Virus clearance validation across continuous capture chromatography

Continuous Countercurrent Chromatography in Protein Purification

Continuous countercurrent chromatography can be applied for both capture and polishing steps in the downstream processing of biopharmaceuticals. This chapter explains the concept of countercurrent operation, focusing on twin-column processes and how it can be used to alleviate the trade-offs of traditional batch chromatography with respect to resin utilization/productivity and yield/purity. CaptureSMB and MCSGP, the main twin-column continuous countercurrent chromatography processes, are explained, and the metrics by which they are compared to single-column chromatography are identified. Practical hints for process design and application examples are provided. Finally, regulatory aspects, scale-up, and UV-based process control are covered.

Development of a transient inline spiking system for evaluating virus clearance in continuous bioprocessing -- Proof of concept for virus filtration

The development of continuous/connected bioprocesses requires new approaches for viral clearance validation, both for specific unit operations and for the overall process. In this study, we have developed a transient inline spiking system that can be used to evaluate virus clearance at distinct time points during prolonged operation of continuous bioprocesses. The proof of concept for this system was demonstrated by evaluating the viral clearance for a virus filtration step, both with and without a prefilter upstream of the virus filter. The residence time distribution was evaluated using a previously identified non-interacting fluorescent tracer, while viral clearance was evaluated from measurements of the virus titer in samples obtained downstream of the virus filter. The measured log reduction values (LRV) for ϕX174, Minute Virus of Mice (MVM), Xenotropic Murine Leukemia Virus (XMuLV), and a non-infectious Mock Virus Particle (MVP) were all within 0.5 logs of those obtained using a traditional batch virus challenge for both model and real-world process streams (LRV between 2.2 and 3.4 for ϕX174 using a single layer of virus filter). The results demonstrate the effectiveness of transient inline spiking to validate the virus clearance capabilities in continuous bioprocessing, an essential element for the adoption of these processes for products made using mammalian cell lines. This article is protected by copyright. All rights reserved.

Mimicking continuous capture chromatography for virus clearance using a single chromatography column model

Continuous chromatography is increasingly being used across the biotechnology industry due to its economic advantages. For adoption in commercial manufacturing, also models for virus clearance studies must be available. We demonstrate how for a virus clearance study for a multispecific antibody, the continuous protein A capture chromatography process, being run on multiple interconnected columns, can be mimicked with only a single column. With this mimicking small-scale model, resources and complexity can be minimized, when conducting virus clearance studies at a contract research organization (CRO) lab. Obtained log reduction values (LRV) for xMuLV and MVM virus, used as model viruses, are comparable to batch protein A chromatography and results described by other groups. The feasibility of this mimicking small-scale model helps to further reduce barriers to adoption when implementing continuous chromatography. This article is protected by copyright. All rights reserved.

Continued insights into virus clearance validation across continuous capture chromatography

Multi-column capture chromatography (MCC) has gained increased attention lately due to the significant economic and process-related advantages it offers compared to traditional batch mode chromatography. However, for wide adoption of this technology in the clinical and commercial space, it requires scalable models for viral validation. In this study, additional viral validation studies were conducted under cGLP guidelines to assess retro-(X-MuLV) and parvo-virus (minute virus of mice) clearance across twin-column continuous capture chromatography (CaptureSMB) to supplement work previously performed. A surrogate model was validated using standard batch mode chromatography equipment based on flow path modifications to mimic the loading strategy employed in CaptureSMB. In addition, aged resin was used in this surrogate format to assess the impact of resin lifetime on viral clearance during continuous capture operation. The impact of column loading was also explored to shed light on the viral clearance mechanisms of protein A chromatography in overloading conditions. The proposed approach greatly simplifies MCC virus validation studies, and provides a robust strategy for regulatory filing of continuous biomanufacturing processes.

Biomanufacturing evolution from conventional to intensified processes for productivity improvement: a case study

Process intensification has shown great potential to increase productivity and reduce costs in biomanufacturing. This case study describes the evolution of a manufacturing process from a conventional processing scheme at 1000-L scale (Process A, n = 5) to intensified processing schemes at both 1000-L (Process B, n = 8) and 2000-L scales (Process C, n = 3) for the production of a monoclonal antibody by a Chinese hamster ovary cell line. For the upstream part of the process, we implemented an intensified seed culture scheme to enhance cell densities at the seed culture step (N-1) prior to the production bioreactor (N) by using either enriched N-1 seed culture medium for Process B or by operating the N-1 step in perfusion mode for Process C. The increased final cell densities at the N-1 step allowed for much higher inoculation densities in the production bioreactor operated in fed-batch mode and substantially increased titers by 4-fold from Process A to B and 8-fold from Process A to C, while maintaining comparable final product quality. Multiple changes were made to intensify the downstream process to accommodate the increased titers. New high-capacity resins were implemented for the Protein A and anion exchange chromatography (AEX) steps, and the cation exchange chromatography (CEX) step was changed from bind-elute to flow-through mode for the streamlined Process B. Multi-column chromatography was developed for Protein A capture, and an integrated AEX-CEX pool-less polishing steps allowed semi-continuous Process C with increased productivity as well as reductions in resin requirements, buffer consumption, and processing times. A cost-of-goods analysis on consumables showed 6.7–10.1 fold cost reduction from the conventional Process A to the intensified Process C. The hybrid-intensified process described here is easy to implement in manufacturing and lays a good foundation to develop a fully continuous manufacturing with even higher productivity in the future.

Novel spiking methods developed for anion exchange chromatography operating in a continuous process

Many manufacturers of biopharmaceuticals are moving from batch to continuous processing. While this approach offers advantages over batch processing, demonstration of viral clearance for continuous processes is challenging. Fluctuating output from a continuous process chromatography column results in a nonhomogeneous load for the subsequent column and must be considered when designing viral clearance studies. One approach to clearance studies is to downscale the connected unit operations and introduce virus by in-line spiking. This is challenging to be implemented at the contract research organization performing the clearance study given the complexity of systems and level of expertise required. Alternately, each unit operation could be evaluated in traditional batch mode but the spiking and loading conditions be modified to mimic the variance introduced by the transition between two connected columns. Using a standard chromatography system, we evaluated a flow-through anion exchange chromatography step in a monoclonal antibody (mAb) manufacturing process using five different methods to introduce the virus to the column. Our data show that whether the virus or the mAbs were introduced in concentrated peaks, or as a homogeneous batch, the clearance of mouse minute virus was similar. This study introduces an alternative way to evaluate viral clearance in a continuous process and demonstrates the robustness of anion exchange chromatography unit operating in continuous processing.