Improvement of monoclonal antibody stability by modulating trace metal iron concentration in cell culture media: A case study

Monoclonal antibodies are among the fastest-growing segment of drugs. The stability of the protein drugs is particularly challenging due to their high susceptibility to physico-chemical stresses that may make them unsuitable for human health applications. Aggregation is considered a main stability indicator, potentially raising safety and immunogenicity concerns. Self-aggregation pathways can be triggered by a series of protein modifications that could be due to the intrinsic characteristics of the protein itself or during the manufacturing process. Macro and micronutrient content in cellular culture media can represent a source of oxidative stress, leading to a higher self-aggregation rate. This work aimed to explore the impact of iron content variability in the manufacturing cell culture media on drug substance purity and quality, and linked the effect of iron content on antibody degradation by self-aggregation, methionine oxidation, and decreased stability under long-term conditions. This work highlights the importance of maintaining strict control of raw materials, as unexpected lot-to-lot variability could compromise the entire antibody manufacturing process and patient safety due to undesired issues in the quality of the final product.