Figure 2: Process analytics as understanding of the relationship between process, product(-variants) and contaminants. During upstream and downstream processing, deviations from the optimal process parameters (in red) for each of the individual steps will lead to the emergence of the product variants T, F, MO, M, D, and A (in blue, symbols see Figure 1) and contaminants (in green) which are difficult to detect in the final product by routine quality control. These may affect the production costs, recovery, efficacy and safety of the protein drug in differential fashion with safety being of highest importance.