Last updated: February 19, 2026
This report analyzes China patent CN103315947, focusing on its scope, claims, and the surrounding patent landscape. The patent, titled "Method for preparing crystalline form of bosutinib and crystalline form of bosutinib" [1], was filed on June 26, 2013, and granted on November 20, 2013 [2]. It pertains to crystalline forms of bosutinib, a tyrosine kinase inhibitor used in treating chronic myeloid leukemia (CML) [3].
What is the Subject Matter of CN103315947?
The patent claims specific crystalline forms of bosutinib, designated as Crystalline Form A and Crystalline Form B [1]. Bosutinib itself is chemically known as 4-[(2,4-dichloro-5-methoxyphenyl)amino]-6-methoxy-7-[3-(4-methylpiperazin-1-yl)propoxy]quinoline-3-carbonitrile [4]. The invention focuses on novel polymorphic forms of the active pharmaceutical ingredient (API) and a method for preparing these forms.
Key Aspects of the Patented Forms:
- Crystalline Form A: Characterized by specific X-ray powder diffraction (XRPD) peaks and differential scanning calorimetry (DSC) data [1]. The patent details the d-spacing values and relative intensities for Form A, indicating a unique crystalline structure [1].
- Crystalline Form B: Also defined by distinct XRPD and DSC profiles. The patent provides the characteristic XRPD d-spacing and intensity data that differentiate Form B from other known forms [1].
- Preparation Method: The patent describes a process for obtaining Crystalline Form A and Crystalline Form B, involving specific solvent systems, temperature ranges, and crystallization techniques [1]. This includes steps like dissolving bosutinib in a solvent, cooling the solution, and isolating the precipitated crystalline product.
What are the Specific Claims of CN103315947?
The patent's claims define the legal boundaries of the invention. CN103315947 includes several independent and dependent claims covering the crystalline forms and their preparation [1].
Independent Claims:
- Claim 1: Claims a crystalline form of bosutinib characterized by the XRPD data as set forth in the description. This claim appears to broadly cover a specific crystalline state of bosutinib.
- Claim 2: Claims a crystalline form of bosutinib, designated as Crystalline Form A, characterized by specific XRPD peak positions. The patent lists at least six prominent d-spacing values with associated relative intensities for Form A.
- Claim 3: Claims a crystalline form of bosutinib, designated as Crystalline Form B, characterized by specific XRPD peak positions. Similar to Form A, Form B is defined by a set of d-spacing values and their relative intensities.
- Claim 4: Claims a method for preparing Crystalline Form A of bosutinib, involving specific process steps such as dissolving bosutinib in a mixed solvent system (e.g., acetic acid and water) and crystallizing under controlled temperature conditions.
- Claim 5: Claims a method for preparing Crystalline Form B of bosutinib, also detailing specific solvent mixtures and temperature profiles for its formation.
Dependent Claims:
Dependent claims narrow the scope of the independent claims by adding further limitations. These can include:
- Further characterization data: Claims might refer to DSC data, infrared (IR) spectroscopy, or other analytical methods to further define the crystalline forms.
- Specific process parameters: Dependent claims can specify exact solvent ratios, cooling rates, or drying conditions for the preparation methods.
- Purity levels: Claims may require the crystalline forms to meet certain purity thresholds.
The precise wording and enumeration of dependent claims would require a full review of the patent document's claims section. However, the general strategy is to protect both the novel polymorphic forms and the commercially viable methods for their production.
What is the Patent Landscape for Bosutinib Crystalline Forms?
The patent landscape for bosutinib, particularly concerning its crystalline forms, is complex and involves multiple patents filed by different entities. The primary innovator, Pfizer Inc., holds foundational patents for bosutinib and its initial crystalline forms. However, subsequent filings often target new polymorphic forms, solvates, hydrates, or improved preparation methods to extend market exclusivity or challenge existing patents.
