Introduction

Bispecific/multispecific antibodies (bsAbs/msAbs) — with their unique dual-targeting mechanisms and synergistic effects — have emerged as novel therapeutic options for refractory cancers and autoimmune diseases, unlocking new opportunities to address longstanding unmet clinical needs.

As a result, bsAbs/msAbs have become one of the most competitive and commercially attractive biologic modalities. However, their promise comes with complexity. Intricate molecular design, challenging manufacturing, and heightened regulatory expectations can slow development and delay patient access if not addressed systematically.

With a great amount of bsAbs/msAbs candidates in global clinical development, accelerating market approval is pivotal to building product lifecycle competitiveness as it allows for longer patent-protected sales windows, earlier prescriber adoption, and greater access flexibility.

A Unique CRDMO Business Model Designed for Speed and Certainty

WuXi Biologics brings a differentiated end‑to‑end CRDMO model, aligning research, development, and manufacturing from the very beginning, with commercialization as a design principle rather than a downstream afterthought.

In 2025, WuXi Biologics expanded its integrated projects to 945, with complex molecules accounting for over 50%. BsAbs/msAbs have become a core growth engine for the company, with the project count growing 30% year-over-year to 196.

Figure 1: bsAbs/msAbs modalities at WuXi Biologics platform

Partnering with WuXi Biologics unlocks end-to-end value through a unique CRDMO model, aligning strengths across research, development, and manufacturing.

From research, for every client project, early research — supported by leading platforms — fully considers development and manufacturing feasibility, giving programs a meaningful head start.

Through development, WuXi Biologics compresses conventional bsAbs CMC development timeline from the typical 12–22 months to as short as 6 months. In addition, commercial requirements are integrated early to balance quality, speed, and cost, enhancing product accessibility at launch.

Into manufacturing, WuXi Biologics collaborates with clients to optimize commercial launch plans and support successful BLA approval, further accelerating market entry. Client projects typically take 6 months from technology transfer to PPQ completion and 10 months to BLA submission, which is 3–6 months and 8–15 months faster than industry norms. With an accelerated timeline, technology transfer to PPQ takes only 3.5 months.

This end-to-end empowerment delivers customized, smoother transition from clinical supply to commercialization for both global pharma leaders and innovative biotech innovators.

WuXi Biologics’ First-Mover Advantage in bsAbs/msAbs

The concept of bispecific antibodies (bsAbs) was first proposed in the 1960s, but critical bottlenecks, including molecular design complexity, manufacturing challenges, and immunogenicity risks, have long constrained their R&D.

Unlike monoclonal antibodies (mAbs), bsAbs require precise pairing of multiple distinct heavy and light chains — a process that randomly forms mispaired byproducts. This complicates purification and can cause protein degradation, aggregation, or fragmentation due to structural constraints, ultimately reducing overall yield. The result is greater technical uncertainty, longer development timelines, higher manufacturing costs, and increased COGS.

In 2009, Catumaxomab, the world’s first bsAb drug¹, was approved in Europe for the treatment of malignant ascites, targeting CD3 and EpCAM. This marked the beginning of the bsAbs era and set the stage for the sector’s rapid expansion. By the end of 2025, 20 bsAbs drugs had been approved globally, generating approximately USD 16 billion in annual sales. A recent Nature article highlighted that bsAbs accounted for one-quarter of the top 20 highest-license deals in 2025, signaling a potential inflection point toward a new dominant modality². This strategic momentum is reflected in market forecast, with the global bsAbs market forecast to grow at a CAGR exceeding 40% through 2030³.

Competition in the bsAbs/msAbs is intensifying. According to the Pharmcube NextPharma database, approximately 1,800 bsAbs therapies are in development, with over 75% in preclinical stages and 23% in Phase I–III. Meanwhile, about 280 trispecific antibodies and 90 multispecific antibody programs are in development⁴.

In response to growing industry demand, the outsourcing of bsAbs/msAbs development is expanding rapidly, positioning CXO companies with end-to-end capabilities as preferred partners for pharmaceutical companies. As an industry pioneer, WuXi Biologics has invested in bsAbs/msAbs technologies suite, translating deep technical expertise and cumulative project experience into a sustained first-mover advantage.

