Using the Parexel investigator database, we surveyed principal investigators specialized in Alzheimer’s disease (AD) and Parkinson’s disease (PD).  The survey was sent via e-mail link and consisted of multiple-choice questions covering reasons for participating, protocol specific factors, and aspects that deter participation.  The data was collected online and is presented in descriptive terms.  

Investigator response rates were modest for both Alzheimer’s disease (n=98, 27%) and Parkinson’s disease (n=48, 21%).   Among AD investigators, 83% identified as community-based/non-academic, compared to 54% of the PD respondents.  The most cited reason for participation was limited disease modifying treatments currently available, followed by the potential to help patients at an individual level.  The primary motivator for both AD (30%) and PD (29%) investigators was the novel mechanism of action of the investigational therapy. Reasons for non-participation included concerns about the trial burden for the participants, particularly the protocol limitations of concomitant or rescue medications and the number of the required procedures for each participant.  Additionally, many investigators noted the burden on the site staff, citing the number and duration of assessments as significant challenges.

These results provide insights into investigator motivation and barriers to participation in neurological disease trials. A clear explanation of the potential of the experimental approach to meet an unmet need is important, moreover, the burden of the study assessments and the related workload on staff and patients will hinder participation. More streamlined protocols that are investigator and participant friendly are essential to improve recruitment strategies for the success of future Alzheimer’s and Parkinson’s disease studies.