A comprehensive assessment of the applicability of RoboColumn as a chromatography scale-down model for use in biopharmaceutical process validation.

High-throughput process development has become a standard practice in the biopharmaceutical industry to enable time, cost, and material savings. In downstream biopharmaceutical process development, miniaturized, parallelized chromatography columns, known as RoboColumn, have become the standard for process development, as RoboColumn have shown generally comparable performance to bench and manufacturing scale columns. However, RoboColumn have yet to be widely implemented in process validation and characterization, where many multifactor experiments are typically executed, and there is a strong value proposition for performing high-throughput experiments. The hesitancy to utilize RoboColumn in process validation arises from scale differences that result in exacerbated peak broadening at RoboColumn scale relative to traditional bench or manufacturing scales. Thus, to support reliable application of RoboColumn in process validation, the present study provides a comprehensive investigation to understand how scale differences affect chromatographic performance by comparing RoboColumn, bench, and manufacturing scales using seven different production processes covering three different antibody formats, five different resin types, and three chromatographic modes of operation. RoboColumn chromatographic performance was compared at target and off-target conditions to emulate scale-down model qualification and multifactor studies, respectively. RoboColumn demonstrated good comparability at both target and off-target process conditions. To further demonstrate an understanding of comparability, a study was performed to show a rare case in which product quality offsets may occur as a result RoboColumn scale differences. By showing scale comparability and an understanding of potential offsets, this work demonstrates that RoboColumn can be used in any stage of process development, including process validation and characterization.

Effects of copper on CHO cells: insights from gene expression analyses.

Copper concentration can impact lactate metabolism in Chinese Hamster ovary (CHO) cells. In our previous study, a 20-fold increase in initial copper concentration enabled CHO cultures to shift from net lactate production to net lactate consumption, and achieve higher cell growth and productivity. In this follow-up study, we used transcriptomics to investigate the mechanism of action (MOA) of copper that mediates this beneficial metabolism shift. From microarray profiling (days 0-7), the number of differentially expressed genes increased considerably after the lactate shift (>day 3). To uncouple the effects of copper at early time points (days 0-3) from that of lactate per se (>day 3), and to validate microarray hits, we analyzed samples before the lactate shift by RNA-Seq. Out of 6,398 overlapping genes analyzed by both transcriptomic methods, only the early growth response 1 gene-coding for a transcription factor that activates signaling pathways in response to environmental stimuli-satisfied the differential expression criteria (fold change ≥ 1.5; P < 0.05). Gene expression correlation and biological pathway analyses further confirmed that copper differences exerted minimal transcriptional impact on the CHO cultures before the lactate shift. By contrast, genes associated with hypoxia network and oxidative stress response were upregulated after the lactate shift. These upregulations should boost cell proliferation and survival, but do not account for the preceding shift in lactate metabolism. The findings here indicate that the primary MOA of copper that enabled the shift in lactate metabolism is not at the transcriptional level.

Near-infrared and two-dimensional fluorescence spectroscopy monitoring of monoclonal antibody fermentation media quality: aged media decreases cell growth.

In biomanufacturing processes, the influence of feedstock components on product yield and quality is considerable and often poorly understood. Here we describe the capabilities of near-infrared spectroscopy (NIRS) and two dimensional (2D)-fluorescence spectroscopy in detecting chemical changes over time in two types of culture media (one basal media and one feed media) used in the production of monoclonal antibodies (mAbs) by Chinese hamster ovary (CHO) cells. Both spectroscopies were able to detect compositional changes in basal media over storage period of 12 weeks. NIRS was more effective in detecting changes in feed medium composition. The impact of storage time in process performance was evaluated by using aged media components in mAb cultivations. The study suggests that basal media aging results in a decrease of the integral of viable cells (IVC) (cell growth over time), while product titer is not significantly affected. Feed media appears to be less sensitive to storage and no correlation between the age of the media and cell culture performance was detected. Results obtained provide a basis on which to further improve cell culture raw material quality assessment using vibrational (e.g. NIRS) and optical (e.g. 2D-fluorescence) spectroscopic methods.

At-line NIR spectroscopy as effective PAT monitoring technique in Mab cultivations during process development and manufacturing.

The application of at-line NIR transmittance spectroscopy on supernatant samples from Chinese Hamster Ovary Cells (CHO) based monoclonal antibody (Mab) cultivation processes spanning several scales from 2.5L to 1000 L, cell-lines and development years is described. The collected and preprocessed spectra were used to do process state estimation and to obtain several culture parameters. Multivariate process trajectories were computed from NIR spectra acquired at-line. These were used to enhance process understanding across different scales up to industrial scale, assess batch-to-batch variability, and examine the relative importance of different sources of process variability. Many parameters of interest in industrial cell culture, like nutrient or product concentrations can be reliably estimated by NIRS with an accuracy of 15% or better, compared to reference methods General calibrations (scale and cell-line independent) are valid across a range of process conditions and different feed regimes. The proposed approach is therefore applicable throughout process development as well as to existing large-scale validated CHO bioprocesses for continuous improvement.

Predicting Mab product yields from cultivation media components, using near-infrared and 2D-fluorescence spectroscopies.

The yield of monoclonal antibody (Mab) production processes depends on media formulation, inocula quality, and process conditions. As in industrial processes tight cultivation conditions are used, and inocula quality and viable cell densities are controlled to reasonable levels, media formulation and raw materials lot-to-lot variability in quality will have, in those circumstances, the highest impact on process performance. In the particular Mab process studied, two different raw materials were used: a complex carbon and nitrogen source made of specific peptones and defined chemical media containing multiple components. Using different spectroscopy techniques for each of the raw material types, it was concluded that for the complex peptone-based ingredient, near-infrared (NIR) spectroscopy was more capable of capturing lot-to-lot variability. For the chemically defined media containing fluorophores, two-dimensional (2D)-fluorescence spectroscopy was more capable of capturing lot-to-lot variability. Because in Mab cultivation processes both types of raw materials are used, combining the NIR and 2D-fluorescence spectra for each of the media components enabled predictive models for yield to be developed that out-performed any other model involving either one raw material alone, or only one type of spectroscopic tool for both raw materials. For each particular raw material, the capability of each spectroscopy to detect lot-to-lot differences was demonstrated after spectra preprocessing and specific wavelength regions selection. The work described and the findings reported here open up several possibilities that could be used to feed-forward control the process. These include, for example, enabling specific actions to be taken regarding media formulation with particular lots, and all types of predictive control actions aimed at increasing batch-to-batch yield and product quality consistency at harvest.