The Michael J. Fox Foundation’s Parkinson's Progression Markers Initiative (PPMI), a landmark biomarker clinical study, has completed enrollment of its initial 600-member cohort of Parkinson's patients and controls, and will launch additional study cohorts to leverage the existing PPMI infrastructure and evaluate multiple potential biomarkers for Parkinson's disease (PD). The first of these new cohorts has launched and will investigate risk factors for PD that may enable diagnosis before the onset of motor symptoms.
The pre-motor arm of PPMI will enroll participants who do not have Parkinson's disease but do have one of three potential risk factors for PD: a reduced sense of smell (hyposmia); rapid eye movement sleep behavior disorder (RBD); or a mutation in the LRRK2 gene (the single greatest genetic contributor to PD known to date). Research to date indicates that each of these factors can be linked to an increased risk of developing Parkinson's disease, though many people with these conditions do not go on to develop PD.
Validating these risk factors and better characterizing their connection to Parkinson's could enable detection of the disease prior to the onset of motor symptoms and open new avenues toward identifying biomarkers—critical tools in the quest for therapies that can slow or stop disease progression.
"If scientists can learn more about the biological processes taking place in people with any of these three risk factors, we may be able to define biomarkers even before typical symptoms begin," said Ken Marek, MD, principal investigator of PPMI, and president and senior scientist at the Institute for Neurodegenerative Disorders in New Haven, Conn. "Finding a biomarker for PD could mean earlier diagnosis of the disease and lead to new drugs that may delay or even prevent the onset of motor symptoms."
PPMI seeks 10,000 individuals to complete a brief online survey to determine eligibility for the loss-of-smell cohort. Participants in the other groups will largely be enrolled via research centers. This new arm will take place at 23 sites across the world where participants will undergo the same clinical assessments, imaging and collection of biospecimens as the original study.
PPMI's open-source design and infrastructure has opened the door to evaluating multiple potential biomarkers under one umbrella, building on a precedent created by the Alzheimer's Disease Neuroimaging Initiative (ADNI). All PPMI clinical data and characterized biosamples are available in real time, providing researchers around the world with an unprecedented resource to help speed and unify disparate biomarker validation studies.
To date, 460 scientists from academia and industry have downloaded PPMI data more than 50,000 times in over 30 countries worldwide, and 21 applications have been made for use of PPMI biospecimens in biomarker research. Initial baseline data from PPMI's original newly diagnosed and control cohorts will be presented this June at the Movement Disorders Society and is expected to be published later this year.
"Lessons learned from Alzheimer's have taught us the importance of pursuing biomarker research concurrent with therapeutic development," said Todd Sherer, Ph.D., CEO of the Michael J. Fox Foundation. "In the third year of PPMI, it is evident that a large-scale biomarker study is not only possible in Parkinson's disease, but is already yielding scientific insights that could help transform the field's pursuit of a cure."