Gentle Cell Processing for Cell Therapy
Handling therapeutic cells is a delicate process. Processing should be sufficient to reliably purify the cells of interest, but gentle enough to avoid compromising their viability. Finding the right solutions to achieve this balance can be tricky. We talked to Summer Gunn, Product Specialist, and Prasad Kakarla, Global Product Manager, about how Sartorius approaches this problem.
The continuing evolution in the biotherapeutic market requires innovative technologies to keep up. Existing platforms and methodologies might not be appropriate for new modalities. For example, the preparation of therapeutic cells requires solutions that protect cell viability while still achieving sufficient purification to ensure safety and efficacy.
In this blog post, Summer Gunn and Prasad Kakarla share their thoughts about cell processing.
What are the main hurdles when preparing cells to be included in live therapies?
“After producing the therapeutic cells, the first hurdle is that they need to be carefully separated from the media components used to cultivate them. This means that the cells need to be extensively washed. The second hurdle is that the cells should not be damaged or lost while they are being separated. These hurdles fall at opposite sides of the spectrum. It’s a bit of a balancing act to achieve both at the same time.”
Summer Gunn elaborated further, “Removing impurities is essential for cells that are to be used in therapies as there are no additional viral clearance or filtration steps. To make them safe, cells must be washed and concentrated multiple times, and these multiple washes need to be gentle so as not to damage the cells, but effective enough to produce a high-quality product.”
How are cells typically isolated during bioprocessing, and why is it tricky to get right?
“A common and extremely versatile way to harvest cells is by manual centrifugation complying with cGMP standards. You can concentrate the cells at relatively low speeds and remove debris from the supernatant before resuspending them in a clean buffer. The more times you repeat this process, the more impurities you remove. However, the longer you centrifuge, the more you expose the cell to damage and potential lysis.”
Prasad Kakarla also pointed out some of the challenges with manual centrifugation:
“traditional centrifugation can also lead to errors and batch-to-batch variability, and it is time intensive with long hold times that can negatively affect cell quality.”
Other than the cell viability vs. purity balancing act, what other challenges do your industry partners face during the preparation of cell therapies?
“Scalability is a big one,” noted Summer Gunn. “Even for individual therapies, large numbers of cells are needed. Unfortunately, there aren’t many processes that can be used at both pilot-scale and full-scale production, complicating the transition to commercial-scale manufacturing. However, during process development, it is important to know that the work done can ultimately be applied to a full manufacturing process.”
How does Sartorius approach gentle cell harvesting processing?
“At Sartorius, we developed a simple, robust system that balances centrifugal and fluid flow forces to create a gentle environment for effective cell harvest. Ksep® 50's unique design retains cells in a concentrated, fluidized bed, in a continuous flow of media or buffer. Counterflow centrifugation reduces shear by balancing centrifugal and fluid flow forces.”
“Ksep® 50 users can recover 90-99% of their cells in our gentle environment while retaining properties like stem cell pluripotency, and phenotypic markers of T-cells.”
Aside from a gentle environment, what are the other benefits of the Ksep®50 for cell therapy applications?
Prasad Kakarla referred back to their comments about the challenges of manual centrifugation: “You avoid all of that with the Ksep® 50 because it is automated. So, it supports aseptic processing by reducing the risk of contamination and is reproducible and efficient. It can also integrate multiple steps into one unit operation to reduce the manual intervention and processing time.”
Summer Gunn added, “It also performs really well in terms of recovery. Ksep® 50 users can recover 90-99% of their cells in our gentle environment, greatly increasing overall productivity and product quality. I’d say the biggest advantages of Ksep® 50 are gentle, efficient processing, scalability from small to large processes, automation with flexibility for process development, and high recovery of viable product.”
What process steps can the system be used for? Just cell harvesting?
“The system also comes with an automated cell wash feature for efficient media or buffer exchange, independent of cell densities, to improve target product quality.”
“And because multiple steps in cell harvesting are combined into this closed unit operation, manual interventions and contamination risks are minimized, reducing waste.”
What about considering the other hurdle you mentioned, scalability. Can a gentle, effective cell harvesting process be scaled?
“Yes! Our Ksep® portfolio is built with exactly that in mind. It can handle anything from 100 mL to 2,000 L batches. This means that a proof of concept can be done on the same instrument as a full-scale manufacturing run.”
Summer Gunn told us more about how the Ksep® portfolio achieves this scalability.
“Process time, system modularity to cover broad process volume range, and scalable recipes between all Ksep® variants are the three main factors that contribute to robust scalability.”
Summer Gunn has been with Sartorius since 2019 and currently holds the position of Product Specialist for Ksep® systems. She earned her bachelor’s degree from Clark Atlanta University in Atlanta, Georgia, and her Master's degree from Case Western Reserve University in Cleveland, OH.
Since joining Sartorius, Summer has played a vital role in supporting product development, fostering external collaborations, and creating sales collateral to enhance the success of the Ksep® systems. With a solid background in cell therapy process development, she possesses significant expertise in identifying and overcoming the challenges associated with establishing efficient and scalable processes. Her contributions have been crucial in helping bring cell therapy products to market.
Dr. Prasad Kakarla, Global Product Manager for Ksep® technology
Dr. Prasad Kakarla has been with Sartorius since 2020, serving as the Global Product Manager for Ksep® technology. He holds a Ph.D. in Biochemical Engineering from Jacobs University Bremen, Germany.
With extensive experience in mammalian cell processes and in vitro assays, Prasad has become an integral part of the Ksep® product development team at Sartorius. His role involves engaging in customer collaborations to understand the specific needs of cell therapy manufacturing processes. Through these interactions, he has been instrumental in optimizing the Ksep portfolio to address bottlenecks in cell therapy process development and scale-up, thereby enhancing manufacturing efficiency and effectiveness.
To find out more about the Ksep® family of products watch this video, which showcases how the system works, and the features that enable high rates of cell recovery.
