GMP Manufacturing of Cryopreserved peripheral Blood Stem Cell Products

ABSTRACT

Background: Hematopoietic stem cell preparations are pharmaceuticals that are typically transfused as fresh products. Due to the travel restrictions caused by the Covid-19 pandemic since March 2020, the supply of fresh stem cell preparations to patients became significantly challenging. To maintain global patient supply, a GMP-compliant manufacturing process for cryopreservation of allogeneic stem cell donations was established and validated. Method(s) The donor leukapheresis is transported from the collection center to the manufacturing site at 2-6degreeC using qualified containers. In class D clean rooms, this material is further processed in a completely closed process. If necessary, volume reduction is performed by centrifugation. The suspension is mixed with the cryoprotectant Cryostore CS10 to achieve a final DMSO concentration of 5%. The formulated product is filled into cryobags and cryopreserved under controlled freezing conditions. The frozen products are stored and transported at <= 140 degreeC. The cell counter NC-200 is used to determine the cell count and viability of the product. 97 products in 2020 and 127 products in 2021 were successfully cryopreserved and transported worldwide. Result(s) The mean values of viability of 215 products are 99.3 % (+/- 1.1 % SD) for fresh apheresis products and 93.1 % (+/- 6.2 % SD) for the corresponding cryopreserved final product after thawing. For a good recovery after thawing, the age of the apheresis as well as the DMSO contact time are generally considered to be critical factors. The analysis of the viability of 222 cryopreserved end products after thawing shows a correlation in relation to the age of the apheresis (Fig. 1). As the age of the apheresis increases, the viability decreases. Therefore, care should be taken about the age of the apheresis. A correlation between the DMSO contact time and the viability of the end products after thawing was not observed (Fig. 2). Conclusion(s) GMP-compliant closed system manufacturing of cryopreserved allogeneic stem cell products provides safe and high quality drugs that can be used for transplantation. We have shown that with our manufacturing process, DMSO, which is potentially toxic to cells, has no effect on cell recovery after thawing. Cryopreservation is therefore a suitable and safe method to provide patients with essential therapy worldwide. (Figure Presented).