Caroline Williams-Gray discusses the AZA-PD trial, a new clinical trial testing the immunosuppressive drug azathioprine in Parkinson’s disease, which is due to begin here at the Cambridge Centre for Brain Repair in the coming weeks. The trial is funded by the Cambridge Centre for Parkinson-Plus (https://ccpp.cam.ac.uk/) and by the Cure Parkinson’s Trust (https://www.cureparkinsons.org.uk/news/azathioprine-in-pd), and is supported by the NIHR Cambridge BRC. (Disclaimer: the views expressed are those of the researcher and not necessarily those of the NIHR or the Department of Health and Social Care.)