Manufacturing Allogeneic Cell Therapy Products at Scale

The cell therapy field is seeing a gradual shift from autologous cell therapy to allogeneic cell therapy.

Autologous cell therapy uses cells derived from a patient to treat that same patient. This approach comes with the advantage of immunological compatibility. However, cells for autologous therapy are usually derived from patients who may be genetically predisposed to the illness that needs to be treated or may have been exposed to chemotherapeutic agents or other treatments that can cause DNA damage.

Allogeneic cell therapy uses cells derived from a healthy donor to treat multiple patients and has the potential to provide off-the-shelf treatments that are more readily available and significantly less expensive to produce.

Here are the advantages of allogeneic cell therapy and considerations for scaling up cell production and creating a sustainable seed train.

Advantages of Allogeneic Cell Therapy

CRISPR-Cas9 gene editing technology can be used to modify genes by editing DNA for cell therapy, for example, to enrich autologous cells for CAR-T cell therapy or modify allogeneic cells to avoid immune rejection. These modifications can take time, which makes autologous cell therapy unrealistic for situations that require prompt treatment, such as rapidly progressive diseases or spinal cord injuries. For allogeneic cell therapy, the cells can be genetically modified in advance and cryopreserved until needed.

Much of the recent work in allogeneic cell therapy has focused on mesenchymal stem cells (MSCs) and induced pluripotent stem cells (iPSCs). MSCs have the advantage of being immunoprivileged, so they don't elicit an immune response. The advantage of iPSCs is that they have the potential to differentiate into any cell type in the body, so multiple disorders can be treated with the same iPSC line.

Scaling Up Cell Production

As cell therapy treatments move from proof-of-principle experiments to clinical trials, huge numbers of cells must be produced. A single dose of MSC therapy may require hundreds of millions of healthy cells. Furthermore, most of the cell types being considered for cell therapy are adherent cells typically grown in small cell culture plates or T-flasks, which are poorly suited to the production of millions or billions of cells. This mismatch has led to the development of innovative products and techniques that facilitate the transition to cell therapy manufacturing.

Corning® CellSTACK® Culture Chambers have the same solid polystyrene growth surface as traditional T-flasks but are available with up to 40 layers (totaling 25,440 cm2 of growth surface) in a single vessel to reduce handling time and space. Even more compact are Corning HYPERFlask® and HYPERStack® vessels, which use an ultra-thin, gas-permeable polystyrene growth surface that can contribute to improved cell growth.

For preliminary experiments, HYPERFlask includes 10 interconnected layers totaling 1,720 cm² of growth surface in the footprint of a single T-flask. When it's time to scale up, HYPERStack vessels are available with up to 36 layers, totaling 18,000 cm² of growth surface in a closed system that reduces contamination risk. To maximize scalability, multiple vessels can be joined together with manifolds and handled by the Corning Automated Manipulator Platform, which can improve efficiency and reduce operator-to-operator variability.

Maximizing Cell Production

To maximize the production of adherent cells in an efficient and cost-effective manner, consider the Corning Ascent® Fixed Bed Bioreactor (FBR) System. While other FBRs support the culture of adherent cells and the harvest of cellular products like proteins, the Corning FBR system was designed specifically to facilitate cell harvest.

In cell therapy, the cells are the actual product used for treatment, so they must remain healthy to be effective. Furthermore, unhealthy cells can be potentially dangerous if they differentiate into unintended cell types. The FBR system provides something close to a 3D growth environment by supporting a high density of adherent cells on layers of specially treated PET mesh. The mesh can also be treated with laminin, fibronectin, collagen, or other coatings to provide an optimal surface for different adherent cell types.

The Ascent controller monitors pH, dissolved oxygen, and temperature for optimal growth and is currently available in a benchtop version that supports single-use Ascent bioreactors with up to 5 m² of growth surface. Ascent FBR Pilot systems are in development to support bioreactors with up to 100 m² of growth surface.

For maximum output, microcarriers can be used in a traditional bioreactor to provide a growth surface for adherent cells in a suspension environment. Corning Dissolvable Microcarriers are innovative beads made of a PGA polymer that can be dissolved with EDTA and pectinate, allowing for a gentle cell harvest that preserves cell health.

Creating a Sustainable Seed Train

Cell therapy researchers should plan ahead to create a sustainable seed train from Phase 1 onward. Consider the number of cells that will likely be required per dose and the number of doses required for a clinical trial.

While a bioreactor may not be necessary for early work, consider how your team will make the transition from multilayer vessels, such as CellSTACK and HYPERStack vessels, to a bioreactor, like the Ascent FBR system. In Phase 2 and Phase 3 trials, a bioreactor will likely be essential to producing a sufficient number of allogeneic cells at a reasonable cost.

Your team should work ahead to ensure the conditions used for cell growth at smaller scales — including the growth surface — are available and effective at larger scales. If not, you may need to find a suitable alternative to avoid costly delays.

Many cell and gene therapy options are available, and Corning Scientific Support Specialists can help you find an appropriate solution for you.