Membrane chromatography is routinely used to remove host cell proteins, viral particles, and aggregates during antibody downstream processing. The application of membrane chromatography to the field of antibody-drug conjugates (ADCs) has been applied in a limited capacity and in only specialized scenarios. Here, we utilized the characteristics of the membrane adsorbers, Sartobind® S and Phenyl, for aggregate and payload clearance while polishing the ADC in a single chromatographic run. The Sartobind® S membrane was used in the removal of excess payload, while the Sartobind® Phenyl was used to polish the ADC by clearance of unwanted drug-to-antibody ratio (DAR) species and aggregates. The Sartobind® S membrane reproducibly achieved log-fold clearance of free payload with a 10 membrane-volume wash. Application of the Sartobind® Phenyl decreased aggregates and higher DAR species while increasing DAR homogeneity. The Sartobind® S and Phenyl membranes were placed in tandem to simplify the process in a single chromatographic run. With the optimized binding, washing, and elution conditions, the tandem membrane approach was performed in a shorter timescale with minimum solvent consumption and high yield. The application of the tandem membrane chromatography system presents a novel and efficient purification scheme that can be realized during ADC manufacturing.

During a CHO cell culture production process, important parameters are generally well controlled by a feedback mechanism (PID loop) in order to ensure consistency in both productivity and product quality. These parameters typically include pH, dissolved oxygen (DO), and temperature. While most of these parameters are very well controlled within their specific deadband, stable DO control can be challenging. Oscillations in DO concentration are not uncommon and these fluctuations can be exacerbated with an efficient mass transfer aeration strategy. In this study, where an IgG producing cell line was used, we observed increased lactate accumulation accompanied by decreased titer production in lots with fluctuations in DO concentration (DO ) when compared with lots with stable DO control (DO ). We demonstrate that DO had a greater impact on performance with respect to titer production and lactate accumulation than DO setpoint. Furthermore, we report that estimated specific oxygen uptake rates (qOURs) were lower in DO lots when compared with DO lots. We also report that purified mAb sourced from DO lots yielded lower drug-to-antibody ratio (DAR) after the sulfhydryl-targeted maleimide conjugation process when equivalent reducing agent was used. All mAb lots were within the analytical specifications for release, though a slight increase in measureable trisulfides were observed in DO mAb lots. DO control aimed to minimize fluctuations around DO setpoint was essential for us to produce consistent DAR without adjusting the conjugation process. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 2018.