The basic principle behind development of a cell culture fed-batch process is to increase the area under the cell growth curve (IVC) while maintaining the specific productivity of the cells to maximize the final product yield. During process development of a mAb product, the area under the cell growth curve was increased significantly through feed development and process optimization. However, the final product yield increased only marginally due to a loss in specific productivity of the cells. Spent media analyses revealed that three key amino acids were limiting in this cell culture fed-batch process. The feeds designed for increasing IVC were then fortified with these specific amino acids to restore the specific productivity of the cells. Furthermore, a detailed metabolomic study was performed to analyze the intracellular metabolites of these cells and extracellular nutrient environment. The data indicated that, as the culture progressed, the cells encountered limitations in the following metabolic pathways - (1) Amino acid biosynthesis, (2) Vitamin biosynthesis, (3) Phospholipid metabolism, and (4) Nucleotide and Nucleoside metabolism. Interestingly, limitation in any of these metabolic pathways did not affect the growth profile of the cells but exhibited a negative impact on productivity. The media and feeds were augmented with specific nutrient groups tailored to mitigate the corresponding limitations with an objective of improving the process performance. The final optimized fed-batch process delivered multi-gram per liter of titer. This experience demonstrates the utility of spent media and metabolomic analyses to understand cell line specific nutrient requirements while optimizing a cell culture fed-batch process.

Understanding cell nutrient requirements through spent media analyses and metabolomics: A prerequisite for developing a high titer cell culture fed-batch process

243rd National Meeting (2012)

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