A longitudinal program for biomarker development in Parkinson's disease: a feasibility study.

Long-term follow up is necessary to understand the natural history of treated Parkinson's disease (PD). The Longitudinal and Biomarker Study in PD (LABS-PD) is an observational study designed to prospectively measure the evolution of motor and non-motor features of PD and sample promising biomarkers from early to late stage illness. LABS-PD is organized on the premise that cohorts from completed clinical trials can be re-recruited for long-term follow up. LABS-PD will eventually contain multiple cohorts, but to test the feasibility of the strategy, we examined enrollment and biomarker sampling in the initial cohorts. The first PD cohort (PostCEPT) comes from the de novo clinical trial of a mixed lineage kinase inhibitor (PRECEPT). We assessed the recruitment from PRECEPT to PostCEPT, the ability to link data from the two studies, and sample collection for a variety of biomarkers. A total of 537 of 709 eligible PRECEPT subjects (76%) enrolled in PostCEPT; 509 (95%) had repeat dopamine transporter imaging. PRECEPT clinical and imaging data were successfully linked to PostCEPT, to provide 3 to 4 year follow-up. A biomarker sub-study enrolled over 100 PD cases from PostCEPT and 100 controls to measure olfaction and blood markers of gene expression, alpha-synuclein, and proteomic profiles. We were also successful in linking clinical and biomarker data to DNA samples that have been collected in the publicly accessible Coriell repository. The PostCEPT cohort and associated studies strongly support the feasibility of the LABS-PD approach of retaining and repurposing clinical trial cohorts to collect longitudinal clinical and biomarker data.