Potential clinical value of cryopreserved haematopoietic precursors stored longer than 20 years

A survey of cell processing practices for hematopoietic cell transplantation

BACKGROUND

There is considerable heterogeneity in cell handling practices for hematopoietic stem cell transplantation in cell processing centers in Spain. The European Directorate for the Quality of Medicines and international standards are not intended to establish best practices or to include all procedures; therefore, each cell processing laboratory must define its own practices and procedures.

METHODS

A survey was conducted to better understand the differences among cell processing laboratories in Spain in terms of type of facilities and equipment available, service portfolio, staff, informatics systems, product handling, environmental and product quality control tests, batch release criteria, storage and shipping conditions, and criteria for product disposal or recall, to identify areas for harmonization.

RESULTS

In this study, 31 authorized centers responded to the survey. Fifteen centers do not usually wash cryopreserved grafts, in contrast to others that perform washing systematically (n = 5) or when the product contains >1 g/kg/dimethyl sulfoxide or recipient body weight is <25 kg (n = 11). We observed high variability in terms of handling of thawed samples, such as in protocols used to enumerate CD34+ cells, compensation solution, temperature and time delay between thawing and CD34+ enumeration. Storage time for cell therapy products varied between 5 and 30 years. Additionally, 12 centers do not reduce plasma before cryopreservation to save space.

DISCUSSION

Overall, this survey demonstrates variability in activity, logistics and staff among cell processing laboratories in Spain. Some issues remain ongoing and further efforts should be undertaken to harmonize practices in these facilities, such as indications and procedures for washing cryopreserved stem cells and handling of cryovials to enumerate viable CD34+ cells after thawing. Efforts are needed to regulate product storage to optimize space utilization and reduce associated costs.