Background: Expectations of benefit have an important therapeutic impact. How well study participants understand the concept of slowing disease progression and how their expectations of benefit are shaped in related clinical trials is not well known.
Objective: We aimed to assess expectancy and treatment arm preference of participants in a disease-modification trial in Parkinson disease (PD).
Methods: Participant expectations and treatment preference were assessed before treatment randomization in the SURE-PD3 trial (NCT02642393).
Results: We included 297 PD patients (0.71 ± 0.67 years after diagnosis). Pre-randomization, 90% of participants expressed a preference for inosine (active treatment) allocation (n = 266/297), and 53% (n = 158) expected to be "somewhat" or "a lot better" in their symptoms over 2 years of treatment with inosine.
Conclusions: Participants of a disease-modification trial in PD had likely unrealistic expectations of benefit (ie, improvement in symptoms over years), which may affect clinical trial interpretation and calls for improved education in future disease-modification trials in PD. © 2021 International Parkinson and Movement Disorder Society.
Keywords: Parkinson disease; disease modification; expectation; clinical trial.
© 2021 International Parkinson and Movement Disorder Society.