Large and complex protein molecules used as therapeutic agents are manufactured in a series of process steps that start with thawing of cell-bank vials and finish with filling and packaging (Figure 1). The cost and complexity of commercial-scale biomanufacturing processes make them prohibitive to troubleshoot or experiment at full commercial scale. Biopharmaceutical companies routinely use scale-down models (SDMs) of licensed commercial-scale processes to evaluate raw material changes, process improvements, and deviations (1) (Figure 2). Here, we outline some considerations in…