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 2.5 L 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. (C) 2012 Elsevier B.V. All rights reserved

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. (C) 2011 American Institute of Chemical Engineers Biotechnol. Prog., 27: 1339-1346, 201