Last updated: February 19, 2026
This report analyzes China drug patent CN1678406, focusing on its granted claims, scope of protection, and the surrounding patent landscape. The patent, titled "Preparation method for recombinant human TNF-alpha inhibitor," was granted on November 29, 2006, to the Beijing Wecare Biotechnology Co., Ltd. (now Zhejiang Wecare Biotechnology Co., Ltd.) [1]. The invention relates to a method for preparing a recombinant human tumor necrosis factor-alpha (TNF-α) inhibitor.
What Are the Core Claims of CN1678406?
The patent CN1678406 has five granted claims. These claims define the exclusive rights granted to the patent holder.
Claim 1: The Central Process Claim
Claim 1 is the broadest process claim and defines the core inventive step. It claims a method for preparing a recombinant human TNF-α inhibitor, characterized by the following steps:
- Construction of an expression vector: This involves inserting a gene fragment encoding a human TNF-α inhibitor protein into a suitable expression vector. The patent specifies that the gene fragment is derived from specific sequences, including SEQ ID NO:1 and SEQ ID NO:2, or their functional equivalents. These sequences likely represent the genetic code for the inhibitor protein.
- Transformation of a host cell: The constructed expression vector is then introduced into a host cell, such as Escherichia coli (E. coli) or yeast. This process, known as transformation, allows the host cell to carry the genetic instructions for producing the TNF-α inhibitor.
- Cultivation of the transformed host cell: The transformed host cells are grown under specific culture conditions designed to promote the expression of the desired inhibitor protein.
- Extraction and purification of the inhibitor protein: After expression, the TNF-α inhibitor protein is extracted from the host cells and purified to obtain a pharmaceutically acceptable product.
The claim broadly covers any method that incorporates these fundamental steps using the specified or equivalent genetic sequences and host systems [1].
Claim 2: Specific Host Cell and Vector
Claim 2 narrows the scope of Claim 1 by specifying particular elements. It claims the method described in Claim 1, where the host cell is Escherichia coli and the expression vector is a specific plasmid, pET-28a [1]. This claim provides a more concrete embodiment of the invention, identifying a common and well-established system for recombinant protein production.
Claim 3: Modified Protein Sequence
Claim 3 further refines the invention by claiming the method where the human TNF-α inhibitor protein is a modified protein. This modification involves a substitution at position 22 with alanine (Ala22) and a deletion at position 23 (del23). This specific modification suggests an attempt to improve the protein's properties, such as stability or activity. The claim links this modified protein sequence to SEQ ID NO:3 and SEQ ID NO:4, which presumably represent this specific modified protein and its encoding sequence [1].
Claim 4: Post-Translational Modification
Claim 4 focuses on a specific post-translational modification. It claims the method as described in Claim 3, where the modified human TNF-α inhibitor protein undergoes glycosylation. Glycosylation is a common post-translational modification that can significantly impact protein function, solubility, and immunogenicity [1]. This claim indicates that the patent holder is interested in a glycosylated form of their specific modified inhibitor.
Claim 5: The Isolated Protein
Claim 5 shifts from a method claim to a product-by-process claim. It claims an isolated human TNF-α inhibitor protein, prepared by the method described in any of Claims 1 to 4 [1]. This claim protects the specific protein produced by the patented method, regardless of how it is subsequently used, provided it is isolated.
What Is the Scope of Protection Afforded by CN1678406?
The scope of protection for CN1678406 is primarily focused on the process of preparing a recombinant human TNF-α inhibitor. The claims delineate specific steps and components involved in this preparation.
The broadest protection comes from Claim 1, which covers any method employing the core steps of vector construction, transformation, cultivation, and purification, using the specified or equivalent gene sequences and host cells. This means that competitors attempting to use a similar process for producing recombinant human TNF-α inhibitors, even with minor variations in non-claimed elements, could infringe.
Claims 2 and 3 provide more specific embodiments, offering a clearer definition of what constitutes infringement for those using E. coli and pET-28a, or the specific Ala22 substitution/del23 deletion variant. Claim 4 further specifies protection for the glycosylated form of this modified protein.
Claim 5, the product-by-process claim, protects the isolated protein that is produced by the patented method. This is a crucial aspect, as it can prevent others from obtaining and using the inhibitor even if they did not perform the patented preparation steps themselves, provided they acquire the protein made via the patented process.
The scope is limited by several factors:
- Specificity of Sequences: The patent references specific SEQ ID numbers. While it includes "functional equivalents," this leaves room for interpretation and potential challenges regarding what constitutes an equivalent.
- Process-Centric: The core claims are method claims, not composition of matter claims for the inhibitor itself in a general sense. This means that if a competitor develops an entirely different method to produce the same or a similar TNF-α inhibitor, they may not infringe CN1678406.
- Human TNF-α Inhibitor: The patent is specific to human TNF-α inhibitors. It does not cover inhibitors of other cytokines or TNF-α from different species.
- Geographic Limitation: As a Chinese patent, its protection is limited to the territory of the People's Republic of China.
What Is the Patent Landscape for Recombinant TNF-α Inhibitors in China?
The patent landscape for recombinant TNF-α inhibitors in China is dynamic and competitive, characterized by significant patent filings by both domestic and international pharmaceutical companies. TNF-α inhibitors are a crucial class of biologics used to treat inflammatory and autoimmune diseases such as rheumatoid arthritis, psoriatic arthritis, and Crohn's disease. Key players in this landscape include companies that developed first-generation TNF-α inhibitors like infliximab and adalimumab, as well as biosimilar manufacturers.
Key Players and Their Patenting Strategies
Major global pharmaceutical companies, including AbbVie, Amgen, and Pfizer, have historically filed patents protecting their TNF-α inhibitor biologics and related manufacturing processes in China. These patents typically cover:
- Composition of Matter Claims: For novel antibody or protein structures.
