A bioprocess to produce stem-cell-derived CAR-T cells for cancer treatment

Göksu Dilek, Nick Herzog, Brianna Lee, Ralph Rocard, Don Salongsongan and Erin Yont

Degree:
- Bachelor of Applied Science
Program:
- Chemical and Biological Engineering
Campus: Vancouver

Our project

Chimeric Antigen Receptor-T (CAR-T) cell therapy is used to treat relapsed blood cancers or cancers that do not respond to their initial treatment. Currently, CAR-T cells are manufactured from each patient’s own immune cells, which makes the process slow, expensive and difficult to scale.

Researchers and industry are exploring the idea of CAR-T cell production using stem cells from healthy donors to mitigate the current therapy's limitations. This is what our industrial-scale CAR-T cell production process is based on.

These cells can be engineered and stored in advance, creating an off-the-shelf supply that is more accessible and cost effective for patients.

Our proposed batch operation is capable of producing 22,000 CAR-T cell doses annually, representing 40% of market demand in the US.

Our design solution

Our process begins with unspecialized induced pluripotent stem cells from a healthy donor that we advance through a series of bioreactors and separation steps to become fully engineered CAR-T cells.

Process diagram of stem cell expansion and multi-step differentiation into CAR‑T cells, illustrating progression through bioreactors over several weeks.

The first stage is a one-week expansion in a vertical wheel bioreactor using an acoustic separator perfusion to achieve 50-fold expansion. The cells then go through a three-stage differentiation process, where they transform into specialized blood stem cells in a wave bioreactor, then differentiated into T cells on coated microcarriers, and are finally differentiated into CAR-T cells using signalling beads and lentiviral vectors. Finally, the CAR-T cells are purified using magnetic-activated cell sorting and are then preserved for distribution to cancer treatment centres.

The technical challenges we faced

This is a new technology and there are currently no fully scalable commercial processes comparable to what we have proposed. As a result, we had to make numerous assumptions about how each stage might operate at scale. We relied on our prior knowledge and completed significant research to come up with reasonable and justifiable assumptions.

One early design choice that shaped our process was wanting to have the potential for future expansions in production.

To achieve this, we proposed a train of reactors. Although this increases equipment costs, it allows us to optimize throughput and allows for future flexibility. This increases the profitability of the process with increased production capacity and reduced operating costs.

How we validated our solution

We used proxy data and assumptions from scientific papers throughout the initial design process. We then consulted with various industry and academic professionals to confirm the validity of our most critical assumptions. About a month ago, Japan approved two stem-cell-derived therapies for clinical trials: one for treating Parkinson’s disease and one for repairing heart tissue following severe heart failure. Although these therapies target different conditions, they demonstrate that large-scale stem-cell-derived therapies are feasible.

The future of this project

We identified areas where the process could be improved, including addressing bottlenecks and reducing the cost of raw materials.

In the broader biopharmaceutical industry, the next stage would be to confirm the assumptions made and demonstrate pilot scale production, before embarking on the clinical trial and regulatory approval process. Given the rapid pace of innovation and the value of this kind of therapy, we imagine there is a bit of a race going on in industry to see the development of scalable CAR-T cell manufacturing.

What we’re most proud of

We are proud that six undergraduate engineering students were able to design a complete, economically viable bioprocess for a therapy with the potential to transform cancer care.

There were many long weeks where we struggled to develop a realistic process or had to rethink our approach as new information emerged. We spent considerable time on each element – such as the control strategies for our reactors – and worked closely as a team to evaluate options and make informed decisions.

This project reinforced the importance of being able to see both the big picture and the fine details. While many researchers focus on a single component of this process, our task was to design an integrated process from start to finish.

The scale and impact of this project also highlighted the responsibilities that come with being an engineer—responsibilities that were underscored for many of us at our recent Iron Ring ceremony.

By staying curious and expanding our knowledge, we were able to develop a process that is both innovative and grounded in real-world constraints.