Background and importance Tisagenlecleucel is available in frozen bags stored and shipped under –120°C. The Summary of Product Characteristics (SPC) allowed storage in a cryogenic freezer (vapour phase of nitrogen (LN2) is cited only as an example). As the pharmacy does not have LN2 storage facilities, tisagenlecleucel bags are stored in a freezer set at –150°C. With only one freezer available, another freezer located in the biological haematology laboratory was chosen as a back-up freezer in case of failure.

Aim and objectives The aim of this work was to validate the thermal performance of the container transfer system between our facility and our back-up ones.

Material and methods Freezer and rooms were equipped with Cobalt2 sensor, with Thermoserver software allowing monitoring, temperature recording, and triggering of the alarm in case of temperature excursion. A Cryoexpress polystyrene transport container was preloaded with 10 × 100 mL sodium chloride bags and one aluminium cassette used for tisagenlecleucel bag storage in order to mimic real-life conditions. The transport container was equipped with an Emerald sensor, with Oceaview software allowing real-time monitoring of the temperature inside the container. The transport container was placed inside the freezer, the cover was opened, and the temperature was set on –140°C in order to mimic a temperature excursion. After temperature stabilisation, the freezer was opened, the container was hermetically closed and the temperature inside it was measured every 30 s until an overrun of –120°C. Two situations were tested: the container left at room temperature (+20°C), and, in order to mimic the worst case scenatio, left in a room maintained at +30°C. Each measurement was done in duplicate. Measurement of transfer time from the pharmacy to the back-up freezer was done by two different operators in triplicate.

Results Whatever the external temperature, conditions needed by the SPC is maintained for more than 25 min (28 min and 33.5 min for an external temperature of +20°C and +30°C, respectively). The transfer time from the pharmacy to the biological haematology laboratory was 3.25±0.25 min.

Conclusion and relevance Transfer duration to the back-up installation is far lower than the time for which an optimum storage temperature for tisagenlecleucel is maintained with our transport system.

Conflict of interest No conflict of interest