In the age of biotechnology, making medicines at scale is a complex and multistage process. This cluster explores process development, looking at how a drug candidate goes from being a promising compound to a product that is manufactured and distributed to patients. This is divided into three broad categories. In drug substance process development, experiments are performed to establish the process for making a drug substance on a large scale. In drug product process development, a drug substance is formulated into a final, marketable product that can be used by patients. In attribute sciences, a drug product’s quality attributes (measurable properties or characteristics of a drug that help to define its overall quality) are monitored. Throughout this cluster, the development of monoclonal antibodies as therapeutic proteins will serve as an example for the individual steps involved in each stage of process development.