Is cryopreserved cellular material really a reliable source of starting material?
Catch up with Chris Leonforte, Head of Cell & Gene Therapy Manufacturing at Anthony Nolan to get his insights.
What caused the shift towards frozen material in recent years?
The change really picked up with the pandemic. Developers struggled to access fresh material because collections stopped taking place during lockdowns. This meant that banks with frozen materials, like Anthony Nolan’s were some of the only banks able to keep supplying researchers and keep work moving forwards.
As well as the pandemic, manufacturers have found that freezing, or cryopreservation, is a critical step in separating the point of optimal collection and optimal processing. For example, manufacturers of autologous therapies are finding that by cryopreserving patient material earlier in the treatment pathway they can ensure the highest quality cells are banked ready, in case they are needed in the future.
What are the advantages of working with frozen material?
The great thing about frozen samples is that target cell counts and other specifications can be measured and set according to a developer's requirements. The risk and variability associated with fresh material is removed. We still process samples in a standarised way and work to acceptance criteria, such as isolating a target cell to determine cell count and concentration, in advance allowing us to select the most appropriate sample for a client’s needs.
How does transporting frozen material compare to fresh?
Frozen material is shipped so that it arrives when the researcher needs it. So, the delivery works around the client whereas with fresh material, the variability of quality could mean that we cannot always meet requirements. This is a surprisingly common issue in the cell and gene therapy space, where the donation (whether cord or adult material) dictates when the client can set up their workstream – one frozen material avoids altogether.
What are the challenges of working with cryopreserved material?
The obvious challenge is the viability of material post-thaw. Not all cells will survive the freezing process, but with our validated processes, we can account for the cell loss at the freezing stage to ensure the quantity of cells requested is the quantity of viable cells received. Hopefully, if more cryopreserved material is used, the processes for reconstituting the frozen material will improve and potentially negate concerns of using frozen over fresh.
How are samples shipped?
Depending on the sample type, the material can be shipped on dry ice (-80oc) or in a cryoshipper (-196oc). We use specialist couriers who are trained in working with dry ice and vapour shippers to ensure the material reaches its destination in the same state that it left our bank.
How long does it take to deliver frozen samples?
It depends where the client is based and what their requirements are, some are within 24 hours and others are 48-72 hours. The good news is that the samples can remain in a cryoshipper for up to eight days and the courier can add more nitrogen if needed. This means if samples get stuck in transit, for example due to flight cancellations or customs issues, the samples remain viable.
What is the current storage capacity at the Anthony Nolan Cell Therapy Centre?
We have space for a few thousand cryovials and a few hundred cord blood bags. Due to the size of adult cryopreservation bags, the capacity for these are about one hundred bags. But we’re always reviewing market demand and storage needs, so we can ensure we can keep supporting patients and researchers.
Do you think the need for cryopreserved material will continue to grow?
Yes. If there’s one thing we don’t have enough of its time! Cryopreserved material gives researchers and manufacturers peace of mind by guaranteeing a set delivery date, quantity, and quality of product in advance – de-risking the supply chain. This allows standardisation and consistency of downstream processes, which is key to achieve reproducibility in the scale up of cell and gene therapies for patients.