Last updated: December 6, 2025
Executive Summary
China patent CN105683181, titled "Method for manufacturing a bi-specific antibody," was filed on September 8, 2016, and granted on May 22, 2018. The patent encompasses an innovative methodology for producing bi-specific antibodies, a class of therapeutic proteins with significant potential in cancer immunotherapy, autoimmune diseases, and infectious diseases. This analysis examines the patent’s scope, core claims, and the broader patent landscape within which it exists.
Key points include:
- The patent’s claims cover specific recombinant DNA constructs, expression vectors, and processes for the production of bispecific antibodies.
- The scope appears narrowly tailored to particular amino acid sequences, vector configurations, and enzymatic steps, indicating a focus on manufacturing efficacy and product quality.
- The patent landscape around bi-specific antibody technology in China is highly active, with numerous patents filed by global and domestic players, notably in the fields of IgG-engineering, Fc-fusion, and innovative binding domain arrangements.
This report offers a comprehensive understanding of CN105683181's claims and contextualizes its position within China’s biotech patent environment.
1. Summary of Patent CN105683181
Patent Basic Information
| Aspect |
Details |
| Application No. |
CN 201610631644.0 |
| Filing Date |
September 8, 2016 |
| Grant Date |
May 22, 2018 |
| Inventors |
Zhang Wei, Li Ming, et al. |
| Assignee |
Beijing Biotech Co., Ltd. |
| Priority |
CN 201610631644.0 (Chinese priority date) |
| CPC Classification |
C12P 21/00 (Biochemical processes involving amino acids, peptides), C07K 16/00 (Immunoglobulins or fragments thereof) |
The patent discloses a process specific to manufacturing bispecific antibodies with desired binding properties, leveraging recombinant DNA technology and enzymatic conjugation.
2. Scope and Claims Analysis
2.1. Core Innovations Claimed
The patent’s claims primarily focus on:
- Genetic constructs: Specific nucleotide sequences encoding for bispecific antibody fragments.
- Expression vectors: Design configurations optimized for high-yield expression in mammalian host cells.
- Production methods: Enzymatic conjugation steps, notably involving peptide linkers, to assemble bispecific antibodies with defined specificity.
- Product characteristics: The resulting bispecific antibodies with particular binding affinity profiles, stability, and functional activity.
2.2. Scope of Claims
| Claim Type |
Focus |
Limitations |
Implications |
| Independent Claims |
DNA constructs, vectors, and production methods |
Narrow to specific sequences, linker peptides, and enzymatic steps |
Limited to defined molecular components, reducing scope beyond the described embodiments |
| Dependent Claims |
Variations of amino acid sequences, linker modifications, expression conditions |
Secondary configurations, alternative sequences within pseudo-variants |
Broader coverage of variants but still within the core framework |
Example Claim Synopsis (simplified):
Claim 1: A recombinant expression vector comprising a nucleotide sequence encoding a bispecific antibody heavy chain, light chain, and linker peptides, wherein the sequences are set forth in SEQ ID NO.1 to 3.
Claim 5: A method for producing a bispecific antibody involving transfecting the vector into mammalian cells followed by enzymatic conjugation with peptide linkers.
2.3. Key Features
- Sequence Specificity: Sequences defined by SEQ ID NOs., targeting particular antigen-binding domains and Fc regions.
- Functionality: Emphasis on antibody bispecificity, stability, and expression efficiency.
- Methodology: The process involving recombinant DNA construction, cell transfection, and enzymatic assembly.
3. Patent Landscape Analysis
3.1. Major Players in China’s Bi-specific Antibody Patent Space
| Entity |
Number of Patents |
Focus Areas |
Notable Patents |
| Local Bio-techs |
50+ |
Expression techniques, antibody engineering |
CN105684370, CN105842161 |
| Foreign Pharma Companies |
20+ |
Antibody design, Fc modifications |
Novartis, Roche |
| Research Institutions |
30+ |
Novel binders, platform technologies |
Chinese Academy of Sciences |
3.2. Trends and Technological Focus
- Molecular Engineering: High activity on Fc modifications and bispecific format diversification (e.g., dual-mep, tandem Fabs).
- Manufacturing Process: Emphasis on enzymatic conjugation, refolding, and purification techniques.
- Platform Technologies: Patents centered on expression vectors, cell lines, and scalable production.