At the end of 2025, WuXi Biologics’ integrated platform was hosting a total of 196 bsAbs/msAbs projects, including 9 in Phase III and 3 in commercialization (all high-potential assets), with multiple PPQ programs scheduled for 2026. With one of the largest and most technically advanced bsAbs/msAbs development pipelines in the industry, WuXi Biologics is positioned at the forefront of this fastest-growing biologics sector. Furthermore, the company has published nearly 46 bsAbs-related papers in peer-reviewed journals, reinforcing its technical leadership and industry recognition.

Technology Innovation for bsAbs/msAbs R&D and Manufacturing

The stringent requirements of bsAbs/msAbs — spanning structural design, protein expression, purity, and stability — extend across the entire lifecycle, demanding systematic optimization grounded in professional expertise, project experience, and state-of-the-art technologies.

WuXi Biologics has established a bsAbs/msAbs discovery and CMC development platform, which is seamlessly integrated with GMP manufacturing, providing global clients with integrated, high-efficiency solutions to accelerate the development of next-generation biologics — from concept to commercialization.

Figure 2: Addressing bsAbs/msAbs challenges with WuXi Biologics’ Key Technologies and Strategies

• Early Research (Biologics Discovery) – designing for the entire lifecycle

The key challenges in bsAbs/msAbs R&D stem from molecular design: structural complexity, high mispairing risk, poor stability, and intricate functional mechanisms. Unresolved issues at the early stage can result in significant risks and cost burdens in development and manufacturing.

WuXi Biologics’ early bsAbs/msAbs research embeds development, manufacturing, risk, and cost considerations into molecular design to enable robust and end-to-end operational excellence.

The WuXiBody™ platform delivers a highly effective solution to longstanding industry bottlenecks, enabling multispecific development beyond the limitations of other current multispecific platforms. By addressing critical discovery and CMC barriers, WuXiBody™ supports bsAbs development with high expression yield, reliable stability, good solubility, and easy purification to homogeneity; expediting the process by 6-18 months; and reducing manufacturing costs significantly. The WuXiBody™ enables broad mAb pairing to be assembled into multispecific formats⁵, with the potential to extend in vivo half-life. The platform also offers unique structural flexibility, which allows for convenient generation of diverse formats with different valency combinations (1+1, 2+2, 1+1+2, etc.) tailored to different target biology.

WuXiBody^TM adopts an innovative design, replacing the CH1/CL region of one antibody Fab by the corresponding T-cell receptor (TCR) Cβ/Cα domains to facilitate correct heavy-light chain pairing. The unique characteristics of this domain can differentiate the target heterodimer from homodimers, supporting easier removal of homodimers. The mAb-like CMC performance accelerates the drug development process for bsAbs/msAbs developed by WuXiBody^TM.

As of December 2025, WuXiBody™ has secured over 50 global collaborations, demonstrating its leading position as a preferred platform for bsAbs/msAbs R&D.

In addition to WuXiBody™, WuXi Biologics offers a comprehensive, industry-leading bsAbs/msAbs technology suite to address global clients’ diverse needs across different molecule types and R&D stages, including the VHH-based Multispecific antibody platform SDArBody™, scFv-based platform SkyBody™, OmniFlic‘s common light-chain platform, and universal bsAb platforms.

Figure 3: WuXi Biologics’ Leading TCE Platform and Collaborations with Leading Global Pharma Companies

Through integration of WuXiBody™ and its CD3 antibody platform, WuXi Biologics has built sustained momentum in CD3 TCE molecule partnerships, reflected in broad adoption by multinational pharmaceutical companies and Chinese biotech innovators — such as MSD, GSK, Vertex, and Sino Biopharmaceutical.

• Development Excellence backed by Extensive Experience and Comprehensive Approaches

The structural diversity and molecular complexity of bsAbs and msAbs are widely recognized as major challenges in their development.

Leveraging extensive experience from nearly 200 bsAbs/msAbs projects spanning more than 150 formats, WuXi Biologics has systematically mapped structure-specific development challenges and established a mature, multi-tiered development framework to help clients accelerate the development of complex molecules.

