In its current state, cell therapy manufacturing comprises several open and manual operations which increase the risk of contamination. Members of BioPhorum’s Cell & Gene Therapy Commercialization workstream have generated a ‘mock’ process detailing the manufacture of a generic autologous CAR-T product operated through a series of process steps combining some open and some closed system elements. The mock process has undergone an end-to-end closure analysis to identify those operations that pose the highest contamination risks, and to provide suggested mitigation solutions to minimize such risks. Suggestions include options that are currently available, as well as potential future ‘desired state’ options. This paper details the full process and summarizes potential risks and possible mitigations. The primary aim of this paper is to demonstrate systematic application of a closure analysis method on an ex vivo gene therapy (also known as gene-modified cell therapy) process so that organizations can apply similar analyses to their own processes. The secondary aim is to propose process closure solutions that companies could implement in their own operations.