Expectations of Benefit in a Trial of a Candidate Disease-Modifying Treatment for Parkinson Disease

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. (c) 2021 International Parkinson and Movement Disorder Society

Automated summary

This study aimed to assess expectancy and treatment arm preference of participants in a disease-modification trial in Parkinson disease. The results showed that participants had likely unrealistic expectations of benefit and preferred inosine treatment, highlighting the need for improved education in future trials.