Biomarkers are characteristics that provide an objective measure of an underlying biological process, such as how a patient is responding to treatment.1,2 This can be useful for both clinical and regulatory purposes.1 A biomarker that can reliably demonstrate the efficacy of a treatment may provide a valuable surrogate endpoint, which can be used to supplement clinical evidence of a response.1
An ideal biomarker is clinically relevant; precise in its ability to predict risk; robust and reliable; non-invasive, so that it can be measured without harm to the patient; and sufficiently cost-effective to be used as part of routine care.1,2 One example of a widely used biochemical biomarker is plasma cholesterol, which provides an approximate indicator of future cardiovascular disease risk.3 It is hoped that a similar biomarker – simple, reliable, and cost-effective – can be developed to predict the likelihood of someone developing PD.2,3