Biosorption of process-equipment-related leachables (PERLs) in biomanufacturing: A quantitative approach to study partitioning of PERLs in a cell culture system

The assessment and potential risk of process equipment-related leachables (PERLs) in the production of biopharmaceuticals and cell therapeutics using single-use (SU) equipment has been discussed previously. However, potential interactions of cells with PERLs have not yet been considered. Here, we present a quantitative adsorption study of neutral, organic small-molecule leachable compounds - known for extractables & leachables (E&L) analysis of SU equipment - in aqueous suspensions of CHO and T cells. The solid-water partition coefficient K_d was obtained for all compounds that showed adsorption. The findings implied that hydrophobic interactions are dominant; however, there was no unambiguous correlation between the derived adsorption coefficient K_d and the octanol-water partition coefficient K_ow. Interestingly, a maximum affinity of both cell types to the leachable bis(2,4-di-tert-butylphenyl)phosphate, which is known to be detrimental to cell development, was observed. A comparison of both cell types revealed that they generally interact with the same compounds in most cases but to different extents. Using partition coefficients enables estimation of the concentrations of leachable compounds associated with the biomass phase and in the aqueous suspensions and could be used for risk assessment of SU systems in biopharmaceutical and cell therapy (CT) manufacturing processes.

Risk analysis of leachables in cell and gene therapy using a CAR-T model process

With the rapidly emerging field of autologous therapies, Single-Use (SU) technologies are increasingly used in personalized medicine due to their manifold advantages. Although qualification of the starting material of autologous therapies such as the CAR-T process has been highlighted, little attention has been paid to the effect of leachables on cell-based therapies, even if recent studies indicate interactions of leachables with cells. To close this gap, this study presents a risk-analysis of SU-material on a CAR-T process and identifies hazards imposed by tubing materials and leachables thereof. In order to represent a CAR-T process in its entirety, two test systems, namely a lentivirus production process and primary T-cells, were used. While the effects on lentivirus production are comparable to those reported for antibody production processes in CHO cells, we found that PVC material and corresponding leachables, i.e. plasticizer, inhibit cell growth of primary T-cells to a great extent. Additionally, our results indicate that critical quality attributes are affected by the PVC material.