Biomarkers allow clinicians to measure the effects of treatment, helping determine how patients respond to therapeutic intervention. While biomarkers have been crucial in diseases such as cancer, they have not been as widely available in the field of neurodegenerative diseases.
However, there is new hope for an emerging biomarker for neurodegeneration known as neurofilament light chain (NfL) — a protein found in neurons. When neurons die, NfL is released from the brain, which can be subsequently measured in blood. In April, FDA granted accelerated approval, based on a reduction in plasma NfL, for the drug tofersen in the treatment of amyotrophic lateral sclerosis (ALS) in adults who have a mutation in the superoxide dismutase 1 (SOD1) gene. FDA has also voiced its support in using NfL as an exploratory endpoint for clinical trials for neuronopathic Hunter Syndrome, a progressive, life-threatening disease that primarily occurs in young boys.
Certainly, we’ve seen significant progress identifying sensitive and specific biomarkers for neurodegenerative diseases like Alzheimer’s disease and ALS, but supportive biomarkers for Parkinson’s disease (PD) have remained a bit more elusive. With NfL emerging as another promising biomarker, there are new possibilities to evaluate therapeutic responses in patients being treated for PD and greater hope to bring safer and more effective drugs into their hands.
World-leading institutes like the Michael J. Fox Foundation continue to provide support to researchers evaluating biomarkers for PD as demonstrated by the foundation’s landmark study, the Parkinson’s Progression Markers Initiative (PPMI). Continued development of NfL as a biomarker for PD and other neurodegenerative diseases will be crucial to the discovery of novel drug candidates and better clinical outcomes for patients.