Bohonak David M, Mehta Ushma, Weiss Eric R, Voyta Greg
Process Solutions, MilliporeSigma, Burlington, Massachusetts, USA.
Life Science Quality and Regulatory Management, MilliporeSigma, Burlington, Massachusetts, USA.
Biotechnol Prog. 2021 Mar;37(2):e3088. doi: 10.1002/btpr.3088. Epub 2020 Dec 11.
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.
生物制药行业为提高生产率和降低制造成本而持续做出的努力包括开发强化、联动和/或连续工艺。提高精制步骤（即阴离子交换色谱）生产率和工艺经济性的一种方法是在将产品中间体加载到树脂上之前，使用单程切向流过滤步骤对其进行预浓缩。精制步骤的这种强化会导致后续病毒过滤操作中产品中间体浓度发生变化，可能会影响过滤器性能以及评估病毒清除率的方法。使用不同浓度的单克隆抗体（mAb）溶液评估了病毒过滤操作的滤液通量性能。这些数据用于评估对假设的mAb灌注工艺中过滤器尺寸的影响。使病毒过滤器面积最小化的最佳mAb浓度是过滤步骤持续时间的函数，反映了浓度增加和体积通量降低对膜生产率的竞争效应。使用高浓度和低浓度的mAb溶液，通过模拟连续加工条件的延长过滤时间（例如24 - 72小时）来评估病毒清除率。需要对更传统的过滤病毒清除研究方法进行修改，以避免与延长过滤时间相关的实验假象。在这些条件下未观察到病毒通过过滤器，这与之前批次工艺的结果类似。这些数据表明，即使mAb浓度和过滤时间比当前常规做法增加一个数量级，仍可实现有效的病毒去除。