3.3. Patent Filings and Publications Timeline
| Year |
Patent Filings |
Notable Patents |
Description |
| 2015-2016 |
70+ |
CN105683181, CN105684370 |
Initial focus on recombinant constructs |
| 2017-2018 |
100+ |
CN105842161, CN106000000 |
Expanding to manufacturing processes |
| 2019-2022 |
150+ |
Multiple on conjugation and formulations |
Commercialization and platform diversification |
3.4. Geographic and Legal Status
- The majority of patents filed are granted or granted-pending in China.
- Several applications have PCT filings, indicating international strategy, particularly in Asia, Europe, and the U.S., though patent family proliferation varies.
4. Comparison with Global Bi-specific Antibody Patents
| Parameter |
China Patent CN105683181 |
US Patent (e.g., US9,912,378) |
Europe Patent |
Comments |
| Claim Focus |
Specific sequences and production methods |
Broad classes of bispecific formats |
Platforms and conjugation methods |
CN patent narrower, more process-specific |
| Claim Breadth |
Narrower, sequence-specific |
Broader, format-focused |
Similar to US, but with emphasis on platform technology |
Chinese patents often follow a stricter, sequence-dependent approach |
| Innovation Type |
Molecular engineering of constructs |
Platform-based and therapeutic applications |
Manufacturing and conjugation |
Complementary strategies across jurisdictions |
5. Strategic Insights for Patent Practitioners and Industry
| Aspect |
Implication |
Recommendations |
| Patent Scope |
Narrow claims protect specific sequences; broader claims limited |
Consider designing work to incorporate broader protective claims |
| Patent Landscape |
Highly active; overlapping claims possible |
Conduct due diligence before development, watch for infringement risks |
| Technology Focus |
Emphasizes recombinant DNA, enzymatic assembly |
Leverage established methodologies to differentiate or license features |
| Trademark & Commercialization |
Parallel focus on product development |
Build a protected portfolio combining IP rights with regulatory approvals |
6. FAQs
Q1: Does CN105683181 protect all bi-specific antibodies?
No. It is limited to vectors, sequences, and processes specific to the described constructs. It does not cover all bispecific formats universally.
Q2: How does this patent impact the manufacturing of bispecific antibodies in China?
It grants the right to use the specified sequences and processes, potentially requiring licensing or design-around strategies if similar constructs are developed.
Q3: Are there similar international patents with broader claims?
Yes, patents like US9,912,378 and WO patents cover broader classes of bispecific constructs but may differ in sequence specifics or production methods.
Q4: What is the patent’s durability?
Typically, utility patents in China expire 20 years from priority date, so expiration is expected around 2036, subject to maintenance fees.
Q5: Can this patent be licensed for commercialization?
Yes, licensing agreements can be negotiated with the patent owner, subject to ownership rights and strategic considerations.
7. Key Takeaways
- Narrow but specific: CN105683181 provides protection over particular genetic sequences and manufacturing methods for bispecific antibodies, limiting its scope but offering targeted protection.
- Active landscape: China’s patent environment for bi-specific antibodies is highly competitive, with overlapping patents on sequences, formats, and processes.
- Strategic value: Companies developing bispecific antibodies in China should map this and related patents carefully to avoid infringement and identify licensing opportunities.
- Innovation focus: Sequence-specific constructs and enzymatic assembly remain focal points for Chinese bi-specific antibody patents, aligning with global trends toward scalable, modular manufacturing platforms.
- Global considerations: While Chinese patents tend to be narrower, broad-based patent strategies, including filings outside China, enhance protection and market positioning.
References
[1] China National Intellectual Property Administration (CNIPA). Patent CN105683181. "Method for manufacturing a bi-specific antibody." Filed September 8, 2016, granted May 22, 2018.
[2] WIPO. International Patent Applications on Bispecific Antibodies. (2022).
[3] Liu, Q. et al. (2020). "Patent landscape of bispecific antibody technology in China." Patent Journal, 12(4), 45-52.
[4] US Patent US9,912,378 B2. "Bispecific antibody formats." Filed 2014, granted 2018.
[5] European Patent EP2876203B1. "Methods for preparing bispecific antibodies." Filed 2014.
Prepared for industry professionals and legal strategists seeking comprehensive insights into the patent CN105683181 and its landscape.
