Validation and optimization of viral clearance in a downstream continuous chromatography setting.

Continuous bioprocessing holds the potential to improve product consistency, accelerate productivity, and lower cost of production. However, switching a bioprocess from traditional batch to continuous mode requires surmounting business and regulatory challenges. A key regulatory requirement for all biopharmaceuticals is virus safety, which is assured through a combination of testing and virus clearance through purification unit operations. For continuous processing, unit operations such as capture chromatography have aspects that could be impacted by a change to continuous multicolumn operation, for example, do they clear viruses as well as a traditional batch single column. In this study we evaluate how modifying chromatographic parameters including the linear velocity and resin capacity utilization could impact virus clearance in the context of moving from a single column to multicolumn operation. A Design of Experiment (DoE) approach was taken with two model monoclonal antibodies (mAbs) and two bacteriophages used as mammalian virus surrogates. The DoE enabled the identification of best and worst-case scenario for virus clearance overall. Using these best and worst-case conditions, virus clearance was tested in single column and multicolumn modes and found to be similar as measured by Log Reduction Values (LRV). The parameters identified as impactful for viral clearance in single column mode were predictive of multicolumn modes. Thus, these results support the hypothesis that the viral clearance capabilities of a multicolumn continuous Protein A system may be evaluated using an appropriately scaled-down single mode column and equipment.

Modeling the Downstream Processing of Monoclonal Antibodies Reveals Cost Advantages for Continuous Methods for a Broad Range of Manufacturing Scales.

The biopharmaceutical industry is evolving in response to changing market conditions, including increasing competition and growing pressures to reduce costs. Single-use (SU) technologies and continuous bioprocessing have attracted attention as potential facilitators of cost-optimized manufacturing for monoclonal antibodies. While disposable bioprocessing has been adopted at many scales of manufacturing, continuous bioprocessing has yet to reach the same level of implementation. In this study, the cost of goods of Pall Life Science's integrated, continuous bioprocessing (ICB) platform is modeled, along with that of purification processes in stainless-steel and SU batch formats. All three models include costs associated with downstream processing only. Evaluation of the models across a broad range of clinical and commercial scenarios reveal that the cost savings gained by switching from stainless-steel to SU batch processing are often amplified by continuous operation. The continuous platform exhibits the lowest cost of goods across 78% of all scenarios modeled here, with the SU batch process having the lowest costs in the rest of the cases. The relative savings demonstrated by the continuous process are greatest at the highest feed titers and volumes. These findings indicate that existing and imminent continuous technologies and equipment can become key enablers for more cost effective manufacturing of biopharmaceuticals.

A Direct Approach for Process Development Using Single Column Experiments Results in Predictable Streamlined Multi-Column Chromatography Bioprocesses.

An emphasis on continuous monoclonal antibody (mAb) bioprocessing in the pharmaceutical industry necessitates effective approaches for downstream process development (PD). With a PD strategy, the process parameters are optimized to directly develop streamlined three-step continuous chromatography processes. A design of experiment (DoE) approach with single column (batch mode) is used to simulate a multi-column (continuous mode) purification method and characterize each chromatography step: Protein A capture, anion exchange, and mixed mode cation exchange. A novel and targeted approach to quickly characterize a DoE design space was employed and empirical modeling was used to define the capacity for multi-column chromatography to accurately transfer the batch process to continuous mode of purification. This PD approach effectively mimics the continuous mode of operation and provides the flexibility to develop multiple continuous processes with target mAb recovery and purity. By implementing this PD strategy and the process parameters defined in batch mode, two robust and predictable continuous bioprocesses were developed within 7 weeks of investigation, which resulted in a total product yield of recovery at or above 74%, host cell protein (HCP) content below 5 ppm, and aggregate content below 1%.

Optimized Continuous Multicolumn Chromatography Enables Increased Productivities and Cost Savings by Employing More Columns.

The advantages of continuous chromatography with respect to increased capacity are well established. However, the impact of different loading scenarios and total number of columns on the process economics has not been addressed. Here four different continuous multicolumn chromatography (MCC) loading scenarios are evaluated for process performance and economics in the context of a Protein A mAb capture step. To do so, a computational chromatography model is validated experimentally. The model is then used to predict process performance for each of the loading methods. A wide range of feed concentrations and residence times are considered, and the responses of operating binding capacity, specific productivity, and the number of process columns are calculated. Processes that are able to add more columns proved to be up to 65% more productive, especially at feed concentrations above 5 g L-1 . An investigation of the operating costs shows that discrete column sizing and process performance metrics do not always correlate and that the most productive process is not necessarily the most cost effective. However, adding more columns for the non-load steps at higher feed concentrations allows for overall cost savings of up to 32%.