Scaling the next generation of cell therapies

Over the past decade, cell therapy has evolved from a promising scientific concept into an established therapeutic modality. Multiple approved products have demonstrated durable clinical benefit in hematologic malignancies, while a growing pipeline is expanding into solid tumors, autoimmune diseases, regenerative medicine, and other indications. As the field matures, however, success will depend not only on clinical efficacy but also on the ability to manufacture these therapies consistently, efficiently, and at commercial scale.

One of the greatest challenges is cell expansion. Unlike traditional biologics manufacturing, where scaling primarily means increasing production volume, cell expansion directly shapes the therapeutic product itself. It influences not only the number of cells available for dosing, but also their phenotype, functional potency, metabolic fitness, durability and consistency.

This fundamentally changes how manufacturing must be approached. In cell therapy, the manufacturing process is inseparable from product quality. Even small changes in culture conditions, media composition or process controls can alter cellular behavior and ultimately affect therapeutic performance. As developers move toward commercialization, achieving reproducible cell expansion while preserving critical quality attributes has become one of the field’s defining manufacturing challenges.

Meeting that challenge requires more than larger culture vessels or higher cell yields. It demands an integrated manufacturing strategy that combines process development, analytical characterization, automation, digital technologies, and quality-by-design principles to deliver scalable, reproducible production without compromising biological function.

Cell expansion is fundamentally different

Cell expansion occupies a unique position within the cell therapy manufacturing workflow because it directly shapes the therapeutic product itself. Unlike recombinant proteins or monoclonal antibodies, living cells continuously respond to their surrounding environment throughout culture. Nutrient availability, cytokine concentrations, oxygen transfer, shear forces, metabolite accumulation, and culture duration all influence cellular behavior.

The objective, therefore, extends well beyond producing larger numbers of cells. Successful expansion requires generating sufficient quantities of cells while preserving the functional properties that drive therapeutic activity. Expansion protocols should balance proliferation with maintenance of desirable phenotypes, avoiding excessive differentiation, cellular exhaustion, or metabolic stress that may compromise clinical performance.

This challenge becomes particularly apparent as developers move beyond early process development. Laboratory workflows prioritize biological feasibility, while commercial production demands reproducibility across operators, facilities, and manufacturing campaigns. Process variability that seems minor in research can become a major risk when therapies are produced at scale.

As a result, expansion is increasingly viewed not as an isolated unit operation, but as the central process connecting upstream biology with downstream manufacturing quality.

Commercialization raises the stakes

As cell therapies move toward commercialization, manufacturing expectations continue to evolve. Early clinical programs often operate with relatively small patient populations and limited manufacturing volumes. Commercial success, however, introduces new pressures.

Developers should consider increasing manufacturing throughput while maintaining consistency across every batch. Regulatory agencies expect increasingly robust demonstrations of process understanding and manufacturing comparability. At the same time, healthcare systems continue to place pressure on reducing manufacturing costs while expanding patient access.

These pressures affect both autologous and allogeneic manufacturing models, although in different ways.

Autologous therapies rely on patient-derived starting material, introducing substantial biological variability before manufacturing even begins. Differences in disease state, prior treatment history, collection quality and individual patient biology can significantly influence expansion performance. Manufacturers should therefore build sufficiently robust processes to accommodate variability while consistently delivering products that meet predefined quality attributes.

Allogeneic therapies reduce many patient-specific logistical challenges but introduce different manufacturing considerations. Large-scale production requires maintaining consistent cell phenotype and functionality throughout extended expansion periods while generating many doses from a single manufacturing campaign. Small process deviations can become amplified when production is scaled, increasing the importance of process control and manufacturing consistency.

Rather than viewing autologous and allogeneic therapies as competing approaches, many organizations are increasingly recognizing that each presents distinct manufacturing challenges. Regardless of modality, successful commercialization depends on reliable, scalable expansion processes capable of producing consistent therapeutic products.