At project initiation, WuXi Biologics conducts a systematic assessment of each molecule to define the Quality Target Product Profile (QTPP) based on its mechanism and structure, underpinning a comprehensive quality analysis and control strategy. This proactive quality management approach identifies potential quality risks early, supports robust clone screening and process optimization, ensures consistent quality from early development through commercial manufacturing, and significantly shortens the overall R&D timeline.

A robust quality analysis and control strategy relies on strong analytical capabilities. WuXi Biologics has built a tiered analytical toolbox to systematically address common challenges in bsAbs/msAbs development at different phases.

Mispairing byproducts are a typical challenge. A 4-chain bsAb, normally composed of two distinct heavy chains and two light chains, could theoretically form 9 different 4-chain byproducts. Among these, the light chain-swapped species could display the exact same molecular weight and similar physicochemical features as the target molecule, posing significant challenges for differentiation using conventional analytical methods.

To address this challenge, WuXi Biologics applies a suite of advanced analytical methods and technologies — such as intact mass spectrometry, subunit mass spectrometry, and hydrophobic interaction chromatography (HIC) — to accurately identify and quantify byproducts and/or variants. By deploying multiple bioassays, the company thoroughly characterizes bsAb potency, enabling the early prediction, monitoring, and control of quality risks.

Prior to stable transfection, WuXi Biologics systematically optimizes key parameters related to molecular design and expression via early-stage research pool studies, including signal peptide selection, codon optimization, vector design, chain expression ratios, and host cell selection, thereby laying a solid foundation for successful cell line generation.

WuXi Biologics’ proprietary WuXia™ cell line platforms are widely employed in bsAbs/msAbs development, and have supported over 1,000 clinical and commercial manufacturing projects. Utilizing these advanced cell line platforms, and drawing on its experience in speeding COVID-19 drugs to market, the company is able to offer clients various strategies in accelerating cell line development.

Notably, WuXi Biologics’ next-generation targeted integration cell line development platform WuXia™ TrueSite delivers an average mAb titer of 8+ g/L, enabling the rapid development of high-expression, high-stability cell lines, with the timeline from DNA to Master Cell Bank (MCB) shortened to just 9–10 weeks, halving conventional cell line development timelines. WuXia™ TrueSite has been successfully applied across multiple bsAb development programs and has demonstrated the following advantages⁶:

• Average pool titer reaches 6.5 g/L, with monomer purity above 90%
• Over 99% of clones maintain stable expression after 60 PDLs
• The cell line development cycle was shortened to 2.5 months, compared with the traditional 4-5-month timeline

Figure 4: Application of the Novel WuXia™ TrueSite Achieved Improved bsAbs Titer and Purity.

For downstream processes, WuXi Biologics’ purification strategies are based on shared structural characteristics of bsAbs/msAbs, significantly improving process development efficiency. The company has systematically evaluated and validated chromatography technologies to remove various byproducts. Leveraging its mature platforms, deep chromatography expertise, and extensive project experience, WuXi Biologics achieves rapid process development and scalable bsAbs/msAbs purification processes.

• Manufacturing: Scaled manufacturing designed for speed, scale, and resilience

Technology-enabled manufacturing: Cost Efficiency With Uncompromised Quality:

Built on its years of development experience and technical know-how in bsAbs/msAbs, WuXi Biologics converts project execution experience into superior manufacturing capabilities, encompassing advanced cell line development and innovative manufacturing technologies.. Leveraging extensive CMC expertise across diverse complex molecules, WuXi Biologics drives excellence in bsAbs/msAbs upstream and downstream manufacturing, while providing clients with tailored optimization strategies to ensure process robustness and supply resilience.

In response to more dynamic market demand in the global biopharmaceutical industry, WuXi Biologics combines single-use technology (SUT) with flexible scale up and scale out strategies, enabling agile adaptation to projects of varying scales and development stages. This model allows manufacturing capacity to flexibly align with project phase and market demand without sole reliance on large-scale scale-up, thereby reducing scale-up risks, enabling seamless transition from clinical supply to commercialization, and significantly shortening overall delivery timelines.

