Scaling Antibody Production for ADC Programs

• Scaling antibody production for Antibody-Drug Conjugates programs requires a delicate balance of scientific rigor, strategic timing, and collaboration. The field has expanded rapidly in recent years, with over 200 ADC candidates in clinical trials worldwide. 
• The ADC market has grown from approximately $1.4 billion in 2016 to $7.2 billion in 2022, with forecasts predicting significant growth from $9.7 billion in 2024 to over $30 billion by the early 2030s. 
• Each ADC program must produce a high quality monoclonal antibody scaffold and efficiently conjugate a toxic drug linker to that antibody. Scaling up antibody production for ADCs requires careful timing and strategy to meet these technical and regulatory demands. 

Determining Optimal Scale-Up Points for ADCs 

Establishing the ADC manufacturing process in compliance with GMP standards is a complex endeavor. Early in development, manufacturers often adopt a phase-appropriate GMP approach. This strategy aligns with U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines, which mandate full cGMP adherence by late-stage clinical and commercial manufacturing.  

Applying just enough control in preclinical and Phase 1 stages ensure basic compliance. However, a common pitfall is postponing consideration of introducing GMP standards until too late. A lack of early GMP strategy can become a weakness in regulatory filings. To avoid this, many teams initiate preliminary GMP frameworks even at small scale, so that quality systems ramp up smoothly with each scale increase.^1,2 

Choosing the right moment to upscale the antibody production is critical. Scaling up too early can waste resources on an ADC candidate that may not succeed clinically, whereas scaling up too late can lead to capacity shortfalls or process inefficiencies during pivotal trials. 

Process design for scale-up also incorporates regulatory expectations from the outset. By Phase 2, sponsors typically initiate process characterization studies to identify critical process parameters (CPP) that impact antibody quality. Key attributes like charge variants, glycoform distribution, and aggregation propensity must remain in tight ranges as batches grow larger. Employing Quality by Design (QbD) principles during scale-up enables manufacturers to define proven acceptable ranges for process parameters and to establish a control strategy ensuring consistent output. In practice, this means performing small-scale stress studies to see how such changes might alter the antibody. The knowledge gained feeds into a robust scale-up plan with built-in controls and monitoring. 

Notably, even with meticulous planning, scaling an ADC’s antibody component remains challenging. The development of robust, scalable processes for ADC production is still considered a highly challenging task for drug developers and their manufacturing partners. Unforeseen issues can arise. Therefore, determining optimal scale-up points is an iterative technical exercise. Many programs use a stepwise scale-up aligned with clinical phases. At each step, process engineers verify that product quality remains comparable and that yields scale roughly linearly. By Phase 3 clinical trials, the process should be essentially fixed, with the manufacturing scale matching commercial needs. 

Mabion Scaling Antibody Production Framework for Transitioning From Clinical to Commercial Operations

Mabion exemplify a framework for scaling antibody production that smoothly bridges clinical-scale output to commercial volumes. The strategy hinges on joint development of the mAb and ADC processes from an early stage. Rather than developing the antibody production in isolation and later handing off to a separate team for conjugation, Mabion’s model synchronizes these workflows. In practice, this means that as the antibody process is scaled from bench to pilot plant, the conjugation process is co-optimized to accommodate the qualities of that antibody. This joint development prevents misalignment and thus improves overall manufacturability. 

A critical aspect of transitioning from small-scale clinical to at-scale commercial manufacturing is technology transfer and scale adaptation. Our framework involves reproducing the small-scale process conditions as faithfully as possible in larger bioreactors, then fine-tuning parameters only as needed to fit the commercial equipment. By maintaining consistent culture environment and kinetics, the antibody’s quality profile remains unchanged at scale. After the upscale translation, process development continues with emphasis on quality and manufacturability. Mabion model ensures that both the antibody production and the subsequent drug-linker bioconjugation steps are robust and efficient. 

Mabion’s co-development approach also leverages concurrent analytical and regulatory planning. By uniting developer and CDMO process teams, the company can develop analytical methods that serve both the unconjugated mAb and the conjugated ADC. This includes assays for aggregation, potency, and impurity profiles that are used throughout development. A strong analytical platform is essential to control each step and the final ADC. Mabion integrates quality control (QC) and quality assurance (QA) units early in the scale-up program, creating a feedback loop where any drift in antibody attributes is immediately evaluated for its impact on conjugation and product safety. This holistic oversight accelerates troubleshooting and streamlines the path to commercialization. 

