Adapting virus filtration to enable intensified and continuous monoclonal antibody processing

Abstract

Ongoing efforts in the biopharmaceutical industry to enhance productivity and reduce manufacturing costs include development of intensified, linked, and/or continuous processes. One approach to improve productivity and process economics of the polishing step (i.e., anion exchange chromatography) is to preconcentrate the product intermediate using a single-pass tangential flow filtration step before loading on the resin. This intensification of the polishing step consequently leads to changes in product intermediate concentration for subsequent virus filtration operations, potentially impacting filter performance and methods for evaluating viral clearance.The filtrate flux performance of a virus filtration operation was evaluated with monoclonal antibody (mAb) solutions of varying concentrations. These data were used to evaluate the effect on filter sizing for a hypothetical mAb perfusion process. The optimum mAb concentration to minimize the area of the virus filter was a function of the filtration step duration and reflected the competing effects of increasing concentration and decreasing volumetric flux on the membrane productivity. mAb solutions at high and low concentrations were used to evaluate viral clearance with extended filtration times (e.g., 24-72 h) simulating continuous processing conditions. Modifications to more traditional filtration viral clearance study methods were required to avoid experimental artifacts associated with the extended filtration time. No virus passage through the filter was observed under these conditions, similar to previous results for batch processes. These data demonstrate the feasibility of obtaining effective virus removal even when mAb concentration and filtrations times are increased by up to an order of magnitude from current common practices. K E Y W O R D S connected processing, continuous manufacturing, intensified processing, next generation processing, virus filtration 1 | INTRODUCTION Viral safety assurance is a key component for biologics production processes. While viral safety measures in upstream processes focus on reducing the risk of contaminants entering production processes, for biopharma and plasma products, downstream purification operations are designed to meet specific virus clearance targets outlined in guidance documents. 1,2 These documents have provided a framework for viral safety that has enabled global manufacturing of a broad range of therapeutics to meet the expanding needs of diverse clinical indications.Recently, interest has been growing in the biopharmaceutical industry to develop significantly improved, next generation manufacturing processes. [3][4][5][6] As biomanufacturers have optimized

The effects of flux on the clearance of minute virus of mice during constant flux virus filtration

“…It was found that low flux conditions could lead to a reduction of the virus retention of 20 L/m 2 bacteriophages spiked mAb feed solutions with some of the commercial filters. On the other hand, another recent 4.5 LMH constant flux virus filtration study (Bohonak et al, 2020) with a more viscous feed at high product titer did not exhibit MVM breakthrough. These studies support the important role of diffusion plays in virus filtration at low‐pressure low flux conditions.…”

“…Diffusion appears to play an important role in virus retention for Filter V particularly when longer filtration time is needed at such a low flux. An earlier study (Bohonak et al, 2020) shows that a low flux at 4.5 LMH did not lead to virus breakthrough. This is likely due to the fact that particle diffusion is restricted with a more viscose feed stream at a product titer of 50 g/L.…”

“…Virus filtration validation studies are often performed using a scale‐down model to achieve viral clearance targeting more than four logs of reduction value (LRV) while maximizing product throughput (Lute et al, 2007). Continuous downstream processing requires a consistent operation mode for virus filtration and the other chromatographic purification steps including protein A capturing step and cation or anion exchange chromatographic polishing steps (Bohonak et al, 2020; Kozlov et al, 2018; Shamashkin et al, 2013). One strategy is to conduct virus filtration at constant flux mode in line with other chromatographic operation modes.…”

“…Continuous downstream processing requires a consistent operation mode for virus filtration and the other chromatographic purification steps including protein A capturing step and cation or anion exchange chromatographic polishing steps (Bohonak et al, 2020;Kozlov et al, 2018;Shamashkin et al, 2013). One strategy is to conduct virus filtration at constant flux mode in line with other chromatographic operation modes.…”

Converting a mAb downstream process from batch to continuous using process modeling and process analytical technology

“…PQ surge tank was used to homogenize output from the AEX step and make it ready for the VF step. Although there were publications about performing low‐pressure VF in a continuous process, [ 18,19 ] VF in this work was carried out in the same way as the batch process. This manner was chosen for two reasons.…”