C-25: Evaluation of closed system medical device for low volume storage for clinical studies involving regulatory T cells

Abstract

Clinical use of low volume cellular therapeutics requires closed system medical devices for storage, transport, and delivery. The regulatory T cells have been considered as key regulators in various immunological processes and there has been a great interest in using them as immunotherapy. The objective of the current study was to evaluate the use of CellSeal ® Closed-System Cryogenic Vial (Cook Medical, IN, USA) for the application of short-term low volume storage of separated and expanded regulatory T cells and preparation for clinical studies. The CellSeal cryogenic vial is a newly CE Marked medical device intended for the freezing and storage of tissue, cells, blood and blood components for the purpose of introduction into the body by means of infusion or other means of administration. The CellSeal cryogenic vial is made of materials that are stable and durable during freezing and low temperature storage. The design of the CellSeal cryogenic vial has an loading port for ease of loading, a microbial barrier vent to prevent pressure from building up in the vial during loading and to allow air back into the vial during retrieval, tubing that can be sealed to create a functionally closed system, and a retrieval port allowing maximum recovery of the stored volume. The retrieval port on CellSeal offers seamless transfer at the point of care to standard delivery needles or infusion sets for delivery to patients. The current study provides supportive data for use of a single dose of autologous regulatory T cells cryopreserved using CellSeal vials to be injected in vivo to induce prolongation of organ allograft survival. For cryopreservation, separated and expanded regulatory T cells were counted and resuspended in Cryostor CS10 (BioLife Solutions Inc., WA, USA). The cell concentration per single dose was calculated so the volume of the final dose (3 × 10 6 /kg of patient’s body weight) was frozen and stored in 2 mL CellSeal cryogenic vials using a controlled rate freezer and stored in vapor phase of liquid nitrogen. After cryopreservation, the cells were thawed, resuspended in 5% human serum albumin, and evaluated for viability, phenotype, potency and recovery. After 12 weeks of storage, the phenotype and the potency of the cells remained stable. The viability of the cells was complied with the release criteria of the study (>70%). The cells also had a high degree of recovery. The current results indicate that CellSeal cryogenic vials met expectations in preparation for two clinical trials using regulatory T cells. We conclude that the CellSeal cryogenic vials can be highly suitable for low volume storage in clinical trial settings in cellular therapy.