Joint development of mAb and ADC processes has clear benefits in time and cost. By synchronizing scale-up decisions Mabion avoids bottlenecks that can occur when one part of the process outpaces the other. This coordination reduces redundant work and prevents costly delays. Moreover, the manufacturing risk is reduced. Potential issues are caught early by the integrated team. The co-development strategy ultimately improves the likelihood that when the ADC program reaches a commercial scale, both the antibody supply and the bioconjugation process are ready and optimized. This approach aligns with industry observations that close collaboration between R&D and manufacturing expedites tech transfer and scale-up.  

In essence, Mabion example illustrates how synchronous up-scaling of the monoclonal antibody and ADC conjugation processes can accelerate progress from clinical batches to full commercial production while maintaining quality and controlling costs. 

Strengthening Early-Phase ADC Development Through Commercial Manufacturing Platforms 

Even in early-phase development, adopting a commercial-ready manufacturing platform can greatly benefit ADC programs. Established CDMO companies often provide platform processes that a sponsor can tap into at Phase 1 or Phase 2. Using a proven platform for monoclonal antibody production means that from day one, the process is designed with eventual large-scale output in mind.  

This minimizes the need for drastic changes later. For example, a sponsor might choose a standard CHO cell line and media used by the CDMO in commercial manufacturing, ensuring that the cell culture process is inherently scalable. By doing so, scale-up becomes a matter of linear expansion of a well-characterized process, rather than an overhaul, thus reducing technical risks in early clinical stages.³ 

One clear advantage of leveraging commercial-grade platforms early is accelerating timelines. An experienced CDMO with platform processes can rapidly produce GMP-grade antibody for Phase 1 trials and then scale it up for following phases and commercialization without major redesigns. This continuity speeds up development because the team can progress through clinical phases without pausing to re-develop the process for larger volumes. Additionally, platform processes come with established analytical methods and validation protocols, which strengthen early-phase development. Quality metrics are monitored with the same rigor at 100 L as they would be at 1000 L, yielding high confidence in the product even in Phase 1. Employing such a strategy effectively bridges the gap between laboratory scale and manufacturing scale during the formative stages of an ADC program. 

Another benefit to embracing a commercial manufacturing mindset early is improving operational efficiency. CDMOs often utilize single-use technologies and modular facilities for ADC production, which can be scaled out or scaled up as needed. 

Coordinating mAb and ADC process development from the start also reduces scientific risk. Challenges unique to ADCs – such as maintaining a stable drug-to-antibody ratio or preventing aggregation after conjugation – can often be traced back to characteristics of the antibody or the conjugation conditions.⁴ If the antibody production process is developed in a silo, these issues might only surface in late development. But a coordinated early-phase approach addresses such issues proactively. Process scientists can modify the antibody’s cell culture conditions to influence attributes that might affect conjugation efficiency. Likewise, knowledge of the conjugation chemistry informs the selection of buffer components in the upstream/downstream process. The result is an antibody that is “fit for conjugation” right from the initial GMP batches. 

Market Demand for Outsourcing of Biologic Drug Manufacturing 

The market need for reliable biologics outsourcing is further amplified by the surge in ADC clinical activity. By 2025 there were over 200 ADC drug candidates in trials, an all-time high that many in-house teams would struggle to support alone. 

The rise of ADC programs has fueled a high demand for outsourcing to specialist CDMOs for antibodies manufacturing. Many smaller pharma and biotech companies developing ADCs do not possess in-house manufacturing capacity. As a result, the majority of ADC developers now partner with CDMOs to produce their monoclonal antibodies and perform conjugation under GMP. Industry analyses indicate that CDMOs have strategically invested in end-to-end ADC capabilities to serve as one-stop shops, covering antibody production, cytotoxic drug-linker synthesis, and bioconjugation services. This trend is driven by both the complexity of ADC manufacturing and the need for rapid scaling.⁵ 

Outsourcing offers ADC developers access to cutting-edge manufacturing technology and expertise without the need to build it all from scratch. For instance, a CDMO experienced in ADCs will have established protocols for handling toxins and may have dedicated high-containment suites for conjugation. This is invaluable for ensuring safety and regulatory compliance. Integrating external platform elements early can also reduce overall development cost (even if upfront costs appear higher). Using external manufacturing capacity also means that an ADC developer can initiate production of a clinical batch relatively quickly by leveraging the CDMO’s ready infrastructure.  

Quality expectations from regulators provide another impetus for outsourcing. Biologic drugs, including the mAb component of ADCs, must be manufactured to very high quality standards. Specialized CDMOs bring deep expertise in biologics process development and validation, which can ensure that even early clinical batches meet rigorous criteria. Sponsors recognize that partnering with such experienced manufacturers early can smooth the path to later approvals. In effect, outsourcing has become a strategic decision to de-risk ADC development both operationally and financially.

