In the face of various pressures (slowdown in research, loss of patents, generics, strengthening of regulatory bodies, emergence of the BRICS), improving production performance is an essential option to work on in order to guarantee its sustainability. The implementation and development of the lean philosophy, directly adapted from Toyota production plants, offers a new vision with promising performance results. Whether economic, strategic, social, organisational, commercial or competitive, each will be impacted to varying degrees by lean. Copying other systems is a waste of time. The further the new system moves from the initial organic state, the more difficult it will be to maintain. Improvements to the production process should, on the contrary, be developed little by little in an environment conducive to these developments, with a supportive management team and management support. Thus, improvements relating to a production line will be specific to that line.