As manufacturing strategies evolve, developers are increasingly adopting scale-out approaches that expand capacity through parallelized systems rather than larger production units. This strategy offers greater flexibility for both autologous and allogeneic workflows by replicating standardized expansion processes across multiple units, increasing throughput while maintaining consistency. As next-generation expansion technologies mature, success will depend not only on the size of individual systems, but on the ability to efficiently coordinate production across interconnected platforms.

Understanding the sources of variability

Cell expansion is influenced by numerous interacting biological and environmental variables, making process consistency inherently complex.

Variability often begins with the starting material itself. Patient-derived cells may differ substantially in composition, viability, activation status and proliferative capacity. Even healthy donor-derived cells often exhibit biological differences that influence expansion performance.

Once culture begins, process conditions become equally important. Oxygen availability, pH, nutrient consumption, waste accumulation, cytokine concentrations, mixing characteristics and environmental control collectively shape cellular metabolism. Because living cells continuously respond to these conditions, maintaining a stable culture environment becomes essential for preserving product quality and consistency.

Importantly, higher cell yields do not necessarily translate into improved therapies. Excessive expansion can expedite cell differentiation, promote cellular exhaustion and reduce functional potency. Manufacturers therefore face a continual balancing act between maximizing dose availability and preserving biological performance.

This growing understanding has shifted industry thinking away from measuring manufacturing success solely through expansion efficiency. Instead, developers increasingly focus on maintaining critical quality attributes throughout culture while ensuring consistent process performance across manufacturing campaigns.

As manufacturing scales, this emphasis on process understanding becomes even more important. Identifying sources of variability early during development allows manufacturers to establish robust control strategies before commercial production, thereby reducing risk and improving reproducibility.

Building manufacturing around process control

Addressing the cell expansion bottleneck requires greater visibility into manufacturing rather than relying solely on end-product testing.

Automation has become a key strategy for reducing operator-dependent variability and improving reproducibility. Closed manufacturing systems minimize manual interventions, lower contamination risk, and standardize workflows across facilities. But automation alone is not enough. It must also generate meaningful process data that support informed manufacturing decisions.

Advances in process analytical technologies (PAT), in-line sensing, and integrated monitoring now enable continuous measurement of parameters such as dissolved oxygen, pH, nutrient availability, and metabolic activity, providing a more complete picture of culture performance throughout expansion.

The ability to effectively leverage these technologies is closely tied to the underlying expansion platform. Dynamic bioreactors promote continuous mixing, creating a more homogeneous culture environment that enables more representative sensor measurements. By minimizing localized gradients in nutrients, dissolved oxygen, and metabolic byproducts that develop in static cultures, dynamic systems improve process visibility and enable more responsive process control.

These technologies support a transition from reactive manufacturing toward proactive process control. Rather than identifying variability only after manufacturing has been completed, developers increasingly seek to detect and predict process drift during production, enabling corrective actions before product quality is affected.

Digital integration further strengthens this approach by connecting equipment and process data across manufacturing operations, improving consistency while supporting scale-up. Ultimately, the goal is not simply to expand more cells, but to expand them more predictably.

Scaling for the future

Cell expansion has evolved from a necessary manufacturing step into one of the defining challenges of modern cell therapy, sitting at the intersection of biology, engineering, manufacturing and quality. As the field expands into new indications and larger patient populations, overcoming this challenge will be essential to improving scalability, reducing costs, and ensuring consistent product quality.

Meeting that challenge will require more than incremental technological advances. Quality-by-design approaches are being incorporated earlier in process development to identify critical process parameters and establish robust manufacturing strategies before commercialization. At the same time, artificial intelligence, machine learning, and predictive analytics are creating new opportunities to optimize expansion conditions using large manufacturing datasets, while emerging platforms and digital integration support more adaptive, responsive manufacturing systems.

Success will depend on integrating biology, engineering, analytical characterization, automation and digital technologies into scalable processes capable of consistently producing high-quality therapies. The next decade of cell therapy will be defined not only by the discovery of new treatments, but by the industry’s ability to manufacture them reproducibly, efficiently and at scale.