Key Cost Drivers in ADC-Oriented Scaling Antibody Production 

Scaling up antibody production for ADC programs has significant economic implications. ADCs are inherently more complex to produce than conventional monoclonal antibodies, and this complexity translates into higher production costs. One major cost driver is that an ADC requires multiple GMP manufacturing processes in parallel.  

The key cost factor is process yield and efficiency during scale-up. Monoclonal antibody production has benefitted from yield improvements over the years, which lowers cost per unit of antibody. However, if those yields drop at larger scale due to suboptimal scaling or cell performance, the cost of goods (COGS) rises. Similarly, the conjugation step yield impacts cost. Loss of antibody or drug during conjugation means wasted expensive materials. Process optimization is thus critical. This is why manufacturability assessments early in development are emphasized. A drug candidate that is prone to aggregation or has a narrow conjugation window could be significantly more costly to make. Developers may even choose one linker technology over another because it gives a cleaner conjugation reaction or easier purification, thereby improving yields and reducing cost.⁶ 

Timing of scale-up decisions directly impacts overall cost structure as well. If scale-up is done too late, a company might produce Phase 2 material in numerous small batches, which is inefficient and labor-intensive, driving up cost per gram. Conversely, scaling up too early (to a larger bioreactor or production train before it’s fully needed) can lead to underutilized capacity and wasted expense. The optimal strategy balances these: for instance, scale up the antibody production to a volume that can supply not just current clinical needs but anticipated Phase 3 demand, thereby achieving some economies of scale at the right time. Production economics models often identify a cost inflection point – a batch size beyond which the cost per unit significantly drops. ADC programs strive to hit that sweet spot when increasing scale. Studies have shown, for example, that beyond a certain chromatography column size, the cost of purification per gram of antibody decreases sharply before leveling off. Recognizing such inflection points informs scale decisions that minimize COG. 

Facility and equipment requirements for ADC manufacturing also drive costs. The need to handle potent cytotoxins compels manufacturers to invest in engineering controls like isolators, ventilated hoods, and specialized HVAC systems. These add capital and maintenance expenses beyond a standard antibody production suite. Moreover, to ensure worker safety and product purity, many CDMOs use single-use bioreactors and production trains based on closed, disposables systems for both antibody and conjugation production. While single-use systems can lower cleaning validation costs and prevent cross-contamination, they come with a higher per-batch consumable cost. Yet this can be an advantageous trade-off: using disposable technology can reduce the need for large fixed stainless-steel installations, thus lowering initial capital investment. It also accelerates turnaround between batches (no lengthy cleaning), potentially increasing throughput and offsetting some costs.

Conclusion 

Economically, scaling antibody production for ADCs remains challenging but manageable with informed strategy. ADC programs must contend with higher costs of goods due to multi-part production and high-potency handling, but through process innovation and smart planning these costs can be contained.⁷ 

Close coordination between sponsor and CDMO teams in co-development has emerged as a best practice. As seen in integrated frameworks like Mabion’s, joint development strategies eliminate silos and streamline the transition from clinical to commercial manufacturing. This approach accelerates timelines by synchronizing scale-up activities and prevents costly last-minute reworks. Likewise, engaging experienced CDMO partners and platform processes from the outset can inject valuable expertise and infrastructure, allowing even small companies to harness commercial-scale capabilities in early development. The strong market trend toward outsourcing in the ADC space speaks to its benefits in risk mitigation and efficiency.

FAQ

Prepared by:

Marta Bednarek

Director of Manufacturing and Operations

m.bednarek@mabion.eu

Marta Bednarek

Director of Manufacturing and Operations

Marta has been the Director of Manufacturing and Operations with Mabion for over 13 years. She is a biotechnologist by profession, in love with molecular biology and cell cultures. As an engineer, she combines scientific knowledge with advanced technology and turn it into innovative projects, responsible for Drug Substance and Drug Product manufacturing.

Jakub Knurek

Marketing Specialist

j.knurek@mabion.eu

Jakub Knurek

Marketing Specialist

Jakub Knurek is a marketing and business development expert specializing in CDMO operations with scientific and biopharmaceutical background. During the COVID-19 pandemic, he contributed to the development of the Novavax protein vaccine. As a side project, he runs his own pharma company.

As the author of numerous articles, he is recognized as an important voice of the younger generation of scientists. He is a member of Mabion’s representation at industry trade shows, including BIO International Convention 2025 in Boston, 2nd Global Biologics India 2025 in Hydrabad, CPHI 2024 in Milan, CPHI 2023 in Barcelona, Life Sciences Baltics 2023 in Vilnius. He actively participates in academic, business and industry discussions, such as the “Building the Future Pharma Workforce” panel at CPHI Milan 2024.

References

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