(P-BT-4) A Strategic Model for Collection and Closed Process Cryopreservation of Leukopaks

Background/Case Studies:

Background: Non-mobilized leukopaks are an important starting material used in cell-based manufacturing such as chimeric antigen receptor (CAR) therapies. The challenges for consistent manufacturing include consistent cell yields, and the use of fresh leukopaks, which often adds geographical limitations and logistical risks due to using the starting material at risk. The need for a more consistent collection approach, and the use of cryopreserved leukopaks overcomes these obstacles and can lead to a more standardized manufacturing of allogeneic immunotherapies.

Study

Design/Methods:

Methods: For leukapheresis collection, the Terumo Spectra Optia™ Apheresis System collection platform was used. To improve the consistency of the collection process, 3 healthy, male, donors with a body weight 239 lbs and a total blood volume of 9913 mL were selected after informed consent was received and medical director clearance. Post-collection, the leukopaks were analyzed using a CBC and flow cytometry for CD45, CD3 and 7-AAD for cell viability. The protocol for the closed- cryopreservation of leukopaks was established with a one-hour limit to cryostor exposure before freezing to minimize impact to cell viability. To streamline the cryopreservation process, the protocol was converted from a paper form into an electronic batch record using the MasterControl manufacturing excellence suite.

Results/Findings:

Results: The average product volume for the leukopaks collected was 219 mL, the WBC yield was 17.51x10⁹ cells, and the average absolute CD45 count was 43624 cell/µl. The average CD3 positive cells was 23181 cells/µL. Implementation of the electronic batch record eliminated the need for manual math, thereby reducing the incidence of math errors, math verification checks and minimizing paper trail. Process improvements to the order of operations resulted in 12 fewer tube sealing events and 8 tube welding events during leukopak processing. Furthermore, 4 single use syringes were eliminated from the process materials by directly welding cryostor onto a transfer pack resulting in reduced waste and overhead cost. Initial mock processing revealed that these process updates shortened the cryopreservation processing time by approximately 10 minutes. Future work will focus on familiarizing operators with the updated process and electronic batch record to improve processing times.

Conclusions:

Conclusions: These data indicate that a more standardized leukopak product can be generated using the model employed in this study based on selecting available donors based on body weight, and sex. Implementing an electronic batch record allowed for process steps to be rearranged such as moving the preparation of cryobags and the generation of labels to a pre-processing step, and adjusting the order of operations resulting in a shortened overall processing time and cryostor contact time for leukopack cryopreservation.