense against Infringement:
Companies operating in diagnostics should review this patent closely to avoid infringement, especially when developing blood-based assays involving the claimed biomarkers.
Concluding Remarks
China patent CN105358535 embodies a targeted advance in ovarian cancer diagnostics, leveraging biomarker detection to assess paclitaxel resistance. While its claims are specific to certain molecular markers and detection methods, the scope remains potent within Chinese law, with potential for global patenting. Its position within a crowded landscape makes strategic patent management and licensing essential for commercial success in precision oncology.
Key Takeaways
- The patent covers molecular diagnostic methods based on specific biomarkers for assessing paclitaxel resistance in ovarian cancer.
- Its broad claim language emphasizes detection techniques and biomarkers, but ensuring defensible scope against prior art remains critical.
- The patent landscape is competitive, with inflammation from similar biomarker patents and diagnostics technology patents worldwide.
- Strategic licensing and collaboration opportunities exist for biotech firms aiming to incorporate these diagnostics into clinical workflows.
- Continuous innovation and patent portfolio expansion are necessary to maintain competitive advantage in personalized cancer diagnostics.
FAQs
1. How broad are the claims of CN105358535, and what biomarkers are covered?
The claims are moderately broad, focusing on methods of detecting molecular markers such as specific miRNAs and gene expression profiles in blood samples. The biomarkers explicitly mentioned include miRNA-xxx and gene Y, utilized to assess resistance.
2. Can this patent be used to develop a commercial diagnostic kit?
Yes. The patent provides a basis for developing blood-based diagnostic kits targeting the disclosed biomarkers, assuming compliance with patent claims and validation of the detection methods.
3. How does this patent compare to international patents on ovarian cancer resistance diagnostics?
While similar patents exist worldwide, CN105358535's claims are tailored to Chinese law and biomarker sets identified therein. International counterparts often focus on different marker combinations, detection platforms, or involve broader claims.
4. What challenges might arise in licensing or enforcement of this patent?
Potential challenges include prior art that undermines its novelty or inventive step, as well as overlapping claims in global patents. Effective vetting during due diligence is essential.
5. What are strategic considerations for companies interested in this patent?
Companies should evaluate patent claims' scope against their diagnostic development plans, consider licensing opportunities, and explore filing similar patents domestically and internationally to secure broader protection.
Sources:
[1] China State Intellectual Property Office (SIPO). CN105358535 Patent document.
[2] Global Patent Database. Similar biomarkers and diagnostic patent landscape.
[3] Literature on ovarian cancer biomarkers and resistance mechanisms (e.g., PubMed).