WuXi Biologics continuously boosts productivity through proprietary process development and manufacturing platforms — such as WuXia™ TrueSite, WuXiHigh™ 2.0, WuXiUI™, WuXiUP™ — integrated with lean manufacturing principles from the WuXi Biologics Business System (WBS). This integration delivers increased resource synergy, enhanced process optimization, reduced unit production costs, and enhanced overall cost-effectiveness for commercial manufacturing of complex molecules.

Through full technology-enabled manufacturing, WuXi Biologics addresses the industry-wide challenge of balancing quality, speed, and cost. By delivering accelerated, stable-quality, and cost-controlled end-to-end solutions, the company enhances the success rate of complex molecule commercialization and builds long-term client trust.

Supply Chain Resilience Strengthened by a “Global Dual Sourcing” strategy: WuXi Biologics has established an integrated global manufacturing system covering drug substance and drug product, providing end-to-end commercial manufacturing support. The company operates 16 drug substance and 9 drug product facilities and, as of December 2025, has manufactured over 2,350 batches of drug substance and more than 2,260 batches of drug products, achieving a 100% success rate for all PPQ campaigns. The manufacturing capacity is expected to support approximately 30 tons of biologics production annually from 2029.

To navigate rising global supply chain uncertainty, WuXi Biologics continues to advance its “Global Dual Sourcing” strategy, building compliant redundant capacity across key regions. Its facilities span Asia, Europe, and North America, with approximately 50% of planned capacity located overseas, effectively supporting clients’ regional supply needs and assuring long-term stable delivery.

With an unwavering commitment to quality and compliance, by the end of 2025, WuXi Biologics has passed 46 global regulatory inspections (including 22 FDA and EMA inspections), achieving a 100% pass rate for FDA Pre-License Inspections, and securing 136 facility license approvals.

Digitalization and automation: Where Automation Evolves into Prediction. WuXi Biologics elevates digitalization and automation to a strategic priority, ensuring stable manufacturing with advanced control strategies. By deeply integrating Raman Process Analytical Technology (PAT) with computational predictive modeling, the company enables real-time online monitoring, trend forecasting, and risk alerts for over 40 key process indicators.

Sophisticated digital systems underpin electronic batch records (EBR) and enterprise resource planning, allowing clients real-time access to project data and the tracking of manufacturing and delivery progress via a one-stop platform.

Consistent performance and quality across batches is enhanced through standardization driven by the Golden Batch benchmark, providing reliable assurance for commercial supply.

Ending: A Partner for Complex Innovation

As the bsAbs/msAbs sector continues its rapid expansion, the winners will not be defined by science alone, but by who can execute with speed, quality, and trust.

Leveraging its fully integrated CRDMO platform, WuXi Biologics empowers global partners to rapidly advance bsAbs/msAbs programs across critical R&D, clinical development, and regulatory milestones. By accelerating the journey from laboratory research to commercialization, the company helps partners secure first‑to‑market advantages in an increasingly competitive landscape, maximize the commercial value of their bsAbs/msAbs assets, and deliver innovative therapies to patients worldwide—faster and with greater confidence.  

References:

1. Labrijn, A.F., Janmaat, M.L., Reichert, J.M. et al. Bispecific antibodies: a mechanistic review of the pipeline. Nat Rev Drug Discov 18, 585–608 (2019). https://doi.org/10.1038/s41573-019-0028-1
2. Grand View Research. Bispecific Antibodies Market (2023 – 2030), www.grandviewresearch.com.

3. Marshall, A. The year of the bispecific in oncology and beyond. Nature, 1 December 2025.
4. Pharmcube. Innovation and Integration: Exploring Next-Generation Innovative Drugs – Bispecific/Multispecific Antibody Report, March 2026.
5. Guo G, Han J, Wang Y, Li Y. A potential downstream platform approach for WuXiBody-based IgG-like bispecific antibodies. Protein Expr Purif. 2020 Sep;173:105647. doi: 10.1016/j.pep.2020.105647. Epub 2020 Apr 23. PMID: 32334139.
6. Sun T, Chen X, Zhou H. Developing next-gen cell lines using targeted integration. BioPharm International. 2025. https://www.biopharminternational.com/view/developing-next-gen-cell-lines-using-targeted-integration.