Dr Alan Whone FRCP, PhD is Consultant Senior Lecturer in Movement Disorders Neurology at the University of Bristol and Honorary Consultant Neurologist at North Bristol Trust. He leads a regional movement disorders clinical service at the Bristol Brain Centre that conducts approximately 4000 people with Parkinson’s visits per year from the diagnostic to the palliative stage. This service includes one of the largest deep brain stimulation surgery programmes for movement disorders in the UK, performing over 60 new implantations per annum. His PhD research, supervised by Professor David Brooks (Imperial College) and Professor Robert Y Moore (University of Pittsburgh) employed Positron Emission Tomography. One investigation assessed rates of progression in people with early Parkinson’s randomised to L-dopa or the dopamine agonist Ropinirole (Ann Neurol. 2003). The REAL-PET study is in the canon of controversial trials in Parkinson’s but nevertheless sparked Alan’s interest in disease modification and clinical research. From late 2011 to early 2017 he was chief investigator of two single-centre academic-led studies assessing the efficacy of Glial Cell Line-Derived Neurotrophic Factor (GDNF) in Parkinson’s. These investigations undertaken with Professor Steven Gill employed a novel mechanism of administration, involving a skull-mounted port, to achieve intraputaminal convection-enhanced delivery (CED) of study-drug on a monthly basis. The studies recently reported in Brain and the Journal of Parkinson’s disease raise important questions on where next for neurotrophic factor research?