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PPMI Dispatch: Closer to Predicting Disease Progression and Symptoms

Two researchers in lab looking at samples

The coronavirus pandemic has forced many research operations to go remote, including in our landmark Parkinson’s Progression Markers Initiative (PPMI) study. While progress may be happening differently, it is still steadily marching forward.

PPMI is The Michael J. Fox Foundation’s (MJFF) global clinical study that aims to better define and measure Parkinson’s disease (PD). More than 1,400 PPMI participants across 33 international sites have helped build a robust biosample library and dataset, which has been downloaded by qualified researchers more than 5.5 million times.

“Our goal is to accelerate Parkinson’s treatments, which is an urgent issue for people with PD,” said PPMI principal investigator Ken Marek, MD, at PPMI’s virtual annual meeting in May. “And we want to examine the natural history of PD. PPMI gives us that opportunity.”

Over the last few months, site teams have swiftly pivoted to phone call check-ins with study participants rather than in-person visits. And scientists continue to analyze PPMI data for new insights into Parkinson’s onset and progression.

In this latest PPMI dispatch, we share scientific findings presented at the annual investigators meeting and published in the scientific literature.

Annual Meeting Highlights Progress toward Study Goals

Each spring, PPMI study and site leads meet to share study updates and scientific findings. In mid-May, more than 350 investigators and researchers joined the annual meeting, which took place virtually for the first time.

“We’re incredibly proud of the study’s accomplishments in the past decade, which would not be possible without the enormous effort of clinical site teams, study leadership, working groups and committees, academia and industry partners, and particularly the participants from our patient community who have been so dedicated to this initiative,” said MJFF CEO Todd Sherer, PhD, in his welcoming remarks.

Here we share two highlights from analysis of PPMI data and samples.


  • Closer to a Blood Test to Measure Progression: Brit Mollenhauer, MD, of the University Medical Center of Goettingen in Germany, led a study that analyzed levels of neurofilament light chain (NfL) — a protein released when brain cells are damaged. Her team assessed NfL in blood collected over five years from PPMI participants with PD or with Parkinson’s risk factors and from control volunteers. Participants with PD or with risk factors had significantly higher NfL levels than control participants, and the protein levels increased over time and correlated with motor symptoms. Scientists are conducting further analysis and may be able to use NfL levels from blood samples to measure progression in Parkinson’s.
  • Potential Tools to Predict Disease: PPMI studies the biology and health of people with PD risk factors (specific genetic mutations, smell loss, REM sleep behavior disorder) but not yet with the disease to help better understand Parkinson’s and diagnose at early stages. “To plan for future trials where we try to prevent disease onset or progression, we need to figure out which participants are at highest risk,” said Lana Chahine, MD, of the University of Pittsburgh. She and investigators looked at 38 participants with REM sleep behavior disorder (acting out dreams). Over three years, 14 developed Parkinson’s disease. Compared to the 24 participants who did not develop PD, the 14 diagnosed had more dopamine loss (seen on a DAT brain imaging scan) and more motor symptoms and were more likely to lack a sense of smell. These findings provide a solid rationale to study more people with REM sleep behavior disorder and demonstrate the possibility of using DAT imaging as a potential method for predicting Parkinson’s.

Paper Outlines Progression of Non-Motor Symptoms

Results from PPMI data are also being published in scientific journals, which helps doctors build their knowledge base to optimize care and seeds future research to build on these findings.

The journal Annals of Clinical and Translational Neurology published a study led by Daniel Weintraub, MD, at the University of Pennsylvania, using PPMI data to determine how non-motor symptoms and cognitive abilities evolve over time in people with PD. This could help doctors predict prognosis and provide better care. And the findings offer evidence for more studies targeting non-motor symptoms and cognitive abilities in Parkinson’s.

Examining data from 423 participants with PD at baseline (first visit) and 315 five years later, they found that volunteers experienced more non-motor symptoms — including depression, insomnia, anxiety and fatigue — after five years. At that time more than half of the participants had three or more non-motor symptoms. Most common were insomnia and REM sleep behavior disorder. In control participants, non-motor symptoms remained stable or declined over time. In addition, they found that cognitive abilities — such as thinking and memory — slightly declined over time in participants with PD.

Study Plans for Expansion and Inclusivity

As findings arise, PPMI readies for a substantial expansion to recruit an even larger group of people recently diagnosed with Parkinson’s as well as people with PD risk factors. The study aims to recruit the largest-ever group of at-risk individuals. Studying these individuals could provide insight on why some people develop PD while others don’t, potentially enabling prevention studies and stopping Parkinson’s before it starts. This expansion will occur at existing clinical centers as well as new locations in the United States, Canada and Europe.   

“We have a bold and ambitious program to move forward,” said Dr. Marek. “And we’re thrilled to begin.”

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