In January 2020, the US Food and Drug Administration (FDA) published a series of seven guidances regarding cell and gene therapy. These have not come too soon, given some much-publicised regulatory rejections. For example, the FDA turning down the Biologics License Application of BioMarin valoctocogene roxaparvovec for severe haemophilia A. Following relatively recent European regulatory revisions, the FDA guidances, as usual, apply to the manufacture as well as the development and clinical trials of drugs. A major challenge of cell and gene therapy developers is balancing clinical considerations with logistical demands such as manufacture.