- Process Claims: For methods of manufacturing these biologics, including cell line development, fermentation, purification, and formulation.
- Formulation Claims: Specific drug product formulations that enhance stability, delivery, or efficacy.
- Method of Use Claims: For treating specific diseases or patient populations.
Alongside innovator companies, a significant number of Chinese biotechnology firms and Contract Development and Manufacturing Organizations (CDMOs) are actively involved in patenting biosimil versions of TNF-α inhibitors. Their patenting strategies often focus on:
- Process Patents: Developing novel or improved manufacturing processes that confer advantages such as higher yield, lower cost, or improved purity, which can be patentable even for known biosimilar molecules.
- Formulation Patents: Creating new formulations that offer differentiated characteristics compared to originator products.
- Polymorph Patents: Identifying and patenting specific crystalline forms of the active pharmaceutical ingredient (API).
- Manufacturing Cell Line Patents: Protecting proprietary cell lines used for producing the biosimilar.
CN1678406, granted in 2006, represents an early filing by a Chinese entity in the recombinant protein preparation space. At that time, the focus might have been on establishing foundational intellectual property for producing such biologics. Given its age, the patent is approaching the end of its 20-year term (expiring in 2026). This means that the specific process it protects is likely nearing or has already entered the public domain in China, making it potentially available for generic or biosimilar manufacturers to utilize without infringing this specific patent.
Overlapping and Differentiating Technologies
The patent landscape often involves overlapping technologies. Multiple patents may cover aspects of TNF-α inhibitor production, leading to complex freedom-to-operate (FTO) analyses for new market entrants. For instance, a company developing a TNF-α inhibitor biosimilar would need to ensure their manufacturing process does not infringe any active, valid patents related to:
- The specific protein sequence of the originator drug.
- The cell lines used for production.
- The purification methods.
- The formulation of the final drug product.
- Methods of treating specific diseases.
CN1678406 contributes to this landscape by protecting a specific recombinant preparation method. Its claims, particularly those related to the Ala22 substitution and del23 deletion, suggest an attempt to protect a particular variant of a TNF-α inhibitor. While the patent itself is old, the technologies it covers—recombinant protein expression, vector construction, and purification—remain fundamental to biopharmaceutical manufacturing.
Impact of Patent Expirations
The expiration of patents like CN1678406 opens opportunities for biosimilar development. As the patent protection for this specific preparation method wanes, companies can leverage the knowledge and techniques described in the patent without seeking a license. This is a critical factor for biosimilar manufacturers aiming to bring more affordable versions of TNF-α inhibitors to the Chinese market.
However, the overall FTO for producing a TNF-α inhibitor biosimilar is determined by the existence of other, more recent patents. Innovator companies continue to file patents on improvements, new formulations, and novel therapeutic uses, creating layers of protection that must be carefully navigated.
Summary of Claims and Scope
CN1678406 claims a method for preparing a recombinant human TNF-α inhibitor. The core claim involves constructing an expression vector, transforming a host cell (specifically E. coli with pET-28a in claim 2), cultivating the cell, and purifying the inhibitor. A further refinement involves a specific modified protein with an Ala22 substitution and del23 deletion (claim 3), potentially in a glycosylated form (claim 4). Claim 5 protects the isolated protein produced by this method. The patent's scope is process-centric and limited to China.
Key Takeaways
- Patent CN1678406 protects a specific method for preparing a recombinant human TNF-α inhibitor, including key steps and specific protein modifications.
- The patent holder is Zhejiang Wecare Biotechnology Co., Ltd.
- The claims cover the process of vector construction, host cell transformation, cultivation, and purification, with specific embodiments detailing host cells, vectors, and protein modifications.
- The patent is a process patent, with a product-by-process claim for the isolated inhibitor produced via the patented method.
- The patent's geographic scope is limited to China, and its term is nearing expiration.
- The broader patent landscape for TNF-α inhibitors in China is characterized by innovation in both originator drugs and biosimil development, with a focus on process, formulation, and composition of matter patents.
- The upcoming expiration of CN1678406 may reduce barriers for certain manufacturing approaches related to its specific claims within China.
Frequently Asked Questions
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When does patent CN1678406 expire?
Patent CN1678406 was granted on November 29, 2006, and typically has a term of 20 years from the filing date. Assuming a filing date prior to grant, it is expected to expire around 2026.
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Does CN1678406 cover the final drug product itself, or just the manufacturing process?
The primary claims (1-4) cover the method or process of preparation. Claim 5 is a product-by-process claim, protecting the isolated protein produced by that specific method. It does not claim the final drug product in general composition of matter terms unless produced by the defined method.
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Can other companies use the method described in CN1678406 if they are developing a biosimilar?
After the patent expires, other companies may use the method described in CN1678406 without infringing this specific patent, provided they do not infringe any other active and valid patents in China.
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What specific TNF-α inhibitor does this patent likely relate to?
While the patent does not name a specific marketed drug, the claims suggest it relates to a recombinant human TNF-α inhibitor with a specific modification (Ala22 substitution, del23 deletion). This indicates an effort to patent a particular variant of a TNF-α inhibitor molecule.
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What is the significance of the SEQ ID NOs mentioned in the claims?
The SEQ ID NOs (Sequence Identification Numbers) are standard identifiers for biological sequences, such as DNA or protein sequences. They allow for precise reference to the specific genetic material or protein structures that are part of the invention claimed by the patent.
Citations
[1] Beijing Wecare Biotechnology Co., Ltd. (2006, November 29). Preparation method for recombinant human TNF-alpha inhibitor. Chinese Patent CN1678406B.
