Container system for enabling commercial production of cryopreserved cell therapy products

Abstract

Aim: The expansion of cellular therapeutics will require large-scale manufacturing processes to expand and package cell products, which may not be feasible with current blood-banking bag technology. This study investigated the potential for freezing, storing and shipping cell therapy products using novel pharmaceutical-grade Crystal Zenith® (CZ) plastic vials. Materials & methods: CZ vials (0.5, 5 and 30 ml volume) with several closure systems were filled with mesenchymal stem cells and stored at either -85 or -196°C for 6 months. Vials were tested for their ability to maintain cell viability, proliferative and differentiation capacity, as well as durability and integrity utilizing a 1-m drop test. As controls, 2 ml polypropylene vials were investigated under the same conditions. Results: Post-thaw viability utilizing a dye exclusion assay was over 95% in all samples. Stored cells exhibited rapid recovery 2 h post-thaw and cultures were approximately 70% confluent within 5–7 days, consistent with nonfrozen controls and indicative of functional recovery. Doubling times were consistent over all vials. The doubling rate for cells from CZ vials were 2.14 ± 0.83 days (1 week), 1.84 ± 0.68 days (1 month) and 1.79 ± 0.71 days (6 months), which were not significantly different compared with frozen and fresh controls. Cells recovered from the vials exhibited trilineage differentiation consistent with controls. As part of vial integrity via drop testing, no evidence of external damage was found on vial surfaces or on closure systems. Furthermore, the filled vials stored for 6 months were tested for container closure integrity. Vials removed from freezer conditions were transported to the test laboratory on dry ice and tested using pharmaceutical packaging tests, including dye ingress and microbial challenge. The results of all stoppered vials indicated container closure integrity with no failures. Conclusion: Pharmaceutical-grade plastic CZ vials, which are commercially used to package pharmaceutical products, are suitable for low-temperature storage and transport of mesenchymal stem cells, and are a scalable container system for commercial manufacturing and fill-finish operation of cell therapy products.