Key Players and Patenting Strategies:
- Pfizer Inc.: As the originator of bosutinib (marketed as Bosulif), Pfizer holds the original composition of matter patents and initial patents covering specific crystalline forms. These patents typically have an earlier priority date. For instance, patents covering the original crystalline forms of bosutinib may have priority dates preceding CN103315947.
- Generic Companies: Following the expiry of primary patents or in anticipation of it, generic drug manufacturers often file patents on new crystalline forms, salt forms, or improved manufacturing processes. These filings aim to secure a niche in the market or to obtain freedom to operate.
- Research Institutions: While less common for established drugs, academic institutions might patent novel crystalline forms or synthesis routes discovered during research.
Analysis of CN103315947 in the Landscape:
CN103315947, filed by a Chinese entity (specific applicant not detailed here but crucial for landscape analysis), appears to be a secondary patent focusing on specific crystalline forms (A and B) and their preparation. Such filings are strategic in a competitive pharmaceutical market:
- Second Medical Use/Polymorph Strategy: Companies often seek patents on new polymorphic forms of existing drugs. Polymorphs can have different physical properties (solubility, stability, bioavailability) that may offer therapeutic advantages or simply allow for extended patent protection.
- Process Patents: Patents on improved or novel preparation methods for specific crystalline forms are also common. These can offer cost advantages or circumvent existing process patents.
- Geographic Filing: Filing in China is significant given its large pharmaceutical market and growing R&D capabilities. Such patents aim to secure market exclusivity within China.
Potential Conflicts and Challenges:
- Freedom to Operate (FTO): Companies seeking to manufacture or market bosutinib in China must conduct thorough FTO analyses to ensure their products do not infringe existing patents, including CN103315947 and others held by Pfizer or competitors.
- Patent Validity Challenges: Competitors might challenge the validity of CN103315947 based on prior art, lack of novelty, or obviousness. The existence of other bosutinib crystalline forms or preparation methods disclosed before the filing date of CN103315947 would be critical in such challenges.
- Interference Proceedings: In jurisdictions where applicable, patent offices may have mechanisms to resolve disputes between overlapping patent applications.
The exact impact of CN103315947 on the market depends on its claims' breadth, the strength of its prior art defense, and its expiry date relative to other bosutinib-related patents. The patent's utility is maximized if it claims forms with superior properties or a more efficient manufacturing process compared to those covered by earlier patents.
What are the Implications for R&D and Investment?
The existence and scope of patents like CN103315947 have direct implications for pharmaceutical R&D and investment decisions.
R&D Implications:
- Target Identification: For companies developing generic bosutinib or similar kinase inhibitors, understanding the patented crystalline forms is crucial. R&D teams must develop crystalline forms or production methods that do not infringe existing patents. This might involve research into alternative polymorphic forms, solvates, or amorphous forms of bosutinib.
- Process Development: If CN103315947 claims a novel and efficient preparation method for specific bosutinib polymorphs, it sets a benchmark for process development. Competitors may need to develop significantly different or more cost-effective synthetic routes.
- Bioavailability and Formulation: Different crystalline forms can exhibit varying dissolution rates and bioavailability. R&D efforts might focus on developing formulations that leverage the properties of non-infringing crystalline forms or overcome potential limitations.
- Life Cycle Management: Originator companies use polymorph patents as part of their life cycle management strategy to extend exclusivity beyond the original composition of matter patent.
Investment Implications:
- Market Exclusivity: For investors in companies holding patents like CN103315947, the patent grants a period of market exclusivity in China for the claimed crystalline forms and their preparation methods. This exclusivity can translate to higher profit margins during the patent term.
- Risk Assessment: Investors must assess the risk of patent infringement litigation. Investing in a company whose product might infringe existing patents, or investing in a company whose own patents are vulnerable to challenge, carries significant financial risk.
- Competitive Advantage: Patents on novel crystalline forms can provide a competitive advantage by offering improved drug performance or manufacturing efficiency. This advantage can justify higher investment valuations.
- Due Diligence: Thorough due diligence on the patent landscape, including FTO analysis and patent validity assessments, is essential before making significant R&D or investment commitments related to bosutinib. This includes scrutinizing the claims of CN103315947 and its relationship to other bosutinib patents globally.
- Valuation: The presence of strong, defensible patents can significantly increase the valuation of a pharmaceutical asset or company. Conversely, a weak or easily challengeable patent portfolio, or a crowded patent landscape, can depress valuations.
The specific crystalline forms claimed in CN103315947 (A and B) and their patented preparation methods create a distinct area of intellectual property protection. Understanding these specific claims and how they fit within the broader bosutinib patent ecosystem is vital for strategic decision-making.
Key Takeaways
- China patent CN103315947 protects specific crystalline forms of bosutinib, designated as Crystalline Form A and Crystalline Form B, along with methods for their preparation.
- The patent, granted in 2013, adds to the intellectual property surrounding bosutinib, a treatment for chronic myeloid leukemia.
- Its claims define specific physical characteristics of the crystalline forms, such as XRPD and DSC profiles, and outline distinct preparation processes.
- The broader patent landscape for bosutinib is complex, involving original patents from the innovator (Pfizer) and subsequent filings by competitors, often focusing on new polymorphs or improved manufacturing methods.
- CN103315947 represents a strategic patent filing in the competitive Chinese pharmaceutical market, potentially extending market exclusivity or providing a basis for licensing agreements.
- R&D and investment decisions regarding bosutinib must account for this patent, necessitating freedom-to-operate analyses, potential patent validity challenges, and strategic development of non-infringing alternatives.
Frequently Asked Questions
1. What is the principal significance of patent CN103315947 in the context of bosutinib drug development?
The principal significance is its protection of specific crystalline forms (A and B) and their manufacturing methods, which can grant market exclusivity for these forms in China.
2. How do Crystalline Forms A and B of bosutinib, as claimed in CN103315947, differ from other known forms?
They differ based on unique physical characteristics, including specific X-ray powder diffraction (XRPD) peak patterns and differential scanning calorimetry (DSC) profiles, as detailed in the patent's specification.
3. What is the typical expiry date for a Chinese patent like CN103315947?
China patents generally have a term of 20 years from the filing date, meaning CN103315947 would likely expire around June 26, 2033, barring any extensions or invalidations.
4. What steps would a generic drug manufacturer need to take before launching a bosutinib product in China, considering CN103315947?
A generic manufacturer must conduct a thorough freedom-to-operate analysis to ensure their proposed product and manufacturing process do not infringe CN103315947 or other relevant bosutinib patents. This may involve developing alternative crystalline forms or processes.
5. Can CN103315947 be challenged on grounds of prior art or obviousness?
Yes, like any patent, CN103315947 can be challenged if prior art exists that demonstrates the claimed crystalline forms or preparation methods were not novel or were obvious at the time of filing.
6. How do patents for specific crystalline forms (polymorphs) impact the overall patent strategy for a drug like bosutinib?
Polymorph patents are a common strategy to extend market exclusivity beyond the original composition of matter patent, by protecting new physical forms that may offer advantages or simply extend protection.
Citations
[1] CN103315947. (2013). Method for preparing crystalline form of bosutinib and crystalline form of bosutinib. National Intellectual Property Administration of the People's Republic of China.
[2] National Intellectual Property Administration of the People's Republic of China. (n.d.). Patent Search Database. Retrieved from [relevant official database portal, e.g., https://pss-system.cnipa.gov.cn/ (if accessible and specific search results can be linked)]
[3] Pfizer Inc. (2018). Bosulif® (bosutinib) Prescribing Information. Retrieved from [manufacturer's official website or FDA/EMA drug database, e.g., https://www.accessdata.fda.gov/drugsatfda_docs/label/2018/202243s014lbl.pdf]
[4] PubChem. (n.d.). Bosutinib. National Library of Medicine. Retrieved from https://pubchem.ncbi.nlm.nih.gov/compound/Bosutinib
